TRANSMISSION DEVELOPMENTPLAN 2012-2021

TRANSMISSION DEVELOPMENT PLAN 2012-2021

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ver. 1.0 Page 1 of 125 Office: Development and long term development

TRANSMISSION DEVELOPMENT PLAN

2012 - 2021

Prishtina, 2011


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ver. 1.0 Page 2 of 125 Office: Long-term development and planning

Content: ABBREVIATIONS ............................................................................................................. 4 1. INTRODUCTION ..................................................................................................... 5

1.1 Role of the Transmission System and Market Operator ....................................... 7 1.2 Transmission network .......................................................................................... 8 1.3 Plan context ......................................................................................................... 9 1.4 Plan content ....................................................................................................... 11

2. GRID CODE REQUIREMENTS ............................................................................ 13 2.1 Introduction ....................................................................................................... 13 2.2 Relevant data for planning –requirements for the transmission system users ...... 14 2.3 Data Attributes .................................................................................................. 14 2.4 Standards and criteria for transmission network planning ................................... 15 2.5 400 kV, 220 kV and 110 kV Network Planning Criteria ..................................... 16 2.6 Long-term planning criteria for the re-vitalizing of the transmission network ..... 19 2.7 Planning methodology ....................................................................................... 20 2.8 Planning substation configuration ...................................................................... 21

3. FORECASTING ELECTRICITY DEMAND ......................................................... 25 3.1 Introduction ....................................................................................................... 25 3.2 Background history of Demand and current situation ........................................ 25 3.3 Demand profile .................................................................................................. 26 3.4 Long term forecasts of demand 2012-2021 ........................................................ 30

4. GENERATION CAPACITIES OF KOSOVO POWER SYSTEM ......................... 32 4.1 Introduction ....................................................................................................... 32 4.2 Planning of the new generating units .................................................................. 33 4.3 Renewable sources ............................................................................................. 34

4.3.1 Small hydro plants .......................................................................................... 34 4.3.2 Wind energy ................................................................................................... 34

5. KOSOVO TRASSMISSION NETWORK DEVELOPMENT PROJECTS ............. 37 5.1 History of the transmission network .................................................................. 37 Transmission network infrastructure development – 2012-2021 ............................. 39 5.2 .................................................................................................................................. 39

5.2.1 Introduction ................................................................................................... 39 5.3 Development projects completed during the period 2006- 2010 ......................... 40 5.4 Development projects in implementation and in the process ............................. 43 5.5 Project-applications for connection to the transmission network, ongoing and in development, during the period 2010-2011 .................................................................... 44 5.6 List of new development projects planned for the period 2012-2021 ................. 45

5.5.1 The list of new projects in the category of transmission network reinforcement 46 5.6.2 Projects planned for the category of revitalization of KOSTT substations ..... 49 5.6.3 Projects planned in the category of supporting transmission system operation 50

5.7 Technical description of projects planned in transmission .................................. 51 5.7.1 Introduction ................................................................................................... 51


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5.7.2 Transmission network reinforcement projects ................................................ 51 5.7.3 Projects on the re-vitalizing of the lines 110kV ............................................... 64 5.7.4 Projects for the re-vitalizing of the substations ............................................... 70 5.7.5 Projects for the improvement for monitoring, controlling and measuring of the transmission system ................................................................................................... 73

6. TRASSMISSION NETWORK PERFORMANCE ANALYSIS ............................... 75 6.1 Current transmission network capacities; Q4-2011 ............................................. 76 6.1.1 400, 220 and 110kV lines capacity .......................................................................... 76 6.1.2 Transformation capacities; Q4-2011 .................................................................... 77 6.2 The current load exchange capacity with neighbouring countries ....................... 79 Analysis of the transmission network condition as per topology ............................. 80 6.3 Q4-2011 ............................................................................................................. 80

6.3.1 N-security criterion analysis ............................................................................ 81 6.3.2 Voltage profile and losses ............................................................................... 83

6.4 Analysis of the transmission network condition as per topology Q4-2012 .......... 88 6.4.1 N-security criterion analysis ............................................................................ 90 6.4.2 N-1 security criterion analysis ......................................................................... 91 6.4.3 Voltage profile and losses ............................................................................... 92

6.5 Analysis of the transmission network condition as per topology - 2016 .............. 96 6.5.1 N Security criterion analysis ........................................................................... 96 6.5.2 N-1 security criterion analysis ......................................................................... 97 6.5.3 Voltage profile and losses ............................................................................... 97

6.6 Analysis of the transmission network condition, topology 2021 ....................... 102 6.6.1 N security criterion analysis .......................................................................... 102 6.6.2 N-1 security criterion analysis ....................................................................... 103 6.6.3 Voltage profile and losses ............................................................................. 104

6.7 General conclusion .......................................................................................... 108 7. FAULT CURRENTS IN THE TRASSMISSION NETWORK .............................. 113

7.1 Introduction ..................................................................................................... 113 7.2 Calculation of fault currents level ..................................................................... 113

7.2.1 Mathematical model, calculation methodology and applied software ............ 113 7.2.2 Features of the power circuits of the transmission network .......................... 114

7.3 Results of the calculated fault currents ............................................................. 115 7.3.1 Assessments of the calculated fault currents (2009) ...................................... 115 7.3.2 Assessments of the calculated fault currents (2011) ...................................... 117 7.3.3 Assessments of the calculated breaking currents (2013) ................................ 118

8. ENVIRONMENTAL IMPACTS ............................................................................ 120 9.1 Environmental protection ................................................................................ 120 9.2 Environmental problems in the transmission system ........................................ 120

9.2.1 Environmental problems caused by the lines ................................................ 120 9.3 Caution on the other environmental impacts .................................................... 122 9.4 Environmental plans ........................................................................................ 122

9. REFERENCES ....................................................................................................... 124


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ABBREVIATIONS

ENTSO/E – (European Network of Transmission System Operators for Electricity)

ESTAP I &II - (Energy Sector Technical Assistance Project)

GIS - (Generation Investment Study)

KOSTT – System, transmission and market operator JSC

KEK – Kosovo Energy Corporation J.S.C.

MEM – Ministry of Energy and Mining

MTI – Ministry of Trade and Industry

OPGW – Optical Ground Wire

TSO – Transmission system operator

PSS/E- Power System Simulator/Engineering

TDP – Transmission Development Plan

REBIS - (”Regional Balkans Infrastructure Study”)

EES –Power system

SCADA/EMS – Supervisory Control and Data Acquisition/Energy Management System

SECI – South East Cooperative Initiative (Regional transmission planning project)

EMS – Environment management system

TACSR/ACS – (Special conductor with high level of thermal resistance, Al-Çe)

IT – Information technology

ERO – Energy Regulatory Office


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1. INTRODUCTION

Electricity sector as one of the most important industrial sectors in the economy of Kosovo

should be developed and planned appropriately. Transmission network, which is operated by

KOSTT, plays an important role in the energy and electricity system enabling the

transmission of power from generators to large customers and distribution nodes.

The vision of KOSTT is to “be a profitable company for safe and stable transmission of

electricity, responsible to society and the environment and integrated with the European

mechanisms”.

KOSTT mission is to provide:

• Quality services by implementing technical and technological achievements in the

development of the transmission system;

• Transparency and non-discrimination in competitive electricity market;

• Advancement of its position in regional and European levels, supported by a

continuous increase of human capacities.

Related to the above-mentioned responsibilities on the transmission system development

and legal obligations, KOSTT hereby drafts the Transmission Development Plan (TDP),

which represents one of the main foundations of development planning of KOSTT. The

importance of preparing and implementing such document is faced also in the legislative

requirements related to the preparation and treatment of this document and as such belong

to the primary and secondary level legislation.

Legal requirements:

Law on Energy: TSO and DSO draft and publish development plans, in accordance with the requirements of the Law on

Energy Regulator. These plans must be compatible with license requirements and the energy strategy, strategy

implementation plan, and energy balances.

Law on Electricity:


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TSO shall be responsible for fulfilling requirements related to the ten (10) year system development plan, as

per sub-paragraph 5.6 and paragraph 6, Article 14, Law on Energy Regulator.

Law on Energy Regulator The Energy Regulatory Office shall examine whether the ten-year development plan submitted by the

transmission system operator covers all investment needs identified in the consultation process, and may

require the transmission system operator to amend the ten-year system development plan as appropriate.

Licenses for the Transmission System Operator: In accordance with the article 8 of the Law on Energy and article 16 of the Rule for licensing energy activities

in Kosovo, the Licensee will prepare, issue and publish the development plan for the transmission system.

Grid Code: Each year KOSTT will prepare and issue a detailed plan on transmission development (TDP) for the next

10 years.

Rule on licensing energy activities in Kosovo: An applicant for receiving the license for system transmission operator shall submit a system

development plan as provided by article 12, paragraph 1 (1.20) 13.1 of the Law on

Electricity, including the impact of system development on tariffs approved by ERO.

ENTSO-E Requirements: According to the article of the (EC) Regulation No. 714/2009 of the 3rd package that

defines the coordination of the operation and development of the transmission system "an

extensive network plan for the community-wide should include modeling of integrated

network, scenario development, an adequacy concept generation and an assessment of the

resilience of the system”. Furthermore, TDP (Transmission Development Plan) should

“build on national investment plans and, if appropriate under the guidelines for energy

networks”.


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Pursuant on the above mentioned legal obligations, KOSTT is obliged to draft and after

approval from Energy Regulatory Office, to publish and implement such document, which

is drafted in full compliance with Energy Strategy of Kosovo.

1.1 Role of the Transmission System and Market Operator

KOSTT mandate is defined by the Law on Electricity, secondary legislation and licenses

issued by the Energy Regulatory Office (ERO). KOSTT as an independent operator of

transmission system and market is responsible for operating and developing the transmission

system, including network transmission and operation of electricity market.

KOSTT responsibilities dealing with development of the transmission network are:

• Organization of preliminary studies for possibilities for new constructions of transmission capacities,

facilities and equipment, supported by technical, economic and financial studies

• Compilation and publication of short and long term plans for expansion and modernization of the

transmission network.

• the development of transmission network and interconnection with neighboring networks in order to

guarantee the security of supply,

• provide sufficient information on any other system operator to which the system is connected to ensure

that it is a matter related to their development requirements

• Coordination on the planning and development of transmission network with counterpart companies

in the region and drafting of the ten-years plan at the ENTSO-E level

Under the granted license, KOSTT shall prepare and publish the transmission

development plan for the next three years as part of the ten-year development plan. TDP

after approved by the Energy Regulatory Office should be published by KOSTT.

Network users can use this plan to plan their future activities, for new connections or

strengthening the existing ones.


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1.2 Transmission network

Transmission network of the Republic of Kosovo operates three levels of voltage 400

KV, 220 KV and 110 KV. Kosovo as electricity-energy area is connected through cross-

border lines with neighboring countries: Serbia, Macedonia, Montenegro and Albania.

Boundaries of generation and distribution assets that are managed and maintained by

KOSTT is in lower terminals of the power transformer 110 kV by the load, or upper

transformer of the generator, while the boundary for the eligible customers is in the

connection portals.

Kosovo Power System is characterized by strong network interconnection voltage of

400 kV, which is strongly interconnected in the regional network. Powerful interconnection

of the transmission network with the surrounding networks around the ranks the Power

System of Kosovo, as one of the important nodes of Power in the region and beyond. The

continuous increase of electricity consumption in the country and the region, increase power

flows in the internal lines and those of interconnection. This increase of power flows

continuously narrows safety margins of the stability of Kosovo’s Power System, and other

systems interrelated with our system. Necessary reinforcements in the transmission network

in the country and in the region are vital in maintaining the stability and reliability of the

system in the near future.

Currently the main problems identified in the transmission network, appear in 110 kV

network. The 110 kV network is characterized by rings containing multiple substations

connected in series, which cause the voltage drop in the final node.

This TDP identifies the network reinforcements needed that will ensure safe operation

and reliable quality system and better supply for the customers, in accordance with

technical requirements specified in the Grid Code.

Another reference used for the present plan is the study performed by the consultancy

company (2010) Fichner on optimization of transmission network topology, mainly at 400

and 110 kV levels.


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1.3 Plan context

The process of planning and development of transmission network is a long and

complex process. The process involves a number of activities, such as network development

in relation to energy demand prediction, generation prediction, enabling the identification of

necessary reinforcements and extensions needed to achieve network operating within the

parameters of reliability and environmental impact. Although TDP takes as a reference

prediction for a certain period of time based on the ten-year Balance of Power, the plan

must also convey the strategic development of the transmission system over the long term

timeframe.

The planning process is a result of the process of restructuring the energy market. The

planning process has changed in some respects, compared to the previous process in the

vertically integrated companies:

• Uncertainties coming from the market environment and input data.

• Objectives of different network users (generators, traders, suppliers, customers and network

operators) and

• Incompliance and disproportion between the technical, economic, environmental and social

requirements.

• Uncertainties coming from the level of integration of energy from the renewable sources

Also, the need for regional market integration requires increasing and strengthening of the

interconnection capacity, which affects the planning process at national level. Network

development options based on the Planning Code and on the general planning rules

recommended by the ENTSO/E. Determinative methodology (defining), which is based

on the security criteria N-1, presents the basic methodology applied in this plan, the purpose

of identifying and determining the list of projects necessary for development of the

transmission network.

This plan contains information on the development and reinforcement expected to occur in

the transmission network in Kosovo for 10 years in the following:


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• Building of new transformation and transmission capacities,

• Strengthening of existing transmission and transformation capacities,

• Construction of the interconnection lines with the neighboring countries,

• Re-vitalizing of the existing equipments of the high voltage (lines and substations)

• Development of supporting systems of transmission system (SCADA/EMS, metering etc.)

It also contains information on the possibilities of connecting new generating units and new

loads on the transmission system.

The main objective of the ten-year plan is to identify projects which will increase

capacity, reliability, and efficiency of the operation of the transmission network. This plan

will enable consumers, energy market participants, energy producers, prospective investors

to get familiar with the transmission development plan for the next ten years. This document

presents development plan drafted in KOSTT, and unlike the first TDP (2007-2013), it now

covers a period of ten years from 2012 until 2021, in compliance with the requirements

arising from ENTSO/E, where the year 2011 presents the reference year or the so-called

year zero. All information in the development plan as project details, the expected date of

the start of the project, applications for connection to network transmission that occurred

during 2010, and ongoing to the end of 2011, are taken into consideration in developing this

document.

For the preparation of development plan appropriate calculations were made with the

relevant software PSS/E 33, simulating computer models of the system based on data

provided by KOSTT and network users, and based as well on the load prediction for the

next 10 years.. Load forecast is based on historical data (consumption, maximum load, the

load duration curve, etc.), as well as the expected demand from industrial and commercial

consumption and new connections expected to occur. Generation data are provided by

KEK - Generation and other generators. Data for interconnections expected to be built in

the region, were provided by studies made in the Planning Group for Regional Transmission

Network Planning - SECI, in which group KOSTT contributes as well through its

representatives


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For each year of development, studies were conducted for the power flows,

simultaneously following the increase of the demand for maximum load. Also calculations

were made for failures during different periods of time. Based on results of calculations, it is

possible to provide estimates on how the network will operate for the estimated next years.

Bottlenecks are identified and possible solutions were presented by analyzing their impact on

improving the operating performance of the transmission network. The transmission

network was analyzed also for minimal loads, thereby identifying eventual problems in

overloads at 400, 220 and 110 kV levels, which may appear in summer minimal load regimes.

KOSTT has been carefully evaluating the accuracy of information, which does not fall

under KOSTT responsibility, making clear that KOSTT is not responsible for information

or incorrect information received from other parties.

1.4 Plan content

TDP is structured in 8 chapters including the introduction:

Chapter 1– Introduction

Chapter 2 - Technical requirements of the Grid Code - presented the process of data

collection, planning criteria and standards, and configuration of substations by voltage

level 400 kV, 220 kV and 110 kV.

Chapter 3 - Presents forecast demand for electricity consumption divided in the past

three years and forecast consumption for the next 10 years.

Chapter 4 - List of existing generators and planned ones. It is also presented the

renewable generation and KOSTT policies in support of this technology.

Chapter 5 - Describes the KOSTT network transmission, and interconnection with its

neighbors. A part of this chapter describes in details the future developments of the

network.

Chapter 6 - System performance is presented for different network conditions for

certain periods of development plan.

Chapter 7 – Contains the results of the short circuit currents for certain periods of

time, in order to assess the disconnection ability of existing switchers and dynamic


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stability of high voltage equipment in case of occurrence of failures in the transmission

network.

Chapter 8 - Includes access to environmental planning policy in relation to the

Transmission Development Plan

Chapter 9 - Contains a list of references.

Results of the calculations and simulations, diagrams, electrical maps are presented in the

Annexes.


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2. GRID CODE REQUIREMENTS

2.1 Introduction

One of the main KOSTT objectives is development of the transmission system with

the purpose of safe operation, efficient and reliable in order to enable transmission of the

electricity in covering the requirements in full compliance with the legal obligations.

Transmission System Operator plans development in the network based on long-term

electricity needs. Demand for electricity transmission depends on many factors: increased

consumption, installation of new generating units, new boundary lines, development of

heavy industry, etc.

The need for reinforcements in the transmission network is determined based on the

study of network performance against the planned technical standards outlined in the Grid

Code respectively Planning Code.

The Grid Code covers the operational procedures and provisions governing the

interaction between KOSTT and users of the Transmission System in Kosovo. This code

also includes the processes of planning, connection, operation and balances system in

normal and emergency situations. Processes include different periods based on the situations

in the past, current situation and long-term domain.

The Planning Code specifies technical criteria and procedures to be applied by

KOSTT in planning and development of the Transmission System of Kosovo. Even users

of the Transmission System during the planning and development of their systems should

consider the Planning Code. This code also sets requirements for the collection of reliable

information from users, so that KOSTT can make planning and development of

transmission system in Kosovo.

Based on Article 14 of the 'License of the Transmission System Operator'

Transmission System Operator also has developed the basic planning criteria which are

detailed in the document approved by the ERO, "Transmission System Security and

Planning Standards ”. This document defines a range of criteria and methodologies that


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KOSTT should adopt (enforce) in the planning process of developing the transmission

network in Kosovo

2.2 Relevant data for planning –requirements for the transmission system users

In order for KOSTT to implement its Transmission Network development plan ,all network

users are required to submit relevant data affecting the determination of the plan. This

section will briefly describe the process of collecting data needed for long-term planning,

since more detailed ones can be found in Planning Code - Grid Code, which can be

downloaded from the official site of KOSTT: www.kostt.com

During the process of applying for new connections to the transmission network, to

enable the completion of each connection offer - each user must submit to KOSTT the

standard data of planning and preliminary project planning, attached to the application for

connection application, and within two months from the date of the receiving the bid, the

detailed planning data should be submitted. Any change from the previous data network

users, the party is obliged to inform KOSTT in order to revise data.

KOSTT is also required to present users with the system data to enable users to model their

network related to the contribution of the fault currents.

2.3 Data Attributes

The data, which transmission system users are obliged to send to KOSTT, are characterized

depending on the type of system users. They usually fall into two main categories:

• Generator, and

• Load

Existing and new generators are required to submit data for generating units’ plants, which

are required by KOSTT, and all data changes that occur for different reasons. Each

generation in the application for connection to KOSTT for getting a new connection or

modification of an existing connection, must provide the necessary information as required

by Planning Code.


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The data which are filled must contain the information such as plant location, name and type

of facility, estimated date of commission etc.., and information of the technical nature such

as expected monthly production of power, features of the power generator, the technical

characteristics of synchronous machine, turbine, adjustment equipment (speed regulator,

exciter, fluctuations stabilizers), the data of step-up transformer, the connection

configuration, data allocation and the type of relay protection, data for the own consumption

needs of the plant, etc..

The load has the character of distribution points that use the transmission network. They

represent all the substations and distribution network, the network included 220 kV and 110

kV, and industrial customers connected to the transmission network.

Each user with the loading application for connection submitted to KOSTT for a new

connection or modification of an existing connection must provide the necessary

information as required by Planning Code. This information should contain information

about the substation location, time of becoming operational, load forecasting for the next 10

years, etc.., and technical data such as configuration of the substation, voltage level,

transformers data, data on high voltage equipment, nature of the load, type of obstacles in

low voltage level, etc.

Detailed description about the user data at this point is made so that the reader could have a

clear perception that any inconsistence in this document is subject to the user if they follow

the criteria listed above.

2.4 Standards and criteria for transmission network planning

Transmission network planning based on the criteria set out in Planning Code, which are

described in detail in the document " Transmission System Security and Planning”

Standards.

Standard method of planning or determinative methods of transmission network

planning, which presents the classical method used in many countries, which also applies to

KOSTT. The main principle according to which the transmission network is dimensioned, is

the necessity of fulfilling all technical requirements in accordance with Grid Code, and that

the N-1 elements at work facing the most difficult conditions for operation. So basically this


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method of planning is mainly based on critical conditions of operation of the transmission

network. In principle, planning the transmission system in Kosovo is conduct is such a

manner that the operation of the system meets the criteria 'N-1'. However, in some

situations where it is not efficient to fulfill the 'N-1' criteria there will be applied exemptions

for a period of time.

2.5 400 kV, 220 kV and 110 kV Network Planning Criteria

Kosovo's transmission system at 400 kV and 220 kV has technical and economic

characteristics which differ from the 110 kV systems. Investment cost and their

dimensioning criteria are much higher than at 110 kV. Transmission system is

interconnected with regional transmission systems through the network of 400 kV and 220

kV, so the effects of investment in network voltage 400 kV and 220 kV are not isolated but

have a regional character. KOSTT has defined the strategy for developing the transmission

network which is oriented in strengthening / development of the network 110 kV and 400

kV, whilst network 220 kV will not be develop further, except for specific cases where no

other solution could be found.

Transmission System Planning is made according to the criteria defined by the Grid Code,

considering the fulfillment of the N-1 criteria, meaning that the system must be capable of

normal operation in case of occurrence of the fault in the network (in Kosovo or in other

systems) and the loss of one of the following elements:

• airline or cable lines

• transformer,

• compensator, and

• generator (this criteria cannot be seen in the plan, but it is a requirement for the developers of generation

capacity)

In case of loss of one of the above elements as a result of failures or maintenance,

transmission system must fulfill the following operation conditions:

• transmission lines should not be charged beyond their thermal limits,


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• reduction of the supply capacity is not allowed

• level of voltage tension and speed change cannot exceed certain limits,

• transient and dynamic stability of the Power System should not be endangered, and

• power transformers should not be over-loaded.

The 110 kV network, whose development is done in accordance with the Transmission

Connection Tariff Methodology of KOSTT, includes all equipment, voltage 110 kV (lines

and facilities) in addition to the distribution transformers 110/10 (20) kV and 110/35 kV.

In normal operating conditions the performance of the transmission system should be

operating in accordance with criteria outlined in the Grid Code.

The Grid Code defines the permitted limits of the voltage in the transmission system as in

Table 2.1

Table 2.1 Permitted limits of the voltage

Loading the transmission lines above the designed thermal limits of the conductors,

will be perceived as overload of the line. Also, each load of the transformer above their

nominal power will be considered as their overloading.

In the table below are presented thermal margins for conductor of the cross sections,

which standards are applied in KOSTT.


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Table 2.2 Standard electrical parameters for air lines and cables

High voltage facilities operating in the transmission network should be durable and

sufficiently safe in case of failures of the system. The Electrical Equipment Code provides

on nominal maximum currents, maximum fault currents and durations of faults allowed. The

table 2-3 shows nominal currents for high voltage equipment.

Table 2-3 Standard electrical parameters for disconnection equipment


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2.6 Long-term planning criteria for the re-vitalizing of the transmission network

The revitalizing plan for the electro-energetic elements as air lines, transformers, cables

and substations, generally depends on the technical situation, their age and intensity of use of

these elements in retrospect. The re-vitalizing plan of the transmission network equipment is

done as follows:

Air lines: their revitalization depends on two factors: their age and level of losses incurred

in the line during a long – term period. For phase conductor and earth wire, insulator,

connection bridges, the time of 40 years represents a condition for adding them into the

revitalization list. Fault frequency in lines represent additional indicator to select the line in

the list of re-vitalization.

In terms of losses in the list for re-vitalizing are included the lines of cross section of

150mm2, which are also associated with the first factor, since the initial development phase

of the transmission network (1950-1970) 110 kV lines are built with the cross section

conductor of 150mm2. This development concept is now being applied in all ENTSO/E

transmission systems. 220 kV lines are considered to be older lines (>50-60 years), since

their development took place mainly during the 60-ies and 70-ies. The European concept

consists on the point that 220 kV lines are gradually re-raised to 400 kV level, mainly using

only their routes. The difficulties faced in expropriation of private properties for

development of new lines are distinct in all countries in Europe.

Power transformers: plan of replacing the power transformers of the transmission

network is based on their expected lifetime, which is estimated at 50 years. Another

important factor which affects that the transformers will be included in the list for the

replacement is their factual situation, which is monitored by maintenance teams through

their periodic testing. Historical statistical data of events in specific transformers (load level,

number and frequency of measures in protecting transformers, gas analysis, etc.) are an

important factor in selecting new transformers to replace the old ones.

Substations (overhead line bay and transformers): the re-vitalizing plan of the

substations areas, which are included in the defined boundaries of the transmission network,

is also based on age of the equipment and their factual situation. Priority for re-vitalizing

have substations with high impact on transmission systems, but also all the substations that


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their age has passed 40 years. Systematic transition from oil-containing disconnection

equipment to gas equipment SF6 is an objective of KOSTT, provided by development and

investment plans.

2.7 Planning methodology

The approach of the methodology of planning for the transmission network consists of the

following steps:

• Collection of input data (creation of data base for computer modeling of the network).

• Definition of different scenarios taking into account factors strengthening the development of generation,

load, applications for connection, balance of power system, exchanges etc...

• The creation of computer models of the network transmission format to PSS/E.

• Determine the plan for re-vitalizing the existing electrical equipment on the basis of their life cycle.

• Identification of network constraints (N-1 tests).

• Definition of the possibilities of strengthening the network on the basis of N-1 tests.

• Analysis of the voltage profiles and losses in the system.

• The final definition of the reinforcement plan and plan for re-vitalizing transmission network

The table 2.1 provides the planning methodology of the transmission network


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Figure 2-1 process of the planning development and re-vitalizing of the transmission network

2.8 Planning substation configuration

KOSTT has prepared a document on the Transmission System Security and

Planning Standards, which sets forth planning standards for substations 400/220 kV,

400/110 kV, 220/110 kV and 110/10 (20) kV, a document by ERO.

All 400/110 kV substations planned will be configured with double bus bars with

coupler and open system. Dimensioning of electrical equipment shall be based on the

Electrical Equipment Code, always being supported by computer analysis of power that

define the power flows and short circuit level to the respective substations. These criteria

may exempt those substations to which power generators and consumers of such

Gathering of input data and Creation of system model in PSS/E

Creation of models with current andPlanned conditions

Technical analysis of the performance ofsystem ( Power flows , criteria N -1

with PSS/E

Identification of needs for

system reinforcement

Creation of different scenarios ofsystem reinforcement

Selection of most optimal scenarios andCreation of final list of development

Projects and revitalization of the TN

Technical analysis of the performance ofsystem (power flows, criteria N-1)

with PSS/E

Evaluation of applications forconnection to TN

Connection approved

Revitalization plan of transmission network

Data on the state andageing of equipments


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importance can be connected, so as to require a higher operational security level in a link.

In these cases the design of bus bars can take into account additional specifications.

Figure 2-2 presents a standard configuration for substations of 400/110 kV voltage level.

Double bus bars system for 400 kV voltage level shown in figure 2-2 can be advanced

with the additional system of the auxiliary bus bars in substations that are connected to

more than three 400 kV lines.

Figure 2-2 Standard planning of the bus bars configuration of new substations in the transmission

network

220/110 kV substations’ configuration will be similar to the 400/110 kV substations.


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Configuration of substations 110/10 (20) kV is designed based on two standards regarding

system bus bars of 110 kV. Number of lines planned to be connected in the 110 kV

substations will be determinant for the bus bars system. For substations that will be

connected in the long term only with two lines, “H” type bus bar system applies, as shown in

figure 2-3.

Figure 2-3

Whilst for the substations that will be connected with more than two lines, the double bus

bar system with couplers applies, as shown in the figure 2-4.


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Figure 2-4

The dimensions of the phase conductors and the protective for transmission lines are also

standardized as follows:

For 110 kV lines: conductor 1x240/40mm2 of ASCR, earth wire C 1x50 mm2;

For 220 kV lines: conductor 1x360/65mm2 of ASCR, earth wire C 2x50 mm2 or

1x490/65 mm2 of ASCR earth wire C 2x70 mm2.

For 400 kV lines: conductor mm2 of ASCR 2x490/65, earth wire Al 2x126 mm2.

There is also another technology and conductors that have been applied in KOSTT. These

conductors called "Hot wire" are the work of special alloy TACSR/ACS, which has the

ability to work at higher temperatures. Usually used for short length of lines and where there

is no possibility of strengthening the pillars. Their transmission capacity, e.g. a conductor of

TACSR/ACS of 150/25mm2 / is the same with the transmission capacity of a conventional

conductor 240/40mm2, while the weight is almost the same as conventional 150/25mm2

conductor. Their handicap is that such replacement of conductors does not help reduce

power losses, and therefore they are preferred only in short circuit lines and those cases

where there is no possibility of reinforcement of the towers, which is not possible to install

because of the weight of the conventional conductor of 240/40mm2.

All the new routes (enforced as well) will be equipped with at least 48 OPGW fibers in

protective conductor to support the planned telecommunications network SCADA/ EMS.


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3. FORECASTING ELECTRICITY DEMAND

3.1 Introduction

One of the basic data determining future transmission capacity development is to

forecast electricity load or power. The load forecast represents an integral part of planning

the transmission network, generation and operation. Forecasting electricity demands over

the long term presents no easy task. The main source of data for development of load

forecast in the next 10 years is the demand forecast model developed by KOSTT, based on

the document Long Term Energy Balance 2011 to 2020[2]. This model provides a 10 year

forecast, hourly electricity demand. As such, this model allows forecasting of load for each

hour in the next 10 years, including seasonal peak loads (winter and summer).

3.2 Background history of demand and current situation

For several years the electricity sector in Kosovo has faced electricity supply problems.

Daily shedding, planned or unplanned are still present. This means that the recorded

consumption is not the same as demand which would exist if there was a safe and quality

supply of electricity. Planned reductions (scheduled) are mainly done in the hours when

required consumption cannot be covered by local generation capacity and lack of imports, or

because of capacity limitation of the DSO. The unplanned reductions happen due to

unexpected and unforeseeable faults, and because of interruptions in generation units, in the

distribution and transmission network.

Figure 3-1 shows a historical chart of development of maximum load for our country. The

unusual nature of the load curve in years reflects the political and economic situation in

Kosovo. After the end of the war in Kosovo (1999) and to date, the maximum load has

marked an average annual growth of 6%.


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Figure 3-1 Maximum load history over years in Kosovo

Table 3-1 shows maximum loads registered for years 2002-2010, for winter and summer

seasons. The maximum load for 2010 increased for 7.3%.

Table 3-1. Maximum active loads, summer and winter, for the period 2002-2010

3.3 Demand profile

Characteristics of the load duration curve of the Power System of Kosovo has undergone

constant changes, both in terms of growth but also proportional to the change of load

factor. In figure 3-2 we can see the load duration curve for the previous year in 2010.

Summer consumption growth has led to increased load factor, 2.7% of the year the load

exceeded 1000 MW, while 21.4% of the year, the load was over the figure of 800MW.


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Figure. 3-2 Curve of the duration of the load for 2010

The electricity demand in Kosovo marks a curve which in a considerable time of the year

(winter season), is not constant as a result of reduced consumption in times of peak loads.

Such a curve may be seen in the figure 3-3, which provides a weekly chart in the winter

season, for a typical week of January 2010. Latent consumption provides the real

consumption, if there would not be any consumption reduction. Load shedding causes

deformation of the consumption curves, and as such it differs them from no-shedding

curves, which do not display any obvious surge. Peak loads are marked between 19 and 21

hrs, while the minimum loads between 4 and 6 hrs in the morning.


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Fig. 3-3 Daily load diagram, for a typical day in January 2010

In Fig. 3-4 is shown on the characteristic diagram day of the month in January 2010 who

answered one of the reference points by ENTSO/E. In this diagram presents two curves

which realized consumption, while the other latent consumption based on data recorded in

the Dispatching diary in KOSTT. Reducing the load on normal working conditions of the

country's power system usually occur in two generations time consumption: 9:00 to 12:00

and 17:00 to 23:00. The difference between maximum and minimum value of winter load for

2010 is around 383MW or 36% of the peak


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Fig 3-4 Daily load diagram for a typical day in January 2010

Figure 3-5 provides a daily chart for a typical day in July 2010. There is no load shedding in

this chart, and the difference between maximum and minimum values of daily loads is 51%.

In this time period, this difference in loads makes it very difficult to balance the system,

especially after midnight, when loads are minimal, and fall under the boundaries of technical

minimums of existing plants.


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Fig. 3-5 Daily load chart for a typical day in July 2010

3.4 Long term forecasts of demand 2012-2021

The power and load forecast is based on the forecast provided by the document approved

by ERO: “Long Term electricity Demand 2011-2020”, thereby adding 2021.

For forecasting power and load demands in Kosovo, a complex mathematic model was

created in Excel, which relates the influence of four variables (correction factors) in

calculating power and electricity demands. The above-mentioned factors are presented in the

following:

Factor 1: Implementation of the Government program for efficient electricity use;

Factor 2: Reduction of consumption due to a more efficient billing, and more effective metering and

checking procedures (reduction of commercial losses);

Factor 3: Influence of GDP forecast in consumption development;

Factor 4: Forecasting technical losses in transmission and distribution networks

The forecast of demand development for power in the period 2012-2021 according to three

scenarios of growth is presented by figure 3-6, while numerical data corresponding with

figure 3-6 are presented in the table 3-2.


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The basic scenario of load development is characterized by an average annual growth of

2.53%. This load development scenario shall be the main input in assessing operational

performance of the transmission network.

Figure 3-6. Low, basic (average) and high growth scenarios for peak loads (maximum load)

Table 3-2. Respective data of peak forecast, related to Figure 3-6


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4. GENERATION CAPACITIES OF KOSOVO POWER SYSTEM

4.1 Introduction

Electricity in Kosovo is produced by two relatively large power plants: PP Kosovo A and

Kosovo B. These two power plants use coal - lignite as fuel. Pursuant to the Government

Energy Program, it has been foreseen that in the period between 2016-2017, capital

overhauls will be performed on B1 and B2 units, which is to reflect on reliability of

operation of these two units. Units A3, A4 and A5 of the TPP Kosova A according to the

Energy Strategy 2009-2018, shall be operating until the end of 2017, until they are ultimately

decommissioned.

Table 4-1. Main features of Kosovo A and Kosovo B generation units

Instaled Net Available min/max

TPP KOSOVA AUNIT A3 200 182 100-130 Lignit/naphtha 1.7-1.9 23-24.5* 1970UNIT A4 200 182 100-130 Lignit/naphtha 1.7-1.9 23-24.5 1971UNITA5 210 187 100-135 Lignit/naphtha 1.7-1.9 23-24.6 1975TC KOSOVA BUNITB1 339 310 180-260** Lignit/naphtha 1.4 -1.45 31.5- 32 1983UNITB2 339 310 180-280** Lignit/naphtha 1.4 -1.46 31.5- 32 1984

StartTPP Unit Capacity [MW]

GENERATION UNIT Fuel ton/MW Eficience

Apart from Kosovo A and B power plants, managed by KEK, there is also a hydro-power

plant Ujmani (2x17.5MW), managed by the HPP Ibër-Lepenci. There are also low capacity

hydro-power plants in operation. The table 4-2 provides the key data on small HPP-s

connected to the distribution network.


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Table 4-2. Main features of existing hydro-power plants of Kosovo

Instaled Net Available HPP UJMANIG1 17.5 16 16 1983G2 17.5 16 16 1983HPPLUMBARDHI*G1 4.04 4.00 4.00 1957 (2005)G2 4.04 4.00 4.00 1957 (2005)HPP BURIMIG1 0.34 0.34 0.34 1948(2010)G2 0.136 0.13 0.13 1948(2010)HPP DIKANCE*G1 0.67 0.66 0.66 1957(2010)G2 0.67 0.66 0.66 1957(2010)HPP RADAVC 0.00G1 0.14 0.14 0.14 1934 (2010)G2 0.14 0.14 0.14 1934 (2010)

GE. UNIT HPP Unit Capacity [MW] Start

4.2 Planning of the new generating units

Estimates of new generating units for the period 2012-2021 is designed based on the

expected generation from existing generating units, including the continued operation of

some units of PP Kosovo A until 2017, existing hydro plants and new ones planned to be

built, as well as production from PP "New Kosovo" and HP Zhuri.

In order to achieve the objectives in the energy sector under the Energy Strategy in the next

10 years numerous activities are expected to improve or increase generating capacity in the

country in the following manner:

Generation from PP Kosovo A units A3, A4 and A5 to be operational. To achieve the operation

of these units until the end 2017 when it will be de-commissioned in accordance with European

Directive on fossil fuel plants, it takes investment for maintenance and repairs due to aging of the

plant and also obsolete technology.

Generation of PP Kosovo B, B1 and B2 units in operation. It is expected that these two units will

be rehabilitated during the period 2014 - 2015, including the investments needed to meet gas


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emission standards required by European Directive on fossil fuel plants. Then, these units will

continue operating until 2027 to 2030

Generation from HP Ujmani after maintenance and rehabilitation can continue operating for a long

period of time.

Generation from the small hydro plants: Lumbardhi, Dikanci, Burimi and Radavci.

Generation from HP Zhuri expected to be built by 2015 and start operating in 2016.

Generation of new generating units from PP "New Kosovo". The first generating unit expected to

enter into operation in 2017.

4.3 Renewable sources

According to European Directive 20-20-20 Renewable Energy Directive, until 2020, 20% of

total electricity produced should be produced from renewable sources such as wind power

plants, hydropower plants, etc. Kosovo has as well set a strategic objective of achieving these

goals. Renewable energy sources in Kosovo do not have a high potential, both in water and

wind sources. There are still certain areas with such potential, which must be harnessed.

4.3.1 Small hydro plants

Based on the strategy of the Ministry of Energy and Mines for renewable energy, it is

foreseen that during the period 2012-2021, about 16 small hydropower plants will be built,

with total installed capacity of 60 MW. As well as existing small hydropower plants will be

rehabilitated and will come into operation. In terms of impact on operational performance

of the transmission network, development of small HPP-s, which would mainly be

connected at distribution networks, should have a positive impact. Injection of generation in

end points of grid reduces the load flows at transmission levels.

4.3.2 Wind energy

The approval of incentive tariffs by the ERO for renewable energy generators, such as wind

energy parks, already provides much more favorable conditions for potential investors.

Throughout Europe, Kosovo included, there is a growing tendency of investors applying to


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obtain the rights to connect various wind turbine capacities to the network. Numerous

studies have shown that in regions where annual average velocities of wind, at a 50 m height,

are >5 m/s, there is economic feasibility for installing wind energy capacities. The basic

factor in investing in a certain area is the potential and velocity profiles in a year. Since 2009,

several foreign investors have applied to connect to the network, thereby proposing

development of total capacity of 157 MW. So far, KOSTT has received three applications

for connection of wind turbines in the electricity network:

• Shtime 1 project with a capacity of 100 MW, the southeastern part of Kosovo

• Shtime 2 project with a capacity of 27 MW, the southeastern part of Kosovo

• Kitka project with a capacity of 30 MW-eastern part of Kosovo1.

For all three applications, KOSTT has clearly provided the manners and configuration of

connection to the transmission network.

Currently in Kosovo there are no assessment maps of wind potential, whilst investors on

their own initiative have undertaken the measurement of the wind speed in certain areas.

The figure 4-1 shows a general wind potential map for the Western Balkan region, namely

annual wind speed, as obtained from http://interface.vortex.es (50 m height)

1 A connection agreement was signed by KOSTT and investor in Kitka, while the difficulty remains in

crediting investment, finance to be obtained by the investor by loaning from international banks.


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fig. 4-1 Wind map, Balkan Region (source: http://interface.vortex.es)

In technical aspect, these applications mainly have connection possibility in 110kV voltage

level. Transmission network in aspect of power flow, can integrate wind generation

capacities that are accepted as applications for connection, however in aspect of balance the

system these capacities with a vary variable nature and difficulty of predicting can cause

problems for System Operator from the fact that our Power System presently has no

sufficient regulation reserves. This fact can change in the future, if development plans of

new generation capacities are realized with conventional generators, which as a result shall

have increase of regulation reserves that shall cover for unpredictable variability of

generation from wind turbines.


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5. KOSOVO TRANSMISSION NETWORK DEVELOPMENT

PROJECTS

5.1 History of the transmission network

Kosovo Transmission Network during the years has been developed in several stages

of expansion, reinforcement and consolidation.

Between 1953 and 1958, the first line of 110 kV was built in Kosovo, Novi Pazar (Serbia)

until Butel (Macedonia), by interconnecting the substations (SS): SS Vallaç, Trepca SS, SS

Vucitrn, SS Kosovo A, SS Prishtina 1 and SS Prishtina 4, SS Ferizaj 1 and SS Sharri. 110 kV

conductor built in the initial development of the network were 110 kV cross section

conductors of 150mm2.

In 1960 the first line of 220 kV was built in Kosovo, SS Krushevci (Serbia) to SS Kosovo A,

which was at that time in the construction phase. From 1962 to 1975 it was constructed (PP)

Kosovo A with its five units. In 1978 was built the first line of 400 kV in Kosovo connecting

to the SS Nish (Serbia) with SS Skopje (Macedonia) through SS Kosovo B.

In 1981 was built the HP Ujmani connected through 110 kV line with SS Vallaçi.

In 1983 was built the second line of 400 kV of the interconnection Ribarevina

(Montenegro) to SS Kosovo B, two 400 kV lines connecting TP Kosovo B (1983) with SS

Kosovo B. In the same year it was built the 220 kV lines from SS Kosova B to SS Prizren 2,

through the switch gear Drenas. In the same year was also built the second 220 kV line to

Drenas followed by the double line for the supply of industrial facilities of Feronikeli.

In 1988 was built the interconnection 220 kV line from SS Prizren 2 to Hydro power

plant (HPP) Fierza (Albania), also in the same year it was built the 220 kV double lines from

the SS Kosovo B to SS Prishtina 4. Also in the mid 70s and 80s the network of 110 kV

undertook visible development, using conductors of the large section of 240mm2. The year

1991 represents the end of investments in transmission network for a period of 10 years

until 2001, which represents a break of 10 years without investing in the development of the

transmission network. This can be seen in figure 5-1 and figure 5-2.


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Fig. 5-1 Intensity of investments in lines through the years 1980-2010

Fig. 5-2 Intensity of investments in substations 1980-2010

After the war in Kosovo, the condition of the SEE in Kosovo was dire, in generation,

transmission and distribution areas. Emergency investments in the SEE begun at this time,

supported by the Kosovo Budget and international donors. Due to great demand, the

transmission network did not match the rapid consumption growth marked after 2020. the

table 5-1 shows relevant projects completed in the transmission network until the

establishment of KOSTT.


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Tab. 5-1 Projects implemented 2000-2006

5.2 Transmission network infrastructure development – 2012-2021

5.2.1 Introduction

This chapter presents and examines the development projects of the transmission

network in the period 2011-2021. Considering the planning process of the transmission

network as an extremely complex process, with greater dependence on many factors, the

ten-year domain that defines this document is divided into two periods: first five years 2012-

2016 and the second period of five years, 2017 – 2021.

The first period of five years is considered relevant and influential in the long term

development of the network and with high probability of implementation and as such the

projects that are included in this period of time are analyzed in detail. Second period of

2017-2021 includes optional projects in a comprehensive manner that have internal or

regional character for which KOSTT considers their importance and their contribution in

achieving the technical standards for operation of the transmission system in order to

support the electricity market.

Development projects of the transmission network are divided into five categories:

Transmission network reinforcements

New load connections (connection applications)

Rehabilitation of the transmission network

Supporting projects of the transmission system (management, monitoring, measurement and control).


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All projects are presented in the following tables separated in the above mentioned

categories.

List of projects includes projects that are in various stages of planning or implementation:

Projects that are in construction phase

Projects approved, in the process of specification or procurement

Projects for which applications by third parties have been submitted for connection to the transmission

network.

Projects considered necessary to the transmission network in planning, and are in pre-feasibility stage.

KEK - Distribution Projects that are included in the first development plan and with a low certainty of

implementation

Projects of a strategic nature2 with impact into the transmission network are in the public process of

planning.

Because of considerable complex dependence on the various factors for the

implementation of the projects, the time and manner of such implementation can be

considered as subject to possible changes and as such the next document will revise the data

and update them.

Tables contain the project identification codes (ID), a general description of the project, the

expected completion time and reasons and effects of project implementation.

5.3 Development projects completed during the period 2006- 2010

The unbundling of the Transmission and System Operator from the vertically integrated

company, KEK, fostered a rapid development, focused on reinforcing capacities of the

transmission network, increasing reliability and security of supply in consumption. Financial

support from the Kosovo budget, donors, engagement of the professional staff at KOSTT,

by clearly defining development priorities, have largely influenced the implementation of

many projects of utmost importance for the transmission system, and generally the power 2 Based on 2009 – 2018 Electricity sector Strategy


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system. During the period between 2006-2010, substantial investments were made in the

transmission network, in compliance with objectives and aims identified with the long-term

development plan for the transmission system. If one would refer to earlier development

plans as approved by the ERO, it may be considered that the completion rate of projects

planned is rather good. The following table shows all projects related to grid reinforcement,

completed during the period 2006 - 2010.

Tab.5-2 Projects in grid reinforcement, completed during the period from 2006 until 2010.

Such an increase of the transmission infrastructure requires support by advanced technology,

based on current criteria and standards relating to the conduct of modern transmission

systems. For this purpose KOSTT has implemented many important projects that belong to

the category of system support. In the framework of these projects include: modernization

of defense equipment, modernization of the system and command transmitter. Table 5-3

lists the projects is carried out until the third quarter of 2011. Major project realized in the


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category of projects supporting the system is SCADA / EMS project completed in June of

2011.

Tab 5-3 System supporting projects completed from 2006 until Q2 2011

Parallel with consolidation of transmission network capacities, KOSTT has planned a

rehabilitation program for substations and high voltage equipment, at a view of increasing

reliability of security of transmission system operations. A considerable number of projects,

part of high priority project list, has already been implemented. Results of investment in this

category of projects are rather encouraging, due to the fact that the number of outages due

to failure of high voltage equipment in the recent years has visibly decreased.

Table 5-4 shows projects completed by the third quarter of 2011.

Tab.5-4 Substation rehabilitation category projects, completed by Q3-2011.

Tables 5-2, 5-3 and 5-4 show that years 2009 and 2010 were two of the most successful years

of KOSTT, thereby implementing 17 projects of high importance for the transmission

system.

No Title of project Technical description Year

1 Rehabiliation of Substation SS Prishtina 1Rehabilitation of all 110 kV fields in lines and transformers,systems of protection, control and measurement

2009

2 Rehabiliation of Substation SS Kosova ATotal rehabilitation of substation: All 220 and 110 kV fieldsin lines, transformers, systems of protection, control and measurement

2010

3 Rehabiliation of Substation Kosova BRehabilitation of all high pressure equipment ,400 and 220 kV levels

2010-2011


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5.4 Development projects in implementation and in the process

The investment intensity in the transmission system infrastructure continued throughout

2011, thereby pursuing objectives and aims deriving from the long-term development plan

of KOSTT. The table 5-5 shows eight projects in implementation during 2011, or in the

process of tendering.

Tab. 5-5 Projects in implementation, and projects being procured

Five projects from the list pertain to projects of enforcement of transmission capacities.

Major projects: Project Pack Ferizaj 2 was commissioned on 18 October 2011, apart from

the 110kV line SS Ferizaj 2- SS Gjilan 5, which was built, but due to delay in developing the

SS Gjilani 5, it was commissioned to work without load, while the project for the new 400

kV interconnection line SS Kosovo B – SS Kashar, is in the process of bidder selection, and

is expected to be commissioned in 2014.


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Within the process of development, rehabilitation and modernization of the KOSTT

infrastructure, additional activities were planned with a view of enhancing security and

operational reliability of the transmission system. The following table provides a list of

projects planned to be completed this year, and in the following year 2012.

Table 5-6. Substation Rehabilitation and modernization projects 2011-2012

5.5 Project-applications for connection to the transmission network, ongoing and

in development, during the period 2010-2011

Between 2009 until August 2011, KOSTT has received 15 applications for connection to the

transmission network. All applications were analyzed and reviewed pursuant to the

connection tariff methodology applicable at KOSTT, as approved by the ERO. Five of

these applications are for connection of new distribution substations (KEK-DSO), three

request connection of wind energy parks, and seven are related to reinforcement of

distribution capacities (KEK-DSO).

Some of the applications for connection with the transmission network are already complete

projects (in operation), some of them were left incomplete, and their further status is

unknown. From the three wind energy park applications, only one applicant (Kitka Project)

signed the connection agreement, while the two others have stalled. On the other hand, the

KEK-DSO application for SS Vaganica was also halted, and its status remains unclear.

Another application received from the MTI (Ministry of Trade and Industry) for the

industrial park supply was halted, and there is no further activity from the applicant. in the


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following points, the applications for connection to the transmission network which were

completed and expected to realize are provided.

Tab. 5-7 List of applications for connection to transmission network 2010-2012

5.6 List of new development projects planned for the period 2012-2021

The following is a list of projects planned as per category, as an outcome of an optimal

selection of various scenarios of network reinforcement during the planning process. These

projects span through the period 2012-2021. The projects are presented in tables categorized

as per respective specifics. A large number of these projects is part of the Development Plan

2010-2019, as approved by the ERO, while there are some new projects, resulting from a

detailed analysis of the network during the planning process. Factors considered influential

in redesigning some earlier projects, in changing their implementation period, and selection

of some new projects, are processes which are not dependent on KOSTT, such as:

applications for new power or generation connections, funding security aspects, property


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expropriations, etc. for the reasons mentioned above, the planning process and projects

selected are adapted to the changes which pursued in the meantime.

5.5.1 The list of new projects in the category of transmission network reinforcement

The table 5-8 provides a list of projects planned for the next 10 years, which are considered

to be influential in establishing network capacities, pursuant to requirements of the Grid

Code. Projects are sorted by their planned implementation period. Some of the projects

should be funded or co-funded by donors such as the IPA 2011 program, KfW etc. The

commissioning date of the projects will depend on procedures implemented by donors.

Network performance analysis has shown that projects such as second transformer at SS

Peja 3 are necessary much earlier (2012-2013), but due to their incorporation with the IPA

2011 program, cannot be implemented earlier. For the IPA 2012 program, a certain number

of projects have been proposed, as shown by table 5-8. The vast majority of investments is

to be made by KOSTT with soft loans offered by the German Bank for Reconstruction

(KfW), while the remaining part shall be a donation of the European Union.

Table 5-8 List of projects planned for reinforcement of transmission network 2012-2021

PROJECTS: REINFORCEMENT of the TRANSMISSION NETWORK (2012-2021)

N O ID Project name Technical description Reason for development Year

1

T-L

/R

AH

New 110 kV line SS Rahovec- SS Theranda -Development of new 110 kV line (15km)

a) 15km, Al.Çe240mm2 b) 110 kV line field in SS Theranda

Elimination of radial supply. Criterion N-1

Q3-2013

2

TR

IV/

L15

5/2

Revitalization of 110 kV line: L155/2 in coordination with development of SS Leposaviq 110/10kV

(a) Replacement the line conductor from and earthing wire up to Leposaviq (14km) (b) Reinforcement of portal type towers and replacement of existing insulators with composite insulator

Reinforcement of transmission capacities and load support

Q4-2013

5

T&

D-L

/D

RA

GA

SH

SS Dragashi and new 110 kV line SS Kukës-SS Dragash- SS Prizren 2 a) Construction of new 110kV Line SS Prizren 2 - SS Dragash, 21km; b) SS Dragash - SS Kukës, 39km.

(a) SS Dragashi, 2 transformers field, 2 lines field and one coupling field b) Line, 8km, ACSR 240mm2 from SS Prizreni 2 up to Zhur (double towers). c) Double circuit line 13km,ACSR 2x240mm2 from Zhuri up to SS Dragashi d) One circuit line 26km, ACSR 240mm2 from Zhuri up to Kukës

Optimisation of the operation of two systems of Kosovo and Albania. Quality and reliable supply for Dragash. Reduction the power flows in SS Prizren 1.

Q2- 2014


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(from border up to Kukës 17km)

3

T-R

IV/

L16

3/1 Revitalization of 110 kV line:

L163/1 a) Replacement of phase conductors and earth wiring (b) Reinforcement of towers and replacement of insulators

(a) Replacement the line conductor from 150mm2 to 240mm2, 32km , from SS Kosova A up to SS Vallaqi; (b) Reinforcement of portal type towers and replacement of existing insulators with composite insulator

Increased transmission capacity of the line from 83 MVA to 114 MVA in order to reduce power losses, improving the security criteria N-1 for the ring 110 kV substations Kosovo-A-Bardhi Vaganica-Vallaq

Q4- 2014

4

T-A

TR

/P

EJA

3

AT2-300 MVA at SS PEJA3 a) Installation of second AT 300 MVA, 400/110 kVsi and construction of transformer basements; (b) Construction of transformers field

(a) One transformer 300 MVA, 400/110 kV; (b) Installing high voltage equipment for transformer field 400 kV and 110 kV

Increasing the transformation capacity and fulfillme

Q2-2015

6

T-A

TR

/F

ER

-2 AT2-300 MVA at SS FERIZAJ 2

a) Installation of second AT 300 MVA, 400/110 kV and construction of transformer. basements; (b) Construction of transformer fields.

(a) One AT at a capacity of 300 MVA, 400/110 kV;

(b) Installation of high voltage equipment for transformer fields 400 kV and 110 kV

Increasing the transformation capacity and fulfillment of N-1 security criterion .

Q4-2015

7

T-L

PE

JA3-

PE

JA1 New line 110 kV SS Peja 3- SS Peja

1 and revitalization of SS Peja 1 a) Construction of new 28 km new line b) Revitalisation of SS Peja 1 (110kV side)

a) 28km, ACSR 240mm2; b) Line field in SS Peja 3; c) Revitalisation of SS Peja 1,the equipment and system busbar at 110kV level, passing in double busbar system and GIS system 110kV equipment .

Construction of transmission line enables meeting the N-1 Revitalisation of SS Peja 1 also leads to increased safety and reliability of system operation.

Q4-2016

8

T-R

IV/

L12


L126/2 SS Peja 2- SS Deçan a) Replacement of phase conductors and earth wiring (b) Reinforcement of towers and replacement of insulators

(a) Replacement the line conductor from 150mm2 to 240mm2, 14.57 km from SS Peja 2 up to SS Deçan (b) Reinforcement of portal type towers and replacement of existing insulators with composite insulator

Increased transmission capacity of the line from 83 MVA to 114 MVA in order to reduce power losses, improving the security criteria N-1 for the ring 110 kV substations Peja3-Peja1-Peja2-Deçan –Gjakova1.

Q4- 2016

9

T-R

IV/

L11


L179/1 a)Replacement of phase conductors and earth wiring (b) Reinforcement of towers and replacement of insulators

a) Replacement the line conductor from 150mm2 to 240mm2, 4.69 km from SS Prizreni 1 up to NS Prizreni 3 b) Reinforcement of portal type towers and replacement of existing insulators with composite insulator

Increased transmission capacity of the line from 83 MVA to 114 MVA in order to reduce power losses, improving the security criteria N-1 for the ring 110 kV substations Therandë-Prizren 3- Prizren 1.

Q3-2016


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10

TL

-PE

J3-U

JM

New 110 kV line SS Peja 3- HPP Ujmani – Construction new line 25km

a) 25km, ACSR 240mm2; b) 110kV Line field in SS Peja 3 c) b) 110kV Line field in HPP Ujmani

Reinforcement the capacity of transmission and meeting of N-1

Q2-2017

11

TL

PZ

1-P

Z2

New 110 kV line SS Prizren 1- SS Prizren 2 a) Construction new line, 3.5km

a) 3.5km, ACSR 240mm2 b) 110kV Line field in SS Prizren 2 c) 110kV Line field in SS Prizren 1

The continuous growth of consumption in the Prizren region endangering the security of supply substations ring Prizren 1, Prizren 3, Theranda. Construction of new transmission line will enable meeting the N-1. .

Q3-2018

12

T-L

/P

EJ1

-DE

Ç

New 110 kV line SS Peja 1- SS Deçan - Construction of a new 16 km line

a) 16km, ACSR 240mm2 b)110kV Line field in SS Peja 1 c) 110kV Line field in SS Deçan

Reinforcement the capacity of transmission and meeting of N-1 criterion in the Dukagjini area

Q2-2019

13

T-R

IV/

L11

8/1 Revitalization of the line 110 kV:

L118/1 a)Replacement of phase conductors and earth wiring (b) Reinforcement of towers and replacement of insulators

(a) Replacement the line conductor from 150mm2 to 240mm2, 7.3km from SS Prishtina 2 up to SS Kosova A (b) Reinforcement of portal type towers and replacement of existing insulators with composite insulator.

Increased transmission capacity of the line from 83 MVA to 114 MVA in order to reduce power losses, improving the security criteria N-1 for the ring 110 kV substations Kosova A-Prishtina 1- Prishtina 4

Q2-2020

14

T-L

/P

EJ_

MIT

New 110 kV line SS Peja 3- SS Mitrovica 2 - Construction of a new 32 km line

a) 32km, ACSR 240mm2 b) 110kV Line field in SS Peja 3 c) 110kV Line field in SS Mitrovica 2

Reinforcement the capacity of transmission and meeting of N-1 criterion in the Mitrovice area.

Q3-2021

15

T/

RIN

G_4

00kV

Package roject pack RINGROAD 400kV GJAKOVA-PRIZREN-FERIZAJ - Construction of distribution station 400kV DS Gjakova 3 - Development of SS Prizreni 4, 400/110kV - Development of 400kV line: DS Gjakova 3- SS Prizreni 4

(a) Construction of the switching yard 400kV SY Gjakova 3, 3 lines field and one coupling field (b) Construction of SS Prizreni 4, 400/110kV, 1x300MVA close to SS Prizreni 2, 2 lines field 400kV and one coupling field 400kV c) Construction of line 400kV, 31.5km from SY Gjakova 3 up to SS Prizreni 4 d) Construction of line 400kV ,56.5km SS Prizreni 4- SS Ferizaj 2

Configuration in the form of loops of the 400 kV network in order to optimize the power flows , and support of the new generation and load

Q4-2021


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5.6.2 Projects planned for the category of revitalization of KOSTT substations

The following table contains a list of projects related to the process of revitalization of

substations managed by KOSTT.

Tab. 5-9. List of projects of the category of revitalization of substations

PROJECTS OF CATEGORY: REVITALIZATION OF SS (KOSTT) - (2012-2021)

No

ID Project Title Technical Description Rationale Year

1

TD

/R

_PZ

3 Revitalization of HV equipment at SS Gjakova 2

(a) Replacement of three (3) 110 kV line fields, replacement of (2) transformer fields 110 kV, and one 110 kV connection field. Replacement of protective equipment for all line fields

Increased security and reliability of operation of this 31-year old substation

Q4- 2012

2

TD

/R

_GJA

2 Revitalization of HV equipment at SS Prizreni 3

(a) Replacement of three (3) 110 kV line fields, replacement of (2) transformer fields 110 kV, and one 110 kV connection field. Replacement of protective equipment for all line fields

Increased security and reliability of operation of this substation, important for the supply of some consumption in Prizren

Q4-2012

3

TD

/R

_TH

ER

Revitalization of HV equipment at SS Theranda - Is related to the new line project SS Rahovec-SS Theranda

(a) Replacement of three (3) 110 kV line fields, replacement of (2) transformer fields 110 kV, and one 110 kV connection field. b) Transition to double bus bar system

Increased security and reliability of operation of the substation 36 years old. Optimisation through coupling field

Q3-2013

4

TD

/R

_TH

ER

Revitalization of HV equipment in SS Vallaqi

a) Replacement of 5 110 kV line fields,b) replacement of two transformer fields 110 kV.

b) Replacement of 110 kV bus bar system, portals and development of a connection field 110 kV.

Increased security and reliability of operation of this substation

Q4-2013

5

T/

CB

_PR

4 Replacement of circuit breakers in SS Prishtina 4

Replacement of circuit breakers110kV and 220kV except two ATR3 field

Increased security and reliability of operation of this substation

Q4-2016

6

TD

/R

_PZ

3

Revitalization of HV equipment in SS Vitia (a) Replacement of 2 110 kV line fields,

replacement of (2) transformers field 110 kV Increased security and reliability of operation of this substation

Q2-2018

7

TD

/R

_PZ

3

Revitalization of HV equipment in SS Klina

(a) Replacement of 2 110 kV line fields, replacement of one transformer fields 110 kV

Increased security and reliability of operation of this important substation for supply to a part of the consumption of Klinës

Q2-2019

8

TD

/R

_PZ

3

Revitalization of HV equipment in SS Lipjan

(a) Replacement of one 110 kV line field, replacement of (2) transformer fields 110 kV, and c) changing into double busbar system with coupling field 110 kV

Increased security and reliability of operation of this substation, important for supply of Lipjan consumption

Q2-2021


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5.6.3 Projects planned in the category of supporting transmission system operation

The following table provides the projects planned in the category of supporting transmission

system operation. This list was selected through an identification of transmission system in

complying to technical requirements as per Grid Code and those recommended by

ENTSO/E.

Tab. 5-10. List of projects in the category of support to system operation; 2012-2021

PROJECTS IN CATEGORY: REVITALIZATION OF SS (KOSTT) - (2012-2021)

No

ID Project Title Technical description Rationale Year

2

T/

TE

LE

K_O

PG

W

OPGW installation at interconnection lines 400 kV - Installation of telecommunication routes with optical fiber, in 400 and 220 kV interconnection lines up to the borders.

a) Existing earthing wire 65mm2 in 400 kV lines up to border, will be replaced with earthing wire with the same dimensions containing the optical fiber 96

(a) Existing earthing wire 65mm2 in 400 kV lines up to border, will be replaced with earthing wire with the same dimensions containing the optical fiber 48

Q3-2015

3

T/

MA

T_M

ET

ER

S

INTER-TSO Meters - Installation of metering points at cross border lines, in compliance with the Metering Code

(a) Installation of two-core metering transformers for commercial metering, same characteristics in 400, 220 and 110 kV interconnection lines (b) Replacement of existing meters with meters compliant to the Metering Code

The project will enable the completion of meters installation in border in accordance with the Metering Code.

Q4- 2015

5

T/

GIS

-SY

STE

M

GIS System supporting the Transmission System

(a) Full set of remote controlled equipment: laser locator, thermal camera, digital area photo camera, GPS equipped, internal navigation system (b) Respective software for data integration and processing from equipment, and CAD and GIS data presentation

Increasing the maintenance level of lines and substations . Processing of the towers data , track lines, identification of properties by cross lines, etc.

Q2-2016


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5.7 Technical description of projects planned in transmission

5.7.1 Introduction

The first stage of transmission network consolidation was completed with the

completion of the projects: SS Peja 3, L112 line, AT 150 MVA at SS Kosovo A. The

second stage of transmission network reinforcement, expected to end in 2012, is

characterized as a stage aiming for increased reliability and network security, in terms of N-1

criterion. This stage is dominated by the major project SS Ferizaj 2, which on 18th of

October of this year (2011) was commissioned successfully. The transmission network

planning process, based on high voltage line planning criteria, is a dynamic one, and as such,

it aims for fulfillment of technical criteria which in the long term secure a safe prospect of

load and generation development .

The following is a description of development projects from the list of projects

planned for the period 2012-2021. A series of projects planned to complete by the end of

2021 will bring the transmission network to a condition which guarantees security and high

reliability in operation, in full accordance with the Grid Code. This period includes projects

which influence directly the reinforcement of the transmission network, substation

revitalization projects and load support projects, for which the parties have applied to

KOSTT for connection to the transmission network.

The following paragraphs present the impacts of main projects during the period between

2012-2016 as per project category, and listing as per implementation period aimed.

5.7.2 Transmission network reinforcement projects

The following are descriptions detailed for projects planned, pertaining to the category

of reinforcement of network, or increase of transmission network capacities for the planning

period 2012-2021.

Project: New 110 kV line SS Rahovec - SS Theranda

Radial load supply (island) for SS Rahovec as of today is not really preferred, since the N-1

security criterion, while the process of single-line maintenance causes lack of supply for as


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long as line and equipment maintenance goes on in both sides thereof. Computer

simulations undertaken on several options for a new connection for SS Rahovec, a

comparison of results as per key planning criteria; technical and economic criteria have

defined that the new 110 kV line from SS Rahovec must be connected to SS Theranda. On

this occasion, a new 110 kV ring is created: SS Prizren 2 – SS Rahovec – SS Therandë – SS

Prizren 3 – SS Prizren 1.

The 110kV, 240mm2 line shall be approximately 15km long. This project must be

coordinated with the SS Theranda equipment revitalization project, which plans for

replacement of 110 kV voltage equipment, and transition to the double bus bar system. At

SS Rahovec there is already a 110 kV line field, while at SS Theranda a new line field needs

to be developed. The figure 5-2 shows the geographical location of the new line. The project

is planned to complete by the third quarter of 2013.

Figure 5-2. Geographical location of the 110 kV line SS Rahovec – SS Therandë

Project: SS Dragash and 110 kV line SS Kukës-SS Dragash- SS Prizren 2

The project includes the development of SS Dragash 110/10(20)kV to be supplied with two

lines: SS Dragashi – SS Prizreni 2 (21km) and SS Dragashi - SS Kukës (39km). From Zhur to

Dragash, the line shall be double, while from Prizren 2 to Zhur, the line will be single, but

with doubled pillars, so that the other pillar line is used for the HPP Zhur project. the Figure

5-3 presents the geographical location of the project, with relevant data. The project


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coordinated between KOSTT and KEK-DSO is considered to be of importance for both

parties. For KEK_DSO the project allows for a better supply for the southern area of

Kosovo (Dragash and surroundings), reduction of technical losses at distribution, and relief

of 110/35kV transformers at SS Prizreni 1. The project is expected to be operational by the

second quarter of 2014.

In terms of benefits created by the transmission system project, we can underline a

few:

- Optimization of load flows between two systems KOSTT (Kosovo) and OST (Albania),

and minimization of electricity generation costs for both system generators.

- Relief of load from 110kV lines SS Prizren 1-SS Prizren 2 and SS Prizren 1-SS Prizren 3,

equivalent to the Dragash load.

- Exchange of electricity surpluses between systems, which can be facilitated by radial

operation.

- Secure supply for SS Dragash and SS Kukës, thereby fulfilling the N-1 criterion (outage of

a line does not interrupt supply for SS Dragash or SS Kukës, due to doubled supply)


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Figure 5-3. SS Dragash Project, and 110 kV line with SS Kukës.

Project: Second AT 300MVA at SS PEJA 3,400/110kV

The consistent increase of the load in the Dukagjini Plain region directly influences the

increased load in the single AT 300MVA at SS Peja 3. Computer analysis have shown that

during winter peak 2012-2013, around 3% (260 hours) of the year, the substation Peja 3

operates at risk as per security criterion N-1. The percentage of hours at risk will continue to


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grow for 5% for the winter peak 2013-2014, and 7% for the winter peak in 2014-2015. Based

on planning criteria, the need for a second transformer at SS Peja is rather pressing, but due

to financial limitations, this project was proposed for support from the IPA 2011 program.

European Union procedures for funding and implementing projects to be supported by the

IPA program determine the time of project commissioning, and this time is expected to be

the second quarter of 2015.

Project: Second AT 300MVA at SS FERIZAJ 2, 400/110kV

A consistent increase of load in southeast Kosovo (Ferizaj, Viti, Sharr, Gjilan, Therandë)

influences directly in the increased load on the single AT 300MVA at SS Ferizaj 2. The

second AT will influence the increased load flows from 400kV to the 110kV level at SS

Ferizaj 2, thereby relieving sensibly the load on AT-s SS Kosova A and SS Prishtina 4. With

the installation of the second auto-transformer, the substation Ferizaj 2, will comply to the

N-1 criterion for a long term, thereby increasing transformation capacities of the

transmission system for 300MVA. A project similar to the SS Peja 3 auto-transformer

project will be funded by the IPA 2011 program, which its commissioning is expected in the

fourth quarter of 2015. The project funds the installation of AT2/300MVA/400/110kV,

from a transformer field 400kV and 110kV.

New 110 kV line SS Peja 3- SS Peja 1, and revitalization of SS Peja 1

Following completion of the L1806 line allocation project from SS Gjakova 2 to SS Gjakova

1, the Dukagjini Plain area will comply fully to the criterion N-1. Based on a long term load

forecast, and based on computer simulations, the security criterion N-1 will not be complied

with until after 2015. A critical outage would be the outage of 110 kV line SS Peja 3-SS Peja

1, in which case there would be an overload in the line SS Gjakova 1- SS Deçan and SS Peja

3 - SS Klina. For this reason, to eliminate this problem, it is necessary to build a second 110

kV supply line, 240mm2, at a length of 28km, from SS Peja 3 to SS Peja 1. The project

should be coordinated with the SS Peja 1 revitalization project, which provides for a full

rehabilitation of 110 kV equipment, and transition to the double bus bar system. This project

is proposed for funding from the IPA 2012 program, while the commissioning of the project

is expected in the fourth quarter of 2016. Due to an over-urbanized area close to the Peja 1


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substation, the five pillars close to the substation must be constructed instead of existing

pillars, and they must be doubled. If there are problems in property expropriation, an

optional solution will be to dismantle the existing line, and construction of a new doubled

line, thereby avoiding a new route. The figure 5-4 shows a geographical position of the

project.

Figure 5-4. Second line SS Peja 3- SS Peja 1

Project: New 110 kV line SS Peja 3- HPP Ujmani

A consistent growth of consumption in the Mitrovica region, and a single 110 kV line

connecting HPP Ujman with the transmission network, are factors necessitating

construction of a new 110 kV line to connect the plant with the strong network node SS

Peja 3. The figure 5-5 shows the geographical location of the 25 km long line. This project

allows for development of a new 110 kV ringroad, which is important for the optimization

of the transmission network for the Mitrovica region. The expected consumption growth in

the region, especially due to the Trepca mine, will be more secure in terms of electricity

supply, in due consideration of increased transmission capacities. The new line will enable a

relief of supply lines for the 110 kV ring SS Kosova A – SS Bardhi – SS Vushtrria 1&2 – SS

Trepça. The project is expected to be complete in 2017.


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Figure 5-5. Line SS Peja 3- HPP Ujmani

Project: New 110 kV line SS Prizren 1- SS Prizren 2

The consistent growth of load in the Prizren region shall put at risk the N-1 criterion for that

area of the transmission network. This risk will be present after 2017, when the peak load in

Kosovo is foreseen to be 1340MW. The second 110kV line from SS Prizreni 1 to SS

Prizreni 2 is necessary since with the current network configuration, an outage of the line SS

Prizren 2- SS Prizreni 3 would cause an overload on the L164/3 line. The project plans for

the construction of a new 110 kV line, 240mm2 (114MVA/605A) 3.5 km long, as shown in

the figure 5-6. In this case, there are two other options of implementation, depending on

difficulty of expropriation and urban obstacles:

- Transformation of the existing L164/3 line to a double line

- Underground 110 kV cable

The project is due to be completed by 2018. This project is important for the realization of

110 kV consumption grouping concept as per main substations. The same project is also

considered by the Fichner study on redesign of the configuration of the transmission

network 400kV and 110kV.


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Figure 5-6. Project – Second 110kV line SS Prizren 1- SS Prizren 2

Project: New 110 kV line SS Peja 1- SS Deçan 2

To realize the creation of connection and disconnection reserves, grouping of distribution

points 110kV, avoidance of adverse impacts of sectional power flows between consumption

groups, supplied by two substations SS Peja 3 and SS Prizreni 2, it is necessary to build a

new 110kV line between SS Peja 1 – SS Deçani. This line would enable an optimization of

the Dukagjini area transmission system operation, thereby enabling support for the

increasing load, and in full compliance with technical requirements as per Grid Code. The

realization of this line would allow for the creation of substations groups: SS Peja 1, SS Peja

2, SS Deçani, SS Klina and SS Burimi, to be supplied only by SS Peja 3, while the relief from

the other group would be realized at SS Gjakova 1, by a connection field. The whole group

of substations would be supplied in full compliance of the N-1 criterion, while the influences

of unplanned outages of 110 kV lines in one of load groups would not affect the other

group. This modus operandi should be chosen by system operators at times of peaks, and as

such would allow for a higher operational security, thereby enjoying the availability of


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capacity connection and disconnection reserves at the 110 kV lines. The figure 5-7 shows the

geographical location of the new line, as per 2019 configuration, the expected year of project

implementation. The project provides for construction of a new 110 kV line, 15km, AlÇe-

240mm2 (114MVA/605A) and two line fields at both ends.

Figure 5-7. Project: 110 kV line SS Peja 1- SS Deçan

Project: New 110 kV line SS Peja 3- SS Mitrovica 2

The new 110kV line from SS Peja 3 to SS Mitrovica 2 (planned by KEK-DSO) will be

necessary to increase supply capacities for the Mitrovica and Vushtrri regions. The current

network configuration in the area would not be able to comply to the N-1 security criterion

after 2020, always in reference to the load forecasted for the next 10 years. Depending on

the future load development, according to three scenarios, the time of implementation may


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be revised. The project is expected to complete in 2021. The project provides for

construction of 32km of a new single 110kV line, 240mm2 (114MVA/605A) and two 110 kV

line fields, one at SS Peja 3 and the other at SS Mitrovica 2. Figure 5-8 shows the

geographical position of the project.

Figure 5-8. Project: 110 kV line SS Peja 3- SS Mitrovica 2

Packing Project RING 400kV GJAKOVA-PRIZREN-FERIZAJ

The current 400 kV network configuration is characterized as a star network, where the

centre of the star is the SS Kosova B. The optimal configuration of high voltage electricity

networks is the ring configuration, which ensures a higher operational flexibility and security

in the power system.

The expected development in terms of new generation capacities and load forecast, the

forecast of increasing flux of loads in regional exchanges, determine the need for

reconfiguration of the 400 kV network. Earlier studies, such as ESTAP I, have


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recommended the reconfiguration of the 400 kV network in a ring form, thereby avoiding

220 kV network development.

Computer simulations undertaken in complex models, which incorporate regional systems,

in consideration of new generation capacity development scenarios in the country and the

region, and the forecasted load development also in the country and the region, reflect the

need for creation of the 400 kV ring in the territory of Kosovo.

This configuration is presented as an optional long-term project also in the earlier

developments of KOSTT, as approved by the ERO. A detailed study on redesigning of the

400 kV network, and its impact on the Kosovo power system, was undertaken by a German

consultancy “Fichner”. The study’s concept recommends the establishment of powerful

400/110 kV nodes, which are to supply load groups, and by establishing capacity reserves in

110 kV lines, with a view of optimization of load flows. Computer simulations in complex

models undertaken by KOSTT have shown that the network area of the Prizren region will

not be compliant to the N-1 criterion after 2020, due to high impedance of two 220 kV

supply lines of SS Prizren 2. A larger problem would occur if the 220 kV interconnection

line Fierzë-Prizren 2 would fail. In this case, voltage collapse may occur, coupled with the

disconnection of the load at SS Prizren 2. If one would view the transmission network

before the construction of the 400 kV ring, one would be able to spot the existence of four

powerful and sufficient nodes of transformation to 110kV: SS Peja 3 supplying Dukagjini

consumption, SS Ferizaj 2 supplying southeastern part and SS Kosovo A, together with SS

Prishtina 4, which mainly supply Prishtina consumption. All these nodes are connected to a

powerful horizontal network, while SS Prizren 2 remains connected to a 220 kV network,

which is relatively poor.

The 400 kV network reconfiguration from the star shape to the ring shape configuration

brings about the following benefits:

Allows support for new generation capacities.

Increases reliability and security of the 400 kV network.

Facilitates security of load exchange between Kosovo and regional countries, or

transits passing through our country.


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Allows for reconfiguration of the 110 kV network, with a view of optimizing load

flows, and optimization of operational conditions of the transmission system

Improves quality of supply for the Prizren Region.

Facilitates maintenance of 400 kV lines.

The ring project is due to be completed in two stages:

First stage: Includes construction of the 400 kV distribution station Gjakova 3, which will

be positioned very closely to the 400kV interconnection line SS Kosova B – SS Tirana 2,

where it should be connected at a length of 51 km from SS Kosovo B, as shown in the

figure 5-8. DS Gjakova 3 is expected to perform the function of the new interconnection

point in a 400 kV ring. It should include three 400 kV line fields, with a possibility of

expansion, and one 400 kV connection field. Simultaneously, the SS Prizreni 4 400/110kV

will be developed, which initially will have an installed 300MVA auto-transformer. The

substation will be positioned in a sequence to SS Prizreni 2, to use the existing 100 kV bus

bars, with a difference in placing a 110 kV sectional bus bar divider. The substation provides

also for the development of double 400 kV bus bars, to contain two 400 kV line fields, and

sufficient space for reserve line and transformer fields. The figure 5-10 shows the

configuration of SS Prizren 4. Both substations would operate in parallel at the 110 kV level,

which means the use of existing 3x150MVA auto-transformers at SS Prizren 2. Existing

220/110kV auto-transformers will be used to the end of their life cycle, to be replaced with

additional AT-s 400/110kV to be installed at SS Prizreni 4. The distribution substation

Gjakova 3, 400kV will be connected by a 400kV line, 2x490mm2 (1316MVA/1900A), at a

length of 31.5km with SS Prizren 4, 400/110kV. The first stage is planned to be completed

in 2021.

Second stage: Includes the stage of ring completion, with the development of a 400 kV

line, 56.5 km line from SS Prizren 4 to SS Ferizaj 2, as presented by figure 5-9. The

construction of this line may be completed in the period between 2021-2025, and must be in

timely coordination with generation capacity development projects, as per Energy Strategy

2009-2018.


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Fig.5-9 Geographical positioning of the 400 kV ring DS Gjakova 3-SS Prizreni 4- SS Ferizaj 2


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300MVA

SSH GJAKOVA 3 NS FERIZAJ 2

Fusha Rez.

Rezervë

3x150MVA

400kV 220kV

110kV110kV

Fusha lidhese

Fusha lidhese

Fusha lidhese

Linjat 110kV Linjat 110kV Linjat 110kV

Ndares terthor

Figure 5-10. Single line diagram of modified substation SS Prizren 2, 220/110kV to SS Prizreni 4,

400/110kV

5.7.3 Projects on the re-vitalizing of the lines 110kV

The important factors that are taken into account for determining the list of lines which will

have the conductors replaced with larger transmission capacity are:

o The age of the lines,

o Line overload frequency (N-1)

o The level of power losses in the line

The first factor is clearly defined; while the second and third factors are identified by

computer analysis, thereby simulating load flows for different transmission system operation

conditions, in due consideration of perspective development of projects, which would

considerably impact the change of load flows in the transmission network. All 110 kV lines

with 150mm2 section, in the transmission network, have been analyzed in terms of load

losses, thereby pursuing reinforcement at the long term.


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Lines that are 40 years old and lines with larger losses are listed in the first place.

The main objective of this category of projects is to increase the capacity of 110 kV

lines with section conductors of 150mm2 (83 MVA), in conductor 240mm2 (114 MVA).

Some very old lines mainly have concrete towers and replacement of the existing conductors

with conductor on greater weight in mechanical and statically terms require reinforcement of

towers, with special emphasis on angular towers. Also portal towers require reinforcement

and eventual addition of the towers in order to increase the mechanical stability of the whole

line. For the period 2012-2021 are selected the following 110 kV lines that will be reinforced:

Project: Revitalization of the 155/2 line, in coordination with development of

the SS Leposaviq 110/10kV

The new SS Leposaviq 110/10(20)kV is planned to he supplied by the existing cross border

line SS Vallaq - SS N.Pazar, which shall be realized by a section close to the SS Leposaviq

35/10kV. The line currently does not have sufficient capacity due to its sectional width

(150mm2). On the other hand, this line is one of the oldest lines of the transmission system

of Kosovo, therefore its reinforcement is necessary. Replacement of the conductor is

planned for 15km of the line, starting from SS Vallaqi to the point where the section is

planned to occur in the line L155/2. The figure 5-10 shows the geographical position of the

project. The project is due to complete by the second quarter of 2014.


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fig. 5-11 Revitalization project for the line L155/2 in coordination with construction of SS

Leposaviq 110/10(20)kV.

Project: Revitalization of line 163

From all results obtained from computer simulations, the current line L163 from

Kosovo A to SS Vallaq at the capacity of 83MVA (150mm2) seems to be more

problematic in comparison to other lines (150mm2) which are in the list for replacing

conductors. By the end of 2012, the project of reinforcement of SS Bardh supply is

expected to be completed, thereby allowing for connection to the existing line SS

Kosova A – SS Vallaq. Improvement of capacity of this line should relief its overload, in

the case of disconnection of supply line SS Kosova A – SS Vushtrri 2. The project allows

for an improvement of security and reliability of supply for the load in the Mitrovica

region. The figure 5-11 presents the part of the line planned for revitalization. The

Project includes replacement of conductors 150mm2 (83MVA/440A) with 240mm2

(114MVA/605A) conductors, and necessary reinforcement in portal pillars, due to the

added load on the conductor. The project is planned to complete by the fourth quarter

of 2014.


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Fig. 5-12 110kV line SS Kosova A – SS Bardhi – SS Vallaq, at length of 38.5km

Revitalization of the 110 kV line: L126/2

Line of 14.57 km connecting SS Peja 2 with SS Deçan, it’s a line built in 1967, which

contains 52 towers of portal type and conductor of 150mm2. Line L126/2, is an important

line, segment of the substations ring of 110 kV Peja 3 – Peja 1, - Peja 2 - Deçan-Gjakova 1.

The project for the re-vitalizing of this line includes strengthening of the angular towers of

the portal form, installing new insulators and changing phase conductors. Protective

conductor will be replaced with the project SCADA/EMS. The project will assist in the

increase of the transmitting capacities and will assist in improvement of the N-1 security

criteria. The project is planned to be finalized in the fourth quarter of 2016.


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Fig. 5-13 the 110kV line SS Peja 2 – SS Deçan, length of 14.57km

Revitalization of 110 kV line: L179/1

The project provides for replacement of conductors, from 150/25mm2 to 240/40mm2 at a

length of 4.69km, from SS Prizren 1 to SS Prizreni 3, as presented by figure 5-13. The

project also provides on static reinforcement of existing pillars, placement of new composite

insulators, and replacement of phase conductors.

The line is an interconnecting segment for the supply of SS Prizren 3. Revitalization of this

line shall substantially impact the increase of security and operating reliability of that part of

the 110 kV network. The project is planned to be completed by third quarter of 2017.


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Fig. 5-14 The 110kV line SS Prizren 1 – SS Prizren 3, at the length of 4.69 km

Re-vitalizing of the line 110 kV: L118/3 Project includes replacement of the conductor

from 150/25mm2 to 240/40mm2 in the length of 28.7km in length from SS Ferizaj 2 up

to SS Sharri. The project also includes reinforcement of the concrete towers, installment

of the new composite insulators and changing of the phase conductor and protective

conductor.

The line represents a ring segment of the important substation of 110 kV Ferizaj 2 -

Sharr - Viti - Gjilan 5 which represents one of the oldest lines of 110 kV transmission

network so that its re-vitalization will significantly affect the increase of security and

operational reliability of that part of the 110 kV network. The project is scheduled to be

finalized in 2020.


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Fig. 5-15 The 110kV line SS Sharr - SS Ferizaj 2, at a length of 28.6 km

5.7.4 Projects for the re-vitalizing of the substations

In determining the list of substations that need re-vitalizing the following factors

were taken into consideration:

Impact of the failure of the substations in the transmission system

The age of the substation

Frequency of the failures and damages in the equipments of the high voltage

The level of the fault currents in the substations

Probability of failures in high voltage equipment begins to rise with age of equipment,

especially equipments that are greatly used. Also the substations which are characterized by


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large currents failures considerably influenced in the accelerating the loss of their credibility.

Based on data archived in KOSTT related to the above mentioned factors a list of

substations that need to be re-vitalized in the first five years of the development plan.

Projects: Revitalization of substations SS Prizren 3 and SS Gjakova 2: These projects are categorized into projects, which increase security and reliability of supply

in distribution nodes. The first two substations, SS Prizren 3, 110/10kV and SS Gjakova 2,

110/10kV, are quoted as top priority, based on the above-mentioned factors. The frequency

of outages, as a result of age of high voltage equipment, marks a tendency of increase, and

therefore, the revitalization of substations SS Prizren 3 (Q3 2012), SS Gjakova 2 (Q42012) in

a medium term is more than necessary. The projects provide on replacement of existing 110

kV high voltage equipment with new equipment, pursuant to the Electrical Equipment

Code, and replacement of relay protection in line fields with modern numerical protection.

Project: Revitalization of SS Theranda:

This project is of special importance, since it is related to the new 110 kV line SS Rahoveci-

SS Theranda project. The current bus bar (H system) configuration of the SS Theranda does

not allow for an optimization of system operation, while representing a difficulty in the

process of maintenance. Based on planning standards, substations that have three or more

lines must be configured in double bus bar systems and connection fields. This project

provides for the replacement of existing 110 kV high voltage equipment, development of a

double bus bar system (360mm2), installation of a 110 kV connection field, and the new 110

kV line field SS Rahoveci-SS Theranda. The existing relay protection system in line fields is

planned to be replaced with modern numerical relays. The new 110 kV line project SS

Rahovec – SS Theranda, and the substation revitalization project must be integrated in a

joint project, which is planned to be undertaken until the third quarter of 2013.

Project: Revitalization of SS Vallaqi Substation:

SS Vallaqi was one of the first substations to be built in Kosovo. Revitalization of this

substation is necessary, due to the fact that 5 110 kV lines are connected to its 110 kV bus


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bars, one of which conveys the load generated by the HPP Ujmani. The technical condition

of the substation is not satisfactory, and as such, it hampers the security and reliability of

consumer supply. Revitalization of the substation includes replacement of 110 kV high

pressure equipment, replacement of bus bar and portal systems with double bus bars and

connection lines. The project is due to finish by the fourth quarter of 2013.

Project: Replacement of the circuit breaker in SS Prishtina 4

SS Prishtina 4, 220/110kV, 3x150MVA, is a very important transformation node for the

transmission system of Kosovo. Due to its proximity to existing and planned generation

capacities, the high occurrence of fault currents in the substation may endanger the dynamic

stability of the system. Historical data on incidents recorded as a result of outages in

disconnectors state the necessity of their replacement. The project aims to replace all 110kV

and 220kV switches, except the 110kV and 220kV switches of the new transformer field of

AT3, installed in 2010. This project is selected to apply for funding by the IPA 2012

program, and as such, it is planned for implementation by the fourth quarter of 2016.

Projects: Revitalization of SS Vitia, SS Klina and SS Lipjani substations:

The time sequence of implementation of these projects covers a longer term from 2014 to

2021. Exploitation of high voltage equipment for these substations until the planned time

period for revitalization is economically feasible. If one refers to the age of substations,

frequency of outages and the technical state of equipment, their operation is considered

feasible for another 5-9 years.

Revitalization of 110 kV high voltage equipment at SS Vitia, 110/35kV is planned to be

completed by 2018.

Revitalization of 110 kV high voltage equipment at SS Klina, 110/10kV is planned to be

completed by 2019.

Revitalization of 110 kV high voltage equipment at SS Lipjani 110/35/10kV is planned to be

completed by 2021.


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5.7.5 Projects for the improvement for monitoring, controlling and measuring

of the transmission system

In the following are presented the projects of TDP that are considered as necessary to fulfill

the criteria deriving from the Grid Code and ENTSO/E Operation Handbook.

Project: OPGW in the interconnection lines Currently there are no telecommunications routes OPGW at the boundary lines.

Requirements of Policy 6 of the ENTSO/E (UCTE) Operation Handbook require that an

TSO must have at least two lines of communication with neighboring systems. Therefore,

the project of establishment of OPGW in the interconnection lines up to the border point is

considered important for KOSTT and regional system as a whole. In order for the project

to be operational there should be an Inter TSO Agreement so the OPGW will be installed in

the entire length of the line on both sides of the border.

The main objective of this project is installation of protective conductor with OPGW (up to

the border with neighboring TSO) and telecommunications equipment in the existing

interconnection lines of 400 kV:

L 407, SS Kosovo B – SS Nish, in total length 41 km

L 437/2 SS Peja 3 – SS Ribarevina , in total length 28.8.km

L 420 SS Ferizaj 2 – SS Shkupi 5, in total length 69 km

The total length of the OPGW installment is 138.8km

The finalization of the project is expected in the third quarter of 2015.

Project: INTER-TSO Meters Currently there are measuring points in all interconnection lines; however, they are not

completely in compliance with the Metering Code and the technical requirements of

ENTSO/E. The problems fall in two aspects:

- Current and voltage metering transformers have only one core for measuring, while the

Metering Code requires to have two commercial cores with identical characteristics.


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- Meters should be of multiple tariffs Project foresees replacement of the measuring points in the interconnection lines:

- Line 400 kV: SS Kosova B – SS Nish

- Line 220 kV: SS Podujeva – SS Krushevc, SS Prizreni 2 – SS Fierza

- Line 110 kV: SS Vallaqi – SS N.Pazari, SS Berivojca – SS Bujanovci

Also the project will include three other measuring points in SS Kosovo B in the border with

TPP Kosova B:

- Line 220 kV, SS Kosovo B – TPP Kosovo B

- Two generation fields B1 and B2 in SS Kosovo B.

This project will complete the measuring points in all border of the transmission system with

others.

This project was presented at IPA 2011 and expected to be implemented in the fourth

quarter of 2015.

Project: GIS System in support of Transmission System

The geographical information system (GIS) is to be used for organizing and processing of

transmission data for the whole territory of the Republic of Kosovo. The main feature of the

GIS system is the possibility of spatial/geographical data inter-relation, classification of all

technical details of transmission assets in correlation with the surrounding areas. The GIS

system also allows for communication with other IT systems.

The application of a GIS system in the Transmission System would enable:

- Accurate geographical positioning of line (pillars) and substations, information on properties in

and around installation positions.

- Detailed Technical information on each line (pillar), substation, telecommunication antenna, etc

- Information on property structure and construction in routes planned for new lines.

- Remote communication by equipment such as: thermal vision cameras, laser height meters, GPS

photo cameras, logistical means of GPS equipped maintenance teams.

- Data collection and processing inside a single collection centre.

- Communication with other IT systems


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Benefits from the GIS system are rather large, both in terms of savings in the maintenance

process, and in the process of operational and long term planning. This system shall also

integrate a system for identification of intensity and positioning of lightning discharges,

which would contribute in further enhancement of preventive maintenance. The project is

due to be completed by 2016.

6. TRANSMISSION NETWORK PERFORMANCE ANALYSIS

6.1 Description of the network model

Transmission network planning begins with creating basic mathematical model which

corresponds to network situation at the end of 2009 using technical data elements that

comprise the Power System. The parameters necessary for creating basic mathematical

model include:

Electrical parameters of existing generators

Electrical parameters of 400 kV, 220 kV and 110 kV lines

Electrical transformer parameters, without including the distribution network transformers

The maximum active and reactive power during winter and summer season in the points of distribution

and other expendable points.

Common power flow in border lines

Normal configuration of the transmission network.

Simulations and technical analysis of system performance in different periods have been

conducted with the help of software package PSS/E 32. This applicable software for the

planning processes of transmission networks is used in most countries of South-East

Europe, but also in many European countries and the world.

Iterative method (recurring), "Full Newton Raphson” is used to calculate the power flows,

while in calculating the security network criteria is used the module ACA " AC Contingency

Solution "which is integrated into the PSS/E.


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For the purpose of calculating the analysis of short circuits to the system nodes, and

disconnection ability of the breakers for voltage level: 400 kV, 220 kV and 110 kV was used

a more complex model, which includes the entire region of South-East Europe, model

which contains the order parameters of positive, negative and nular elements of the network.

To calculate the short circuit currents in the transmission network are implemented the

method of calculation according to the IEC 60909 standard.

Power System is analyzed for the most unfavorable conditions during the maximum load

on the network. Operating conditions and system performance depends on network

configuration, interconnection flows and connection of existing generators.

The analyzed performance of the current network has identified the network sections which

do not comply with technical requirements and the needs for reinforcement in appropriate

time sequences, in correlation with the planned development of the system load.

6.1 Current transmission network capacities; Q4-2011

In the manner of having a clear overview of the capacities of the transmission network in

Kosovo, a special assessment of horizontal network capacity is made, together with the

network capacity in supplying internal consumption. The horizontal network capacity has an

influence on imports, exports and transits of load flows, but its impact is not large in the

internal network capacity, based on the special configuration of the power system in

Kosovo, especially in terms of the 400 kV network. The TDP 2012-2021 considers the

current network capacities to be as per the condition by the end of 2011, which integrates

the projects which are expected to complete by the end of 2011, at a high degree of

certainty. Also, computer analysis of the system for the current network state was made as

per network configuration for the end of 2011, in correlation with the load forecast for that

year.

6.1.1 400, 220 and 110kV lines capacity

The table 6-1 shows the length and transmission capacities per length of existing

transmission lines in Kosovo, based on the network condition as per first quarter of 2011.


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The transmission capacity Ct represents the amount of all length of lines and nominal

thermal capacity of each line. This size is defined by the Grid Code, which provides upon an

estimation of the transmission capacities for 400kV, 220kV and 110kV lines.

Tab. 6-1 Transmission lines’ length and their transmission capacity

The data above show that 400 kV network capacities are considerable, while 220 kV network

capacities are a bit smaller than 110 kV network capacities. If we compare the 110 kV

network capacities in the current year 2011 (80573 MVA*km) and for 2008 (65845

MVA*km), than we would conclude there has been a substantial increase of capacity

(22.3%).

6.1.2 Transformation capacities; Q4-2011

Transformation capacities of the transmission network, managed by KOSTT, are installed at

substations 400/220kV, 400/110kV and 220/110kV.

The largest transformation capacity is installed at SS Kosova B 400/220kV. At this

substation, there are three auto-transformers installed with a nominal load of 400MVA. The

total transformation capacity of this substation is 3*400 = 1200MVA.

At SS Peja 3, 400/110kV, only one auto-transformer of nominal load of 300MVA is

installed. At SS Kosova A, 220/110kV, three AT-s of nominal load of 150 MVA are

installed, with a total transformation capacity of 450MVA.

At SS Ferizaj 2, 400/110kV, there is also another AT of nominal load of 300MVA installed.


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At SS Kosova A, 220/110kV, three AT-s of nominal load of 150 MVA are installed, with a

total transformation capacity of 450MVA.

At SS Prishtina 4, 220/110kV, three AT-s of nominal load of 150 MVA are installed, with a

total transformation capacity of 450MVA.

At SS Prizreni 2, 220/110kV, there are currently two auto-transformers, AT1=150MVA and

AT2 =150MVA, at a total capacity of 300MVA. (by 2012, a third 150 MVA AT should be

installed).

Table 6-2 shows transformation capacities of the transmission network in Kosovo, as per

network configuration Q4-2011.

Tab. 6-2 Transformation capacities at transmission network; Q4-2011

If total transformation capacities for the current year 2011 (3000MVA) are compared with

the capacity of 2000 (1800MVA), a substantial increase would be recorded at 83%.

Direct load supply at 110kV is provided by transformation capacities 400/110 and

220/110kV, at a total capacity of 1800MVA.


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6.2 The current load exchange capacity with neighbouring countries

The maximum capacity of load exchange with neighbors (at natural line power) with high

voltage transmission lines is 1740 MW. At 400 kV lines, the existing cross border

transmission capacity is around 1500 MW (3x500 MW), while at the 220 kV level, some

other 240 MW are added (120 MW line with Albania, and 120 MW line with Krusevac,

Serbia).

NTC3 (Net transfer capacity) of interconnection lines in Kosovo is smaller than their natural

power, and it largely depends on the regional electricity balance in neighbouring countries,

and from limitations to the regional horizontal network, which may appear in various

operational regimes. The table 6-3 shows the current capacities of interconnection lines as

per their natural power (P), average NTC and nominal thermal power (Sterm) [10]

Table 6-3. Current interconnection line capacities

* Nga https://www.entsoe.eu/fileadmin/user_upload/_library/ntc/archive/NTC-Values-Winter-2010-2011.pdf

3 NTC – means max total electricity power exchange between two control areas, compatible to security standards applicable in all regulatory areas, and in due consideration ofo technical uncertainties of the network condition (definition from the ENTSO-E guideline).


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The simultaneous interconnection transmission capacity (KNTI) is different from NTC, and

is calculated for two cases:

When the electro-energy system simultaneously imports through all interconnections (at different time

periods), until a first limitation at the horizontal network appears for the importing country and

exporting countries (for the N-1 criterion).

When the power system simultaneously imports through all interconnections (at different time

periods), until a first limitation at the horizontal network appears for the importing country and

exporting countries (for the N-1 criterion).

Calculation is rendered by the PSS/E software, based on long term demand and generation

forecasts for the regional countries, correlated with regional transmission system

development plans [8]. Natural flows at interconnection lines are flows defined by system

impedance, generation location and loads in case when individual systems are balanced (no

exchange). Natural flows are amongst key factors affecting various capacities of

interconnection for imports and exports.

The Simultaneous Interconnection Transmission Capacity is not calculated as an amount of

Net Transfer Capacity (NTC), and as such, it is much smaller4.

Currently, the KNTI of the transmission system in Kosovo is approximately 900MW for

power imports, and 1000MW for power exports. Considering the electricity balance, it may

be considered that current interconnection capacities are rather large, and allow for any

exchange program for the needs of the power system in Kosovo.

6.3 Analysis of the transmission network condition as per topology Q4-2011

Investments made in the transmission network during 2009 and 2010 have essentially

improved the operational performance of the transmission system. Current investments

ongoing, and those expected to be completed by the end of 2011, will enhance the network

even further towards compliance with the technical requirements as per Grid Code. The

4 ENTSO/E Raport: System Adekuaci Forecast 2009-2020


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figure 6-3 shows a single-pole scheme of the Kosovo power system, as per network topology

Q4-2011.

6.3.1 N-security criterion analysis

The system was analyzed for a gross max load of 1175 MW, with all elements (lines,

transformers, load) at operation. In this case, power flows were monitored, together with the

level of voltage at bus bars, and level of load on 400kV, 220kV and 110kV lines; and in auto-

transformers 400/220kV, 400/110kV and 220/110kV. Simulation results have not identified

any overloaded elements. The maximum capacity of internal transmission network, as per

technical security criterion N for the end of 2011 is around 1450MW. This means that the

transmission system can supply a gross load of 1450MW, while fulfilling the N-security

criterion. If one refers to the estimated maximum load, there is a sufficient security margin,

which is approx. 19% (275MW). Figures A1 and A2 in Annex A show power flows for

normal operation conditions, as per network topology Q4-2011.

6.3.2 N – 1 security criteria analysis

The system performance was analyzed in terms of the N-1 security criterion N-1, thereby

monitoring line and transformation loads, and the level of voltage at bus bars when a critical

element (transformer, line, cable) fails. Table 6-4 presents the lines which do not fulfill the

N-1 criterion, the outage of which causes deviation of load or voltage, beyond the limits

allowed by the Grid Code.

Table 6-4. Lines falling out of N-1 criterion, as per network configuration Q4:2011


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Critical failures numbered 1 and 4 will be eliminated with the completion of SS Gjilani 5

(Q1-2012), with which the 110 kV line SS Ferizaj 2-SS Gjilan 5 will be connected. The line is

constructed, but cannot be connected due to delays in completion of substation

110/10(20)kV Gjilani 5, a project managed by KEK-DSO.

Critical failures 2 and 3 will be eliminated with the completion of the project of line

allocation L1806 from Gjakova 2 to Gjakova 1 (Q2-2012)

The problem of radial supply for SS Lipjan will be eliminated with the completion of the

project for connecting SS Lipjan with L112 line, in the next year 2012. In terms of

transformation, there are still limitations to the fulfillment of criterion N-1. Table 6-5 shows

substations falling out of the N-1 criterion N-1.

Table 6-5. Auto-transformers falling out of criterion N-1 (Q4:2011)


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Computer analysis (simulations in PSS/E in the system model) have shown that currently

the transmission network can fulfill the N-1 criterion for loads smaller than 1050 MW.

Figure 6-1 presents development of N and N-1 capacities of the (internal) network, in

relation to the seasonal load for the period Q1/2009-Q4/2011.

Figure 6-1 Development of internal transmission network capacities from Q1-2009 until Q4-

2011.

6.3.3 Voltage profile and losses

Creation of powerful nodes at SS Peja 3 and SS Ferizaj 2, and construction of 110 kV lines

and their reinforcement has made possible the situation that in normal operation conditions

of the transmission system (at maximum load), the level of voltage as per configuration Q4-

2011 is within allowed limits as per Grid Code. Figure 6-2 shows voltage profiles for two

different network topologies in 2010 and 2011. The chart presents that the voltage levels at

all nodes are within limits allowed by the Grid Code. One may observe the impact of entry

into operation of SS Ferizaj 2, which reflects in a considerable increase of voltage level at

110 kV nodes connected to the substation. In terms of fulfillment of the N-1 security

criterion in terms of voltage, tables 6-4 and 6-5 present the critical failures which cause a

decline of voltage levels under the limit allowed by Grid Code.

Code.


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Fig 6-2. Comparison of voltage profile at 110 by two network topologies, 2010 and 2011

The system was analyzed also in terms of load loss in maximum load, while the computer

calculation results are presented with the table 6-6. Losses were calculated specifically in lines

and transformers, as per level of voltage. Calculated load losses in peak load are based on

ideal resistance and inductivity of elements modeled at PSS/E, and do not reflect real losses,

which are dependent on other factors which cannot be modeled, such as: resistance of

contact of high voltage equipment, resistance of connection bridges in line conductors,

crown effect, impact of temperature change at Ohm resistance, etc. Nevertheless, the results

gained provide important comparisons showing the trend of loss development at the

function of load changes and network capacity. Grid load losses for various years do not

match with energy losses during a year, since in the majority of cases, grid reinforcements

take place in the fourth quarter of a year, while the effects at the volume of energy losses in

the network can only be recorded in the next year, after relevant reinforcements are made.


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Tab. 6-6. Active and reactive power losses at maximum load (Q4-2011)

In terms of active power, the largest losses are caused at transmission lines (87%), where

losses at 110 kV lines dominate with a percentage of 66.7% in comparison to total loss. In

comparison to peak losses in the previous year 2010 (29MW), current year losses have

marked a small decline, which can be justified by the fact that the peak load increased

simultaneously with the network capacity improvement. Reactive power losses are caused

mainly at power transformers, while total lines are rather close to reactive compensation.

The table shows that 400 and 220 kV lines inject capacity reactive power to the network in

an amount almost equivalent to the reactive power absorbed by the 110 kV lines.


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Fig. 6-3 Single pole scheme, Kosovo power system, network topology Q4-2011


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6.4 Analysis of the transmission network condition as per topology Q4-2012

During 2012, rather important projects are due to complete, thereby influencing directly the

improvement of the operational performance of the transmission system. In 2012, we expect

to have operational the following projects:

Connection of the 110kV line SS Ferizaj 2- SS Gjilan5 (completion of Ferizaj 2

project)

Connection of SS Lipjan to the 110 kV line L112 (creation of a new 110 kV ring)

Third AT 150 MVA at SS Prizren 2

Allocation of L1806 line from SS Gjakova 2 to SS Gjakova 1

Replacement of conductor at 110 kV line L125/3 (SS Trepçë-SS Vallaq)

The completion of these projects will allow for a substantial enhancement of the

transmission system in terms of fulfilling criteria as required by the Grid Code. The figure 6-

6 presents a single-pole chart of the power system of Kosovo, as per transmission network

topology in Q4-2012.

6.4.1 N-security criterion analysis

The system was analyzed for the maximum estimated gross load of 1190 MW, for the

network topology Q4-2012, with all elements (lines, transformers, load) in operation.

The simulation results have not identified any lines or transformers overloaded. The

maximal capacity of the internal transmission network, as per N-security criterion for the

end of 2012 would revolve around the amount of 1580MW. This means that the

transmission system can supply a gross power of 1580MW, while fulfilling the N-security

criterion. If one refers to the maximum estimated load, there is a sufficient security margin,

which circles around 25% (390MW). Figures A-4 and A-5, in Annex A, show power flows

for normal operation conditions as per network topology of Q4-2012.


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6.4.2 N-1 security criterion analysis

The system performance was analyzed in terms of the N-1 security criterion N-1, thereby

monitoring line and transformation loads, and the level of voltage at bus bars when a critical

element (transformer, line, cable) fails. Implementation of 2012 projects will eliminate all

critical failures present in the current network topology, excluding only the radial line SS

Rahovec – SS Prizren 2. Therefore, in the winter consumption in 2012, the N-1 criterion will

be fulfilled in terms of 400kV, 220kV and 110kV lines.

The only problem that remains is the radial supply of SS Rahovec, and a single transformer

at SS Peja 3,400/110kV. The failure of this transformer would cause an overload of a single

110 kV line, and a drastic decline of voltage level at the Dukagjini area network section. The

following table shows the impacts of failure of transformer in other sections of the network.

Table 6-7. SS Peja 3 substation does not fulfill the N-1 security criterion in transformation (Q4:2012)

Computer analysis (simulations with PSS/E at a system model of Q4-2012) show that the

transmission network can fulfill the N-1 criterion up to a load smaller than 1160MW. If we

refer the annual time of 8760 hours, only around 5% (438h) of the time, the system will not

fulfill the N-1 criterion, while for 95% of the annual time, the system will fulfill the N-1

criterion.

The figure 6-4 shows N and N-1 capacity development of the (internal) network, in relation

with the seasonal load for the time period Q1/2011-Q4/2012.


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Figure 6-4 Internal transmission network capacity development, from Q1-2011 until Q4-2012.

The figure above shows time periods in which the transmission system is compliant and

incompliant with the N-1 security criterion. From Q2-2012 until the end of 2012, the N-1

criterion will be fulfilled (green areas), excluding the radial line of SS Rahovec. This fact

represents a substantial enhancement of operational performance of the transmission

system, if one refers to the situation of the system before 2008.


Further enhancement of transmission network capacities reflects into a reduction of load

losses and improvement of voltage profiles. The figure 6-5 shows a chart of voltage profiles

at 110 kV bus bars. One may see that the voltage level is very close to the nominal value of

110 kV. Voltages were analyzed also for minimum summer loads, in which occasion higher

voltage levels were recorded, especially at the 220 kV level. In these cases, the automatic

voltage regulation in transformer regulators must be operated manually to reduce dangerous

overloads at the 220 kV level. The 400 kV network voltage level is lead by the situation of

load flows in the region, where the influence of the power system on the increase or decrease

of voltages remains low. system operators may control 220 kV and 110 kV voltages, by


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reconfiguring network topologies, and by optimizing regulatory positions of voltage

regulators.

Fig.6-5 Voltage profile at 110 kV bus bars, network topology Q4-2012

In terms of losses in peak load in 2012, there is an expectation of small decline of loss of

active and reactive power, as a result of reinforcement of transmission capacities of the

network and optimization of active and reactive power. The following table shows the losses

of active and reactive power in total, and based on elements and voltage levels of the system.

In comparison to the current year, the losses of active power for a maximum load of the

system will mark a small decline of around 0.9MW as a result of projects to be completed by

the end of 2012. A considerable reduction of load losses is observed at 110 kV lines 110kV

from 18MW (2011) to 16.5MW (2012). Losses of reactive power in peak loads will be

smaller from 116.6MVAr (2011) to 93.4MVAr (2012). The reactive power is absorbed only

by transformers, while the lines in general are considered compensated.

Tab.6-8. Active and reactive power losses in maximum load (Q4-2012)


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Fig. 6-6 Single pole of the Kosovo power system, network topology for Q4-2012


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6.5 Analysis of the transmission network condition as per topology - 2016

Until 2016, rather important projects are expected to complete and influence directly in

enhancing the operational performance of the transmission system. The time period 2013-

2016 is the time of completion of the following projects:

110kV line SS Rahovec – SS Theranda

400kV interconnection line SS Kosova B – SS Tirana 2

Second AT 300MVA, at SS Peja 3,400/110kV

Second AT 300MVA, at SS Ferizaj 2,400/110kV

New 110kV line SS Peja 3- SS Peja 1

Revitalization of L155/2 and L163 lines

SS Dragash and 110kV line SS Kukës-SS Dragash- SS Prizren 2

Revitalization of 110 kV line: L126/2 SS Peja 2- SS Deçan

The gross peak load in 2016 is foreseen to be 1310MW. Figure 6-10 shows the single-pole

chart corresponding with the computer model 2016.

6.5.1 N Security criterion analysis

The network topology Q4-2012 system was analyzed for a maximum gross load of 1310

MW, with all elements (lines, transformers, load) in operation.

Simulation results do not identify overload lines or transformers. The maximum capacity of

the internal transmission network according to the N-security criterion for the end of 2016,

will considerably increase in comparison with 2012, as a result of reinforcement planned in

the transmission network. The maximum capacity of the internal transmission network

should be approx. 1850MW. This means that the transmission system in 2016 will be able to

supply a gross load of 1850MW, without encountering bottlenecks in the network, and at a

voltage level within allowed limits. If one refers to a forecasted maximum load for 2016,

there is a sufficient margin of security for the transmission system around 41% (540MW).

Figures A-7 and A-8 in the A annex show the load flows for normal operating conditions in

the 2016 network topology.


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Timely implementation of planned projects until the end of 2016 should allow for a

transmission system which for the first time will be able to fulfill technical criteria as required

by the Grid Code, in terms of security and supply quality. From the second quarter of 2015,

the transmission system will fully comply with the N-1 security criterion, for lines (cables)

and transformers, always in reference to forecasted load values for the next 10 years. If the

load forecast pursues the low scenario, then the N-1 criterion can be fulfilled even earlier.

The figure 6-7 shows development of internal transmission network capacities (N and N-1)

in relation to the seasonal load for the time period Q1:2012-Q4:2016

Figure 6-7 Development of internal transmission network capacities from Q1-2012 until Q4-

2016.


The voltage profile at all 110 kV voltage levels in the 2016 topology should remain within

optimal limits in maximum load, as shown in the figure 6-8. Operational voltages will be

within normal values, thereby influencing further reduction reactive load losses, while the

active power losses will increase from 26.1MW (2012) to 28.6MW (2016) as a result of

increased load.


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80859095

100105110115120125130

TSKA-11

0

PRZ-110

PR1PR2

PR3PR5

BARDHLIP

JAGJIL

ABERIV

VITIA

SHARR

FERIZ 1

THERAPRIZ

3PRIZ

1

GJAK2

DEÇAN

PEJA 1

BURIM

VALLA

TREPÇ

KLINA

VUSH.2

RAHOGJIL

5

SKEND

PR-6

DRAGAS

PEJA3

FER2

Nënstacionet 110kV

Tens

ioni

[kV

]

Tensioni (kV) Umax Umin Unominal

Fig. 6-8 Voltage profile in 110 kVbus bars as per 2016 network topology

In operational regimes at summer loads in the system, higher voltage levels are recorded,

especially at 400 and 220 kV horizontal grids, as shown in the figure 6-9. the reason for such

an increase in voltage is development of the 400 kV network capacities in the region

influencing our system; construction of a 239km long line SS Kosova B- SS Tirana 2, which

in minimum load regimes should inject around 75MVAr of capacitative reactive power in SS

Kosovo B bus bars. In this case, the installation of an inductive reactor 120MVAr at SS

Tirana 2 (220kV bus bars) is considered.

The control of voltage level at 400kV bus bars is almost negligible, by undertaking

operational measures within the relatively small power system of Kosovo, while the voltage

level at 220 kV bus bars is partially controllable, by making limited modifications of the

network topology (opening of the SS Fierzë – SS Prizren 2 line, disconnection of a

transformer at SS Kosova B etc). Over-voltage levels at 110kV level can be managed easily,

since the 110 kV network topology can be modified as per certain moduses, with a view of

avoiding line overcompensation. The only technical possibility of controlling overloads on

transmission grids is installation of an inductive static reactor 100MVAr at SS Kosova B (at

220 kV bus bars). Due to high uncertainty of network developments in the region, the

voltage level at the horizontal network (inside and outside the system) will be monitored


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carefully, so as to ensure a timely decision on planning installation of a 100MVAr reactor at

SS Kosova B.

Fig. 6-9 Voltage level at 400kV and 220kV bus bars in summer minimum load regimes

Active power losses will be reduced at 110 kV lines, while at 400 kV lines there will be an

increase of losses, as a result of construction of the 400 kV line SS Kosova B – SS Tirana 2,

and the increased transit flux in the transmission network. The active power losses will

increase in comparison to 2012, while reactive power losses will decrease in comparison to

2012. the following table shows total losses at transmission network, and loss percentages as

per voltage level and type of element.

Tab. 6-9. Active and reactive power losses in maximum load (2016)


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Fig. 6-10 Single line diagram of Kosovo power system, network topology 2016


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6.6 Analysis of the transmission network condition, topology 2021

The operational performance of the transmission system was analyzed for 2021, modeled in

PSS/E by integrating all planned projects for the next 10 years. As per a list of projects

selected by a computer analysis determination, a considerable number of important projects

of transmission network reinforcement is planned for implementation for the time period

2017-2021 such as the following:

New 110kV line SS Peja 3- HC Ujman

New 110 kV line SS Prizren 1- SS Prizren 2

New 110 kV line SS Peja 1- SS Deçan

New 110 kV line SS Peja 3- SS Mitrovica 2

Packet Project Ring road 400kV Gjakovë-Prizren - Ferizaj (phase I)

The figure 6- 14 provides a single-pole scheme corresponding with the 2016 computer

model.

6.6.1 N security criterion analysis

The system was analyzed with 1000 MW of new generation capacity connected to SS

Kosova B and decommissioning of the TPP Kosovo A, referring to the conservative

generation development scenario as per document “Generation Adequacy 2010-2019”

approved by the ERO.

The system was modeled to a gross load of 1446MW as forecasted for 2021. The

construction of SS Prizren 4, 400/110kV and creation of a 400kV ring, should ultimately

bring the transmission network to a condition conducive to further support for the load and

development of large generation capacities, both conventional and renewable. As presented

by the Fichner study, the new 400 kV network topology will enable the sectioning of load

groups connected at 110 kV network, and enhancement of operational security of the

transmission network, by establishing reserve disconnection capacities. The internal network


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capacity will have attained the amount of 2100MW with a 45% (654MW) security margin in

relation to the maximum load for 2021. The figure 6-11 presents a horizontal scheme of the

transmission network, modeled after the regional network (SECI_2020_PSS/E). The model

shows the load flows for certain regimes of regional exchange. The ring configuration allows

for the creation of four consumption groups to be supplied by main transmission

substations.

Fig.6-11 Horizontal network of transmission system, after construction of 400 kV ring - topology

2021


The 2021 network topology transmission system does not identify any lines or transformers,

the outage of which would create any overload or underload in other parts of the network.

Such a network topology allows for a full compliance with the N-1 security criterion up to

the consumption rate of 1500MW. The creation of a 400 kV ring, and creation of four


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consumption supply groups, all create higher flexibility and operation security of the system.

The failure of any single 400 kV line would not influence the security of supply for

consumption and regional exchange. The N-1 criterion is fulfilled both for interconnection

lines and internal lines.

Development of internal network capacities for the period 2016-2021 is presented with the

figure 6-12.

Fig.6-12 Internal transmission network capacity of transmission 2016 -2021.


The reconfiguration of the 110 kV network, by creation of four supply groups I-Peja 3, II-

Kosova A & Prishtina 4, III- Ferizaj 2 and IV-Prizreni 2&4, creates an almost maximal

optimization conditions for load flows, reflected into an ideal voltage profile at all bus bars

400, 220 and 110kV during the winter consumption.

The figure 6-13 shows the voltage profile for 110kV bus bars.


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Fig. 6-13 Voltage profile in 110 kV bus bars as per network topology for 2021

MW-expressed network active power losses will be higher than in 2016, as a result of

growing consumption. As per computer calculations, the losses of active power in peak load

1446MW will be 35.5 MW, from which 88.7% are caused by lines, where line losses

dominate 110kV (62%).

In terms of reactive power in the transmission system, the influence of 400 kV ring is rather

present. Lines inject a total reactive power of 132MVAr capacitative into the network, while

on the other hand transformers can absorb a reactive power rate or approx 142.5MVAr

(inductive), which means that only 10.5MVAr are counted as reactive power losses caused by

the transmission network. The reactive side of consumption is to be covered by domestic

generation sources.


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Tab.6-10. Active and reactive power losses in maximum load (2021)


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Fig. 6-14 Single-line diagram of the Kosovo power system, network topology 2021

TRANSMISSION DEVELOPMENT PLAN 2012 –

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Office: Long term planning and development

6.7 General conclusion

The Kosovo transmission system must develop in a manner of allowing for a secure, reliable

and qualitative supply of consumption, pursuant to technical requirements of the Grid Code

and the operation manual of ENTSO/E. An adequate and sustainable development of the

transmission system provides for favorable conditions of development of conventional and

renewable generation capacities. Appropriate long term planning for transmission system

development is essential to meeting above-mentioned requirements. The Transmission

Development Plan 2012-2021 has identified medium and long term needs for

infrastructure projects necessary to the enhancement and maintenance of the operational

performance of the system, in relation to development in consumption, generation and

regional markets of energy.

The TDP 2012-2021 sets forth the development priorities sorted in categories and

implementation timelines. The full realization of transmission development plans is

challenging to the most developed countries. Difficulties in accessing property, global

economic crisis, lack of financial resources, social implications, are some of the factors which

are necessary to be taken into account by planning engineers. If one would refer to

development of KOSTT in the last 5 years, it may be considered that development

objectives have largely been realized thanks to financial support of the Kosovo Budget and

international donors. Positive impacts of projects completed and those ongoing have been

analyzed in the previous development plan, while the following are general comments on

new development projects presented in the TDP 2012-2021.

Network capacity development

The implementation of projects identified by the TDP 2012-2021 will enable a consistent

enhancement of internal network capacities, which in turn would render conducive to supply

consumption. Reinforcement at key nodes at SS Peja 3, SS Ferizaj 2 and SS Prizren 4, 400kV

and 110kV network reconfiguration with the development of new 110 kV lines, are the key

factors to foster development of transmission network capacities. The figure 6-15 shows a


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chart of development of internal network capacities in relation to load development for the

next 10 years, in two scenarios of peak development.

Fig. 6-15. Development of internal network capacities in relation to load development for the next 10

years

In a period of 10 years, the horizontal network will also be subject to capacity enhancement,

as a result of development of the new 400kV interconnection line SS Kosova B – SS Tirana

2, and construction of the 400 kV ring in Kosovo. The capacity of transmission network

interconnection lines in Kosovo will be much higher than the import margin, or possibilities

of electricity export available to our country for the next 10 years, even in due consideration

of a considerable volume of transit flows (through our network) for the regional countries.

The figure 6-16 provides indicative values of simultaneous interconnection capacity for

export and import, calculated in a regional model. The estimated capacities take into

consideration the N-1 criterion for the whole horizontal network of regional transmission

systems.

When referring to planned generation development in Kosovo, the horizontal network will

be able to accommodate considerable generation capacities in full compliance with technical

requirements of ENTSO/E. In case of construction of a second 400 kV line SS Kosova B


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– SS Skopje, interconnection capacities would be considerably higher. This project remains

optional, and its advancement will largely depend on the changes of transit flows to

Southeastern European countries, and the size of generation capacities to be installed in

Kosovo.

Fig. 6-16 Simultaneous interconnection capacity development 2012-2021

N-1 security criterion

If one was to review the situation in the network before 2009, the N-1 security criterion

would not be compliant even in summer consumption, while in normal operation

conditions, the network would be subject to overloads which were managed by reducing

load. In reference to the current situation (2011), the network condition has changed largely

for the better, in which case the network does not display any bottleneck, while the N-1

security criterion is not complied with only at 10% of the annual time. Full implementation

of the N-1 security criterion requires considerable investment. If we refer to development

processes planned for the next 10 years, the security criterion will be fully complied with

only after 2015, while until then, the criterion will be closely pursued. The figure 6-17 shows

the ability of the network to fulfill the N-1 security criterion, in a relation with the maximum

load for the next 10 years.


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Fig. 6-17. N-1 capacity development of the transmission network 2012-2021

Quality of supply and efficiency

Not long ago, the a considerable part of the transmission network could both provide quality

supply in winter peaks due to the poor network, large active and reactive power losses. All

this resulted in rather low voltage levels at the 110 kV level, especially in areas remote to

generation sources. On the other hand, the amount of energy undelivered to consumption,

as a result of restrictions in the transmission network, was rather high. Reinforcements to the

network, especially after 2008, have created the conditions for a quality supply of

consumption and an extraordinary reduction of power losses in the grid. The voltage level

was stabilized after the commissioning of the Peja 3 project, while with further investments,

the operational efficiency of the network and quality of supply were enhanced to a

satisfactory level. The planned reinforcement in the next 10 years will allow for a further

enhancement of quality of supply and efficiency, but also maintenance, pursuant to technical

requirements of the Grid Code. The figure 6-18 shows a chart of developments in the active

and reactive power losses in peak loads, based on a forecast of load for the next 10 years.


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28.6MW26.1MW27MW35.5MW

10.5MVAr

74.5MVAr

93.4MVAr

116.6MVAr

0

20

40

60

80

100

120

140

2011 2012 2016 2021

∆P

, ∆Q

∆P ∆Q

Fig. 6-18. Developments in power losses at maximum load for years 2011, 2012, 2016 and

2021


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7. FAULT CURRENTS IN THE TRANSMISSION NETWORK

7.1 Introduction

This chapter examines the problem level of fault currents in all bus bars of 400 kV, 220 kV

and 110 kV voltage level. Review of fault currents or three phases and one phase to ground

short circuit level was made for periods in relation to the planned developments in

transmission network and the overall Kosovo Power System.

7.2 Calculation of fault currents level

Kosovo Power System is strongly interconnected to regional transmission network

400 kV and 220 kV. Relevant supplies of fault currents which are characterized by serious

impact on system security are concentrated in two main substations of the system: SS

Kosovo B and SS Kosovo A. In these two substations are connected all existing TP plants.

The objective of the study of short circuits is assessment of the impact of fault currents in

the security of the system. Fault currents in 400 kV, 220 kV and 110 kV bus bars will be

calculated in accordance with Policy 3 of the Handbook of ENTSO-E.

The basic aim of this study is to identify the bus bars in which the level of fault currents

exceeds breaking capacities of the existing breaker and determination of security margin of

all installed breakers or those that will be installed in the transmission system in Kosovo.

7.2.1 Mathematical model, calculation methodology and applied software

In order to determine the maximum fault currents in transmission system of Kosovo

and the impact of neighboring systems in these currents, in study was used regional model

which include 13 models of integrated Power System of the countries of South-Eastern

Europe. For this analysis is also used software PSS/E 32. Part of the network which is

interconnected with this model it’s equal to the Teveneni network (method for simulations

of models in the case of large networks).

Calculation methodology is based on the IEC 90609 standard. Maximum effective value of

the sub-transient component of the total fault currents three-phase and one-phase with

ground, is applied to every bus bars of level 400 kV, 220 kV and 110 kV. In this case the


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generators are equaled to their sub-transient reactance X "d. The time of 100ms is

considered as the time of fault elimination.

Based on IEC 90609 standard, calculations are made for no load operation, while

the initial conditions of the equaled network voltage of the Tevenen is taken as 1.1Un.

Ik” = Effective value of the fault currents

ip = The initial amplitude of the fault currents

Ik= Continual fault currents

idc = Dc component of the fault currents

A = Initial value of the dc component of idc

Figure 7-1 Form of the fault currents and its components

7.2.2 Features of the power circuits of the transmission network

In the transmission system currently in the existing substations of KOSTT are installed

different types of circuit breakers in terms of producers. While in terms of types of

dielectrical medium for extinguish electric arch are installed two types of breakers:

Oil circuits and

Gas circuits SF6

The old generation of the breakers have usually used oil as a dielectric medium for

extinguish the arch, while new generations of breakers use SF6 gas with a dielectric

characteristic and much better durability.


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Breakres with SF6 medium for arch extinguish represent necessary standard of breakers for

installation in transmission network. Also this kind of breaker has general features

significantly better than oil breakers, as in electro-mechanical stability during the process of

normal connections and disconnection, or the occurrence of fault currents.

KOSTT systematically is replacing the oil breakers with the new breakers within the re-

vitalizing projects of the existing substations. Disconnection capacity of circuit breakers is

different starting from 16.5 kA, 18.3 kA, 23 kA, 31.5 kA and 40 kA. The safety margin of the

breakers and other high voltage equipments is estimated by recognizing the level of faults

currents failures in a long-term domain that can occur in all substations and compared with

the level of disconnection capacities of the breakers.

7.3 Results of the calculated fault currents

Based on IEC 60909 standard, are calculated three-phase and one-phase to ground short

circuit for voltage levels 400 kV, 220 kV and 110 kV of the transmission network.

Calculation of currents is made in computer models in relation to the project development

under the network configuration: 2011, 2013 and 2014.

In Chapter 8 in a generalize manner are presented the effects of installing new generators to

increase the value of fault currents in the domain of the second five year planning period,

starting from the lowest scenario development of generating units of PP New Kosovo, HP

Zhuri and different potentials from energy parks that have wind generation which will

eventually be installed in Shtime region.

7.3.1 Assessments of the calculated fault currents (2009)

Results of simulation of three-phase and one-phase fault currents with ground for network

configuration according to the latest situation in 2009 based on the IEC 60909 standards is

presented in Table B-1 of Annex B.

The results of computer calculations in PSS/E show greater level of short circuit power in

two main substations, SS Kosovo A and SS Kosovo B, which are very close to generating

resources and supplies from the powerful interconnection of 400 kV.


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At 220 kV bus bars at SS Kosovo A the one phase to ground short circuit at a value

of 27 kA represents the largest electricity transmission network. Also in the SS Kosovo B at

the both levels of voltage the one phase to ground short circuit are relatively large at 20.9 kA

(at 400 kV) and 26 kA (at 220 kV). In other parts of the network while away from sources

of electricity generation three phase short circuit with ground dominates towards the single

phase. All 110 kV substations that are near SS Kosovo A (area of Prishtina) are

characterized by large fault currents. Results of calculating the level of fault currents lead to

the following conclusions:

400kV, 220kV and 110kV disconnectors installed in the transmission network have

e sufficient security margin (>20%). Their disconnection capacity towards fault currents level

is within the limits allowed under the IEC standards for the high voltage disconnection

equipments.

Plans for re-vitalizing of substations SS Peja 1, SS Gjakova 1 etc will help increase the safety

margin of these substations, which have very old breakers installed that does not guarantee

the stated nominal stability.

Figure 7-2 shows a chart of fault currents for main substations.


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Fig. 7-2 Chart of three and single phase earthed fault currents, for the current network topology

7.3.2 Assessments of the calculated fault currents (2011)

The development of the network and change of the configuration change affects the

values of fault currents. An input in raising fault currents should be given by the new

interconnection line 400 kV SS Kosovo B – SS Kosovo A, which is expected to enter

operation in 2014. Also impedance reduction of 110 kV lines due to their reinforcement

impacts the growth of fault currents. Figure 7-3 shows the values of short circuit currents,

three and single-phased earthed connections in main substations. Table B-2 of Annex B,

presents the results of the calculation of fault currents for configurations in 2016.

Based on the plan for re-vitalization of substations in relation to the disconnection capacity

of high voltage equipments and values calculated for the fault currents in the system for

configuration 2016 can be concluded that:

All circuit breakers installed in the transmission network and all high voltage equipment have

sufficient margins of safety.


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Plans for re-vitalizing of substations SS Peja 1, SS Gjakova 1 etc will help increase the safety

margin of these substations, which have very old breakers installed that does not guarantee

the stated nominal stability.

Fig. 7-3 Chart of three and single phase earthed fault currents, for the 2016 network topology.

7.3.3 Assessments of the calculated breaking currents (2013)

The 2021 model has taken into consideration the development of new generation units, as

per conservative scenario of the Generation Adequacy plan 2011-2020. In this model, the

TPP Kosovo A is disconnected, while three 3x300MW units are modeled as per figure 6-11.

from the results in the table B-3, one may observe an obvious increase of fault currents as a

result of new generation capacity development and the construction of the 400 kV ring.

The figure 7-4 shows a chart of levels of fault currents for main substations of the

transmission system.

In the 400 kV bus bars of the SS Kosova B, the short-circuit single-phase current at 29.3kA

is the largest current in the transmission network. At 220 kV bus bars, the short-circuit

single-phase current also dominates at the value of 26.8kA. Due to decommissioning of TPP

Kosovo A generation units, the fault currents would decrease if compared with values


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calculated in 2011 and 2016 models. In the Dukagjini region, one may observe the effect of

construction of SS Prizren 4, 400/110kV connected to the 400kV ring. Fault currents will be

much higher in substations close to SS Prizren 4, in comparison to the period before. When

comparing disconnection abilities of load switches to the level of fault currents, one may

conclude:

All load switches installed in the transmission network bear a sufficient security margin.

(20%).

Load switches installed at SS Kosova B and SS Kosova A, and all high voltage equipment, are

not endangered by development of New Kosovo TPP 3x300MW. Their disconnection capacity

at 40kA provides for a sufficient margin of security.

Fig. 7-4 Chart of three and single phase earthed fault currents, for the 2021 network topology.


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8. ENVIRONMENTAL IMPACTS

9.1 Environmental protection

Based on the KOSTT Transmission Development Plan 2010-2019, the

environmental issues should have an appropriate place in the planning. Continuous caution

for environment will be part of the overall KOSTT Policy and engagement of this police is

addressed in the certification of KOSTT with ISO 14001:2004 Standard. KOSTT

Development Plan will take measures to prevent and correct any mistake that is referred to

the environmental protection in accordance with the internal and external legal bases.

Negative impacts mainly include terms of the impact of electromagnetic fields (EMF), noise

and visual impact on the environment (more important effects).

9.2 Environmental problems in the transmission system One can say that the Environmental problems in the transmission system is divided into following:

• Environmental problems caused by the lines, and • Environmental problems caused by the substations

9.2.1 Environmental problems caused by the lines

Today when needed energy necessary for the development of our country, appeared

in the Development Plan, we need to adjust the priority of claims being aware of their

impact on the environment. Therefore we can say that the priority is set towards a necessary

development of electricity transmission of high voltage (during the above elaboration this

need is reflected and justified), not eliminate the need to minimize the possible impacts on

the environment. Most of the lines pass through the agricultural areas, while a little less of

those lines that pass on the mountain ecosystems where their impact is not so expressed.

From the aspect of electromagnetic radiation, greater influence has the industrial frequency

electromagnetic fields. The research of harmful effects of this type of non-ionizing radiation


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on man have not yet given the final answer, but it should be noted that nowadays there is a

special interest for the possible effects of electromagnetic fields on electrical equipment as

well as on the living creatures, especially on people. On the moment of the legal sanction of

electromagnetic impact this plan will take into consideration and will be subject to TDP's

implementation.

In the future appropriate recordings should be done and adaption to the

requirements recommended by World Health Organization. Also it should forwarded to any

cause of a wrong automatic action, reduced signal – noise report in communications

equipment and data transmit, etc.

9.2.2 Environmental problems caused by the substations

Besides occupying the surfaces substations carry the biggest visual changes in their

surroundings, but in aesthetic terms do not affect significantly, since under the rules they

should be located outside residential areas. The continuous noise caused (transformers work)

or the non-continuous work (disconnection equipment/circuits), the most direct impact on

the environment of substations, and due to vegetation relief is rarely transferred to the

residential areas, but in the substations location is likely to have greater value than those

allowed.

In modern equipment disconnection/circuits, is present the inert gas, not dangerous to

human health, but with undesirable impact on the ozone cover and toxic products in small

concentrations, caused during the process of working of equipments.

Having in mind that there are strict procedures in accordance with rules therefore the

procedures of using SF6 circuits, proposed that the implementation of SF6 technology, the

maintenance to be unstructured after several decades of exploitation, so that the risk index

will be brought to minimum.

Large quantities of synthetic oils found in power transformers, while a little less in the high

voltage equipment. Having in mind that oils possess a high potential for environmental

pollution, adequate measures are taken, such as the construction of collecting pool and

protection for collections of any oil leakage. These pools at the same time are a kind of

prevention in cases of large failures likely to occur.


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9.3 Caution on the other environmental impacts

At a time when the need for more and more energy is growing, the real impact on

the environment and aims for qualitative protection of this segment including this TDP that

supports the following:

• Reduction of emissions in water, air and land

• Increase of energy efficiency

• Enforcing preventive measures in order to reduce the number of accidents

• Development of systems for data collection and database (electronic forms)

• Reduction of parts and equipment that are outdated, etc

All these are implemented in preliminarily planned time frames, as:

• Reducing the damage done in the past

• Reduce the impact of ongoing activity in the relevant sector, and

• Prevention of pollution from activities in the future (e.g. EIA - Environmental Impact Assessment

and preventive measures in proper reduction)

9.4 Environmental plans

In favor of the implementation of the requirements for environmental protection is the well

supported initiative in setting environmental policy in KOSTT which is under the procedure

to be adopted. Clear definition of environmental issues in KOSTT and orientation on what

will be done to control the environment, means planning. Planning is accomplished through

new projects, which are followed by the Environmental Impact Assessment. The

implementation is started by established the organizational structure, staff responsibilities,

competencies and training. Communication practices, control of documents and procedures,

operational control and emergency preparation, define the operational part of the program.

These points are also included in the EMS Manual (Environmental Management System)


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which will document a program that has determined objectives and targets to be achieved.

This Manual was developed and has 18 procedures included. These, along with routine

audits that are done within the year 2008, 2009 and the first three months of 2010, reporting

the situation recorded along with appropriate recommendations, constitute a program of

controlling acts and corrective ones in EMS. Finally, a review of routine management

activities is lowed by the highest level in KOSTT.

The long term environmental planning will support the benefit and KOSTT development

plan, by aiming:

Proper financial management, which directs a better environmental control Therefore in KOSTT will be included all operational parts that have impact in environment

but by controlling the costs and its impact in the general budget.

Apart from the above mentioned we should also respect:

• Internal legislation (environment, energy)

• EU Legislation (environment, energy)

• Technical codes in KOSTT

• International standards and norms etc.

We have to work on the improvement and update of the new technologies and in

improvement of the infrastructure of the operation system (SCADA) and transmission

system (construction of the double and triple lines)


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9. REFERENCES

In this report the references were made from the following published studies and reports:

[1] Transmission Network Development Plan 2010-2019/KOSTT

[2] Long term energy balance 2011-2020/KOSTT

[3] Generation Adequacy Plan 2011-2020/KOSTT

[4] List of new Transmission Capacities 2011-2020/KOSTT

[5] Grid Code – second edition /KOSTT

[6] Electrical Equipment Code/KOSTT

[7] Transmission Connection Charging Methodology /KOSTT

[8] Transmission System Security and Planning Standards/KOSTT

[9] Operating Security Standards/KOSTT

[10] Electrical Standards Code/KOSTT

[11]. Distribution Code/KOSTT-KEK

[12] ESTAP I, Module C: “Power Transmission Master Plan”, (CESI et al, 2002), World

Bank Grant #TF-027991.

[13] ESTAP II: Feasibility Study for the Kosova – Albania 400 kV Transmission

Interconnection Project (CESI, September 2005), World Bank Grant #H048

[14] UCTE Operation Handbook, Last version

[15] Energy strategy of Kosovo/MEM


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[16] “Transmission Network Expansion Project” FICHNER

(The end of document)

Drafted Checked Approved

Name and Surname

Gazmend Kabashi Safete Orana Kadri Kadriu

Signature

Date 31.11.2011 17.10.2011 24.10.2011

Documents

TRANSMISSION DEVELOPMENTPLAN 2012-2021