SESCO TRANSMISSION SYSTEM INFORMATION BOOKLETs3.amazonaws.com/zanran_storage/ · SESCO TRANSMISSION SYSTEM INFORMATION BOOKLET ... (EHV) Transmission brings about many benefits to

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SESCO TRANSMISSION……. THE RELIABLE

POWER CONNECTION

THE RELIABLE POWER CONNECTION PROVIDING A BRIGHTER FUTURE

SESCO TRANSMISSION SYSTEM

INFORMATION BOOKLET

CONTENTS PAGE

1. INTRODUCTION 1

2. OVERVIEW OF SESCO TRANSMISSION SYSTEM 1-4

2.1 TRANSMISSION SYSTEM2.2 GENERATING PLANTS2.3 SYSTEM DATA AND INFORMATION

3. THE MANAGEMENT AND OPERATION OF SESCO TRANSMISSION 5-8 SYSTEM

3.1 TRANSMISSION DEPARTMENT ORGANISATION STRUCTURE3.2 GRID SYSTEM SECURITY3.3 ASSET MANAGEMENT

4. OVERVIEW OF DIVISIONS IN TRANSMISSION DEPARTMENT 9-16

4.1 GRID SYSTEM OPERATION DIVISION4.2 SUBSTATION OPERATION DIVISION4.3 TRANSMISSION LINE OPERATION DIVISION4.4 PROTECTION, CONTROL AND INSTRUMENTATION DIVISION4.5 SUBSTATION AUTOMATION AND SCADA DIVISION4.6 COMMUNICATION DIVISION

5. QUALITY OBJECTIVES OF TRANSMISSION DEPARTMENT 17-19

6. SYSTEM PERFORMANCE 20-22

7. DEVELOPMENT OF SESCO TRANSMISSION SYSTEM 23-247.1 SYSTEM DEVELOPMENT7.2 FUTURE PLANS

8. TECHNICAL RESOURCES AND SERVICES AVAILABLE 25

9. TRANSMISSION DEPARTMENT MANAGEMENT TEAM 26

Enquiry : Head (Transmission)Transmission Department3rd Floor, Wisma SESCoPetra Jaya, 93673 KuchingSarawak, Malaysia

Tel : 082-491360Fax : 082-444633E-mail : [email protected] : www.sesco.com.my


1

1. INTRODUCTION

The SESCo Transmission System is critical component of the SESCo Power System, verymuch akin in importance to the backbone and artery in the human body. Reliability of theTransmission System therefore has a very major impact on the State’s economic activity andultimately customer satisfaction.

To deliver the level of reliability and security of supply required, the transmission system isbuilt to the highest standard, and must be maintained and operated also in accordance withutility best practices. It is our vision to be the Number One in power delivery in the country,and to be benchmarked among the best transmission system provider in the world.

This Booklet is a compilation of useful information on the SESCo Transmission System forthe benefit of SESCO customers and users of the Transmission System. It contains a briefdescription of the SESCO Transmission Department as its Custodian and System Operator,highlighting its products, goals and objectives.

To provide the reader with an insight into how the System is maintained and operated, therelevant information of the six Divisions of Transmission Department is presented. Thiscovers the main objectives and functions of each Division. Relevant key performance indicesare also included to show the performance of the System and the supporting facilities.

2. OVERVIEW OF SESCO TRANSMISSION SYSTEM

Extra High Voltage (EHV) Transmission brings about many benefits to a growing electricpower system distributed over a wide geographical area. By providing an interconnectionbetween generation plants and load centres which are often separated by long distances, itallows for the common sharing of available resources, optimisation in operations and mutualsupport between areas, all of which will bring about cost savings, increased efficiency andreliability of supply to the interconnected areas.

2.1 Transmission System

The first 216km long 275kV transmission line from Batang Ai to Kuching, commissioned in1985, marked the beginning of EHV transmission in Sarawak. Together with the mammothBatang Ai Hydroelectric Scheme, it signified the quantum leap taken by SESCO in the fieldof electric power system engineering and other state of the art technologies which areassociated with its development.

Subsequently, the 275kV network was extended at Engkilili eastward to Sibu, Bintulu andMiri in 1988, 1991 and 1997 respectively. Presently the Transmission Systems consists of765km of 275kV and 128km of 132kV transmission lines, fifteen 275/132kV Substations.


2

2.2 Generating Plants

The Transmission System interconnects 6 main Power Stations of a total capacity of 819MW, operating on 4 different fuels, namely oil, gas, coal and hydro. Please refer to Figure 2below. Out of these 6 Power Stations, 2 are owned by Independent Power Producers (IPP)with a combined capacity of about 320MW.

Each generating unit has its own unique characteristics in operation mode, dynamic response,operational and fuel cost constraints.

PowerStations

FuelType

No ofUnits

AvailableCapacity (MW)

Normal Modeof Despatch

Kuching(TAR PS)

Kuching (SPC)

Btg Ai

Bintulu(SESCO)(SPG)

Miri

LFODieseline

Coal

Hydro

GasGas

Gas

42

2

4

62

8

4668

100

94

192220

99

Base/Medium/PeakPeak

Base

Medium/Peak

Base/MediumBase/Medium

Base

Total 28 819A summary of the generating units at each Power Station


3

The thermal plants are operated on a baseload mode to minimise start/stop cycles but aremore costly in terms of fuel consumption. The hydro plants are despatched to meet mediumand peak demands; however, the hydro reserve is dependent on the water inflow into thereservoir and hence it requires good management. Plants are despatched in the economicmerit order as far as possible; to minimise total cost of production. However, in some cases,security considerations dictate that more expensive generation be despatched selectively.

The thermal Power Stations store sufficient stock of primary and backup fuels to reduce itsdependency on fuel delivery from the suppliers. All Power Stations, with the exception ofSejingkat Power Corporation, are capable of blackstarting.

Careful planning and management are required to ensure an adequacy of supply at all times,while satisfying all system conditions. Optimisation and least cost production planning arecontinually done.

SESCO Batang AiHydro Power Station (4X23.5MW)Commissioned in 1985

Sejingkat Power Corporation (SPC)Coal Fired Power Station (2X50MW)Commissioned in 1997

SESCO Bintulu (Tjg Kidurong )Gas-fired Power Station (6X34MW)First Commissioned in 1991

SESCO Tun Abdul Rahman (TAR)Oil-fired Power Station (total 106 MW)First Commissioned in 1978


4

2.3 System Data and Information

The connection of Transmission System and Generation Plants, commonly referred to as the‘SESCO Grid System’ has many unique characteristics associated with a relatively smallpower system distributed over a large geographical area. Factors such as operationalconstraints, dynamic system stability, possible disturbances from environment, eg. lightning,vegetation, animals have to be carefully managed to ensure that the reliability and quality ofsupply are not jeopardised.

There are 5 major load centres sparsely distributed throughout the State, with a combinedpeak demand of 546 MW and energy demand of 3,412 GWH for 2001. The fuel cost toproduce this amount of electricity is about RM 209.5 million. This excludes the costs of theoperation and maintenance of the plants.

The average growth rate for SESCO for the last five years has been about 10% and this figureis expected to be maintained for the next 5 years, as shown in below.

Generation Mix for Sarawak 1985 - 2006

The Transmission System has the capacity to meet the present needs and with the ongoingdevelopment, it is well poised to cater for the future needs of SESCo’s customers. With thecriteria of N-2 and N-1 for capacity planning in the generating plants and transmission systemrespectively, there is a guarantee of adequate supply to SESCO customers at most locations inthe State.

With the upcoming 2,400 MW Bakun Hydroelectric project expected to be operational by2006, technical planning studies are underway to look into its integration to SESCO’s andSabah Electricity Supply Board (SESB)’s systems.

0

1,000

2,000

3,000

4,000

5,000

6,000

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

GW

h

Hydro Gas Oil Coal

Generation Mix 2000

Hydro15%

Gas61%

Coal16%

Oil8%

ACTUALFIGURES

FORECASTEDFIGURES


5

3. THE MANAGEMENT AND OPERATION OF SESCO TRANSMISSION SYSTEM

The Transmission Department in SESCO is the Custodian and System Operator of the SESCOGrid System.

The Products of the Transmission Department are:

i. The provision of Transmission System including Grid System supervision and control.

ii. The provision of in-house telecommunication, substation automation and SCADAinfrastructure and services.

iii. The provision of support and maintenance services for system protection, control andinstrumentation.

The Goals of Transmission Department are:

i. To effectively build, maintain, operate and control the Grid System, delivering electricity

which meets the requirements of SESCO customers.

ii. To effectively build and maintain telecommunication, substation automation andSCADA facilities and services to meet the needs of SESCO business processes.

iii. To provide quality technical expertise in EHV substation and transmission line,protection, control, instrumentation, telecommunication, substation automation andSCADA engineering, and power quality appraisal in a timely manner which meet theneeds of internal and external customers.

The Head Office of the SESCO Transmission Departmentis housed on the 3rd Floor of Wisma SESCO in Kuching.The nerve centre, State Despatch Centre (SDC) is locatedon the 1st Floor.


6

3.1 Transmission Department Organisation Structure

The Transmission Department presently has a strength of 127 personnel, consisting of 31engineers, 90 technicians and 6 office staff. Most of the personnel are based in the SESCOHead Office at Wisma SESCO, with some site operations staff based at strategic locationsalong the transmission line route.

The Organisation Structure of Transmission Department is shown below with the primaryfunctions of the six Divisions:

Office Support &Administration

Office of Head(Transmission)

SCADAFacilities

Management

EnergyManagement

System

OperationsTraining

Simulator

SubstationAutomationFacilities

ProjectManagement

SASMaintenance

Manager(Substation Automation

& SCADA)

CommunicationFacilities &

Services

ProjectManagement

CommunicationNetwork

Maintenance

ConsultationServices

Manager(Communication)

PCI Equipment& Facilities

ProjectCo-ordination

Testing &Commissioning

RelayCoordination

Fault LevelStudies

DisturbancesRecording &

Analysis

Manager(Protection, Control& Instrumentation)

OperationalPlanning

GenerationDespatch

SystemMonitoring &

Control

OutageCoordination

SimulationStudies

Manager(Grid System Operation)

TransmissionLines AssetManagement

Wayleave

ProjectCoordination


Civil WorksMaintenance

LinesMaintenance

Manager(Transmission Line

Operation)

EHV AssetManagement

ProjectCoordination


SubstationManning

SubstationMaintenance

TechnicalServices

Manager(SubstationOperation)

Head(Transmission)


7

3.2 Grid System Security

The Grid System has been designed with 100% redundancy (N-1) for all major componentsas shown in the Figure below.

Grid System security is paramount. In the operation of the Grid System, various measuresare being taken to ensure this :

• Power system simulation studies and analysis: Forward planning is continually done andvarious credible scenarios are studied carefully

• Multiple sources of generation in the System and diversity of fuel types

• Generation operating reserve; Spinning reserve is provided for the largest generating unitonline at all times

• Highly sophisticated protection system to clear faults expediently to minimise secondaryimpact on the System

• Strict control and supervision of maintenance and testing activities

• Close communication / coordination with large customers and users of the Grid System

• Operational contingency measures such as nine-stage underfrequency load sheddingscheme

• Fast restoration of supply through SCADA in the event of tripping

• Disturbance recording are done at various locations in the System for post-disturbanceanalysis and corrective actions

• Lightning tracking system will soon be installed to alert SDC operators on approachingthunderstorm and to take any precautionary actions, including shifting generation ifnecessary

Main bus Reserve bus

Generator, transmission, powertransformer can tap on to eithermain or reserve busbar

Redundant powertransformer

Double-circuit transmission that canaccommodate N-1 equipment outagecontingency.

Redundant busisolator design

Redundancy inherent in system design at generation andtransmission level in SESCO power system

275kV

33kV 11kV Ring-Main Unit[RMU]

Ring-Main Unit[RMU]

Circuit-breakernormally open

To tee-off line orlocal transformeror customer


8

3.3 Asset Management

Today, the net operating assets of the Transmission System are valued at about RM758million. The way the assets are managed is fundamental to stakeholder value and businesssuccess. This is put in place by the 5 year Strategic Transmission Asset Management Plan(STAMP) adopted by the Transmission Department in 2000.

The components of STAMP are :

Category ActivityShareholder

(MVA Impact)Customer

(Benefit Impact)

Asset Creation

Asset Disposal

Development(new construction)Augmentation(Upgrade)

DecommissioningMothballingDismantling/sale

Capital Employed(Fixed Assets)Terminal value

Supply SecuritySupply Quality

Operation ConfigurationProtectionSwitching

RevenueTransport CostsAsset life

Price FlexibilityProduct QualityDelivery achievement

Stewardship(Predictive)

ReplacementRefurbishmentModificationInspection/servicingCondition monitoring

Sustainabilitycosts (long runaverageAsset life

Supply ReliabilitySupply Quality

Fault Response(Corrective)

DiagnosticSupplyRestorationRepair

Operating costs(Actual Expensed)

Supply RestorationCustomer Service

The asset strategy links the desired performance and current condition of the asset with thework required to achieve these goals. The key outputs of an asset strategy are :

• Defined levels of performance such as asset life, availability, reliability and efficiency(losses)

• A long term workload described in work categories such as refurbishment, replacement,overhauls and inspections.

• A matching resource requirement by major skill groups

• A cash flow forecast for the plan


9

4. OVERVIEW OF DIVISIONS IN TRANSMISSION DEPARTMENT

4.1 Grid System Operation (GSO) Division

The main objectives of the Grid System Operation Division are:

• To effectively operate and control the SESCO Grid System to ensure reliability, securityand quality of supply to our customers.

• To despatch the generation for the SESCO Grid System according to least cost optionsand optimal generation mix.

• To provide expertise and services to other Divisions on matters related to the SESCOGrid System and its development.

Within the Grid System Operation Division,there are three main Sections:

The Operational Planning Section coversoperational planning ranging from the immediateterm (1 day) to medium term (5yrs) horizon. Thisincludes the Grid Generation Planning,coordination of shutdowns and tests ongeneration, transmission and distributioncomponents. Computer programs such as P-Comand P-Week are used for the optimisation ofproduction. The Annual Grid Generation Plan(AGGP) is produced at the beginning of eachyear and is reviewed quarterly.

The Technical Service Section covers thesimulation studies, contingency planning,disturbance monitoring, trouble shooting, trainingand support to SDC pertaining to the operation ofthe Grid. The computer programs PSSE is used tocarry out the simulation. This Section also doessystem-side PQ monitoring and liaise with largeindustrial customers on PQ issues.

The State Despatch Centre (SDC) is a 24 hourmanned Control Centre housed in WismaSESCO, Kuching responsible for the realtimemonitoring, supervision and control of theSystem, and generation despatching using thestate of the art SCADA technology. All the majorSubstations from 11kV to 275kV are monitorableand controllable from SDC.

SDC works very closely with the Control Centresof the Grid connected Power Stations andRegional Despatch Control (RDC) distributedthroughout the State, coordinating all majorworks such as shutdown, switching and supplyrestoration.

Typical SCADA screen

Power system simulation

Typical daily load pattern andgeneration despatch


10

4.2 Substation Operation (SSO) Division

The main objectives of the Substation Operation Division are:

• To maintain the asset of EHV facilities for safe and reliable operation at all times.• To achieve mean outage duration of < 580 min. for forced and planned outages.• To achieve forced and planned outage rates of <0.4 and <0.76 per 100 MVA respectively.• To achieve 3-Star rating for all EHV substations within the next 2 years.

The SSO Division is the custodian of all EHV Substations in the SESCo Grid System,covering all equipment within the perimeter fencings. However, the 33kV and 11kVSwitchgear for outgoing feeders in these Substations are operationally under the respectiveRegions or Power Stations according to agreed operational boundaries.

A 'Permit to Enter Substation' must be obtained fromSSO Division prior to enter, except for emergencycases such as breakdown, faults.

The type of switchgears ranges from outdoor SF6insulated circuit breakers to indoor Gas InsulatedSubstation (GIS). For major Substations, a doublebusbar configuration is adopted with dualredundancy provided for major components.

Two Specialist Support groups have been formed to:i. carry out maintenance repair works

ii. supervising and commissioning of projects.

Though not all EHV stations are manned, thesubstation operators will conduct a daily routinevisual inspections and monitor the status of all EHVstation equipment. At present there are 5 operationsteams located in the following Substations:

• Muara Tabuan Substation, covering KuchingOuter Ring Substations

• Engkilili Substation, covering Engkilili /BatangAi/ Betong Substations

• Kemantan Substation, coveringKemantan/Sarikei/Tjg Manis Substations

• Deshon Substation, covering Oya/Sibu/BintuluSubstation

• Tudan Substation

Apart from the normal operation duties, theseoperators are supporting the Specialist Supportgroup in carrying maintenance works wheneverassigned. Regular maintenance works includefunctional checks on switchgear, OLTCmaintenance, purification of transformer oil,dissolved gas analysis, tangent delta test.

Manning of EHV substation

275kV SF6 circuit breakers

275/33kV transformer


11

4.3 TRANSMISSION LINE OPERATION (TLO) DIVISION

TLO carries out maintenance for all the 275kV and 132kV transmission lines stretching about765 km and 128km respectively from Kuching to Miri with linesmen located at the majortowns. To meet the needs of the customers, TLO must ensure maximum reliability andavailability of all these transmission lines. The objectives of the division are :

• To achieve the required outage rate and mean outage duration performance indicescomparable to other utilities in the region.

Outage type Outage rate (per 100 cct km) Mean outage duration (mins)Forced 2.0 100Planned 1.0 500

• To restore supply for one circuit within 2 weeks on the event of a damage tower

The main 275kV line linking Kuching and Miri is built of steel lacircuits, each comprising 2 ACSR conductors. The 132kV tee-off linbuilt on either lattice towers or monopoles and with similar formadesigned to international standards of safety standards eg. meclearances and electromagnetic field interference.

The main challenges to the transmission line performance come flightning, vegetation and animals. As the isokeraunic level is verydays per year), special design features are incorporate in the llightning strikes eg. zero angle shielding, low tower footing resistainsulation, belian crossarms for suspension towers. As most of thnature, the single pole auto reclosure had been successful in a numbe

Sufficient ground clearances (minimum 6.5m) and easement wthroughout the route of the transmission line, to minimise the encroaching on to the conductors.

The main activities carried out each year comprise civil and electricaconductor and easement clearing. Tower top inspection, live line inon tower footing earthing and minor repair work are conducted byfoundation repair, hillslope protection and easement clearing by Chas a set of emergency response system (ERS) structures to mifailure.

In addition to maintenance of the lines, TLO Division also providworks done by Contractors.

A 275kV suspension tower
A 275kV tension tower Aerial lineswork in progress ttice towers supporting 2es from the main line are
tion. The lines have beenchanical strength, safety

rom the environment eg. high (180 thunderstormine design to withstandnces, differential impulsee faults are transient inr of operations.

idth (40m) are ensuredlikelihood of vegetation

l inspection of the tower,sulator checking, checks the linesmen while civilontractors. TLO Divisiontigate against any tower

es supervision of project


12

4.4 Protection, Control and Instrumentation (PCI) Division

The Protection, Control and Instrumentation(PCI) Division is responsible for the protection inthe EHV transmission and distribution systems.PCI Division is divided into 2 units ofmaintenance team-one unit for the transmissionsystem and the other for the distribution system.For the distribution system, support and frontlinemaintenance personnel are provided by therespective regions.

This Division also provides technical support andmaintenance services for other Departments andthe implementation of new substation projectsupon request.

The main objectives of the PCI Division are:

• To effectively maintain the protectionsystem to meet the availabilityrequirement of the SESCO Grid Systemincluding all the distribution substations atall times.

• To provide quality technical services onprotection, control and instrumentation ina timely manner to meet the needs ofcustomers.

• To improve and maintain the performanceof the protection system of the GridSystem to a reliability of at least 90%.

• To eliminate incidences of double circuitoutage on the EHV Transmission Systemby the implementation of the fast speedsingle pole autoreclosing scheme.

• To prevent maloperation of protection inthe distribution system due to protectionnon-discrimination and protectionequipment failure.

• To assess the current protection scheme inthe EHV transmission and the distributionsystems and to replace or upgrade theaging relays where the cost ofmaintenance are very high.

The ASPEN Computer program is used for fault level calculation and relay coordination.Computerised injection test sets are used for the testing of relays, CTs and VTs.

A Dynamic System Monitor (DSM) Record

Equipment testing in progress

Transmission Line Disturbance Record


13

4.5 Substation Automation and SCADA (SAS) Division

Supervisory Control and Data Acquisition (SCADA) is the key to effective control of anypower system as realtime information e.g. as status of equipment, alarms, loadings, voltageand frequency can be brought back to a central location and displayed to the Operator. TheOperator can then make the correct control decisions by remotely operate the equipment.

The main objectives of the Substation Automation and SCADA Division are:

• To provide the Substation Automation and SCADA facilities, in a timely and effectivemanner, to meet the needs of the operation of SESCO power system.

• To provide technical support and services on project management, installation, testing andcommissioning and maintenance of Substation Automation and SCADA systems.

• To establish, define and update PPGs and standards of the Substation Automation andSCADA systems to meet the needs of SESCO

Redundant Ethernet

Redundant Ethernet

UserInterface 1

UserInterface 2

ApplicationProcessor 1

Application Processor 2

UserInterface 3

DAC Node

RTUs

MimicProjection

Bridge

2 MbpsChannels

Logger 1 Logger 2

LaserPrinter

GPS

Remote ConsoleServer

Development Node

RDIGSServer

KuchingRDC Sibu

RDCBintuluRDC

Miri RDC

State Despatch CenterSDC

FTPServer

X-term X-term


14

There are three Sections in the SAS Division :

• SCADA Facilities and User Support

This Section provides the SCADA/EMS facilities together with the support and serviceson project management, installation, testing and commissioning of SCADA/EMSsystems. It also establishes SCADA/EMS PPGs and standards.

• Facilities Maintenance

This Section provides maintenance services to both Substation Automation andSCADA/EMS assets. It ensures the assets are functioning as intended at all times.

• Substation Automation Support

This Section provides the facilities together with the support and services on projectmanagement, installation, testing and commissioning of substation automation systems. Italso establishes substation automation facilities’ PPGs and standards.

The existing SAS systems comprise of:

SCADA systems

• Fully redundant master system in SDC to support SCADA facilities for all EHV, 33/11kVand major 11kV substations and power stations. This master system is inter-linked toKuching, Sibu, Bintulu and Miri RDCs’ master systems.

• Four master systems in Kuching, Sibu, Bintulu and Miri RDCs to support SCADA facilitiesfor localised EHV, 33/11kV and major 11kV substations and power stations.

• Two mini master systems in Lundu and Lawas to support SCADA facilities for localised11kV substations and power stations.

Remote Terminal Units (RTUs)

• More than 100 logical RTUs are installed in EHV, 33/11kV and major 11kV substations andpower stations, with a total point counts of exceeding 30,000 points including 5,000supervisory control points.

Substation Control Systems

• Two substation control systems in Miri area.

Testing of RTU equipment EMS Training in progress


15

4.6 Communication Division

The main objectives of the Communication Division are:

• To set up and maintain a reliable communication network throughout the SESCo system.

• To provide an efficient and cost effective communication network facilities and servicesto meet the growing needs of SESCO power system operation and businessadministration in the power utility environment.

The communication network comprises of various media and routes, namely:

• The fibre optic network covers all the Grid connected Regions. SDH channels areoperating at STM4 (622 Mbps) and STM1 (155Mbps) level, linking all Despatch Centres,major Power Stations, EHV Substations and Regional Offices. PDH channels areoperating at 2 Mbps, linking most of the 33KV substations and regional power stations.

• The Micro-Wave Radio link was set up between Wisma Sesco and Biawak 132 KVsubstation. The link forms part of the fibre optic network.

• The Power Line Carrier (PLC) network was set up along the EHV Transmission Lines.All the EHV Substations are linked up by PLC channels. The PLC channels are workingon 4 kHz baseband which can provide analogue speech and low speed data channel ( upto 9600bps ).

• Pilot Cable network: Before the implementation of fibre optic network, the pilot cablenetwork was set up to link 33 KV substations. The pilot cable channels can provide thesame 4 kHz baseband as PLC channels but with limited distance ( about 20 km ) due tothe attenuation effect of the pilot cable.

Signaling test for PLC equipmentFibre optic network management

Discharge test on 48V battery


16

The network facilities support various applications in SESCO:

• Private Automatic Exchange (PAX) for SESCO internal telephone network which isused for operations purposes, eg. despatch centres, power stations, regional offices,substations, offices for operations personnel

• Public Automatic Branch Exchange (PABX): All PABXs have been linked up to form anetwork. The extensions are installed in regional offices for administrative purposes

• Security surveillance System for Kuching Regional Office to monitor intruder alarmsfor EHV Susbtations in Kuching region. The system will be extended to other regions inphases.

• Data Communication Network: Data communication has been setup to link SESCOoffices for IS application

Network channel usage support are provided for other applications in SESCO:

• SCADA System

• EHV and 33kV line current differential protection

• EHV Substation monitoring

Communication channels from 64kbps to 2 Mbps are also available for other applications ifrequired.


17

5. QUALITY OBJECTIVES OF TRANSMISSION DEPARTMENT

The Quality Objectives of Transmission Department are:

i. Monitoring and Control of the Grid System

To operate SESCO transmission system so as to meet the following performance criteria:

Parameter Normal SystemOperating Condition

Emergency SystemOperating Condition

Voltage variation ± 5% ± 10%

Frequency variation ± 0.5 Hz ± 1.0 Hz

Time error control ± 10 seconds ± 10 seconds Note: Emergency condition involves the period subsequent to the tripping of a system component and may last up to 1 minute until operator intervention.

The control of voltage is achieved by the following means:

• Control of excitation at relevant generating unit • Control of onload tap changer of stepdown transformers at transmission delivery

points• Switching of reactive compensation devices, eg. capacitor and reactor banks

SDC continually monitors the voltage fluctuation and activates the necessary controlactions to ensure that the voltage limits are within acceptable ranges. Dynamic SystemMonitors (DSM) are located at 4 locations of the System to automatically record anydeviation of voltage.

The control of frequency and time control is achieved by controlling of the gas turbines atBintulu as they are baseload generation and fine control can be effected. By the middle of2003, the Automatic Generation Control (AGC) will be in place to further improve thesecondary control of frequency.

ii. Grid Generation Despatch

To achieve target cost/kwh of energy delivered to the grid system by despatchinggeneration to the SESCO Grid in accordance with the operational practices of theoptimal utilisation of available generation resources.

iii. Power Reliability and Quality

Transmission Delivery Point Performance (TDPP) ≤ 33 system minutesSystem Availability Transmission System Faults < 3 per year

Power Quality(Voltage dip)

Voltage dip incidents beyond SEMI curve recorded at Tg. Kidurong 275kV & Muara Tabuan132kV buses for grid fault

≤ 2 per month

OutageResponse Time

Restoration tiem to EHV substations following aninterruption other than faulty equipment ≤ 30 minutes

Notes:

TDPP is a measure of weighted average supply availability in system minute; onesystem minute being equivalent to one minute of total system supply unavailability.

SEMI : Semiconductor Equipment and Materials International


In accordance with Prudent Utility Practices, preventive measures are in place to prevent andminimise the possibility of system disturbances and supply interruptions. The strategy is toprevent system faults by the maintenance of equipment in tip-top conditions, control of onlinetests on equipment and proper coordination of shutdown activities.

In the case of unavoidable faults, eg due to environment, the strategy is to clear the faults asfast as possible with fast acting protective relays. This will help minimise the impact ofvoltage dips to the customers and avoid the risk of system instability.

As with any power system, faults and supply interruption may still occur. Restoration withthe aid of SCADA system can be done remotely to minimise interruption time to thecustomers. With the exception of equipment failure, the despatch of switching personnel tosite can be avoided, thus saving valuable time in the restoration process.

With the introduction of high tech sensitive equipment and process in industries, voltage dipshave become an issue. Internationally, standards for voltage quality are evolving, the latestbeing SEMI curve which SESCO has adopted as the Standard. The Figure below shows thecomparison between the old CBEMA and ITIC curves with the SEMI curve.

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

1 1 0 1 0 0 1 0 0 0 1 0 0 0 0 1 0 0 0 00

T im e in m s

% R

ated

Vo

ltag

e

IT IC C B E M A S E M I

Notes: ITIC: Inform CBEMA: Co

SEMI Curve as compared to CBEMA, ITIC curves

18

ation Technology Industry Councilmputer Business Equipment Manufacturers Association


iv. Asset Management

a. To improve and maintain the reliability of major transmission equipment so as to meet the following targets:

EHVEquipment

Type ofOutage

Outage Rate MeanOutage Duration (min)

DurationFactor

Forced < 2.00 per 100cct.km < 100Lines

Planned < 1.00 per 100cct.km < 500Forced ≤ 0.40 per 100 MVA ≤ 580 ≤ 0.06 %

TransformersPlanned ≤ 0.76 per 100 MVA ≤ 580 ≤ 0.2 %

b. To improve and maintain the availability of supporting equipment and facilities so as to meet the following targets:

Division Type of Equipment Reliability

Protection Protection system ≥ 90%

Division Type of Equipment Availability MTTR

Communication

Pilot Cables systemPLC/FO systemPABX/PAX System

≥ 99.9%≥ 99.9%≥ 99.9%

≤ 4 days ≤ 3 days≤ 1 day

SASSCADA Master StationSCADA RTU System

≥ 99.8%≥ 99.6%

≤ 1 day≤ 1 day

Note: MTTR: Mean time to repair

19

c. To increase asset turn from 0.18 to 0.26 by 2005 through improving asset utilisationwith improved value for money from capital expenditure.

d. To achieve value creation for the department in excess of WACC of 6% per annum.

e. To improve and achieve target labour productivity.


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6. SYSTEM PERFORMANCE

The Transmission System has been built with the help of internationally experiencedConsultants and reputable Contractors in accordance to international standards and practices.Local statutory and safety requirements are strictly adhered to at all phases of theimplementation in all components of the Transmission System.

Over the years, SESCO Transmission Department has acquired the technological knowledgeand skills to carry out the planning, design, operation and maintenance of the System. PrudentUtility Practices are adopted at all times to ensure delivery of best performances of theTransmission System at all times.

The performances of the various components of the Transmission System are shown in thefollowing tables:

i) Power Quality

Frequency Controlled by Bintulu Power Station to be within ±0.5 Hz

Time Control Within ±10 seconds.

Voltage Dips Information obtained from the Dynamic System Monitor (DSM)shows target of less than 2 times per month had been achieved.

SESCO had carried out a number of studies on Power Quality (PQ), the most recent one doneby Energex (Queensland, Australia) in 2000. From the 4 years of record at Muara Tabuan S/Swhich is the transmission delivery point to Samajaya Free Industrial Zone in Kuching, therewere 46 voltage dips recorded, averaging 0.95 dips per month. Out of these incidents, 24 didaffect the customer in some way.

Impact Analysis for 1997 - 2000 Major Events Based on MUTB 33 kV Voltage

0

10

20

30

40

50

60

70

80

90

100

10 100 1000 10000

Duration ms

Volta

ge %

Customer Affected No Impact CBEMA SEMI


It can be noted that although some voltage dips were within the SEMI curve, the customerswere still affected, demonstrating that some customers’ equipment could have been moresensitive that expected. The strategy would be for the customer to make his equipment lesssensitive to voltage dips while SESCO will work toward a better voltage conditions.

Cost effective solutions can often achievable through collaborative efforts with customers.

DESENSITISECRITICAL LOADS

[Customer Side)

APPLY CUSTOM POWERSOLUTIONS [Either Side

of Metering Point]

REDUCE NUMBER OF FAULTS (System side)

0

20

40

60

80

100

10 100 1000 10000Duration Milli-Seconds

Vol

tage

%

SEMIS

ES

Co

Vol

tage

Con

ditio

nsC

usto

mer

Sen

sitiv

ity

Figure 10: Strategy to mitigate voltage dip problems

Common solutions to PQ (voltage dip) problems

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On the system side, SESCO had adopted a number of solutions to improve the levelof PQ performance, eg:

• Carry out intensive maintenance programs to minimise number of faults in thetransmission and distribution systems

• Reduce the impact of faults on sensitive loads by reconfiguring the systemwherever possible

• Reduce the impact of faults by reducing the fault current and expediting the faultclearance

• Maintaining extensive database of cause and effect relationships for analysis andcorrective actions

• Providing more baseload generation in Kuching whenever required

ii) Power Reliability

a. The Transmission Delivery Point Performance

Year 1997 1998 1999 2000 2001

TDPP (system minutes) 170.99 9.35 77.33 49.04 1.65

b. The average number of total 275kV and 132kV Transmission Line Trippings is28.2 per year.

Year 1997 1998 1999 2000 2001

Trippings 22 19 17 53 30

The above figures consist of all trippings due to transient faults, eg lightning andvegetation faults, non-line faults eg. substation equipment / relay failure, humanfactors. Efforts had been made to reduce all these faults by replacing faultyequipment, conducting reality checks and enforcing strict procedures for online tests.

iii) Power Restoration Time

Year 1997 1998 1999 2000 2001

Incidents < 45 minutes 4 1 1 4 5

Incidents > 45 minutes 0 0 2 5 0Notes : Outages restored above 45 minutes were mainly due to equipment failure orpermanent fault. From 2001 onward, the target of 45 mins was reduced to 30 mins.


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7. DEVELOPMENT OF SESCO TRANSMISSION SYSTEM

7.1 System Development

The demand in the Grid will continue to grow in the years ahead. The growth expected forthe next five years is as follows:

Year Peak Energy (MW) (GWH)

2002 605 3702 2003 669 4098 2004 720 4458 2005 771 4775 2006 834 5133

There are currently projects being implemented to increase the capacity of the System to caterfor future needs. The main ones are;

• Betong 275/33kV 10 MVA Teeoff Project commissioned in October 2001, providing aninjection point to Betong and Saratok areas and alternative supply source to Sri Aman

• Bintulu - Tjg Kidurong 132kV 120 MVA Transformer Feeder Project scheduled to becommissioned in May 2002, providing a bulk injection point to the Tjg. Kidurongindustrial areas in Bintulu.

• Oya – Salim 132kV 80 MVA Transmission Project scheduled to be commissioned by2003, providing a bulk injection point to the Salim / Upper Lanang areas in Sibu

• Matang – Batu Kawa 132kV Transmission Line Project scheduled to be commissioned inearly 2002, providing supply to the new township at Batu Kawa in Kuching

• Kemena 275 kV Substation Project scheduled to be commissioned by 2004, providing anew injection point to the Kemena Industrial Zone and a future connection to Bakun

To enhance the operation of the Grid System, the following projects are also implemented:

• Lightning Tracking System scheduled to be completed by March 2002, providingadvance warning system for the SDC despatchers

• SCADA based optimisation and training/simulation applications, consisting of EnergyManagement System (EMS), Power Network Application (PNA) , Automatic GenerationControl (AGC) Operator Training Simulator (OTS), these will be completed in stagesbefore middle of 2003, providing increased capability to SDC despatchers andenhancement to the overall operation of the Grid System

• Fibre Optic Channels to 33kV Substations, scheduled to be completed in stages, by Dec2002, extending the LAN network and providing communication channels for digitalfeeder protection systems.

• Upgrading of PAX Network, scheduled to be completed by 1st Quarter of 2002, providinghigh speed links and solving the network congestion at Mambong substation.

• Implementation of the Enterprise Resource Planning (ERP) packages, scheduled forcompletion by middle of 2002, providing computerisation of value-based management,asset management, project development, materials and work management


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7.2 Future Plans

To keep pace with Sarawak’s rapid development and growing demand for electricity, SESCOcontinues to expand the State Grid System. SESCO is committed to a long term multi millioninvestment program to develop the transmission infrastructure to meet the customers’ futureneeds.

Some of the plans in the pipeline are:

• Integration of the System with the 2400MW Bakun Hydro-electric Project, expected tobe operational by 2006 and an associated connection with Sabah Electricity Supply Board(SESB) system

• Additional circuits to increase capacity and reliability of supply to the Kuching system

• Reactive power compensation in Oya and Mambong to increase power transfer capabilityand improve voltage support

• Additional EHV Substations to provide bulk injection points to the regional distributionsystem

Some of the other works which the Transmission Department are involved in are:

• Development of the State Grid Code, in conjunction with the State Government

• Feasibility study of the fibre optic connection from Sarawak to Peninsula Malaysia


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8. TECHNICAL RESOURCES AND SERVICES AVAILABLE

SESCO Transmission Department is prepared to share its experiences and expertise in thefollowing areas with SESCO customers. Technical training, field services and consultancyservices can be arranged upon request.

i. Grid System Operation Division

• Power System Analysis• Operational Planning• Generation, Transmission and distribution outage coordination• Dynamic System Monitoring• Issues related to quality and reliability of supply• Large customer connection• Contingency plans• Monitoring of system

ii. Substation Operation Division

• Maintenance of EHV Switchgear, transformer and ancilliary equipment• Diagnostic test on power equipment• Oil filtration• Project design, management, supervision and commissioning• Asset Management• Safety and Competency

iii. Transmission Line Operation Division

• Maintenance of EHV Transmission Lines• Project design, management, supervision and commissioning• Emergency tower response

iv. Protection, Control and Instrumentation Division

• Fault level calculations• Relay coordination• Design, management and commissioning of PCI systems• Testing of relays• Troubleshooting on PCI systems

v. Substation automation and SCADA Division

• Provision of monitoring and control facilities• Design, management and commissioning of SAS facilities

vi. Communication Division

• Provision of communication channels and network• Design, management and commissioning of communication systems


9. TRANSMISSION DEPARTMENT MANAGEMENT TEAM

William Chin Thien PohHead (Transmission)Tel: 082-491360Fax: 082-444633E-mail: [email protected]

Ong Ngiok SiangActing Manager(Communication)Tel: 082-491361Fax: 082-444633E-mail: [email protected]

Jason Eng Yeon KhiangManager(Grid System Operation)Tel: 082-491340Fax: 082-444633E-mail: [email protected]

Jong Chin ChyuanManager(Substation Automation and SCADA)Tel: 082-491350Fax: 082-444633E-mail: [email protected]

Philip Lim Tiong HuiManager(Transmission Line Operation)Tel: 082-491321Fax: 082-444633E-mail: [email protected]

Mok Yuk BioManager(Substation Operation)Tel: 082-491310Fax: 082-444633E-mail: [email protected]

Chung Koi MainActing Manager(Protection, Control andInstrumentation)Tel: 082-491370Fax: 082-444633E-mail: [email protected]

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SESCO TRANSMISSION SYSTEM INFORMATION BOOKLETs3.amazonaws.com/zanran_storage/ · SESCO TRANSMISSION SYSTEM INFORMATION BOOKLET ... (EHV) Transmission brings about many benefits to