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2014 International Conference on Power System Technology (POWERCON 2014) Chengdu, 20-22 Oct. 2014

POWERCON 2014 Paper No CP1268 Page 1/5

Abstract —At present, the foreign softwares are mainly focused

on calculation, analysis and simulation in the grid design field,

which is not designed specifically for the field of distribution

network planning. In addition, there are still large differences

between the foreign demands in developing ideas, applying habits

and the domestic distribution system, resulting in the foreign

analysis software has not been mature applied in the field of

domestic distribution network planning.In China, the distribution

network analysis softwares developed by the software developers

or universities are also not designed specifically for the field of

distribution network planning, which are mainly used for grid

dispatching system or operation system.Inaddition,thesesoftwares

are given priority to with stand-alone mode, not for many people

working together, which are lack of data interfaces with other

application systems.Thesesoftwares are not in practical operationbecause the bad data quality, low commercialization degree, less

innovative and poor practicability. The distribution-network

planning calculation & analysis system is showed as a

professional analysis tool in this article.The system is based on the

reliability of the power distribution network planning concept.All

kinds of algorithms of analysis in the field of distribution network

are integrated in the system which can meet different demands of

distribution network planning.The system achieves the data

interaction with the other application systems by CIM(common

information model) following IEC 61968/61970. The system also

supports two kinds of access mode as the client/server (C/S) and

browser/server (B/S), which can meet the application

requirements of different users.All algorithm modules can well

meet the demands of distribution network reliability evaluation,

quantitative analysis, technical and economic comparison,

planning scheme optimization,and so on.It has been applied in

large scale in practical distribution network planning.The systemintroduced in this article has strong application value which

effectively realizes the function of scientific and lean in

distribution network planning.

Index Terms —distribution network planning power supply

reliabilitycalculationanalysisCIM common information

model

I. I NTRODUCTION

n order to effectively improve the distribution network

planning of scientific and lean, not only requires systematic

and scientific planning processes and methods, as well as

experienced planning engineers, but also need the perfect

calculation&analysis tools of planning to accomplish a lot of

basic data processing and computational analysis, to effectively

improve the efficiency of planning analysis. This article is

based on geographic information system (GIS), the

introduction of distribution network reliability planning

philosophy by the Common Information Model (CIM) as the

messaging standard, developed distribution network planning

analysis software.It achieve many features, as distribution

power flow, short circuit current , security of supply, supply

reliability and distribution network integrated assessment

calculations, etc.The software achieve the quantitative analysis

of distribution network planning.In addition, a typical area isselected to utilize.The obtained results by the software provide

the necessary quantitative data support for the distribution

network planning.

II. DISTRIBUTION- NETWORK PLANNING

CALCULATION&ANALYSIS SOFTWARE BASED ON GIS

A. Technology architecture of the software

1Data interface providing unified access interface for

the various types of data in this platform, it is mainly

responsible for:1)receiving application access requests to

obtain data from the database and 2) return the data according

to the application specification to the application services.

Before the IPDP(integrated planning and design platform) is

running, DPCAS can extract the required data for calculation

from external data sources such as PMS, GIS ,and get data from

the IPDP after its operation.

2Calculation and analysis moduleMainly used to

deploy the core businesses of the calculation and analysis

procedure. All of the application logic components are

encapsulated in the CAM, and can be called as application

services by several applications. Calculation services can be

called by the clients through the service specification while

information dissemination services are mainly responsible for

analyzing the results demonstrated by the B/S client.

3Man-machine interface as the user's applicationsystem, MMI provides accesses to graphical display and a

Research and Development and Application ofDistribution-network Planning Calculation&

Analysis System

WEI Tao1 SU Jian1 LIU Jun1CUI Yanyan1 ZHANG Jun2 LIU Cong2XU Ke2

(1. China Electric Power Research Institute2. State GridTianjin Electric Power Company )

I

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absorbed and integrated the IECCIM model technology so they

and their attribute data could be exchanged better through theirrespective unique signs. With standard data exchange format,

topology data as well as resource attribute data are expressed as

CIMXML while grid graphic data are expressed as SVG.

E. Calculation & analysis module

1) power supply reliability analysis

FMFA (Failure Modes and Effects Analysis method, one of

the analytical methods) is implemented in the DPCAS

reliability analysis module. There are three steps in FMFA. step

1: search all of the components in the system and list all the

possible system states; step 2,according to appropriate criterion

of fault discrimination, find the clusters of fault modes and

establish the corresponding consequences table; step 3, analyzethe relationship between each fault event and its consequence

and acquire load reliability indexes and system reliability

indexes. With simple and clear principles and accurate models

as well as the consideration of failure-post power and voltage

constraints, FMEA is easily applied in the reliability evaluation

of radial distribution system. Calculation principle shown in

Figure 4.

Fig4 The flow of reliability calculation principle

2) power supply security analysis

According to the actual topologies of MV distribution

network, DPCAS is capable of simulating the system situations

under the N-1 shortage conditions and processing operational

requirement check for other equipments to testify the power

supply security. Calculation principle shown in Figure 5.

Fig5 The flow of N-1 calculation principle

3) power flow calculation

Power flow(PF) calculation is aimed to determine the

steady-state parameters of every component according to the

specific operating condition(such as grid structure, the

parameters of generators and loads, generally including the

power of sources and loads, key bus voltage and the amplitude

and phase of the balanced bus voltage.

4) short-circuit current calculation

Short-circuit current level in the distribution network should

be clear when it refers to selecting the switch equipment

parameters or proposing effective measures to limit

short-circuit current.

5) Reactive power optimization calculation

We can know that if the reactive power compensation is

needed in distribution network by reactive power optimization

calculation.We can auto-achieve the installation location of the

reactive power devices by the calculation.The users can choose

the installation location based on actual requirement,they can

also verify the actual result of the compensation by reactive

power optimization calculation.The software can give

suggestion of reactive power compensation for the users to the

low-voltage nodes.

6) Economic evaluationWe carry out economic evaluation in distribution network by

means of three methods,such as “Minimum cost method”,

“benefit/cost method”, “incremental benefit /incremental cost

method”.We can achieve economic evaluation results of

different planning schemes combining with equipment

comprehensive cost, electric price and electric quantity,

reliability rate,line loss rate etc.The users can choose freely

appropriate evaluation method combining with personal

physical truth, and the evaluation result can provide reference

for optimal selection of schemes.

7) Spatial load forecasting

By automatically importingthe electronic map of urban

overall planning, the software can realize the function of spatialload forecasting.We can get forecasting loadfor different plots

by means of setting different calculation parameters.

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8)Other auxiliary application functions

In addition to the above calculation functions,the DPCASalso includes other auxiliary application functions,such

as:automatic statistics network scale,automatic identification

connection mode,analysis of power distance,comparing a

variety of planning scheme,different planning version

management,coloring according to the different

object,automatic generation of single line diagram,automatic

generation of system diagram,checkingautomatically the

network island,checking the data integrity,etc.These functions

provide important technical supportfor our better analysis of

the distribution network planning schemes.

III. APPLICATION EXAMPLES

The DACPS on GIS has been successfully used in a city areadistribution network planning work. The region contains 692

10kV line, about 65,000 nodes.User evaluated the software that

it is practical convenience using advanced technology which

has played a quantitative supporting role in the distribution

network planning. The overall effect size is shown in figure6.

Some of the 10kV lines are modeled topology which are shown

in Figure7.

Fig6 effect diagram of 10kV distribution networkmodeling of one region

Fig7 Schematic of 10kV line topology modeling

Throughout the application process, the use of software on

the 10kV distribution network trends, short-circuit current,

security of supply, reliability etc were quantified. Among them,

in a different grid structure, load distribution, the line length,equipment failure rates and switching time conditions, the

reliability of the system and load points are calculated by

DACPS,which provides the necessary reference for optimizingdistribution network planning program. Table 1 shows part of

the calculation results. From Tab1,we can find that the

reliability of system was significantly decreased as the

increasing in line length, equipment failure rate and switching

time.TAB 1 R ELIABILITY CALCULATION RESULT WITH DIFFERENT CONDITIONS

reliability rate (%) SAIFI(time/y) SAIDI(hour/y)

Line length

(km)

2.6 99.9411 2.47574 5.15639

3.7 99.9393 2.66393 5.55713

5.3 99.9366 1.04021 2.42400

7.5 99.9321 2.84039 5.94804

Equipment

failure rate

(%)

4.9 99.9630 1.55114 3.24446

6.1 99.9539 1.93101 4.03902

8.2 99.9366 1.04021 2.42400

switching time

(min)

50 99.9461 2.59579 4.72286

70 99.9421 2.59579 5.07618

90 99.9366 1.04021 2.42400

Also it can reflect the investment effect on reliability by

DACPS,the result is shown in Tab2.From Table 2, we can find

that reliability rate will be increased with the network

structureenhancing and the reliability cost increasing.TAB 2 R ELIABILITY INVESTMENT RETURNS

Scheme

Total

investment

Ten

thousand

yuan

Reliability

Cost

Ten

thousand

yuan

reliability

rate (%)

average

outage

time

min

Shorten the

outage time

min

scheme 1

Radiation402 — 99.9328 353 —

scheme 2

Increasingsection switches

414 12 99.9441 294 59

scheme 3

Increasing

contact lines

430 28 99.9562 230 64

IV. CONCLUSION

This paper introduces the concept of supply reliability

planning, GIS-based information to develop a distribution

network planning calculation&analysissoftware.It provides a

visual, interactive, quantifiable means of supporting with

flexible service architecture, the standard CIM model exchange,

component design and convenient features on the distribution

network planning.It offer an effective solution to lack of

analytical tools of distribution grid computing, then it can be

applied to promote.

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WEI Tao was born in Gansu Province, China on January, 1976. He received

the M.S. degree in electrical engineering from Xi'an Jiaotong University, Xi'an

City, China, in 2007. Now, He works on China Electric Power Research

Institute as an electrical senior engineer and his special fields include

distribution network planning, analysis and etc. Tel:010-82813449; FAX:

010-82813495; Email:[email protected].

SU Jianwas born in Xinjiang Province, China on January, 1971. Senior

Engineer.Email:[email protected].

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Tao 2014