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Study On Reliability Evaluation And Optimal Switching Devices Of Electrical Distribution Networks

Posted on:2006-07-12Degree:MasterType:Thesis
Country:ChinaCandidate:J F WangFull Text:PDF
GTID:2132360182977472Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
This dissertation is sponsored by the project ("Study on Optimal Switching Model and Algorithm for Electrical Distribution Networks (EDNs) Using Immune-Algorithm", No.50307015) of the national natural science fund of China.EDNs are connected directly with customers and have great influence on the quality of power supply(including reliability).It was counted that 80% of the total customer interruptions around resulted from EDNs.So It has become a focus to do research on reliability evaluation of EDNS and its configuration optimization.This paper is mainly as follows:(1) Realizing fuzzy reliability evaluation of medium voltage EDNS. In reliability evaluation the component's reliability parameters such as fault rates and fault repairing time have a big effect on the result of reliability evaluation. However these parameters are typical of imprecision, which makes it reasonable that they should be formulated by fuzzy numbers.This essay analyzes the range's changes and solutions in fuzzy operation and concludes the calculation algorithm of fuzzy numbers in different ranges so that reliability evaluation based on fuzzy parameters is practical. Thus the result of reliability evaluation will be more credible.(2) Based on the fault-spreading algorithm,the iteration algorithm of reliability evaluation for medium-voltage EDNS is presented. There exists much redundant search in the fault-spreading algorithm,which lowers the calculation speed.In terms of this,some improved measures are taken as follows:â‘ the algorithm for the formation of switch-layer tablet is presented.Switch-layer tablet is established before fault enumeration.In the tablet,the backward information,loads for example,of the present switch can be partially got from the switches in the backward layer,which spare much time for backward search;â‘¡according to the switch-fixing information of the fault point and its forward point, various fault modes and loads-classification algorithm based on them are presented,which can avoid forward search and use the information of the known fault sequences and that in the switch-layer.It is explained theoretically that the time complexity degree of iteration algorithm is of 1 rank and that of the fault-spreading algorithm is of 2 ranks.(3) Improved genetic algorithm of optimal switching devices in EDNS is...
Keywords/Search Tags:distribution network, iteration algorithm for reliability evaluation, fuzzy calculation, optimal switching devices, improved genetic algorithm
PDF Full Text Request
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