Research On Power Supply Reliability Evaluation Of Distribution Network With Flexible Loads

In recent years,due to the increasingly serious environmental and energy issues,distributed generation technology and electric vehicle technology have been developing rapidly,so more and more distributed power and electric vehicles are connected to the distribution network.On one hand,randomness is the common ground of distributed power and electric vehicle charging,which will affect the power supply reliability of distribution network,and the distribution network power supply reliability is directly related to the life and production of electric users;on the other hand,with the development of the smart grid,part of the traditional rigid load gradually to show flexibility.Therefore,it is necessary to study the power supply reliability of distribution network with various factors.This paper summarizes the principles and advantages and disadvantages of the existing distribution network reliability evaluation methods.A distribution block reliability evaluation method is proposed based on summarization.This method partitions the system according to the nature of switches when the distribution network fails.According to the number of switches between feeder and load switches,the network is automatically partitioned by using the optimization numbering method,and the virtual switches and virtual loads are added to the system to simplify the process.The advantage of this method is the same block have the same load indexes,so it can be used as the unit reliability block fault enumeration.This method not only ensures the computational accuracy,but also improve the calculation speed.This method is used to calculate the reliability of the RBTS example,and the correctness of the method is verified.In this paper,the flexible load is divided into three categories:source load,source-load load and controllable load.Select the typical representative of three types of load to analyze their influence on the power supply reliability of distribution network.The multi states of source load and source-load load model is founded base on the mathematical model of Weibull Markov model.This model can reflect the random characteristics of the two kinds of load,also has advantages of accurate calculation of the analytical method.This model is used to simulate and analyze the influence of two types of load access capacity and position on the power supply reliability of distribution network.At last,the reliability index of power distribution network with different factors with flexible load is calculated,and the relevant conclusions are obtained.