Research On Reliability Evaluation Method On Distribution Network With Distributed Generators

With the drawbacks of large-scale centralized power supply mode gradually appear and global energy security and climate change issues are increasingly prominent,distributed generation technology with its cleanliness,economy and reliability and other advantages has been energetically developed.However,the access of distributed generations(DGs)will bring the influence to the power flow,power quality and power supply reliability of the traditional distribution network,which leads to the complexity of the reliability evaluation process of the distribution network.Therefore,the reliability evaluation method of traditional distribution network is no longer applicable to the distribution system with DGs.It is necessary to study the reliability assessment method of distribution network with DGs so as to adapt to the current development trend of distribution network.First of all,this paper summarizes the correlation theory of reliability evaluation of distribution network,and on this basis,studies the reliability evaluation methods of the traditional distribution network,including:Establish the two-state outage model of components;The system failure state is selected by the state enumeration method and the sequential Monte Carlo method;Then,the failure state is evaluated by the core load division algorithm;Finally,the calculation formula of the reliability index under different failure state selection methods is given.Secondly,the distributed generation technology is presented in this thesis,and the reliability evaluation of distribution network with DGs is studied,including:Establish the random output model of DGs and load time series model;analyze the islanding operation status of distribution network with DGs and establish the islanding model;Meanwhile,the synchronous sampling method is used to study the effect of DGs' faults on distribution network;Finally,the overall process of reliability assessment based on sequential Monte Carlo simulation is given.Finally,the proposed reliability evaluation algorithm is implemented on the software platform Microsoft Visual C++ and applied to the IEEE RBTS Bus6 system,and the corresponding examples are analyzed.Use the analytical method and simulation method to evaluate the reliability of the test system.The evaluation outcomes are consistent with manual calculation results,which verifies the correctness of the algorithm and the program.On this basis,connect the DGs to IEEE RBTS Bus6 main feeder F4 system,and set up different research schemes to evaluate the reliability of system with DGs.It is proved that the distributed generation can improve the reliability of the distribution network effectively.And the effect of the DGs' output randomness,its own fault,access location and access capacity on the reliability of distribution network is quantificationally analyzed.