Research On Relay Protection For Distribution Network With Distributed Power Source

With the rapid development of social economy,energy waste and environmental pollution problems are more and more serious.In order to enhance energy efficiency and improve energy structure,prevent the depletion of fossil fuels,reduce environmental pollution.Therefore,distributed power has become a focus of research in many countries of the world,It is combined with the power grid has become a trend in the power industry.The structure of distribution network is traditional single power supplied radial structure,before distributed power access to distribution network.The structure becomes multiple feed complex structures,after distributed power access to distribution network.Changes in the structure affect traditional relay protection of the power distribution network seriously.This article mainly solves the problems of power relay protection.The first step is analyzed influence of three-step current protection after distributed power access to distribution network,improved setting principle of traditional three-step current protection.Analyzed the influence of dynamic reclosing device and feeder automation device,after distributed power access to distribution network simply and put forward the solutions at the same time.Secondly,put forward coordination optimization method of contains the distributed power distribution network of relay protection based on differential evolution algorithm.On the basis of analyzed the structural change in the system.It presented the calculation method of relay actual action time,established practical optimization model,simulated proposed method with the improved differential evolution algorithm through a numerical example.The results showed that over-current relay coordination optimization model is closer to the actual when considering system structure change.Finally,under the condition of aimed at high DG penetration distribution network,we put forward a kind of intelligent fault location system and protection strategy based on multi Agent technology.This strategy depends on the Agent ? and Agent ? which distribute in different bus node.According to fault current change of distributed power distribution network to find out the location of fault.In the fault area located matrix algorithm,using current amplitude size in multiple node to ensure the fault search due direction;in the fault section positioning located matrix algorithm,using the relationship between fault current and load current phase to search for a particular fault segment.This strategy can locate fault section accurately and has a strong adaptability,selectivity and sensitivity.