The Fault Location Of Tree Form Distribution Network With Distributed Generation

Fault location of distribution network with multi-generation is of great significance to exclude the fault and improve the power supply reliability.But it is difficult to realize due to its multiple branch structure.The distributed power generation technology has developed rapidly for its strengths such as high cleanliness,low energy consumption,high flexibility.Operation of grid connected distributed generations changes the single-supply and radial topology of the distribution network and makes power flow uncertain,which causes accurate fault location more difficult.How to realize the accurate fault location becomes the key problem in multiple branch distribution networks with distributed generatinons.After analyzing the three phase parameters model of electric line,fault circuit and distributed generator model,based on traditional impedance method,a fault locatiion equation is established by use of phase component method.The influence of two cases on the fault location results of traditional impedance method under the condition of DG access and dispersed load access is theoretically analyzed.The fault location result obtained by traditional impedance method is affected by grid connected distributed generations and grid connected dispersed load.In view of above problems,distribution network is analyzed which is configured measurement units in power side,including head end of feeder and DG node.Firstly,DG and load in the faulty circuit are transformed to the injection current and impedance model respectively,therefore,the three-phase fault equivalent network is obtained.Then,in the base of distribution network partitioning,the fault location equation is obtained by analyzing network after the fault point with and without distributed generation.Finally,based on the above,the objective function is constructed and the fault position ratio coefficient for each branch is calculated based on genetic algorithm,so that suspicious fault branch is determined.The simulation results indicate that the algorithm is affected by transient resistance and load in the condition of network after the fault point without distributed generation,and the fault location accuracy is lower than the condition of network after fault point with distributed generation.In addition,the result of fault location is affected by the parallel branch.In the context of big data,information interaction is becoming more and more common and the synchronous measurement technology between different places is also in constant development.Distribution network is analyzed which is configured measurement units in head end of feeder,DG node and load node.To reduce the large amount of computation of node impedance matrices,fault branch is processed via current displacement to remove the fault point and the three-phase fault equivalent network without fault point is established.Based on the measurement of feeder head node,DG node and load node,fault location equation is derivated,and a road-tree-based fault location method is proposed,which avoids traversal operators in branches.The objective function is constructed and solved by genetic algorithm to achieve fault location.The simulation results indicate that the proposed road-tree-based fault location method is accurate when the fault transient resistance,fault location,and fault type changes.It has high location precision,when locating fault point on the fault branch,the result is also not affected by the change of fault condition,the fault location accuracy is high.