Analysis Of Single-Phase Grounding Fault In Distribution Network And Design Of Fault Location Device

In the current distribution network,the main mode of neutral point grounding is the operation mode of arc suppression coil,resistance and non-ground,that is,the center point is not effective(or small current)is grounded.If a single-phase-to-ground fault occurs,the system can continue to run for 1 hour with a fault.However,since the non-fault-to-ground voltage will be increased to a factor of the original level,it is considered that its withstand voltage design value is a phase voltage,and if a long-time operation results in damage to the insulating structure and even a more serious failure.Therefore,The fault point and the fault line need to be locked as soon as possible after the fault has occurred.The fault location method of the distribution network which is more mature is the signal injection method,which has the advantages that the fault point and the fault line are locked as soon as possible.And the positioning accuracy is high.However,the method is still relatively large in faulttolerant capability,automation level,device performance and the like,and needs to be improved gradually.At present,there are 568 10 kV lines in a city distribution network,with a total length of 9475 km.Among them,the length of 10 kV lines in rural power grid has reached 80% of the total length of 10 kV lines in the city,and the scale is still further expanding,and the power supply capacity is also increasing.It can be seen that the agricultural power network is the main part of the distribution network,its coverage area is wide,and there are a large number of branches,so it is more difficult to locate after the failure.In this paper,the fault location principle of the signal injection method is analyzed,and the automatic positioning system is designed for the single-phase grounding fault of the distribution network.The system can accurately and automatically position the fault line.Based on the division of distribution network area,the system uses breadth first algorithm to search and locate the area.Automatic analysis and precise positioning are carried out in the whole network topology.According to the relationship between the location of the remote detection functional elements and the location of the fault occurrence point,an information compensation algorithm is proposed to solve the problem of precise location of the fault without complete and accurate fault information.In order to ensure the accuracy and effectiveness of single-phase grounding fault location in distribution network,this paper uses the scheme of data communication and short message communication to accurately locate the fault of distribution network.