Research On Fault Location Of Overhead Line Based On Fault Indicator

Since the beginning of the 21st century,especially in recent years,with the implementation of the "13th Five-Year Plan",the State Grid Corporation of China has accelerated the progress of the infrastructure construction of the distribution network and the automation of the distribution network.The investment has been increasing year by year.In the past few years,the construction has been gradually improved,and the number of user outages has also been decreasing year by year.At the same time,the number and duration of user power outages reflected in the indicator of power supply reliability have also attracted people's attention,and the tolerance to power outages is getting lower and lower.The power supply reliability of the power grid has become more and more important in the construction of the power grid,and the importance of power supply quality to the national economy has become more and more prominent.Therefore,how to deal with sudden power failures and how to quickly locate the fault area when a fault occurs,so that repair personnel no longer need to spend time patrolling the line,and achieve the purpose of quickly reaching the fault area and repairing the fault.How to achieve the above-mentioned series of specific requirements is more and more worthy of deep investigation.The distribution network of Juye County in rural areas is mainly 10kV overhead lines.Some lines are too long and old.There are no or few distribution automation equipment on the lines.The daily failure rate is high.Therefore,the failure time To meet the needs of power users,and because the related equipment of traditional distribution automation is relatively expensive,it is difficult to realize the huge investment for the vast rural power grid lines.Therefore,this paper uses a relatively cheap fault indicator as the main object of the fault location method,starting from its fault current detection capability,and through the feature of remote communication,researches on the fault location method by installing a fault indicator.The main research contents of this article are:(1)First,the various grounding methods of the neutral point of the distribution network are briefly introduced,and the applicable range of each grounding method is also distinguished.In addition,the working process of the fault indicator is introduced,and the application of the fault indicator is summarized.Several commonly used fault detection techniques.(2)Based on the research of directed graph and tree in graph theory,an improved directed graph distribution network fault location method is designed.This method divides the overhead line into sections by the complex topological structure of the overhead line and the installation position of the fault indicator,and constructs an association matrix;then,when a sudden fault occurs,the control center receives the fault alarm sent by the fault indicator Information,construct the line current vector,multiply with the correlation matrix to obtain the fault current vector,and quickly determine the fault area through the correspondence between the vector elements and the segments.(3)For the load transfer of the connecting line that is often carried out during the normal maintenance of the line.Different fault indicators are used on the line channel when contacting and transferring.This special device can identify the direction of line fault current,and report different information to the dispatch center according to different directions.There is no need to change when contacting and transferring.The incidence matrix of the line solves the problem of difficult fault location caused by frequent load transfer.(4)The abnormality reported by the fault indicator under normal and fault conditions of the distribution network is analyzed.Use the results of preliminary fault location to compare with various possible fault conditions,and then through the inverse calculation of vector elements,obtain the original current vector of each fault condition,and then perform XOR with the fault alarm information received by the control center Calculate to obtain the difference index,and accurately locate the fault section according to the level of the difference index.The research method in this paper is complete in theory and simple in process.It does not require unified processing of correlation matrices.It only needs to perform simple matrix multiplication and inverse operations.The calculations do not involve big data,and can achieve single power supply and multi-power supply for contact lines.Analysis of single fault and multiple faults under different conditions.The established error correction mechanism has a strong ability to judge and correct the malfunction and refusal of the fault indicator,and has an accurate judgment on the actual fault area on the spot.It can help the maintenance personnel to quickly locate the fault area,and at the same time enable the control personnel to perform There is a practical basis for fault isolation,which has good practicability and application prospects.