Research On Online Fault Location Method And Device Of High Voltage Power Cable

In our country rely on the cable line for power transmission has become a common phenomenon in real life,with the operation time of cable line growth,due to aging,cable insulation damp,rolling,bending failure caused by external factors are also increasing.The cable lines are basically in the underground,with a certain degree of concealment,when the cable fault occurs,it is difficult to determine the fault position,which requires us to study the cable fault location of cable fault location technology,realize the accurate measurement and fast removal.At present,after the cable power system in the failure fault region is determined by using the line protection system itself,then in the end of the fault line on the electrical parameters of the test and obtain the relevant electrical parameters,finally according to the calculation formula of single parameter method for fault location calculation.The single terminal fault location method because it is easy to be influenced by the fault point of the fault resistance,the positioning accuracy is not high,long distance transmission line orientation to the variation of parameters calculation is complex,basically or by cable operators to the field to find accurate positioning.This paper puts forward a method of line fault location based on the principle of differential current protection and the two terminal fault location method,which has the function of on-line monitoring of transmission line.Line fault occurs,cable fault location system can respond immediately,and then the regional location and fault type on line fault diagnosis application of the principle of differential current protection,according to the measured fault area at both ends of the electrical parameters of application of double terminal fault location method for fault point is positioned accurately.When the hybrid circuit or T type line is used,the method of adding acquisition points can be used to locate and calculate the fault segment,so as to obtain more accurate positioning results.For the practical application of line fault location device,this paper presents a design scheme of fault location system composed of optical transformer,merging unit MU and multi DSP processor.The positioning system developed for the application in the actual power system,has made the judgment of the fault location accurately,the ranging error of less than 1% of the results,and to find the problems in the application process are also summarized,determine the direction of the next work.