On-line Monitoring Of Cable Insulation In Distribution Network Based On Transmission Characteristics Of Transmission Lines

In the high.voltage power grid,the fault caused by the insulation accident poses a great threat to the reliable power supply of the line,which is an important cause of the fire in the power supply system.At present,the insulation fault diagnosis of high.voltage power supply system is still based on the insulation state detection after power failure,which is seriously inconsistent with the development requirements of intelligent power grid in China.The main research contents are as follows:Firstly,based on the analysis of the operating characteristics of cable lines in distribution network and the problem of on.line monitoring of high voltage cable insulation,this paper puts forward a method of monitoring by analyzing the correlation between grounding line current and database information.Based on the theoretical analysis of correlation degree,on.line monitoring of high voltage distribution network insulation and diagnosis of deterioration types are carried out.Secondly,in order to realize the purpose of monitoring the insulation of the cable tap,the function of the signal detection device installed at the cable tap is discussed,and the relationship between the line current and voltage at the distributed monitoring points is monitored in real time to diagnose the local defects of the line.In this paper,MATLAB software is used to simulate and test the above methods.The results show that the ground current signal noise will not affect the test results,but the voltage and current signal transformers with different precision have a greater impact on the measurement error.Then,this paper designs the software flow chart and function modules of the high voltage distribution network insulation on line monitoring device based on the industrial computer as the core processor,and studies and discusses the corresponding hardware and software of anti.interference measures.Finally,combined with the old cable terminal of some 110 kV substation in Jiangyan City,the research on electrification detection was carried out,and the development of online monitoring and early warning system was completed.According to real.time data,conduct Data analysis and correlation evaluation of the insulation status.The evaluation results are compared with the actual cable insulation state,which verifies the effectiveness of the cable insulation state online monitoring and early warning system and the feasibility of the fuzzy evaluation method.