Research On Lightning Wave Measurement Technology Of Transmission Line Based On Capacitance Dividing Principle

Lightning strike has become the main cause of power system transmission line failure and affecting the stable operation of power system.With the increasing of the installed capacity of power system and the voltage level of transmission line,the impact of lightning disaster on the operation of power system and transmission line becomes more and more obvious.At present,there is no effective method for lightning monitoring of overhead transmission lines,which can not accurately obtain the lightning voltage waveform data,which is not conducive to the analysis and judgment of lightning accidents.Good lightning monitoring of transmission lines can minimize the losses caused by lightning strikes,provide basis for fault analysis and emergency repair of transmission lines,enhance the stability of power system operation,and provide original data for scientific research of lightning,and then do a good job in lightning protection.In this paper,based on capacitive voltage divider sensor,a non-contact measurement system for lightning surge overvoltage is studied.In this paper,based on the equivalent circuit of sensor and matching circuit,the basic principle of capacitive voltage divider is introduced in detail.The simulation is carried out by PSPICE circuit simulation software,and the main factors limiting the bandwidth of the measurement system are analyzed.The bandwidth of the measurement system is improved through the special sensor structure design and optimization of the arrangement of the elements of the calculus circuit.Finally,the measurement system is determined Parameters in the system.In this paper,a calibration platform is designed for the non-contact measurement of lightning wave overvoltage measurement system in the laboratory environment.Based on the programmable arbitrary function generator to calibrate the sensor,the flatness of the sensor is within ± 3d B in the range of 50 hz-1mhz.The square wave calibration test in time domain based on high steep front pulse source can complete the measurement of pulse signal.The calibration test of simulated lightning wave is completed based on the standard lightning wave impulse platform,and the output waveform of the measurement system coincides with the standard lightning wave.The experimental results show that the measurement system designed in this paper has good response characteristics,high measurement accuracy,and can meet the requirements of lightning wave measurement.