GIS局部放电定位的频域时差读取方法

局放(PD)源定位通常依赖于局放信号时域波形获取时差,然而,当信噪比(SNR)很低或者PD信号的初始脉冲较小时,难以获得PD信号的起始脉冲时间.笔者摒弃对时域PD信号分析,结合GIS中电磁波的传播模式特性,通过FFT变换将时域波形转换为频域PD信号进而在频域研究,提出一种精确获取时差的新算法.采用时域有限差分法(FDT...

Method of Time Difference Reading Based on Frequency Domain for PD Location in GIS

The time difference of a UHF partial discharge(PD)signal for PD location is always calculated from the time domain waveforms,however,when the signal to noise ratio(SNR)is low or the initial pulse of the PD single is small,it's difficult to obtain the arrive time of the initial pulse.This paper proposes a new algorithm for achieving the time difference,which is combined with the characteristics of EM-wave modes in GIS and changes the PD signals from time domain to frequency domain by using fast Fourier transformation.A simulation model is built by the finite-difference time-domain(FDTD)method for obtaining the theoretical time difference of PD signals and analyzing the anti-interference ability of the new algorithm.On the experimental GIS model both internal and external antennas are used to obtain the time difference of real PD singles so as to analyze the internal factors of impacting PD location. Simulation and experiment indicate that the proposed algorithm can obtain the time difference of PD signals in GIS with strong anti-interference ability.