【摘要】 为研究变压器局部放电测量的频带问题,通过模拟试验测量了放电信号。信号功率谱密度的分析表明, 典型窄脉冲放电信号能量主要集中在≤10MHz。测量系统带宽对放电信号幅值影响的研究表明,带宽≥12MHz后对信号幅值无明显改善,带宽可根据需要选为8～20MHz。更多还原

【Abstract】 During the detection of partial discharge (PD) in transformer, it is necessary to select a proper frequency bandwidth of measu rement for improving quality of the detection. A suggested frequency range of PD measure3ment is presented in this paper. At first, an imitating experiment with typical narrow PD is carried out in an actual transformer. The imitative curren t of PD pulse is input into the winding at different positions, and response at measuring-terminal is detected so that the PD signal can be gained. Then the en ergy region of PD in transformer is studied by analyzing the power spectral dens ity of the signal. It is found that the energy descends significantly over 10 MH z in frequency domain. It indicates that the energy of PD centralizes in the fre quency below 10 MHz. Finally, the effect of frequency bandwidth of measuring dev ice on the amplitude of PD signal is studied. The PD signal is processed by a se ries of low-pass digital filters, so that influence of different measuring devi ces on signal can be simulated. It shows that the amplitude of the processed sig nal has less relationship with the filter when its upper frequency is over 12 MH z. It is presented that the band width of PD measuring device can be 8 to 20 MHz .更多还原