电缆谐振试验中杂散电容对二阶滤波器衰减特性的影响  

Influence of Stray Capacitance on Attenuation Characteristics of Second-order Filter in Cable Resonance Test

作　　者：张玲俐 曾凡辉 张斌 刘明 陈震宇 张炳生 ZHANG Lingli;ZENG Fanhui;ZHANG Bin;LIU Ming;CHEN Zhenyu;ZHANG Bingsheng(State Grid Jiangsu Taizhou Power Supply Company,Taizhou 225300,China;Yangzhou Xinyuan Electric Co.,Ltd.,Yangzhou 225264,China)

机构地区：[1]国网江苏省泰州市供电公司,江苏泰州225300 [2]扬州市鑫源电气股份有限公司,江苏扬州225264

出　　处：《电工技术》2024年第5期189-191,196,共4页Electric Engineering

摘　　要：电缆谐振试验需测量局部放电,为了减小谐振电抗器本体局放的干扰,常在电抗器后端添加二阶滤波器。试验中,向空载的试验设备本体施加80%额定电压,测量经过滤波后的局部放电为3 pC,不能满足小于1 pC的要求。通过仿真计算可知,衰减度主要受滤波器尾端与分压器之间的杂散电容的影响,该杂散电容值越小,滤波器的滤波效果就越好,且随着放电频率(20~300 kHz)的增大,衰减度先逐渐增大后逐渐减小,最后逐步上升并趋于稳定。针对上述结果,通过改变现场滤波器和分压器的布局改变其之间的杂散电容:当滤波器与分压器呈直角排列时,其间的杂散电容为50.9 pF,电抗器的局放为3 pC;而当滤波器和分压器呈直线排布时,其间的杂散电容为36.5 pF,电抗器的局放减小为0.8 pC,满足小于1 pC的要求,该结果与仿真分析结论基本一致。The partial discharge needs to be measured during the cable resonance test.To reduce the interference of the partial discharge of the resonant reactor,a second-order filter is required for strict occasions.In this test,80% of the rated voltage is applied to the no-load test equipment,and the partial discharge after filtering is 3 pC,which cannot meet the requirement of less than 1 pC.Through simulation calculations,it is found that the stray capacitance between the filter tail and the voltage divider has great impact on the filtering effect,as smaller stray capacitances correspond to better filter effect.Moreover,with the increase of frequency(20~300 kHz),the attenuation first increases to the maximum,then after a steady minimizing the attenuation rises gradually and tends to be stable.For the results above,the layout of the filter and voltage divider is changed to reduce the stray capacitance between them.It can be found that when the filter and voltage divider are arranged at right angles on the test site,the stray capacitance between them is 50.9 pF,and the partial discharge of the resonant reactor is 3 pC.However,when the filter and voltage divider are arranged in a straight line,the stray capacitance is 36.5 pF,and the partial discharge of the reactor is reduced to 0.8 pC which is less than 1 pC.This result is consistent with the simulation analysis conclusions.

关 键 词：局部放电 滤波器 杂散电容 衰减特性 

分 类 号：TM83[电气工程—高电压与绝缘技术]