电容耦合法电缆局部放电带电检测的在线校正  

Online Correction of Partial Discharge On-site Detection for Power Cables Based on Capacitance Coupling Method

作　　者：蒙绍新[1,2] 王昱力[2] 夏荣[2] 杨丹[2] 

机构地区：[1]武汉大学电气工程学院,武汉430072 [2]中国电力科学研究院,武汉430074

出　　处：《高电压技术》2015年第11期3766-3774,共9页High Voltage Engineering

摘　　要：为建立高压电缆高频局部放电带电检测现场在线校正方法,基于高压电缆绝缘接头外置式电容耦合局部放电检测校正回路等效电路模型,通过电缆模拟接头与真型接头的校正试验,分析了带电检测的在线校正与离线校正方法的等效关系及其影响因素;结合实际运行线路超高压电缆接头上的电容耦合法校正比对试验,提出了电容耦合法局部放电带电检测的现场在线校正与灵敏度评估方案。研究结果表明,在线与离线校正等效系数为接头绝缘法兰两侧等效电容与信号注入侧接头等效电容之比,与检测回路阻抗及旁路杂散电容无关;绝缘接头中的局部放电量受接头绝缘法兰两侧等效电容分流及杂散电容影响,现场检测灵敏度为在线校正注入中的最小可检出信号与校正等效系数之积;现场带电检测与校正中,检测用电容耦合传感器的电容值应≥500 p F,并应尽可能接近绝缘环两侧,校正用电容耦合传感器应安装在检测电容外部两侧、且具有良好对称性结构的位置以减少校正误差。In order to establish the online correction method of high frequency partial discharge on-site test for high vol- tage power cable lines, on the basis of equivalent correction model of external capacitive coupling partial discharge detection circuit for high voltage cable insulation joint, we analyzed the equivalent relation of online and offline correc- tion methods for online detection and its influencing factors according to correction tests of simulated and real cable joints. Combining with correction comparison tests of actual operating extra high voltage cable joints based on capacitance coupling method, we proposed on-site online correction and sensitivity evaluation schemes of PD detection based on ca- pacitance coupling method. The results reveal that the equivalent coefficient of online and offiine correction is equal to the ratio of the equivalent capacitance of both sides of insulation joint and the equivalent capacitance of joint on signal injection side, which is irrelevant to the impedance of detecting circuit and the stray capacitance of bypass. The detectable internal PD in insulation joint is affected by the shunting between equivalent capacitance of both sides of insulation joint and the stray capacitance, the detection sensitivity is equal to the product of the minimum detectable signal and correction coefficient in online correction. In the on-site PD detection and correction tests, the capacitance of detecting capacitive coupling sensors should not be less than 500 pF, and sensors need to be arranged as close as possible to the insulating ring on both sides; the correcting capacitive coupling sensors should be installed on the structure which is outside the detecting capacitance on both sides with good symmetry, as it can reduce the correction error.

关 键 词：电缆 局部放电 电容耦合法 等效回路 在线校正 离线校正 灵敏度 

分 类 号：TM855[电气工程—高电压与绝缘技术]