利用熄弧后暂态信息测量谐振接地系统的对地电容  

Measuring Method of Capacitance to Ground in Resonant Grounding System Based on Transient Information after Arc Extinguishing

作　　者：薛永端[1] 李广 徐丙垠[2] Xue Yongduan;Li Guang;Xu Bingyin(College of New Energy China University of Petroleum(East China)Qingdao,266580 China;College of Electronics and Electrical Engineering Shandong University of Technology,Zibo 255000 China)

机构地区：[1]中国石油大学(华东)新能源学院,青岛266580 [2]山东理工大学电子与电气工程学院,淄博255000

出　　处：《电工技术学报》2020年第7期1521-1528,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51477184)。

摘　　要：系统对地电容的准确测量涉及消弧线圈容量配置、补偿度调整、故障点残流控制等一系列问题。该文利用谐振接地系统单相接地故障等效电路,分析了故障点熄弧后的电气特征,发现熄弧后暂态过程为消弧线圈电感与对地电容之间的欠阻尼串联谐振过程,可利用其谐振频率与衰减因子等参数计算系统失谐度,再根据补偿电感(含消弧线圈及接地变零序电感)可计算得到系统对地电容或电容电流。该方法的误差与谐振频率、衰减因子及补偿电感的误差有关,但主要取决于补偿电感误差。利用仿真和实际故障数据验证了该方法的有效性与准确度。作为被动测量方法,该方法不需要外加任何专用设备或调整现有设备运行状态,安全性高。Accurate measurement of capacitance to ground of the system involves a series of problems such as capacity allocation of arc suppression coil, compensation adjustment, control of residual current at fault point, etc. By using the equivalent circuit of single-phase grounding fault in resonant grounding system, the electrical characteristics of the fault point after arc extinguishing are analyzed. It is found that the transient process after arc extinguishing is the unde rdamped series resonance process between the inductance of arc suppression coil and the capacitance to ground. The system detuning degree can be calculated by the parameters of resonance frequency and damping factor. Then the capacitance or capacitance current of the system can be calculated according to compensation inductance, which includes zero-sequence inductance of arc suppression coil and grounding transformer. The error of this method is related to the error of resonance frequency, damping factor and compensation inductance. But it mainly depends on the error of compensation inductance. The validity and accuracy of the method are verified by simulation and field data. As a passive measurement method, this method needs no special equipment or adjustment of the operation status of existing equipment, it has high security and provides a new idea for capacitive current measurement of resonant grounding system.

关 键 词：谐振接地系统 电容电流测量 熄弧 暂态 失谐度 

分 类 号：TM930.1[电气工程—电力电子与电力传动]