电容式电压互感器二次接线板劣化对预试数据的影响及对策分析  

Analysis of Impact and Countermeasures of Deterioration of Secondary Wiring Blocks in Capacitive Voltage Transformers on Pre-Test Data

作　　者：罗赞琛 卢英俊 宋云祥 覃言 LUO Zanchen;LU Yingjun;SONG Yunxiang;QIN Yan(China Southern Power Grid EHV Power Transmission Company Nanning Bureau,Nanning 530021,China)

机构地区：[1]中国南方电网有限责任公司超高压输电公司南宁局,广西南宁530021

出　　处：《湖南电力》2024年第4期118-125,共8页Hunan Electric Power

摘　　要：电容式电压互感器(CVT)二次接线板绝缘劣化会导致电容分压器介质损耗试验数据误差偏大,还会造成中间变压器绝缘电阻试验不合格。针对此问题,分析介质损耗的基本原理及数字式自动介质损耗仪的测量原理,构建介质损耗测量等效分析电路模型,分析计算正接法、反接法、自激法三种CVT介质损耗试验的误差数据,得到正接法、自激法误差较大,反接法误差较小的结论,据此可指导现场采用最优方法。分析CVT中间变压器绝缘结构特点,提出采用屏蔽法测量二次接线板绝缘电阻或介质损耗,以判断二次接线板绝缘状况,再通过测量中间变压器一次绕组对二次绕组的介质损耗,同时结合二次接线板的电容及介质损耗数据,计算中间变压器绕组介质损耗值,由此可正确诊断中间变压器的绝缘状态。The insulation degradation of the secondary terminal board of a capacitive voltage transformer can lead to large errors in the dielectric loss test data of the capacitive voltage divider,and can also cause the insulation resistance test of the intermediate transformer to fail.To address this issue,the basic principles of dielectric loss and the measurement principles of digital automatic dielectric loss meters are analyzed,an equivalent analysis circuit model for dielectric loss measurement are constructed,and the error data of dielectric loss tests for three types of capacitive voltage transformers(positive connection method,reverse connection method,and self-excited method)are calculated.The conclusion is that the positive connection method and self-excited method have larger errors,while the reverse connection method has smaller errors.Based on this,the optimal method can be guided for on-site use.The insulation structure characteristics of the intermediate transformer in capacitive voltage transformers is analyzed,and shielding method is used to measure the insulation resistance or dielectric loss of the secondary terminal board to determine the insulation condition of the secondary terminal board.Then,by measuring the dielectric loss of the primary winding of the intermediate transformer to the secondary winding,and combining the capacitance and dielectric loss data of the secondary terminal board,the dielectric loss value of the intermediate transformer winding can be calculated to accurately determine whether the insulation of the intermediate transformer is good.

关 键 词：二次接线板 劣化 绝缘电阻 介质损耗 中间变压器 等效分析电路 

分 类 号：TM451[电气工程—电器]