内绝缘参量对电容式电压互感器计量精度的影响分析  

Measurement Errors of Capacitor Voltage Transformer With Different Internal Insulation Parameters

作　　者：杜林[1] 陈斌[1] 陈贤顺[2] 张福州[2] 李永森[1] 冉鹂蔓 

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044 [2]国网四川省电力公司计量中心,四川省成都市610045

出　　处：《电网技术》2016年第12期3958-3965,共8页Power System Technology

基　　金：国家创新研究群体基金项目(51321063)~~

摘　　要：在电容式电压互感器(capacitive voltage transformer,CVT)运行过程中,温度、受潮、电容芯子击穿等将导致CVT电容绝缘参量变化,从而改变电容分压器的分压比,引起CVT的计量误差。建立计及绝缘参数的CVT等效模型,研究多节CVT计量精度的影响规律。通过仿真分析,得到多节CVT计量误差随电容分压器等值电容和介损的变化规律,并搭建CVT计量误差试验平台,通过试验对理论分析和仿真结果进行验证。研究结果表明,多节CVT绝缘特性的变化将对其计量精度产生较大影响;电容变化主要影响CVT测量"比差",介损变化主要影响CVT测量"角差",当"低压臂电容"的等值电容增大0.22%时,比差变化-0.2%,介损增大0.20%时,角差变化4.8';电能计量误差会随CVT"高压臂电容"的等值电容和介损增加向"正方向"增加,随"低压臂电容"的等值电容和介损增加向"负方向"增加。In daily operation of capacitor voltage transformer（CVT）, temperature, moisture, dielectric breakdown etc. will change CVT＇s insulation parameters, resulting in ratio change and causing additional measurement error. This paper aims to build a more accurate model incorporating insulation parameters of voltage divider to characterize CVT. Relationship between CVT＇s measurement error and insulation parameters（dielectric loss factor and equivalent capacitor） is obtained with software simulation. Extensive experiments verify theoretical analysis and simulation results. It demonstrates that insulation parameter variation exerts an obvious effect on measurement error. Capacitance change mainly affects magnitude error and dielectric loss change mainly affects phase error. Capacitance change 0.22% can cause magnitude error -0.2% and dielectric loss factor change 0.20% can cause phase error 4.8＇. Increase of equivalent capacitance and dielectric loss in high voltage capacitor will cause positive error in electric energy measurement, while this increase in low voltage capacitor will cause negative error.

关 键 词：电容式电压互感器 电容分压器 绝缘参量 等效模型 计量误差 

分 类 号：TM45[电气工程—电器]