电容式电压互感器谐波测量误差试验技术

Harmonic Measurement Error Test Technology of Capacitor Voltage Transformer

电容式电压互感器(CVT)被广泛应用于高压系统中的电压测量、继电保护及载波通信等场合。文中研究谐波条件下CVT测量误差的试验分析方法。设计了采用试验用小容量升压变压器提供高压谐波源的试验平台,分析了高压侧谐波电压放大和衰减的原因,通过仿真验证了所得结论的正确性。在此基础上提出了将试验升压变压器更换为大容量普通升压变压器的方案,完成了CVT谐波测量误差的试验。建立了CVT的谐波等效电路并分析了谐波条件下其内部电路的谐振模式,通过理论分析和仿真计算对试验平台的有效性和试验结果的正确性进行了验证。

Capacitor voltage transformer （CVT） is widely used for voltage measurement, relay protection and carrier communications in the high-voltage system. In this paper, the measurement error test method of CVT under the harmonic background is researched. First, a test system using a step-up transformer for testing to provide the high-voltage harmonic source is established. The reasons of harmonic voltage amplification and attenuation on high voltage side are analyzed. On this basis, the reformation project which replaces the experimental step-up transformer with the ordinary step-up transformer is proposed. Then, the harmonic measurement error of CVT is analyzed. The harmonic equivalent circuit of CVT is built and the resonant mode of its internal circuit is analyzed. Through the theoretical analysis and the simulation, the effectiveness of the test platform and the validity of simulation results are verified.