一种改进的直测电容电流型电子式电压互感器

An Improved Electronic Voltage Transformer Based on Direct Detecting Capacitor Current

设计了一种改进的直测电容电流型电子式电压互感器,具有体积小、结构简单、无铁磁谐振、绝缘强度高、抗干扰能力强、温度特性好及暂态性能不受高压电容滞留电荷影响等优点。详细分析了互感器的工作原理,提出了互感器的构成方案;利用具有正温度系数和负温度系数的多个电容器串联组成的高压电容器温度补偿方法,有效地提高了互感器的温度稳定性;对互感器的频率特性、暂态性能和抗干扰性能进行了理论和仿真分析。研制了一台10kV电子式电压互感器,进行了准确度、工频耐压及温度试验。仿真和试验结果表明互感器满足IEC 60044—7标准,达到了0.2级测量和3P级保护的要求。

An improved electronic voltage transformer （EVT） based on direct detecting capacitor current is designed in this paper. The EVT offers a variety of advantages, such as： small size, simple structure, no ferroresonance, high insulating strength, high anti-interference capability, good temperature characteristics, and the transient performance is not influenced by the retained charge of the high voltage capacitors, etc. The working principles are analyzed in detail, and the solution of the EVT is designed. The temperature compensation method that employing a number of capacitors half with positive temperature coefficient while the other half with negative temperature coefficient in serial connection to comprise the high voltage capacitor is proposed, which can improve the stability over temperature. The theory and simulation analysis on the frequency characteristic, transient performance, and anti-interference capability of the EVT were carried out. Subsequently a 10kV electronic voltage transformer has been developed. And the accuracy test, power-frequency withstand voltage test, and temperature test were conducted. The simulation and the tests show that the proposed EVT is fully compliant with IEC 60044-7 standard, assuring 0.2 measurement precision class and 3P protective class.