杂散电容对EVT传感性能影响研究

摘要

The accuracy of the electronic voltage transformer is affected by the stray capacitance. The mathematical model of 10 kV electronic voltage transformer was established to analyze the influence of stray capacitance on its sensing characteristics, and the simulation study was carried out under IEC60044-7 standard. The results show that the influence of stray capacitance on REVT makes the reliable bandwidth of the transformer 100 kHz,and the amplitude-frequency characteristic of the sen-sor model in 100 kHz follows the state. The phase-frequency characteristics of the sensor model meet the phase agreement;the larger the stray capacitance to LEVT,The greater the error;the larger the CEVT secondary divider resistor value is, the worse the transmission characteristics and bandwidth smaller. A reasonable choice of resistance values, can be modified CEVT transient characteristics. The presence of stray capacitance causes the secondary output voltage to decrease.%电子式电压互感器的精度会受杂散电容的影响。通过对10 kV电子式电压互感器建立数学模型,分析杂散电容对其传感特性的影响,在IEC60044-7标准下进行仿真研究。结果表明杂散电容对REVT的影响使得互感器的可信带宽为100 kHz,传感器模型在100 kHz内的幅频特性呈跟随状态,其相频特性满足相位一致；在LEVT中对地杂散电容越大,误差就越大；CEVT二次分压电阻的取值越大,其传变特性越差、带宽变小。合理选择电阻值,可以修正CEVT的暂态特性。存在杂散电容会使得二次输出电压变小。