用于VFTO测量的GIS窗口式传感器

摘要

A capacitive sensor based on the access port in the switchgear is developed for the measurements of very fast transients overvoltages(VFTO) caused by the disconnect operation in GIS. The factors which decide the frequency characteristics of the sensor are discussed. The high frequency response characteristic is decided by high voltage capacitor and its the parasitic inductance, and the low frequency characteristic is decided by the low voltage capacitor and the equivalent impedance of the oscilloscope. The amplitude frequency response and the step response of the sensor were performed. The measurement results indicate the intrinsic response time is less than 1.75ns, the unsettle of the response in the range of 10kHz- 80MHz is within ±1db; The sensor is mounted on a GIS test setup to measure the transients induced by the gap discharge which is used to simulate the disconnector switching operation, the measurement results demonstrate that the sensor is able to measure the transients with ns rise-time successfully.%为了测量气体绝缘变电站中（GIS）开关操作引起的快速暂态过电压（VFTO），本文设计了一种基于GIS手孔的窗口式电压传感器。首先分析影响传感器高频特性和低频特性的各项因素，窗口式分压器的高压臂电感、电容参数主要影响传感器的高频特性，低压臂电容和后级等效阻抗构成的时间常数决定传感器的低频特性。其次测量了该传感器的幅频响应和方波响应，所设计传感器在10kHz～80MHz频带范围内的平直度在±1dB之内，其方波响应的固有响应时间小于1．75ns。最后在实验室进行了VFTO模拟实验，测试结果表明所研制的窗口式传感器可以有效地测量GIs中击穿形成的快速暂态现象。