气体绝缘开关设备中特快速瞬态过电压的全过程测量方法

Measurement Methods of Very Fast Transient Overvoltage in Gas Insulated Switchgear With Complete Process

特快速瞬态过电压(very fast transient overvoltages,VFTO)是超/特高压气体绝缘开关设备(gas insulatedswitchgear,GIS)设计和运行中十分关心的问题,试验研究VFTO的特性是非常必要的。VFTO包含特快速瞬态分量、工频分量和准直流分量(空载母线残余电荷电压),其中VFTO的瞬态分量在GIS中以电压波的形式传播,致使不同位置的VFTO波形具有显著差异。因此,试验研究VFTO的关键是对VFTO时间过程和空间分布的全过程测量。研究了VFTO测量方法,采用手孔式电容传感器与阻抗变换器相结合的方法实现了全过程测量,研制出测量频带为0.003 Hz^100 MHz和波形记录时间为200 ms的测量系统;采用多个测量系统,并基于隔离开关触头间隙击穿时的电磁波辐射信号,研制出了同步触发装置,实现了对GIS上不同位置的VFTO空间分布的测量。

In the design and operation of ultra high voltage（UHV） and extra high voltage（EHV） gas insulated switchgear（GIS）,there is a big concern on the very fast transient overvoltages（VFTO）.Experimental investigations are necessary for the full understanding of the VFTO in UHV and EHV GIS.Research was performed in this paper on VFTO measurement method.VFTO includes not only the very fast transient components,but also power frequency component and quasi-DC component（residual voltage in the floating busbar）.Also,the VFTO in different GIS positions have significant different waveforms depending on the propagation and superimposition of travelling waves in GIS.Therefore,the whole process measurement of VFTO,including two aspects of the full time processes and the site distributions in GIS,is required.Based on the port-hole capacitive sensor and an impedance converting circuit,wide frequency band measurement of VFTO was realized;the measurement systems with frequency band of 0.003 Hz^100 MHz and recording time of 200 ms were developed.Synchronous measurement of VFTO in different sites of GIS was performed using several such measurement systems simultaneously;and the synchronous trigging was realized by using the electromagnetic radiation signal generated during the switching operation of the GIS disconnector.