GIS very fast transients overvoltage testing using electric field measurements

Abstract

ABSTRACTThe Insulated problem, which is caused by very fast transients overvoltage (VFTO) associated with the switch operation of GIS (Gas Insulated Substations), is becoming increasingly serious. According to the linear relationship between electric field intensity and the voltage of the circuit, in this paper describes a method for measurement of VFTO based on electric field measurement. To measurement of VFTO, the data, which is collected by electric field sensor on basis of the electric field change along with the voltage change in GIS switch circuits, will be used for examining the relationship between electric field intensity and the voltage of the circuit, as well as be used for seeking the experimental best-fit. Then, this paper firstly makes theoretical modeling of VFTO, make numerical simulation calculation. Meanwhile, the response characteristics and the frequency band of the electric field sensor were tested by sine sweep test and square-wave response test. Especially, the sensor has the low-frequency cut-off frequency (<20 Hz) and the high-frequency cut-off frequency (>134 MHz). After that, the paper will carry out the high voltage amplitude measurement experiment. Finally, according to the assessment by building a simulation test platform based on theoretical modeling to measure VFTO, the finding demonstrates that the sensor can measure the very fast transient overvoltage effectively.