Measurement and modelling of Very Fast Transient Current in 220Â kV GIS

This paper focus on measurement and modelling of Very Fast Transient Current (VFTC). Experiments are carried out on a real sized 220 kV class Gas Insulated Switchgear (GIS). A rogowski coil along with a set of optical fiber transmission system is used to measure VFTCs. The experimental results shows that the upper cutoff frequency of VFTC can be up to dozens of MHz and the amplitude of the VFTC can be up to several kA. An improved Toepler model is built and the values of parameters in it is calculated from experimental waveforms. The simulation results can coincide well with the experimental ones.