Measurements and Simulations of Very Fast Transients at the Connection of High Voltage Cable with Gas Insulated Metal Enclosed Switchgear

The transient enclosure voltage rise (TEVR) in GIS is caused by very fast overvoltages that occur inside the enclosure during the switching operation, mainly during disconnector operations. TEVR is caused by very high frequency overvoltages (the order of MHz), for which even small inductance of earthing leads can represent significant impedance. The level of TEVR strongly depends on design and length of the earthing leads. Therefore, overvoltage measurements were performed for different earthing leads configurations in 110 kV GIS and results are presented in this paper. The earthing leads configurations were first verified by simulation in the EMTP program.