Surge Voltages Induced in Secondary Circuits of 275kV Full GIS

Abstract

The study of surge voltage levels induced in low voltage control or monitoring circuits by lightning surges is very important for the rational design of those circuits in substations. To investigate the induction levels in those circuits, we carried out full-scale lightning impulse tests in a new 275kV full GIS substation. The obtained data clarified that the induced surge levels are under the testing levels of related standards. We analyzed the surge waveforms in the Potential Transformer (PT) secondary circuit by EMTP. The analysis indicated that induced surge levels are almost decided by the ratio of winding and the overvoltage level in a main circuit.