Protection of gas-insulated substations including corona and ohmic losses

The present paper discusses the simulation of a power transmission system, where a ZnO arrester is connected either at the power cable/GIS junction or across the transformer, whilst also considering the effect of line and cable losses. The line losses are corona losses due to corona discharges and ohmic losses in conductors and earth return paths. The cable loss is ohmic loss due to the skin effect. The line and cable are simulated by dividing them into a number of equal sections and each section is represented by a lossless line in cascade connection with a discrete element network to simulate the losses within the section. Computed lightning overvoltage waveshapes at the power cable/GIS junction and across the transformer with and without the arrester are presented and discussed