Evaluation of the Transient Overvoltage Stresses on 132 kV Power Transmission Network

Abstract

Lightning over voltage has been a dilemma since the early days of electricity. Lightning mainly occurs on the Overhead Transmission Lines and overvoltage generated due to lightning travels along the line and ultimately reaches to the substation, where this overvoltage can damage the expensive equipment like Power Transformers, Circuit breakers, Isolators, Current Transformers etc. Power System networks in the urban areas mainly consist of Overhead Transmission Lines, High Voltage XLPE Power Cables and Gas Insulated Substations (GIS). The evaluation of the transient behavior of combined high voltage systems consisting of overhead lines, cables and GIS is an important task. In this research work, the complete model has been developed by using PSCAD/EMTDC computer application. The modeling of each component has been done by using the manufacturer’s datasheets/parameters. The transient over voltages have been observed at different points of the power system by injecting lightning current. Surge arrestors have been used to mitigate the over voltages in the system. The outcome of this research would be to improve the insulation coordination of the 132kV Power System in Pakistan.