A review of switching overvoltage modeling in UHV AC transmission lines

This review article on switching overvoltage modelling in UHV AC Transmission lines, provides a state-of-theart analysis of switching overvoltages and their impact on insulation coordination in UHV AC transmission lines. Switching overvoltages, insulation coordination, switching transient modelling tools, and switching surge flashover rate mathematical models are examined in the paper. It also examines modelling concepts, transmission models, insulation coordination for Ultra High Voltage (UHV) versus Extra High Voltage (EHV) lines, simulation scenarios and platforms, and best practices for insulation coordination limited to transmission lines. The methodology involved extensive research, consulting academic journals and conference papers, and modelling switching overvoltages with a case study. Key findings show that transmission tower insulation decreases because actual switching overvoltages take longer time to reach their peak than the critical wave. Every switching action generates a switching overvoltage with a characteristic waveform, which impacts insulation coordination. The work reveals a gap in existing research, which often focuses on overvoltages generated by a few switching events. This review suggests considering overvoltages from primary switching operations for better assessment of insulation coordination. These aspects must be considered in insulation coordination to improve UHV AC transmission line reliability and security.