Switching over-voltages in UHV systems.

Abstract: Switching overvoltages (SOV) are of concern in transmission networks operating at Ultra High Voltage (UHV) levels. This paper addresses the switching transients when a long UHV line (1200 kV) is charged. The highest switching transients occurring due to the closing/reclosing of the circuit breaker connecting the transmission line were computed using the Electromagnetic Transients Program (EMTP). Statistical analysis was performed to obtain the peak magnitude of SOV’s occurring on the transmission line. The overvoltage profile along the transmission line, when the system is provided with protective measures like pre-insertion resistors and surge arresters, are compared. The results of the study discussed in this paper show that pre-insertion resistors along with surge arresters provided at transmission line ends are capable of reducing the SOV’s on a UHV transmission system, within acceptable levels.

This paper was published at National Conference on High Voltage Engineering and Technology, 2017 held at Central Power Research Institute, Bangalore on 25th Jan 2017.

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