Study and Analysis of Switching Transients in High Voltage Transmission Line from Barapukuria to Bibiyana of Bangladesh

Energizing or de-energizing of a transmission line creates switching-transients that travel along the line following switching. The switching transient over-voltage will reach its highest levels at the transition points connecting an underground cable to an overhead line. The transient over-voltage exceeds the nominal voltage of the system and get transmitted to the lower voltage levels. The magnitude of the transient over-voltage has to be limited to avoid exceeding substation equipment surge ratings. Without such limits, the overvoltage may cause damage to the system protective devices. This paper reports a study on transient over-voltages associated with closing a breaker to energize 400 kV single circuit and 400-230 kV double circuit from Barapukuria to Bibiyana high voltage transmission line in the Bangladesh power system. PSCAD simulation tool has been used for this analysis. The main objective of this study is to find the main reasons for the switching transients and to provide some recommendations to minimize the switching transient's overvoltage.