Temporary overvoltages in the Vietnam 500 kV network

This paper investigates the temporary overvoltages (TOV) in the Vietnam 500 kV system. The modeling of transformers, lines and other elements in the Vietnam system is presented. Several events that can produce high TOV levels, such as three-phase load rejections, single-phase opening with the outage of a shunt reactor, the bypassing of a series capacitor or the disconnecting of a transformer, etc., are examined with the help of the EMTP program. Finally, the methods of limiting the magnitude and duration of TOV levels applied to equipment are presented