Methodology for Metal Oxide Varistor design applied to Fixed series capacitor

Abstract

A series capacitor bank includes internal and external events with high energy through the circuit in a transient time; therefore, a series capacitor bank is equipped with a sophisticated Metal Oxide Varistor (MOV) bypass protection system. This paper proposes a sevent steps methodology for the design of MOVs with the highest energy according the transient analysis; in the case study a single-line diagram representation of the studied 220 kV grid; the overhead lines are represented with distributed line parameters in the PSCAD/EMTDC simulations with sources represented as constant voltage sources behind the short-circuit impedances. The reason for having less MOV energy when the Cotaruse bus reactors. For faults on the line side of the fixed serial capacitors and the dummy source contributing to the fault to ground current. Therefore, the MOV energy only depends on the "through fault current" in the series capacitor bank. The maximum MOV energy is 5.97MJ and the fault initiation time is 0.502493 s respectively. In external fault simulations, the post fault capacitor voltages are not symmetrical in wave shape.Besides, the Maximum MOV energy in XC1/XC2 is 23.0MJ; with initiation time and the line circuit breaker auto reclosure time of 0.52s and 1.42s respectively.