Series capacitors for increased power transmission capability of a 500 kV grid intertie

Two 500 kV series capacitors came on line in Ontario, Canada in 2011 with the purpose of improving transmission capacity in a power interconnector and of meeting rising demands on power transmission within the province of Ontario. The series capacitors are equipped with a novel Fast Protective Device representing an important step forward in series capacitor protection philosophy and technology. The paper will dwell on this as well as on other salient design features of the series capacitors and also highlight their benefits for the functionality of the power system. In particular, the limiting of transient recovery voltage over existing line circuit breakers will be highlighted, as well as the impact on series capacitor design in conjunction with long, inadequately transposed overhead lines.