Thyristor protected series capacitor: design aspects

In spring 1998, Southern California Edison required to refurbish some older series capacitors in the Vincent-Midway corridor located near Los Angeles, California, USA in the southwest of the Pacific AC-system tie. Due to the heavy load and AC fault current requirements, it was decided not to establish a conventional MOV and gap protected series capacitor but a new type of thyristor protection. In June 1999, the SIEMENS company were ordered to refurbish an existing capacitor by using a thyristor protected series capacitor (TPSC) as a turnkey project. The project time schedule considered commercial operation by mid April 2000.