Subsynchronous resonance performance tests of the Slatt thyristor-controlled series capacitor

A thyristor-controlled series capacitor (TCSC) has been designed, installed, and field tested on the BPA 500 kV transmission system. The Slatt TCSC is a variable series capacitor with high control bandwidth. Field test results demonstrate that this TCSC does not participate in or contribute to subsynchronous resonance (SSR). It is SSR neutral in itself, and it can reduce SSR effects due to other nearby conventional series capacitors.