Ercot experience screening for Sub-Synchronous Control Interaction in the vicinity of series capacitor banks

A transmission expansion project, Competitive Renewable Energy Zone (CREZ), in the ERCOT region will be implemented to deliver wind generation from wind resource areas to load centers. Several extra high voltage transmission lines will be equipped with series capacitors to increase the transfer capability. A SubSynchronous resonance (SSR) phenomenon that can be induced by having a conventional generator radially connected to the series compensated line has been well studied and documented. However, a similar phenomenon, Sub-Synchronous Control Interaction (SSCI) can also be induced between a wind generation resource and series compensated lines. It is important to identify proposed points of interconnection at risk of sub-synchronous control interaction. Identifying and sharing this information can prevent damage to transmission and generation equipment. ERCOT anticipates that control settings can be adjusted to mitigate or avoid SSCI or alternate turbine designs selected for a particular location.