SSR Implication Assessment Using Modular FACTS

The increase of distributed, non-conventional generation requires fast installation and low-cost solutions that improve power systems’ flexibility and reliability. Such a solution is series compensation of transmission lines. Despite its numerous benefits, this solution raises concerns related to Subsynchronous Resonance (SSR). Flexible AC Transmission Systems (FACTS) devices constitute an improved alternative compared to traditional series compensation solutions. However, the risk of SSR when using FACTS devices has not been extensively studied. This paper describes a methodology to assess the risk of undamped Subsynchronous Oscillations (SSOs) inflicted by SSR, when a Modular FACTS device is connected in series to a transmission line. The methodology is based on frequency scanning and on the basic conditions that should be met so that SSR occurs. The results show that the device under study will not increase the risk of undamped SSOs inflicted by SSR for networks that are stable prior to the device’s installation.