Project: CREZ Series Capacitors
Client: Alstom Grid
TGS performed a comprehensive sub-synchronous interaction (SSI) analysis to assist a leading manufacturer in their bid to provide series capacitors for the CREZ project. The series capacitors were located in an area containing a large number of wind farms. TGS evaluated the risk of sub-synchronous interactions between the wind farms and the series capacitors, and proposed a novel network based sub-synchronous interaction mitigation method.
The main challenge in this project was the large number of wind farms and the large number of series capacitor locations that needed to be studied. TGS’s dynamic phasor based small signal stability program TGSSR was used to systematically identify the problematic locations and contingencies in a very short time. Another challenge in this project was to propose an SSI mitigation method without by-passing the series capacitors, tripping the wind farms or modifying the wind farm controllers. This was achieved by strategically placing an SSI damping controller equipped SVC. The Eigen properties provided by TGSSR were used to select the best location for the SVC, the best input signals for the damping controller, and tune the damping controller.