Analyzing Subsynchronous Control Interactions in Large-Scale Power Systems in Frequency Domain

In this paper, a generic technique is presented to analyze subsynchronous control interaction (SSCI) between Type-3 wind turbine generators and series compensators. The proposed methodology encompasses three steps: 1) Performing a network frequency scan to identify critical wind generators that may experience a network resonant mode. 2) Finding input impedance of critical generators to identify those that are likely to interact with network resonant mode and cause SSCI; 3) Using frequency of critical modes as initial guess to trace them in the full system and find associated damping. This three-step procedure helps automating process of scanning a large number of generators in a SSCI study while minimizing computational burden.