Mitigating of Sub-synchronous Resonance in a Series-Compensated Hybrid System with Steam and Wind Turbine Using FACTS Controllers

The growing requirement to the clean and renewable energy has led to the rapid development of wind power systems all over the world. With increasing use of wind power in power systems, impact of the wind generators on subsynchronous resonance (SSR) is going more important. The SSR is a well-known phenomenon in a series compensated power systems which can be mitigated with series or parallel flexible ac transmission systems (FACTS) devices. In this paper, wind turbines and steam turbines have been used as a hybrid energy production system. For damping the SSR, thyristor controlled series capacitor (TCSC) as a series FACT devise and unified power flow controller (UPFC) as a series-parallel FACT device have been used. In order to have an optimal control on pitch angle in high speed of wind, a novel method using imperialist competitive algorithm (ICA) has been used. Furthermore, supplementary controllers for UPFC and TCSC have been design and adaptive neuro fuzzy inference system (ANFIS) and fuzzy logic damping controllers (FLDC) are added to these FACTS devises to mitigate the SSR. Finally, the results of two FACTS devises have been compared. Furthermore, the results obtained from imperialist competitive algorithm (ICA) are compared with PID controller optimized by Particle Swarm Optimization (PSO) algorithm.