Novel methodologies with Fuzzy Logic and ANFIS controller based TCSC for mitigating sub-synchronous resonance and low-frequency power oscillations

The Sub-Synchronous Resonance (SSR) phenomenon may occurs when a steam turbine-generator is connected to a long transmission line with series compensation. Flexible AC Transmission Systems (FACTS) controllers are widely applied to damp SSR and Low-Frequency Oscillations (LFOs). The Thyristor-Controlled Series Capacitor (TCSC) is a commercially available FACTS device developed for damping SSR and LFO. In this paper, two novel control methods for damping SSR and LFO is added to the TCSC main control. The control methods are presented, namely: Fuzzy Logic Controller (FLC) and Adaptive Neuro-Fuzzy Inference System (ANFIS) controller. The suggested ANFIS controller combines the advantages of FLC as well as the quick response and adaptability nature of the Artificial Neural Network (ANN). The ANFIS constructions were trained utilizing the generated database by the FLC of the TCSC. Fast Fourier Transform (FFT) is carried out in order to evaluate the effect of TCSC based ANFIS controller in damping SSR and LFO. The study system was adopted from the IEEE Second Benchmark Model (ISBM) by altering a part of the fixed series capacitor to the TCSC. The MATLAB/SIMULINK software program was used to verify the effectiveness of each control method.