Optimized Interval Type-II Fuzzy Controller-Based STATCOM for Voltage Regulation in Power Systems With Photovoltaic Farm

The intermittent characteristics and high penetration of renewables (such as photovoltaic and wind powers) cause voltage and stability problems in power systems. The static synchronous compensator (STATCOM) has recently acquired attention on account of its ability to regulate system voltages and improve system stability. This paper presents a novel interval type-II fuzzy logic system (IT2 FLS)-based controller, which consists of current and voltage regulators, applied to the STATCOM, to mitigate bus voltage variations caused by large disturbances (such as intermittent generation of photovoltaic arrays). The current regulator is used to produce the phase angle at the voltage-source converter in the STATCOM while the voltage regulator outputs the current reference on the quadrature axis for the STATCOM. The parameters of the upper/lower membership functions and control gains are optimized by particle swarm optimization. A realistic 10-bus distribution system is used to demonstrate the effectiveness of the proposed method. Comparative studies reveal that the proposed method outperforms traditional PI and type-I FLS-based methods.