Improvement of power system transient stability by PV farm with fuzzy gain scheduling of PID controller

Abstract

The extensive proliferation of large photovoltaic (PV) farms in power systems deteriorates both system inertia and synchronizing coupling. Under the occurrence of severe faults, the power system transient stability may be jeopardized. Nevertheless, the fast active power control ability of the PV inverter leads to the possibility of transient stability improvement. This paper focuses on the new application of large PV farms equipped with a fuzzy gain scheduling of proportional-integral-derivative (FGS-PID) controller for transient stabilization of a multimachine power system. The FGS-PID controller is used to control the PV inverter, so that the PV power output can be modulated to stabilize the transient power swing when the faults take place. To obtain the stabilizing performance, the scale factors, membership functions, and control rules of the FGS-PID controller are determined by a bee colony optimization. Simulation study in a two-area interconnected power system exhibits the superior stabilizing effect and robustness of the PV with FGS-PID controller over the PV with maximum power point tracking (MPPT) controller, optimal PID controller, and Ziegler-Nichols tuned PID controller, under various faults, line flows, and solar insolations. In addition, without losing the main function of power generation, the PV with FGS-PID control is able to supply energy to the system almost equal as the PV with MPPT, during stabilization.