Load frequency regulation by de-loaded tidal turbine power plant units using fractional fuzzy based PID droop controller

Abstract

This study presents a model to analyse and simulate tidal power generation for hybrid power system in the presence of highly infiltrated tidal units. The response of the hybrid system may be at risk without suitable frequency enhancement techniques. The complete load frequency model is a combination of conventional automatic generation control (AGC) and automatic voltage regulator (AVR). AVR is employed to keep the output voltage magnitude of conventional generator at a particular level. The purpose of integrating AGC with AVR is to maintain the equilibrium between system’s generation and load as well as to keep the frequency of system within suitable range. Owing to inclusion of nonconventional sources, the total inertia of the power system is eventually diminished. Conventional PID droop controller demonstrates inefficacy in diminishing the frequency deviations due to slow controlling action. This research proposes a fractional order (FO) fuzzy PID droop in de-loaded area to improvise the frequency excursion over fixed/Fuzzy PID/PID droop controllers. Imperialist competitive algorithm (ICA) is employed to tune the parameters of the controllers. ICA optimized fractional order PID droop control strategy unveils best performance (settling time = 11.65 s, undershoot amplitude = 0.26pu, performance index = 0.072e−6) over the integer order fuzzy PID control (settling time = 12.02 s, undershoot amplitude = 0.278 pu, performance index = 0.189e−6) and PID droop control (settling time = 30.68 s, undershoot amplitude = 0.95 pu, performance index = 0.215e−6). Examination of dynamic responses for abrupt changes in load request divulges the pre-eminence of proposed droop controller strategy with others controllers. The comprehensive study carried out in this paper implies that ICA optimized controller operates properly and has proven its robustness for ±10% variations in system parameters and physical constraints (Generation rate constraints, governor dead band, and time delay). This study also analyses the effect of tidal power plant contribution in the frequency regulation by inertia, primary and secondary frequency control.