Combined control of voltage and frequency of multi-area multisource system incorporating solar thermal power plant using LSA optimised classical controllers

This study presents the combined model of automatic load frequency control (ALFC) and automatic voltage regulator (AVR) of a multisource multi-area system for control of voltage, frequency and tie-line power. Each area comprises of a solar thermal, thermal and diesel plant. A more realistic system is studied by considering generation rate constraint and governor dead band (GDB) for the thermal plant. Integral (I)-double derivative (DD) controller with derivative (D) filter (IDDF) is proposed for the combined ALFC and AVR model by considering 1% step load perturbation in area1. The controller parameters are optimised using lightning search algorithm (LSA). The performance of proposed controller is compared with other conventional controllers such as proportional-I (PI), I-D and PI-D. The analysis reveals that the proposed controller outperforms the others in terms of settling time and peak deviations. The comparative performance of various performance indices shows that integral squared error is better than others. Analysis of the effect of GDB with IDDF controller and LSA indicates that the presence of GDB leads to more oscillations in the system dynamics. The sensitivity analysis against the change in magnitude and position of disturbance derived the robustness of the IDDF controller parameters obtained at nominal condition.