Optimal Coordinated Frequency and Voltage Control of CCGT-Thermal Plants with TIDF Controller
Satish Kumar Ramoji, Lalit Chandra Saikia
Abstract
This paper deals with unified method of voltage and frequency control of an interconnected three unequal-area systems with the Automatic Load Frequency Control (ALFC) and Automatic Voltage Regulator (AVR) loop. Every area comprises a reheat thermal and the combined cycle gas turbine (CCGT) plant. Concerning the pragmatic system, adequate governor dead band (GDB), boiler system, and generation rate constraint (GRC) are considered in all individual plants. The Tilt-Integral-Derivative with Filter (TIDF) controller is considered in the ancillary controller of the ALFC loops, core controller of the AVR loops, and air-flow, temperature controller of the CCGT Plants. The optimized controller gains are realized through the metaheuristic algorithm called Harris Hawks Optimization algorithm along with the integral square error as a performance index considering a 1% step load perturbation in Area-1. The critical analysis shows that the performance of the TIDF controller is superlative to the classical controllers, such as PI and PID, concerning all time-domain indices. With the TIDF controller, the impacts of the AVR loop, boiler system, and the CCGT plants are analyzed on the unified ALFC and AVR study separately. Sensitivity analysis unveils the sturdiness of the TIDF controller against the change in magnitude of the step load perturbation in Area-1. Finally, the proposed unified ALFC and AVR system of three unequal-area CCGT-thermal plants is analyzed with the OPAL-RT hardware set-up for its real-time validation.