Demand Response Strategy for Frequency Control of a Parabolic Dish Solar Thermal Diesel based Microgrid

Maintaining system frequency in a microgrid is a challenging task in sustaining system stability and providing quality power to the end-user. This paper assesses the capability of demand response using controllable loads such as refrigerators, heat pump and plug in hybrid vehicle in maintaining frequency stability in a microgrid consisting of parabolic dish solar thermal system (PDSTS), diesel generator (DG), plug-in hybrid electric vehicle (PHEV), heat pump (HP) and freezer (FRE) without storage device. Intelligent demand response (DR) controller is employed for controlling the controllable loads in addition to automatic generation control (AGC). The DR controller, proportional plus integral (PI) would continuously monitor the system frequency and adjust the power consumed by the controllable loads accordingly. A Matlab model of a microgrid has been developed considering system inertia, governor action, controllable loads and critical (not curtailable) loads. Simulation results are conducted to investigate the response of the microgrid to different uncertainties such as abrupt changes in generation, and/or random variation of load. The controllers (PI) employed with for AGC and DR are tuned by using Particle Swarm Optimization (PSO) algorithm and Genetic Algorithm (GA). The results indicated a significant improvement in frequency stability along with lesser dependency on backup unit.