Combined voltage and frequency response in a solar thermal system with thermostatically controlled loads in an isolated hybrid microgrid scheme

Abstract

The generation of energy from renewable sources is dependent mostly on weather conditions because of which instabilities in the hybrid microgrid system may arise. To tackle the same in such a system, coordinated frequency and voltage control with appropriate control strategy have been investigated in this work considering a single area independent hybrid system. A combined solar gas turbine, solar chimney, and biodiesel-operated generator along with hybrid electric vehicles and refrigerators as the thermostatic load are used to model the hybrid system. Constraints of the proposed cascaded PI-TID controller are finely tuned with the recently developed DBOA. Coordinated frequency and voltage control of a combined solar gas turbine-solar chimney with thermostatic loads in an isolated hybrid microgrid system have not been reported earlier. Furthermore, the application of DBOA to tune a cascaded PI-TID controller for coordinated control of voltage and frequency is a novel approach. Extensive simulation studies of the model is carried out to obtain the dynamic response by considering various uncertain conditions. Values of maximum overshoot (0.002194), undershoot (0.006042), and setting time (1.781sec) of frequency deviation and peak overshoot (0.002296), undershoot (0.004511), and setting time (1.709 sec) of voltage deviation proved the effectiveness of the proposed system.

Keywords

• combined solar gas turbine
• solar chimney
• dynamic butterfly optimisation
• cascaded pi-tid
• isolated hybrid microgrid