Disturbance rejection based fractional order PID controller for system performance improvement of hybrid power system

The present paper introduces a disturbance-rejection based fractional-order proportional-integral-derivative (DR-foPID) controller as optimal control strategy for performance enhancement of hybrid power system (HPS). The two-area HPS is equipped with various generation sources in the form of solar-thermal-system (STS), conventional thermal, wind-turbine-system (WTS) and geo-thermal power plants establishing a coordinated system frequency and tie-line power control. In addition, electric vehicles (EVs) are integrated with the HPS to check its effect on dynamic characteristics. The controller gains are optimized using an effective bio-geography based krill herd (BBKH) optimization technique to achieve the required performance of the HPS. This study validates the efficacy of the BBKH adjusted DR-foPID controller for efficient operation of system dynamic characteristics. The resilience of DR-foPID controller gains is confirmed by a sensitivity test involving large fluctuations in system load variations from their nominal values. It is also demonstrated that EVs help to increase the performance of HPS. A study involving the power management capability of EVs for improving the system performance is also demonstrated. Moreover, the effect of redox flow battery as energy storage device for system dynamic control are also illustrated. At last, a DR-foPID controller is tested in case study on three-area HPS.