The present paper proposes a novel disturbance rejection-based scheme applied to a power system for concurrent control of system voltage, frequency, and tie-line power. The generating units in the power system comprise varied generating sources, such as thermal, diesel, solar-thermal, and wind sources. Owing to the present rigid limitations on energy assets and environmental alarms, electric vehicles are integrated with the power system in both areas. The complex power system needs a robust controller for stable operation. In response to this challenge, a novel second-order Active Disturbance-Rejection-Control (ADRC) is modeled as a secondary controller for performance studies. An extended state observer is designed for the estimation of system disturbance and uncertainties assisting ADRC in compensating for the impact through disturbance rejection. The magnetotactic bacteria-optimization approach is utilized to optimize the controller gains by reducing the errors in the objective function. Detailed case studies are carried out on two-area and three-area hybrid power-system incorporating different renewable energy plants to test the performance of the proposed controller. The dominance of the developed second-order-ADRC is verified based on system performance improvement concerning testified controllers available in the literature. The developed second-order-ADRC validates the robustness under different system-changed conditions. The fact that electric vehicles assist in system dynamic regulation is studied thoroughly.