Enhanced Protection Coordination for Inverter Interfaced Distributed Generation (IIDG) with a Robust Multi-Loop Controller

Increasing penetration of inverter interfaced distributed generation (IIDG) in distribution networks has severely impacted protection coordination. False tripping, sympathetic tripping, protection blinding, failure of reclosing, and increase in short circuit levels are the critical complications and consequently disturbed the protection setting of the distribution network. This paper presents a novel multiloop current control scheme based on single integrator backstepping with a proportional resonant (PR) controller assisted by the whale optimization algorithm (WOA) to integrate IIDG in the distribution network. This control approach is designed to mitigate the maloperation of the overcurrent protection, due to the IIDG's current contribution during various types of faults. Inner loop backstepping is utilized to track converter side current and in addition, the PR controller is designed to track grid current in an outer loop. Using the proposed methodology, the injected current to the grid is effectively controlled to the rated level during several types of faults or disturbances. The performance of the proposed control strategy is verified by time-domain results and through eigenvalues trajectory and results have been compared with a current state-of-the-art which corroborates the effective control capability of the present controller.