An Adaptive Emergency Approach for Hybrid Networked Microgrids Resilience

The low inertia of renewable-based distributed energy resources (DERs) renders hybrid networked microgrids (N mu Gs) dynamically susceptible to transients. Such fragility makes it very difficult for N mu Gs operators to maintain a reasonable margin for the resilient operation during extreme condition contingencies. This paper presents a three-stage emergency approach to improve resilience of N mu Gs through maintaining dynamic security. The proposed approach targets preserving the resilient operation of N mu Gs by preventing unnecessary tripping of the DERs after unintentional islanding incident. To do so, a resilient operation zone (ROZ) is introduced which determines the secure operating zone for N mu Gs and the limits for implementing the corrective countermeasures for resilience augmentation. The proposed approach is outlined in three stages: First, offline analysis is carried out to model and calculate the ROZ. Second, hybrid N mu Gs operating point is monitored at the pre-event stage and the calculated ROZ at offline stage is adapted to the operating conditions. The third stage is responsible for real-time evaluation of hybrid N mu Gs security using the ROZ and implementation of the countermeasures. Comprehensive simulation studies presented in this paper demonstrate effectiveness of the proposed scheme for enhancing resilience of hybrid N mu Gs.