A multi-stage algorithm based on data structure to deal challenges facing electric-supply restoration in smart grids

• Thirteen challenges face electric-supply restoration are discussed. • A proposed algorithm meeting challenges to restore energy supply. • The algorithm achieves 100% self-healing with occurrence of single fault. • Self-healing is 95.8-98.3% satisfied under simultaneous faults. • Restoration time lies in the range 190-199 ms. . A combined multi-stage algorithm is proposed and built to handle thirteen challenges along with electrical constraints that face electric-supply restoration in smart grids. The challenges include maximization of the number of recovered out-of-service healthy loads, avoiding in-service load shedding, occurrence of multi-simultaneous faults, minimization of total power loss, sequence consideration of commanded switches, minimization of number of switches receiving order, reducing restoration time, independency on system size and achieving self-healing. The electrical constraints include branch current capacity, voltage limits, load priority and system radiality. These challenges are discussed in five stages, each stage represents a step in dealing with these challenges and electrical constraints. The proposed algorithm is aimed at minimizing the energy-not-supplied by minimizing number of out-of-service healthy downstream loads in a tree exposed to a permanent single fault or multi-simultaneous faults without violating the electrical constraints. The proposed algorithm is independent on distribution system size and its restoration time lies within 190-199 ms. The proposed algorithm is tested under IEEE 16-bus, IEEE 33-bus and IEEE 69-bus distribution systems for all maneuvering fault processes. The proposed algorithm achieves 100% self-healing capability under a single fault maneuvering processes against 95.8%, 98.3% and 97. 8% satisfaction of self-healing condition under exposure to two, three and four multi-simultaneous faults, respectively. The proposed algorithm showed better performance compared to other algorithms reported in the literature as regards as capability of self-healing, efficiency, restoration time and number of considered challenges.