Methodology for service restoration in large-scale distribution systems with priority customers

Even in today's smart grid arena, service restoration continues to be an important issue for distribution system operation. Service restoration problem, that emerges after the faulted areas have been identified and isolated, involves network reconfiguration in order to minimize both the number of out-of-service loads and number of switching operations (the objectives of the service restoration problem) without violating the radiality and operational (limits for the bus voltage, network loading, and substation loading) constraints. As a consequence, the service restoration problem can be classified as a multi-objective optimization problem subject to multiple constraints. Additionally, due to the existence of some loads which are of the highest priority (e.g., hospitals and big industries), another need arises for this problem: to prioritize service restoration to priority customers. Thereby, to deal with this problem, in this paper it is proposed a mathematical formulation and a new methodology for determining service restoration plans in contingency situations. The main contribution of the proposed methodology is its ability to provide, in a short running time, service restoration plans in large-scale distribution systems that prioritize the supply to priority customers. Tests with distribution systems ranging from 631 switches and 3,860 buses to 5,158 switches and 30,880 buses have demonstrated the efficiency and the ability of the proposed methodology. The smallest tested system is the real distribution system of São Carlos city, in Brazil.