Strategic intentional islanding method considering temporary overvoltage in disaster situations

Abstract

Under disaster conditions, an intentional islanding operation in distribution systems is required to enhance resilience. This paper proposes a strategic islanding operation utilizing grid-forming (GFM) inverter-based distributed generation (DG) within a grid containing both GFM and grid-following (GFL) inverters. Unlike previous studies, this work uniquely addresses the temporary overvoltage (TOV) constraints that arise during multi-fault and consecutive fault conditions in islanded systems, which is critical for stable grid operation in disaster scenarios. The islanding operation problem is formulated as a knapsack problem and solved by a genetic algorithm, enabling optimal load supply and enhanced DG utilization under diverse disaster scenarios. Numerical simulations validate the effectiveness of the proposed method by exploring the impact of varying the percentage of ungrounded loads, the capacity of GFM inverter-based DGs, and the location of GFM inverters. The results emphasize that the reduction of grounded sources, which has not been evaluated in existing studies, negatively affects TOV and, therefore, impacts the reliability of islanding operations.

Keywords

• Distributed generation
• Intentional islanding
• Grounding
• Resilience
• Temporary overvoltage