An Improved Intentional Islanding Strategy in Distribution Network with Hierarchical Control

Intentional islanding operation can provide uninterrupted power supply for the essential load in case the main grid is failed or overhauled. This paper proposes an improved intentional islanding strategy with the hierarchical control, which can achieve a more flexible scope of islanded area regardless of the point of common coupling (PCC). The procedure of seamless transition at any point of distribution system under hierarchical control is described. During islanding operation, a power sharing method with the coordinated control of various types of distributed generations (DGs) is also proposed. This coordination is able to improve the power output curve of the master DG in islanding operation, reduces the fluctuations of total net load, and prevents the curtailment of intermittent DGs. To verify the proposed hierarchical control strategy, a demonstration application with multiple DGs is designed and implemented in a practical distribution system, which is located in Guiyang, China. The operation result of field test has shown the feasibility of the proposed method.