Feasible method for making controlled intentional islanding of microgrids based on the modified shuffled frog leap algorithm

Intentional islanding is a feasible solution to improve the reliability of the smart distribution system with distributed generations (DGs) when the electrical connections between the smart distribution system and upstream network are lost. In this paper, a heuristic method is proposed for the intentional islanding of microgrids. In this method, some practical and important factors such as reduction of problem solution space; load controllability; load priority; bus voltage; line capacity constraints; and the ability to construct larger islands by the combination of islands are taken into account. The proposed method is a two-stage method. In the first stage, the intentional islanding problem is relaxed and in the second stage, the feasibility of the solution is verified. In the first stage, the intentional islanding problem is assumed as a series of tree knapsack problems (TKPs) and solved by the modified shuffled frog leap algorithm (SFLA). In the second stage, the power flow calculation is carried out to check the feasibility of the islands and essential modifications are provided. The proposed method is applied to IEEE 69-bus test system with 6 DGs. The results are compared with other methods and the effects of different methods on the system reliability indices are discussed. These comparisons indicate that the proposed method is feasible and valid. (C) 2015 Elsevier Ltd. All rights reserved.