Optimum islanded microgrid reconfiguration based on maximization of system loadability and minimization of power losses

• Static voltage stability index is calculated based on both bifurcation points and new concept named reduced islanded microgrid network (RIN) in islanded microgrids.
• An adaptive method for islanded microgrid reconfiguration (IMGR) is proposed.
• IMGR improves loadability as well as decreases power losses of test systems.

Distribution grids are being transformed from passive to active networks. The active distribution systems are constructed through the implementation of microgrids (MGs) which are characterized as the “building blocks of smart grids”. This type of network eases the integration of distributed generation into power networks and makes it possible to define a new index for voltage stability, power flow development and a development reconfiguration method. In this paper, an improved indicator is proposed to estimate the voltage stability margin of a two-bus system based on both saddle node and limited induced bifurcations. A new concept named reduced islanded MG network (RIN), is used for generalization of the proposed index to n-bus islanded MGs and a development power flow algorithm by splitting these networks. The increasing loadability index of microgrids in the islanding mode is more important than the index of the grid-connected mode due to its operational limitations such as reactive power generation. In this process, islanded microgrid reconfiguration (IMGR) is proposed as an operational tool for improving loadability as well as decreasing power losses using an Adaptive Multi Objective Harmony Search Algorithm. The performance and effectiveness of the proposed method are demonstrated on 33- and 69-bus test systems.