Optimum Shunt Capacitor Placement in Multimicrogrid Systems With Consideration of Islanded Mode of Operation

Appropriate implementation of multimicrogrid systems in distribution networks is dependent on the development of new planning methodologies that take into account the special operational characteristics of microgrids. This paper proposes a new algorithm for optimum shunt capacitor placement in multimicrogrid systems with consideration of islanded mode of operation. The cost function of the proposed optimization technique consists of three terms in the planning process: 1) the cost of power and energy losses when multimicrogrid systems operate in normal grid-connected mode; 2) the cost of capital investments of the installed shunt capacitors; and 3) the customers' cost of interruption when microgrids fail to operate in islanded mode due to shortage of reactive power and/or voltage violations. Appropriate power flow and probabilistic models for distributed and renewable energy resources (DER) and loads have been incorporated in the optimization problem to provide proper representation for microgrids during both grid-connected and islanded modes of operation. A genetic algorithm (GA) has been utilized to solve the problem and several case studies have been conducted to validate the proposed capacitor placement methodology. The results show that the new methodology can facilitate successful deployment of microgrids in distribution networks.