Microgrid reactive power management during and subsequent to islanding process

In a microgrid (MG) with high penetration of single phase induction motors (SPIMs), the voltage recovery process after a fault-induced islanding can be very slow. The reason lies in the stall of SPIMs caused by low voltage. During stalling, a SPIM can withdraw as high as three times of its rated power. This phenomenon can cause many problems including the loss of critical load due to the action of protection devices. This paper explores the role of reactive power support during MG islanding and proposes a novel approach to managing the reactive power generation of electronic-interfaced distributed generators (EIDGs). The concept of sensitivity factors is used in the proposed algorithm for regulating voltages at weak load buses. The optimal sharing of reactive power among EIDGs is formulated as a linear programming problem, which can be solved in a very fast manner for real-time control purpose. The proposed method is validated on a MG test-bed evolved from the IEEE standard 13-bus test feeder.