A Hybrid Voltage Regulation Strategy for an AC Microgrid Integrated to LV Distribution Network

Abstract

In the current scenario of larger than ever penetration of renewable energy sources (RESs) in weak distribution networks, the individual power producers are required to participate in the grid voltage support functions. In this context, a hybrid voltage regulation strategy based on a normalized maximum Versoria criterion (NMVC) is developed in this paper. It involves coordinated control operation of the microgrid power sources using power converters. The microgrid consists of a doubly fed induction generator (DFIG) based wind power source, solar photovoltaic (SPV) source and battery energy storage (BES). The microgrid connected to low voltage (LV) weak distribution network with significant line resistances, results in abrupt rise in voltages during peak power production. This strategy utilizes BES for voltage support through its active power control (APC), primary operating mode. To protect BES from overcharging, a hybridization to primary operating mode is introduced, involving grid voltage support through reactive power control (RPC), secondary operating mode. The validation of the presented NMVC based voltage regulation strategy is performed through simulations.