A virtual energy storage system for voltage control of distribution networks

Abstract

—Increasing amount of Distributed Generation (DG) connected to distribution networks may lead to the voltage and thermal limits violation. This paper proposes a Virtual Energy Storage System (VESS) to provide voltage control in distribution networks in order to accommodate more DG. A VESS control scheme coordinating the demand response and the energy storage system was developed. The demand response control measures the voltage of the connected bus and changes the power consumption of the demand to eliminate voltage violations. The response of energy storage systems was used to compensate for the uncertainty of demand response. The voltage control of energy storage system is a droop control with droop gain values determined by voltage sensitivity factors. The control strategy of the VESS was applied to a medium-voltage network and results show that the control of VESS not only facilitates the accommodation of higher DG capacity in the distribution network without voltage violations or network reinforcements but also prolongs the lifetime of transformer on-load tap changer.