A Study on Variable Dead Band Control Method of SVR Considering the Communication Delay

Abstract

Recently, a large amount of photovoltaic generation systems (PVs) has been introduced in the distribution line. However, they may cause voltage fluctuation violently by changing the output of PVs due to variation of the weather conditions. To maintain the voltage of lines, Load Ratio control Transformer (LRT) and Step Voltage Regulator (SVR) are used in distribution network. However, as they have time delay to operate, they could not appropriately suppress violent voltage fluctuation caused by PV's output. Furthermore, frequent operation of LRT and SVR is also severe problem for their lifetime. In order to overcome those problems, the advanced control method of LRT and SVR is required instead of expensive devices, such as Static Var Compensator (SVC) and Battery Energy Storage System (BESS). From this background, this paper proposes the novel control method of LRT and SVR in consideration of the communication delay of the distribution automation system. The proposed method is variable dead band control using the estimated voltage profile correcting with the information from section switches. The proposed method is evaluated by the numerical simulation using the long line distribution model with two SVRs.