The Improvement of Voltage's Unbalance via Voltage Magnitude Control with BESS and SC in Distribution System Connected with PV

Abstract

Nowadays, Photovoltaic generation (PV) and all-electric house are well developed in distribution system which cause the unbalance of voltage and lead the power quality to get worse. Normally, unbalance of voltage is regulated by Static Capacitor (SC) or Static Var Compensator (SVC). However, PV which relies on the solar radiation that can't be accurate predicted varies a lot in short period and causes a reverse power flow, and the established devices come to inadequate with the feature of PV. To regulate the voltage and voltage unbalance factor (VUF) in PV connected distribution system, Battery Energy Storage System (BESS) is taken into using because it can give a fast, accurate, and flexible output, and its feature of absorbing the reverse power flow caused by PV is significant. However, the cost of BESS is relatively huge. To reduce the cost to propel the application of BESS, SC is here to combine with BESS to give reactive power output to decrease the capacity of BESS. The placement of BESS is discussed to give an excellent control as well as reduce the capacity of BESS. In this paper, a simply regulation of voltage magnitude is taken out to realize the improvement of VUF through comparatively accurate control of BESS with using the proved proportional relationship of the difference of line voltage and voltage unbalance factor (VUF).