1106 / 2019-05-20 20:50:20

Influence of PV on Voltage Unbalance in Distribution System

PV；sequence model; voltage unbalance

Due to energy shortage and global warming issues, solar energy has become an important component in the energy market. In distribution system, with more and more distributed generators(DGs), especially distributed PVs installation, the characteristics of voltage performance have changed. Due to unbalanced line impedance or single-phase load, distribution network is usually operated in unbalanced condition. In this paper, the impacts of distributed photovoltaics(PV) on voltage unbalance in distribution system is investigated. Firstly, the positive-sequence and negative-sequence steady-state model of PV converter is proposed. And based on the negative-sequence PV model, an equivalent negative-sequence model of grid-connected PV is derived and the theoretical expression of VUF(voltage unbalance factor) is deduced. Finally, a modified IEEE 33 test system is used for analyzing the impacts of PV integration on voltage unbalance.