Voltage control method based on three‐phase four‐wire sensitivity for hybrid AC/DC low‐voltage distribution networks with high‐penetration PVs

Abstract

The increasing integration of distributed photovoltaics may further aggravate the over-voltage and three-phase unbalance issues of low-voltage distribution networks with three-phase four-wire structures. The voltage control method based on the AC and DC side power flow control and the three-phase power control capability of voltage source converter in hybrid AC/DC low-voltage distribution networks is a solution for the improvement of the above power quality issues. In this paper, an accurately improved sensitivity matrix calculation method considering shunt admittance based on the ABCD parameters is proposed in hybrid AC/DC low-voltage distribution networks with a three-phase four-wire structure. The presented ABCD parameters of the feeders consider the influence of the coupling effect among phases and the neutral line on sensitivity calculation, which makes the sensitivity calculation simple. Then, a power-voltage control method for voltage source converters based on three-phase four-wire sensitivity matrices of the AC side is proposed considering the constraints from the voltage source converter and DC side power flow in hybrid AC/DC low-voltage distribution networks, which can effectively address the over-voltage and unbalanced issues. Simulations are performed to verify the proposed sensitivity calculation method and voltage control method.