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.

Allocation method of coupled PV‐energy storage‐charging station in hybrid AC/DC distribution networks balanced with economics and resilience

“…where n AC , n DC and n VSC are the number of AC lines, DC lines and voltage source converters. P VSCloss i is the power loss of ith VSC, which is 2% of the line power [22].…”

“…The total power loss of AC/DC hybrid distribution network is: $$$$\begin{equation}P_{{\mathrm{total}}}^{{\mathrm{loss}}} = \sum_{i = 1,j \ne i}^{{n_{{\mathrm{AC}}}}} {P_{ij}^{{\mathrm{ACloss}}}} + \sum_{i = 1,j \ne i}^{{n_{{\mathrm{DC}}}}} {P_{ij}^{{\mathrm{DCloss}}}} + \sum_{i = 1}^{{n_{{\mathrm{VSC}}}}} {P_i^{{\mathrm{VSCloss}}}} \end{equation}$$$$where $${n_{{\mathrm{AC}}}}$$, $${n_{{\mathrm{DC}}}}$$ and $${n_{{\mathrm{VSC}}}}$$ are the number of AC lines, DC lines and voltage source converters. $$P_i^{{\mathrm{VSCloss}}}$$ is the power loss of $$i {\mathrm{th}}$$ VSC, which is 2% of the line power [22].…”

EV Integration-Oriented DC Conversion of AC Low-Voltage Distribution Networks and the Associated Adaptive Control Strategy

“…An energy management method is proposed for hybrid AC/DC microgrid in [24], to deal with the impact of uncertainty on the power interaction. An accurately improved sensitivity calculation method based on the ABCD parameters for hybrid AC/DC LVDNs is proposed in [25]. It is still challenging to design the coordinated control scheme for hybrid AC/DC LVDNs under EV integration.…”

Dynamic Management of Flexibility in Distribution Networks through Sensitivity Coefficients

“…Sensitivity-based methods are more and more used for voltage regulation in lowvoltage distribution networks [22,23]. To aggregate an existing distribution system into a cluster of virtual microgrids, a new model of LV distribution systems with DERs has been presented in [22].…”

“…The model is based on a linearized formulation of both the MV/LV supplying system and the branch flow equations. Zhang et al in [23] propose an accurate improved sensitivity matrix calculation method for hybrid alternating current/direct current (AC/DC) low-voltage distribution networks with a three-phase four-wire structure that considers shunt admittance and is based on the three-phase four-wire ABCD parameters. The sensitivity calculation is simplified by the presented ABCD parameters of the feeders, which consider the coupling effect between phases and the neutral line.…”