Optimal placement of phase‐reconfiguration devices in low‐voltage distribution network with residential PV generation

Abstract

As residential PV generation penetrates in the low‐voltage distribution network (LVDN), the unbalance issue may be intensified due to the asymmetry of generations/loads in different phases. Phase‐reconfiguration device (PRD), which can reconfigure connected phases of residential customers, provides an effective method to address this issue. Noting that although the benefit brought by PRDs can vary if they are placed at different locations in the network, little literature has been reported on this topic. To bridge the research gap, this paper presents a novel method to optimally place PRDs in an LVDN aiming at minimizing the power unbalance running through the distribution transformer. The problem considers both installation, operational constraints, and boils down to a challenging mixed‐integer non‐convex programming problem, which is then reformulated as an efficient solvable mixed‐integer linear programming problem. Moreover, operational constraints are relaxed with slack variables penalized in the objective function, which makes sure a feasible solution is always available without or with minimal operational violations. Case studies based on a modified IEEE system and a practical system in Australia demonstrate that an efficient strategy can be provided to address the unbalance issue while improving the network's power supply qualities.

Voltage profile analysis at planning and operational stages with allowable PV hosting capacity

“…In the plot, on the x-axis, the bus position as a distance from the substation is indicated. The UV can be observed on load buses of Region 2 in phase A at 2% PV (bus 10, 28,29,11,33,32,27,30,21), and 5% PV capacity (bus 11,33,32,30,31). The OV is depicted at most of the buses in phase A and phase C because of low load demand, with the integration of PV capacity in the range of 50-100%.…”

“…The varying solar radiation and unbalanced load conditions can result in OV violations, mainly at feeder-end buses, and thus may result in disconnection of PV systems [21]. Similarly, the authors [29] presented use of phase-reconfiguration device in order to reconfigure connected phases of residential consumers, so as to address unbalance issues. However, disconnection of PVs in turn incurs lose in revenue from selling electricity for the owners or scale up the investment.…”

“…From the above literatures review, in summarised form and motivations as highlighted, studies may be inappropriate and inaccurate, that involves; (i) balanced three‐phase network only, since the loading is inherently unbalanced and there exists non‐symmetrical conductor spacing of overhead line segments, (ii) either single‐phase or three‐phase PV installations, since, DN have both single‐and three‐phase PV installations, (iii) uncertainties in either PV output generation or load, but not both, (iv) voltage regulation analysis either at planning or operation stage, but very few have included both, except [29]. Thus, it becomes important to analyse voltage profile at feeder‐end buses, considering points (i)–(iv) in unbalanced DN with maximum level of HC for PVs.…”

Load Balancing in Low-Voltage Distribution Networks via Optimizing Residential Phase Connections

“…Compared with our previous work, this paper focuses on optimal coordination of PSDs in real-time operation, while [12] investigates the optimal locations to place PRDs, [11] focuses on the day-ahead scheduling of both PSDs and static VAR generator based on predicted demand profiles, and [13] mainly discussed the optimal control PRDs when the network cannot be monitored all all nodes, which leads to an sensitivity-based approach. Moreover, an iteration-based algorithm is presented and compared with the complete linearization-based method in our previous work [11] and the method based on the famous UTOPF that is based on linear branch flow model [14].…”