An Optimal Power Flow Algorithm for the Simulation of Energy Storage Systems in Unbalanced Three-Phase Distribution Grids

Abstract

An optimal power flow algorithm for unbalanced three-phase distribution grids is presented in this paper as a new tool for grid planning on low voltage level. As additional equipment like electric vehicles, heat pumps or solar power systems can sometimes cause unbalanced power flows, existing algorithms have to be adapted. In comparison to algorithms considering balanced power flows, the presented algorithm uses a complete model of a three-phase four-wire low voltage grid. Additionally, a constraint for the voltage unbalance in the grid is introduced. The algorithm can be used to optimize the operation of energy storage systems in unbalanced systems. The used grid model, constraints, objective function and solver are explained in detail. A validation of the algorithm using a commercial tool is done. Additionally, three exemplary optimizations are performed to show possible applications for this tool.

Editorial for the Special Issue “Verifying the Targets—Selected Papers from the 55th International Universities Power Engineering Conference (UPEC 2020)”

“…The low-voltage three-phase distribution grids are increasingly considered and, in particular, optimal power flow (OPF) based problems are faced to correctly schedule the resources such as the energy storage systems. When dealing with three-phase distribution grids, unbalances cannot be ignored and, as a consequence, the existing algorithms to solve OPF problems have to be modified to include the models of three-phase four-wire low voltage lines and to determine the voltage unbalances (Held et al [12]).…”

Disturbance Evaluation in Power System Based on Machine Learning

“…Because of the rapid growth of large-scale wind farms, wind energy is playing an increasingly important role in domestic and international power markets as a sustainable and cost-effective renewable energy source. Wind's highly unpredictable capacity, on the other hand, can trigger nonlinear characteristics in the wind power, which can have a number of negative consequences for the wind power system's reliability [19][20][21][22][23][24][25]. As a result, developing an accurate and efficient power prediction model is needed to preserve the grid's reliability while also improving the equal planning, dispatching, control, and risk assessment capabilities.…”

Power Flow Analysis in Unbalanced Distribution Networks Considering High Photovoltaic Production

“…Furthermore, the analysis includes only one time-step, instead of daily results that would showcase the effect of RES production profiles. The authors of [14] study the daily operation of an unbalanced distribution network that includes a battery, PV panels and residential loads. The developed algorithm includes an optimizer which maximizes the network's self-consumption by controlling the battery.…”

“…This paper proposes an advanced BFS-based algorithm for the PFA in unbalanced distribution networks considering RES installations and a variety of load profiles in daily operation. Therefore, it expands the scope of [10]- [14], which either do not utilize BFS-based algorithms or do not examine daily operation. The importance of the proposed algorithm lies on the tree-like approach of the network in combination with BFS, allowing for a faster yet accurate performance with reduced memory allocation, which is valuable especially in large scale networks, as validated by the present research group in a recent paper [8].…”