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Bharat Rao, F. Kupzog, M. Kozek:
"Three Phase Unbalanced Optimal Power Flow using Holomorphic Embedding Load Flow Method";
Sustainability, 11 (2019), 6.

Distribution networks are typically unbalanced due to loads being unevenly distributed over the three phases and untransposed lines. Additionally, unbalance is further increased with high penetration of single phased distributed generators. Load and optimal power flows, when applied to the distribution networks use models developed for transmission grids with very little or no modification. Optimal power flows are traditionally used for system planning and in some instances for real-time system control. Moreover, the performance of optimal power flow directly depends on external factors like weather; ambient temperature and irradiation, since they have strong influence on loads, distributed energy resources like photo voltaic systems. It is also time dependent since they contain daily, weekly, seasonal cycles. To help mitigate the issues mentioned above, the authors present a novel class of optimal power flow algorithm which is applied to low voltage distribution networks. It involves the use of a novel three phase unbalanced holomorphic embedding load flow method in conjunction with a non-convex optimization method to obtain the optimal set-points based on a suitable objective function. This novel three phase load flow method is bench-marked against the well known power factory Newton-Raphson algorithm for various test networks. Mann-Whitney U test is performed for the voltage magnitude data generated by both the methods and null hypothesis is accepted. A use case involving a real network in Austria and a method to generate optimal schedules for various controllable buses is provided.

unbalanced three phase distribution networks; optimal power flows; genetic algorithm; holomorphic embedding load flow method

http://dx.doi.org/10.3390/su11061774