A Practical Tutorial on Phase Balancing in Asymmetric Distribution Grids Using DIgSILENT PowerFactory’s DPL
Abstract
Phase imbalance in three-phase distribution networks is a persistent operational issue that increases power losses, degrades voltage quality, raises neutral currents, and accelerates equipment aging. Traditional manual balancing methods are labor-intensive, reactive, and ill-suited to handle the stochastic nature of modern grids with high penetrations of renewable energy and electric vehicles. This tutorial presents a practical and accessible random search algorithm for phase balancing, implemented entirely within DIgSILENT PowerFactory using the native DIgSILENT Programming Language (DPL). The method minimizes total active power losses by randomly reassigning three-phase load powers across phases using six possible permutation indices. The algorithm requires no external optimization libraries, no co-simulation frameworks, and no specialized programming expertise beyond basic DPL scripting. A complete 12-bus test feeder with 11 unbalanced loads is used as a case study. Numerical results demonstrate that with only 100 random samples, baseline losses of 604.20 kW are reduced to 549.42 kW, representing a 9.1% improvement, with diminishing returns beyond 1,000 samples. The complete DPL source code and the test system are publicly available, providing readers with a ready-to-use, replicable, and extensible framework for automated phase balancing in asymmetric distribution grids.