Convergence of the Z-Bus Method for Three-Phase Distribution Load-Flow with ZIP Loads
Provides theoretical guarantees for a widely used load-flow method in power distribution systems, addressing a gap in convergence analysis for unbalanced networks with ZIP loads.
The paper derives sufficient conditions for the uniqueness of the load-flow solution in unbalanced three-phase distribution networks with ZIP loads and proves that the Z-Bus method converges to this unique solution within an explicitly calculable region.
This paper derives a set of sufficient conditions guaranteeing that the load-flow problem in unbalanced three-phase distribution networks with wye and delta ZIP loads has a unique solution over a region that can be explicitly calculated from the network parameters. It is also proved that the well-known Z-Bus iterative method is a contraction over the defined region, and hence converges to the unique solution.