DISTRIBUTION-SYSTEM SHORT-CIRCUIT ANALYSIS - A RIGID APPROACH

This paper introduces a rigid approach to short circuit analysis for large-scale distribution systems. The approach uses an individual (a-b-c) phase based system representation, a non-trivial transformer model, and includes the contribution due to load. The method can, therefore, be applied to balanced or unbalanced, radial, network, or mixed type distribution systems. Furthermore, this approach is oriented toward applications in distribution system operation analysis rather than the more typical planning oriented analysis. The solution method is an iterative compensation method, which uses a single optimally ordered factorization of the bus admittance matrix [Y(Bus)], commonly used in power flow analysis, to simulate the fault condition. The use of this method in a short circuit analysis program enables a straightforward integration with a power flow program sharing a factorized Y(Bus) solution, resulting in many advantages. Using a common factorization, both power flow and short circuit analysis are possible in a single execution. Since the factorization is unchanged, multiple faults of varying types, including single line-to-ground, double line-to-ground, and three phase, as well as 'cross country', double three-phase, and triple double-line-to-ground faults can be simulated in one run of the program.