TRANSFORMER AND LOAD MODELING IN SHORT-CIRCUIT ANALYSIS FOR DISTRIBUTION-SYSTEMS

Accuracy of short circuit analysis depends on the modeling of transfor mers and loads. This paper addresses implementation of various transfo rmer and load models in a short-circuit analysis for three-phase unbal anced distribution systems. Detailed transformer models are derived an d incorporated into a production grade short circuit program with thre e different load models. Our studies show that different transformer c onnections, load models, and loading conditions may have significant i mpact on post-fault currents and voltages. Some test results on PG&E d istribution feeders are presented.