Simplified loop-type fuzzy feeder models for distribution system calculations

Based on fuzzy set theory, this paper presents loop-type fuzzy feeder models to simplify complicated distribution system analysis. These fuzzy models are formulated using lumped distribution transformer(s) and lumped load(s) to represent nonuniformly distributed loads, which vary by time and type of day and relate to voltage, along a feeder. These equivalent models are developed to accurately simulate first, the maximum voltage drop from substation to the load points of a given loop-type feeder, and then the total copper and core losses. Finally a hybrid model is developed to simulate both maximum voltage drop and losses accurately. A physical loop-type feeder is used to demonstrate the correctness of these proposed fuzzy feeder models. The simulation results show that it is possible to reduce many complex loop-type feeders to simple equivalent models in the study of feeder voltage profiles and losses with negligible error.