Modeling and Simulation of Transformer Inter-Turn Short-Circuit Faults Based on Field-Circuit Coupling

Transformer inter-turn short-circuit (ITSC) fault has long been an issue of concern. This paper presents a direct field-circuit coupling method to investigate power transformer ITSC faults, in which the nonlinear arc-in-oil conductance was simultaneously calculated. Using the numerical approach, ITSC faults of a three-phase three-winding power transformer were simulated and analyzed. Results show that, a large circulating current flows through the shorted turns, with the surrounding flux distribution significantly distorted. Moreover, ITSC faults with more shorted turns will result in lower short-circuit current and larger arc voltage, and more arcing fault energy will be released.