On-load tap changer (OLTC) is widely used in power transformer to adjust voltage output when operating on load. Short circuit is one of the most serious failures for power system with large current, which also brings about quite high risk for OLTC. Simulation and experiment subjected to short circuit current are necessary for evaluating the short circuit withstand capability of OLTC. Based on the existing simulation method, this paper presents an optimized three-dimensional (3D) short circuit simulation method of OLTC considering interaction between heat and force, adding with practical short circuit current input. The simulation can help evaluate and verify the short circuit withstand capability of OLTC. Two typical OLTC productions are used as simulation models and experimental prototypes. The current coils and voltage dividers are respectively used to measure short circuit current and voltage input. Structural stress in contacts system is detected by optical fiber sensors during short circuit current experiment. All the simulations are completed in COMSOL Multiphysics 5.6 by using finite element method. The optimized simulation method improves accuracy and practicability of the short circuit current simulation model of OLTC. The experiment proves that the optical fiber measurement technology is applicable to OLTC short circuit test. The optimized simulation is helpful for design and verification of on-load tap changer, which integrates more influencing factors to improve accuracy and practicability of the short circuit current simulation model of on-load tap changer.

on-load tap changer (OLTC);Short Circuit Current;optical fiber sensing technology