An Optimized 3-Dimensional Simulation of On-load Tap Changer Subjected to Short Circuit Current

On-load tap changer (OLTC) is an important component for adjusting voltage in power transformers. Short circuit fault poses great risk to safe operation of the 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.