Magnetic-Thermal-Flow Field Coupling Simulation of Oil-Immersed Transformer

Accurately understanding the temperature field distribution and hot-spot temperature of oil-immersed transformers is of great significance for ensuring the safe and stable operation of the transformer. A magnetic-thermal-flow coupling simulation model for oil-immersed transformer is established in this paper. In order to better simulate the heat dissipation process of the transformer, the winding uses a pie shaped structure with interval arrangement instead of the traditional cylindrical structure. The losses of iron core and winding are calculated through magnetic field simulation. Then, the losses are used as heat source for coupling simulation of thermal field and laminar flow to obtain the oil flow distribution, 3-D temperature field distribution, and temperature and location distribution of hot-spot. Finally, coupling simulations are conducted under different load currents to analyze the impact of load currents on the temperature and location of transformer hotspots. The simulation results show that as the current increases, the hot-spot temperature increases. When the load current changes, the hot-spot fluctuates within the range of 85% - 90% of the total height of the low-voltage winding, providing a methodological basis for the maintenance of transformers and monitoring of hot-spot temperatures.