Oil Flow Velocity Variations in Transformer Cooling Systems Under Variable Loads and Inter-Turn Short-Circuit Conditions

The safe and stable operation of power transformers is crucial for power systems. The energy losses in transformers mainly consist of two parts: Joule heating losses and eddy current losses. Abnormal heating in transformers can degrade their insulation performance and shorten their lifespan. The oil flow rate in the cooling system indirectly reflects the internal temperature distribution of the transformer and plays a significant role in fault diagnosis. Therefore, real-time monitoring of the oil flow rate in the transformer cooling system is of vital importance. This article analyzes the cooling mechanism of power transformers, establishes simplified models for both the transformer itself and the cooling system, and simulates the corresponding relationship between the oil flow rate at the inlet of the cooling system and the transformer's overload condition under different loads.