A simplified transformer thermal model based on thermal-electric analogy

This paper presents a further simplified thermal-electric analogous thermal model of an oil-immersed power transformer. The method is rooted on the principles of heat exchange and electric circuit laws. A set of differential equations is derived to calculate both the transient-state temperatures and the stationary-state equilibria in the main parts of a transformer. For the problem of thermal parameters identification, a genetic algorithm is employed to search global solutions for thermal parameters with onsite measurements. The validation of the simplified model and calculations of hot-spot temperatures are discussed in detail.