Eddy current losses and hot-spot evaluation in cover plates of power transformers

Heavy current bushings passing through steel cover plates and housing walls of power transformers, generators and other large power equipment are thermally hazardous elements of construction and a source of additional power losses. The safety and reliability of such expensive objects and the safety of power delivery often depend on the proper design of these elements. A computer analysis, based on Maxwell equations and analytical representation of electromagnetic field has been carried out. The nonlinear permeability of solid steel was considered using an analytical approximation. Eddy current losses have been calculated and compared using different experimental and calculation methods. Electromagnetic criteria were used to forecast possible excessive heating and hot spots. Various constructional means of loss and hot spot reduction were considered