Accurate calculation of temperature distribution and hot spot locating for transformer winding in an oil forced and directed（OD） cooling mode can help improve transformer performance and extend service life. Firstly

the heat transfer analysis of a single-turn conductor is carried out

and a thermal network heat transfer model composed of heat flux and thermal resistance is constructed in this paper

based on the basic principles of heat transfer. The temperature of local conductor is calculated and the hot spot locating is achievable by the model. Finally

the comparison verification with computational fluid dynamics（CFD） simulation and case analysis are performed. Results show that the winding temperature calculated by the model is basically consistent with CFD simulation results. The mean relative error of partial discs temperature calculation is 4.64%～7.32%

the mean absolute error for the whole winding temperature is 0.97 ℃

and the correlation coefficient is higher than 0.95

which verify the correctness and validity of the model. The main distribution of the disc temperature and the specific location of the hot spot can be calculated by the model

which can provide quantitative analysis and guidance for the heat dissipation design of the transformer winding area. In addition

temperature distribution can be computed by programming for the model

and compared with CFD numerical simulation for several hours

it can save more than 99% of the calculation time and greatly improve the calculation efficiency of winding temperature rise.