Experimental and numerical thermofluid study of a disc-type transformer winding scale model

In this study, measurements are carried out on an ON disc-type winding scale model that includes all main components usually found on a real transformer. Moreover, 3D CHT simulations of the entire cooling circuit are performed and the computed oil flow rate and winding temperatures are compared with the experimental data for uniform and nonuniform heat loss distributions. The results show that the CFD model can predict with an accuracy of about 10% the oil flow rate circulating in the winding and it can compute with quite good accuracy the discs temperatures. Numerical simulations with a reduced computational domain (i.e., winding region only) are also performed with the CFD model and two in-house THNM codes. The comparison between the predicted and measured disc temperatures shows that the CFD model is the most accurate and that the THNMs can predict quite well the global thermal behavior of the winding, even though discrepancies are locally observed.