Flow Visualization and Numerical Calculation in Gas Insulated Transformer Windings

Abstract

The application of SF₆ gas insulated transformer is increasing instead of oil immersed transformer, for simplification of maintenance and nonflamability of substations, however the heat capacity of SF6 gas is smaller than that of the insulation oil.
To improve the cooling performance of SF6 gas insulated transformers, it is necessary to understand the detail of gas flows and the temperature rise particularly near the windings. In order to attempt cooling optimization of disk windings of SF₆ gas insulated transformers, we have carried out numerical calculation and experiments. This paper describes validity of the numerical calculation to compare with the results of flow visualization by PTV (Particle Tracking Velocimetry) and heat-run tests of the real transformer.