How to make use of transformer heat run test results ? review on thermal parameter derivation methods

Thermal performance of a transformer can be assessed by examining its heat run test results. Apart from the conventional test specification, heat run tests can be conducted in various ways and conditions to obtain more thermal characteristic information. In this paper the measured data, obtainable thermal parameters under different heat run test regimes are reviewed with their applications on the calculation of the hot-spot temperature. How measuring locations of oil temperatures would affect the heat run test results is also discussed, since readings of the top-oil and bottom-oil temperatures may vary significantly with measuring locations and have consequences on the calculated hot-spot temperature.