Investigation of transformer top-oil temperature considering external factors

Abstract

Standard estimation of top-oil temperature uses a thermal model related to load changes and variation of ambient temperature. Attempts have been done to improve the accuracy of top-oil temperature calculations by introducing internal properties into the model i.e. oil viscosity and winding resistance. The interest of this paper is to investigate the effect of external factors on top-oil temperature by looking into the weather, i.e. wind velocity. The results are compared with measurements on a 63MVA-ONAF 55/140 kV transformer unit, which is operated in ONAN cooling mode. The unit is located in subarctic climate, and it is equipped with a monitoring system and a weather station.

Thermoelectric Modelling and Optimization of Offshore Windfarm Export Systems - State of the Art

“…Miscellaneous Models Besides the models mentioned above, there are many models that suggest improvements to the loading guides. For example, [45] investigates the influence of weather conditions (including wind speed and solar radiation) on transformer's TOT, [37] extends these models for smaller transformers, while [38] assesses a transformer's overload capability by estimating standardized error in TOT calculation but uses the design information of the transformer to estimate the heat transfer modes in it. On the other hand, [46] offers a unique perspective of identifying the sources of errors in dynamic modeling of transformers.…”