Weather-Based Quasi Dynamic Thermal Ratings for Power Transformers

This paper presents a preliminary study on climate change’s impact on power transformers’ ratings. This limit depends on the difference between air temperature and the maximum continuous allowable hot-spot oil temperature. On the other hand, atmospheric temperatures are expected to rise in the following years in Europe in a range between 0.52% and 8.18% Celsius degrees, according to the scenario. This will result in a rating reduction for existing and newly installed transformers.This study proposes a methodology to quantify this phenomenon and estimate its effect on several use cases. This is achieved by combining the transformers thermal model described in the IEC 60076-7 loading guide, historical meteorological reanalyses for 1970-2021, and climatic projections for 20222072 based on different greenhouse gas emissions hypotheses. Simulations are carried out using a quasi Dynamic Thermal Rating approach for HV transformers in the southeastern regions of France.Results show how the methodology proposed allows for a 6% rating increase in the cooler hours of the day and that projected future ratings are expected to be 5.031%-0.194% lower than the historical ones.