Extended Dynamic Thermal and Moisture Modeling of Transformers for Operation in Cold Climates

This study presents investigations of the dynamic thermal and moisture behavior of an ester liquid-filled transformer designed for offshore wind applications for operation in cold climates. The case study transformer is investigated through a heat run test by injecting a load while the transformer is exposed to sub-zero temperatures, with the entire transformer placed in a controllable temperature cold chamber. The study includes an extended Dynamic Transformer Thermal Model (DTTM) integrated with a Dynamic Transformer Moisture Model (DTMM) that considers the variation of liquid properties with temperature to predict the dynamic temperature and moisture behavior of the entire transformer during the test.