Finite Element-Based Study on Thermal Effects of Dielectric Window Sensors in UHV Autotransformers

This study employs finite element analysis to investigate thermal effects in dielectric window sensors and leakage magnetic field distributions within a 1000 kV ultra-high voltage (UHV) autotransformer. A coupled electromagnetic-thermal multiphysics model is established to simulate complex leakage flux patterns and predict resulting steady-state temperature fields. The difference of magnetic flux leakage distribution of UHV Transformer under two conditions is analyzed, and the change of temperature on magnetic flux leakage distribution is discussed. Simulation results quantify localized temperature rise at the sensor installation site, revealing a maximum increase of 14.78 °C under rated operating conditions. The validated model demonstrates that eddy currents induced by leakage flux constitute the primary heat source. This work provides critical insights for UHV transformer reliability and the safety of online monitoring systems.