Certainly, here are the explanations for the variables in the equations you mentioned.1
References
1Wang J, Hao J, Xu J, He D. Research on the Dynamic Simulation Process of Hot Spot Temperature Rise of Oil-immersed Transformer. In: 2024 9th Asia Conference on Power and Electrical Engineering (ACPEE). IEEE; 2024:1946-1951. doi:10.1109/ACPEE60788.2024.10532281