Power transformers are among the most important components of modern electrical power systems. During operation, transformers generate significant amounts of heat due to core and winding losses. Effective cooling systems are essential for maintaining transformer reliability, efficiency, and service life. This paper analyzes the main transformer cooling methods, including Air Natural (AN), Oil Natural Air Natural (ONAN), Oil Natural Air Forced (ONAF), and Oil Forced Air Forced (OFAF) systems. Their thermal performance, operational efficiency, and economic characteristics are compared. Experimental and analytical results demonstrate the impact of cooling technologies on transformer temperature, energy losses, and operational reliability. Recommendations for improving energy efficiency and resource conservation in transformer operation are also presented.
Khudoberdiev et al. (2026) studied this question.