How can a transformer oil level gauge be correctly interpreted?

Interpret the gauge using the transformer’s temperature reference and manufacturer markings. Oil level changes with temperature and load, so compare readings at similar conditions or apply correction charts if provided. Conservator systems may have min and max marks for seasonal temperature ranges. Sudden unexplained level drops can indicate leaks, gasket failure, or bushing issues. Sudden rises can signal gas generation or cooling system malfunction. Always cross check with alarms, sight glass, and maintenance records before taking action.