1. Visual inspection of transformer compound
   1. Check for any vegetation.
   2. Check for any signs of oil spill or other abnormality.
2. Visual inspection of transformer
   1. Check for any signs of damage or oil leaks.
   2. Inspection of explosion vent.
   3. Inspection of breather including colour of silica gels.
   4. Check winding and oil temperature readings for any abnormality.
   5. Check for any unusual noise from transformer itself.
3. Visual inspection of transformer feeder panel
   1. Check for any active alarms
   2. Check for phase indication, if installed.
4. Online testing and monitoring:
   1. Transformer oil testing – dissolved gas analysis, moisture content, acidity, breakdown voltage, power factor, interfacial tension, specific gravity, colour test, furan analysis for paper insulation, PCB analysis.
   2. Perform thermography, if IR window is installed.
   3. Check for partial discharge, if online partial discharge monitoring system is installed.

1. Insulation resistance (IR) and polarisation index (PI) test.
2. DC winding resistance test.
3. Transformer turns ratio test.
4. Winding insulation power factor and power factor tip-up test.
5. Bushing power factor test.
6. Sweep frequency response analysis (SFRA).
7. Offline partial discharge (PD) test.
8. Tap changer continuity and ratio test.
9. Contact resistance (Ductor) test of main connection points.
10. Verification of transformer internal protection such as Buchholz relay, winding temperature and oil temperature alarms and trips.
11. Check for earthing connections for continuity.
12. Check for any signs of partial discharge on cables and connections inside the termination box.
13. Inspection of all seals and gasket to ensure their integrity.
14. Any other additional tests that may be recommended by the manufacturer.
15. Any other additional inspections and tests as recommended by the manufacturer.