1. Insulation Resistance Test: Use a megohmmeter to measure the resistance between windings and ground, and between windings.
2. Dissolved Gas Analysis (DGA): Analyze the proportions of characteristic gases (H₂, CH₄, C₂H₂, etc.) in the oil to determine the type of fault.
3. Partial Discharge (PD) Detection: Capture signals using ultrasonic, electromagnetic, or electrical pulse detectors.
4. Infrared Thermography and Temperature Rise Monitoring: Scan the windings and joints with an infrared thermal imager to identify localized hot spots.
5. Vibration and Acoustic Analysis: Acquire signals using accelerometers or sonar probes to locate mechanical problems.
