Q: Some engineers use acoustic devices, others use UHF monitors. Which is superior?
A: They are partners, not competitors. UHF is for scanning electromagnetic waves; AE is for pinpointing mechanical vibrations.
Comparison Matrix:
|
Method |
Signal Type |
Best For |
Sensitivity |
|
UHF |
Electromagnetic |
Insulator voids / Overall scan |
Extremely High |
|
AE |
Mechanical Wave |
Moving metallic particles / Pinpointing |
High (Close range) |
FAQ 1: Sensor Placement - Where to "Stick" them?
Q: GIS is a long pipe. Can I place sensors anywhere?
A: No. The tank acts as a Faraday Cage. You must look for the "Leakage Points."
Optimal Locations:
UHF Sensors: Place over Basin Insulators. Waves "leak" through the resin seals.
•AE Sensors: Place on the tank wall near joints, bottom of busbars, or CB tanks.
Pro Tip: Use ultrasonic couplant (grease) for AE sensors to ensure a perfect mechanical link.
FAQ 2: PRPD Patterns - Identifying the "Tumor"
Q: How do I know if it is dust or a failing insulator from the dot cloud?
A: We use Phase Resolved PD (PRPD) patterns to fingerprint the defect.
|
Pattern Shape |
Diagnosis |
Threat Level |
|
Random Spots |
Moving Metallic Particles |
❌ Critical (Jumping danger) |
|
Symmetrical Clouds |
Internal Voids (Bubbles) |
⚠️ Warning (Electrical treeing) |
|
Stable Brush |
Fixed Protrusion (Burrs) |
❌ Critical (Stress concentration) |