The sudden pressure relay is a protective device that detects transformers sudden increase in pressure caused by internal faults. Internal arcing in an oil-filled power transformer can instantly vaporize surrounding oil, generating gas pressures that can cause catastrophic failure, rupture the tank, and spread flaming oil over a large area.
Sudden Pressure Relay
- Installed usually the upper lid or top side, in the main tank and on the On Load Tap Changers – OLTC.
- Switching contacts NO and NC
- They may be associated with a device to held the alarm: Seal-In Relay
- Signal verification, by a pressure source.
- Connection scheme ANSI, IEC