A Buchholz relay is a gas-operated protection device installed in oil-filled transformers between the main tank and the conservator. It detects faults by sensing gas accumulation and oil flow.
Mechanism of Alarm Circuit:
✅ When a minor fault (like insulation failure or overheating) occurs inside the transformer, it generates small gas bubbles.
✅ These gas bubbles accumulate at the top of the relay, causing the upper float to move.
✅ This movement activates a contact, which triggers an alarm but does not shut down the transformer.
✅ The alarm alerts operators to inspect the transformer before a severe fault occurs.
Mechanism of Trip Circuit:
✅ In case of a severe internal fault (like a short circuit or major insulation breakdown), a sudden surge of oil flow occurs.
✅ This forceful oil flow pushes the lower float inside the relay.
✅ The lower float's movement activates another contact, immediately tripping the transformer to prevent further damage.
✅ This disconnection protects the transformer from catastrophic failure.
Conclusion:
🔸 The Buchholz relay provides early fault detection (via the alarm) and critical protection (via the trip circuit), preventing transformer damage and ensuring reliable power system operation.
0 Comments