Experiment - 6


To Study the gas actuated Buchholz relay for oil filled transformer.


  1. Buchholz Relay Setup
  2. 100 W Lamp


Fig 6.1: Block Diagram of Buchholz Relay Setup


    Valve V1 - Buchholz Relay to transformer tank
    Valve V2 - Conservator to Buchholaz Relay
    Valve V3 - Reservoir to Transformer Tank
    Valve V4 - Oil release in the Buchholaz Relay (left side)
    Valve V5 - Air release in the Buchholaz Relay(right side)

  1. Keep all the front panel switches in OFF condition.
  2. If any pressure is present in the relay, release it first by using Valve V5 and also use the hand valve which is present on the reservoir to release the pressure from the remaining part.
  3. Close all Valves except V2.
  4. Fill the oil in the buchholz relay by using foot pump by little opening of the Valve V5 (only if air lock is present in the relay).
  5. Switch ON the power supply.
  6. Switch ON the buzzer toggle switch.
  7. Open the Valve V1 slightly and decrease the oil level manually below the particular level by carefully seeing the oil level in the buchholz relay. Now the alarm contact will be closed and the buzzer will operate in control panel.
  8. After getting the alarm indication, close the Valve V1.
  9. First release the Valve V1 and V3 and collect the oil into the resevoir then follow the steps 2-8 once again.
  10. After completion of experiment open all the Valves including hand Valve except V4 and V5 to release the air pressure inside all the tanks.