Which equipment is equipped with pressure release valves?

• A. Transformers
• B. Generators
• C. Circuit Breakers
• D. Switchgear

Answer: (A)

Pressure release valves are used on equipment where the enclosure can experience overpressure due to gas formation or oil expansion, and they vent to prevent rupture. In oil-filled transformers, faults or excessive heat cause the insulating oil to decompose and generate gases, which raise the internal pressure. A pressure release valve on the transformer tank opens to vent that gas safely, protecting the transformer from damage (often in combination with other gas-detection devices like a Buchholz relay).

Other equipment like generators, circuit breakers, or switchgear aren’t characterized by a built-in, always-present pressure relief valve on the main enclosure, even though various vents or protective systems may exist for cooling or specific gas-insulated designs. The presence of a pressure release valve in this context points to transformers.