An Explosion Prevention and Fire Extinguishing System (EPFES) at a Power Substation (PSS) protects oil-filled transformers from catastrophic failure. It is designed to prevent explosions and extinguish fires within 30 seconds of activation. 

Fault Detection: Sensors detect rapid pressure rises (arcing/faults) within milliseconds.

Immediate Action: It immediately activates, usually within 13ms, to prevent explosion.

Oil Drainage: It initiates rapid draining of top transformer oil (reducing pressure).

Nitrogen Injection: Nitrogen gas is injected to stir the oil and reduce surface temperature below the ignition point.

Isolation: The conservator tank is isolated to prevent oil from feeding a fire.

Fire Extinguishment: It extinguishes external fires on bushings and radiators within seconds.

Fail-Safe: Ensures operation even if the main power source fails (automatic/manual).

Compatibility: Suitable for varied transformer sizes (750 KVA to 1500 MVA).

Compliance: Complies with NFPA standards, and is ISO/CE ATEX certified.

Damage Mitigation: Saves valuable equipment, reduces downtime, and ensures personnel safety.