Fire in a transformer

The cause of the incident was a fault in a 15 kV circuit breaker voltage transformer which led to a bus bar fault. A short circuit occurred in the bus bar system in a transformer building, causing a fire in adjacent switches. This was followed by the tripping out of the three refinery turbo-alternators, cutting off the National Grid supply, and loss of refinery electrical power, steam and air supplies for some 30 minutes.

During the power loss and shutdown of plant, a hydrogen leak developed on a valve, and a tube of a fin-fan condense bank failed. Total damage attributed to the incident has been estimated at between 500,000 and 700,000 Frs.

The fire fighters were busy for one and a half hours, they had to face ventilation problems and to ensure effective electrical isolation, before opening up electrical equipment casings.

Leak and short circuit, power supply failure

transformer and circuit breaker, hydrogen valve

The pre-event related to the hydrogen-event was a short circuit occurred in a busbar system of a transformer building.

The tanker and adjacent buildings were set on fire and workshops severely damaged. Cars nearby were also set on fire.
Total damage attributed to the incident has been estimated between 500,000 and 700,000 Frs.

Black toxic smoke prevented immediate access to the transformer building despite the opening of doors and ventilation panels, and difficulty was found in extinguishing the fires in the switch cubicles.
The fire fighting was not fully successful in the transformer building for about 1 1/2 hours, the time being employed in dealing with the ventilation problems and to ensure that effective electrical isolation had been established before opening up electrical equipment casings.