Yallourn, Victoria, Australia – A fatal explosion at an Australian Power Station is said to have been the result of a phase-to-phase arc flash. A unit controller with more than 30 years’ experience was critically injured during the explosion in the southeastern-most state of Australia which lead to his death the next day.
EnergyAustralia has identified arc flash as the cause of the explosion at the Yallourn Power Station, however a local union representative is not confident in that explanation and staff at the power station say they are afraid to go to work.
Graeme Edwards died after a high-voltage circuit breaker he was working on exploded last month. Edwards was re-installing a high-voltage circuit breaker on one of the plant’s four generation units when the explosion occurred, a procedure known as “racking.” EnergyAustralia stated that racking is a routine job but potentially hazardous. In this case, the unit burst into flames that burnt most of Edwards’ body. The worker was flown to hospital in a critical condition but died a day later.
EnergyAustralia said it believed the “sudden electrical discharge” was caused by a “phase-to-phase arc flash.” However, they have yet to determine what caused the short circuit which is the source of union and worker worries about the safety of the workplace.
An Arc Flash is an electrical explosion due to a fault condition or short circuit when either a phase to ground or phase to phase conductor is connected and current flows through the air. Arc flashes cause electrical equipment to explode and can result in an arc-plasma fireball with temperatures in excess of 35,000° F. For reference, the surface of the sun is 9000° F. These extreme temperatures cause rapid heating of surrounding air and extreme pressures, resulting in an arc blast. The arc flash/blast can vaporize all solid copper conductors as they expand up to 67,000 times original volume. The arc flash produces fire, intense light, pressure waves, and flying shrapnel.
Yallorn Power Station workers will not be asked to use affect equipment involved in the incident until EnergyAustralia determines that it is safe to do so. An executive of Yallourn Power Station has said that risk assessments are being conducted and that all safety controls will be reviewed prior to resuming work.
A representative of the union which advocates for the workers at Yallourn Power station has voiced concerns that workers were not provided with the most up-to-date protective gear, including arc flash suits, similar to what bomb disposal workers use.