After a workplace incident at Yallourn Power Station on November 12 last year that killed 54-year-old Unit Controller Graeme Edwards, EnergyAustralia has released the results of a complete investigation into the incident.
The investigation found:
- Graeme had reinstalled a circuit breaker following a scheduled major outage maintenance program. The procedure, known as “racking”, is a routine part of operations done by trained and authorised personnel.
- The circuit breaker was in its correct operating position and had not been reactivated, or “closed on”; that is, it was not operating.
- Evidence suggests that around this time a stainless-steel-housed communications cable made contact with the live parts of the circuit breaker. A communications cable relays information about the status of the circuit breaker to a control room.
- A protective panel designed to cover an open area at the top of the circuit breaker frame had not been properly secured. It dislodged during the racking-in process, which left a gap for the cable to get inside the cubicle and touch the live parts of the circuit breaker.
- When the communications cable touched the circuit breaker, a path was provided for electricity to the ground, creating a sudden, brief and intense flash of heat, known as an “arc flash”. The protective panel in place was unable to prevent the arc flash venting through the front of the circuit breaker cabinet.
The investigation found that Graeme performed the racking procedure as he had been trained to do.
EnergyAustralia has shared these findings with WorkSafe Victoria and says it will continue to update other power station operators in the region.
In light of these findings, EnergyAustralia has:
- Installed new protection relay switches at the Yallourn Power Station that increase the speed at which the supply of electricity is stopped when there’s a fault detected.
- Introduced new personal protective gear (for example, heat overalls) to be worn by unit controllers at Yallourn.
- Reviewed the status and condition of relevant high-voltage switchboards at all EnergyAustralia sites. This is in addition to an independent arc flash study, which defines the requirements for PPE when working on or around equipment.
In addition, newly designed blast resistant cubicle doors will be installed at the Yallourn Power Station by the end of the year, alongside second-layer arc flash detection devices.
EnergyAustralia is also exploring new approaches for its unit controllers to remotely rack circuit breakers, supported by machinery.
EnergyAustralia managing director Catherine Tanna said, “Our first duty is to keep people safe when they are on our site. We failed Graeme, his family and his workmates. We’re sorry”.
“We have co-operated with WorkSafe Victoria and Energy Safe Victoria. We have done a thorough investigation of the incident. We will share the main findings with other operators of large power plants.
“We have upgraded protective equipment and technology, and while our people get comfortable with the new measures they will not reinstall circuit breakers on live switchboards. We are determined to make sure no other family goes through what the Edwards’ have experienced.”
Graeme was described as being hardworking, popular and a gentleman. He worked at the power station for 30 years. His death has had a profound impact on his family, workmates, and the community.
