Offshore staff
OSLO, Norway — The Norwegian Petroleum Safety Authority (PSA) has concluded its investigation of a fire in a high-voltage transformer on the Åsgard B gas production platform in the central Norwegian Sea last November.
Smoke and a fire broke out due to overheating and a short circuit/arc flash in a dry-type HV transformer in the utilities area on the lower deck of the platform, part of the Åsgard field complex (the field came onstream in 1999).
The investigation determined that the short circuit/arc flash were caused by impairments to and/or degradation over time in the winding insulation.
Other underlying causes of the breakdown were identified as local failure and partial discharges because of transient surges from the 11-kV switchboard; and issues associated with the configuration of the system for direct electric flowline heating could have contributed over time to internal impairments in the transformer.
Although no one was injured, the incident caused a transformer breakdown and loss of production.
The fire in the transformer room did not appear to have a major accident potential, as the room was designed to withstand fire, with little flammable material present in the area.
But the team did identify one non-conformity related to following up and learning from incidents. And it highlighted two conditions warranting improvement points related to barriers and the door impaired A-60 firewall.
06.09.2023
