Transformer explosion and fire at Duke Energy substation in Maineville, Ohio

In July 2024, an explosion and fire occurred at a Duke Energy transformer substation on the 8600 block of Butterworth Road in Maineville, Warren County, Ohio, United States. Multiple fire crews attended. The responding fire service reported that the substation stood several hundred feet from the nearest houses, that a piece of equipment had exploded, that the fire was still burning on arrival and that equipment within the site remained energised. Duke Energy publicly attributed the fire to an equipment failure and stated that no customers lost supply. No injuries were reported. The consequences were limited to loss of the affected asset and the fire service response.

Duke Energy publicly attributed the event to equipment failure. No further cause was published in the source at the time of reporting, and no investigation findings were available. The source also noted, through the fire service, that the separation between the substation and the nearest housing limited the exposure of third parties, and that supply was maintained to customers, which is consistent with protection operating to isolate the affected plant. Nothing further about the failure mechanism can be stated from the available reporting.

1. Confirm that the separation distance between substation plant and occupied buildings is recorded in the site fire safety case, and reassess it whenever plant is uprated or additional equipment is installed.
2. Provide responding fire services with pre-agreed information on which parts of a substation may remain energised during a fire, and on the isolation points and standoff distances to be used before water is applied.
3. Record protection operation during plant failures, including whether supply was maintained, and feed that evidence into decisions on protection and redundancy investment.
4. Do not rely on the timing of a failure or on the absence of staff on site as a safety control, and check that the fire safety case addresses personnel exposure for both attended and unattended periods.
5. Test out of hours response arrangements for unmanned sites, including callout, access and liaison with the fire service.
6. Carry out root cause analysis on the failed unit using a method that distinguishes unit specific from generic causes, and apply generic findings across comparable units in the fleet.
7. Agree the content and timing of public statements for substation fires in advance, so that customer impact and any public safety advice can be issued promptly and factually.
8. Review condition monitoring and maintenance intervals for transformers operating beyond their original design life, prioritising units where a failure would expose the public or critical supply.

fox19.com/2024/07/05/explosion-fire-duke-energy-substation