Switchgear explosion at Drowell substation causes mass power outage

What happened

At about 18:30 on Tuesday 17 January 2023, one of the main switchgears at the Drowell Substation in Rand West City exploded, shortly after a period of load-shedding. The blast left large parts of the town without power, including Randpoort, Loumarina, Elandsvlei, Townlands, Wheatlands, Greenhills, Helikon Park and Dan Tloome, and parts of Culemborg Park, Homelake and OR Tambo. The electrical department was notified immediately. Smoke and carbon inside the substation meant crews could not begin work that evening.

On 18 January, technicians were on site to replace the switchgear, repair panel damage and clean carbon dust from the panels. The council said power should be restored that day, but warned this could not be guaranteed if further faults were found during the work.

Contributing factors

The source does not state the cause of the explosion. It records only that the switchgear exploded shortly after load-shedding, without linking the two events. Further faults identified during repair were cited as a possible cause of delay.

Lessons learned

1. Switchgear is a single point of failure for wide areas, so thermal scanning, partial discharge monitoring and routine maintenance of main switchgear are worth prioritising.
2. After a switchgear fault, smoke and carbon deposits can prevent safe entry for hours, so ventilation and safe-entry checks should be built into the response plan.
3. Restoration estimates should allow for secondary faults found during repair, and residents should be told that the timeline is provisional.

More lessons on detection and monitoring, electrical protection and isolation, emergency response and public communication, from every incident on the register.

Source

citizen.co.za