Substation fire leaves Pretoria East residents without power

What happened

A fire followed an explosion of an underground cable in Disselboom Street, Wapadrand, Tshwane, on a Saturday evening in July 2021. The fire damaged equipment at the Wapadrand substation, and residents across several Pretoria East areas were left without electricity. On the Monday morning, supply had still not been restored in some areas. The city's utilities department tested the equipment inside the substation and planned to energise the substation first, then the secondary substations and suburbs in turn.

Power was to be restored to users only once that full sequence was complete. Replacement switchgear panels were brought from the Orchards substation to replace the burned panels, and these were to be energised together because they are connected through the busbar. Restoration targets were given as estimates and were subject to change.

Contributing factors

The source reports an explosion of an underground cable and burned switchgear panels at the substation. It does not state the cause of the explosion.

Lessons learned

1. Underground cable faults can cause explosions that damage nearby substation switchgear, so cable condition and joint integrity should be checked as part of routine maintenance.
2. Where burned panels share a busbar, they cannot be energised individually, so operators should plan restoration sequences and communicate them to customers in advance.
3. Keep spare switchgear panels available at nearby sites so that damaged sections can be replaced quickly and supply restored with less delay.

More lessons on electrical protection and isolation, outages, backup supply and restoration, from every incident on the register.

Source

jacarandafm.com