Circuit breaker trip at Chatty substation cuts power to Nelson Mandela Bay industrial areas

What happened

On 27 June 2023, as heavy rain fell in Nelson Mandela Bay, a 133kV circuit breaker at Chatty substation tripped. The Nelson Mandela Bay Municipality confirmed that the industrial areas of Perseverance, Deal Party and Struandale were without power from mid-morning until after 5pm. The cause of the trip was not stated. The Nelson Mandela Bay Business Chamber said it had recorded 36 power failures in the metro's industrial areas since the start of the year, none of them because of rolling blackouts.

Contributing factors

The municipality and the Business Chamber described recurring outages as linked to aged infrastructure that had not been regularly maintained, frequent load-shedding switching across about 3,000 substations, failing switchgear, vandalism of cables and substations, and too few experienced electricians. These points were not confirmed as the cause of this trip.

Lessons learned

1. A confirmed breaker trip should be recorded with the affected circuits and restoration time, even when the cause is not yet known.
2. Repeated unplanned trips on the same network are a prompt to inspect switchgear before the next failure.
3. Where frequent switching, vandalism or staff shortages are already reported, restoration plans should allow for longer outages.

Source

dailymaverick.co.za