Koeberg nuclear station reduces output after transmission line fault
Jan 2026Published 1 Oct 2026Responsible editor: Chief Editor
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Companies named in the reporting of this entry (being named is not a finding of fault): Eskom, National Transmission
What happened
On 20 January 2026 at 16:53, both units at Koeberg Nuclear Power Station were reduced from full power to 100 MW each after a fault on the 132 kV transmission lines supplied from the Pinotage transmission substation near Stellenbosch. Eskom said the reduction was an expected response to protect the station and the national grid. The nuclear reactors were not affected, and the National Nuclear Regulator was informed. The National Transmission Company South Africa approved a start to raising output. Eskom reported no risk of loadshedding and no impact on grid stability.
Contributing factors
A fault on the 132 kV transmission lines supplied from the Pinotage transmission substation. The cause of that line fault was not reported.
Lessons learned
- A fault on lines feeding a power station can require output to be reduced to protect the station and the grid.
- Prompt notice to the regulator supports transparency when a station changes output because of a grid fault.
- Generation reserves can limit supply disruption when a station reduces output.
More lessons on emergency response and public communication, outages, backup supply and restoration, from every incident on the register.
Source
Published 2026-10-01. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
