MONETABRIEF – Sri Lanka's nation-wide power blackout October 18 was triggered by a steep drop in output from a coal plant which set off a cascading failure, Chief executive of the National Systems Operator, Buddika Samarasekera said.
At 11.43.32 am Norochcholai plant which was giving 187 MegaWatts to the system, dropped steeply to around 5MW. Unit 2 was generating 204MW and Unit 3 was generating 125MW.
The system frequency which was around 50.1 Hz had dropped below the lower threshold of 49.5 Hz setting off the cascading failure, he said. By 11.43.50, there was a total failure.
Saliya Panditharatne, Chief Executive of Electricity Generation Lanka Ltd said the boiler pressure had fluctuated and had tripped. On September 29, Unit 1 has been connected to the grid after maintenance.
The other two plants had later gone into emergency shutdown.
Cascading failures are usually set off due to failures of the transmission system, such as a tree fall or animal strike. But this time the culprit seemed to be a generator fault.
Engineers were waiting for the boiler to cool before putting water back into the pressure tank.
The three coal plants would take two to three days to re-start and re-connect to the system.
Until then there would be rolling power cuts in the night peak as the system only had 2,500MW of generators and demand was expected to be around 2700MW. (Colombo/Oct19/2026)