• NSO says supply will be managed as an investigation begins 
• ECA blames low-quality coal

The Norochcholai coal power plant will not be reconnected to the national grid for several days after being shut down as a precaution following the islandwide power failure on Saturday (17), the National System Operator (NSO) Private Limited stated.

In a statement, the company said it was following standard safety procedures and would not reconnect the plant to the system until the necessary steps had been completed.

The shutdown has left the grid without 810 megawatts (MW) of generating capacity. The NSO said it was taking steps to manage electricity supply over the coming days to minimise the impact on consumers.

It added that the prevailing rainy weather had allowed hydropower generation to be maintained at a high level, while electricity demand was also expected to be relatively low. These factors were expected to help maintain supply with minimal disruption, the company said.

The islandwide power failure occurred at around 11.43 a m on Saturday after a generating unit disconnected from the national grid, causing an imbalance that led to the entire system collapsing in less than 30 seconds.

The company said restoration work began shortly afterwards. Main hydropower generating units were brought back into operation from around 12.11 p m, with the system restarted in four separate sections.

It said the restoration process was complicated by small power generation sources that were not under the direct control of the system control centre.

Power supply to essential services, including major hospitals, water treatment plants and the airport, was restored by around 3 p m through the reactivation of distribution feeders that began at 12.37 p m. 

By 5 p m, electricity had been restored to all grid substations, allowing supply to be resumed for most consumers, the company said.

The NSO further said the sudden disconnection of a generating unit was a normal safety occurrence at power plants. However, the collapse of the entire electricity system following such a disconnection or another disruption was not normal.

The company has launched an internal investigation to establish the sequence of events that led to the outage and identify its causes.

NSO Chairperson Pradeep Priyadarshana said a formal investigation was under way and that a report would be submitted to the Public Utilities Commission of Sri Lanka and the Energy Ministry within a month.

Speaking to the media, he said the report would also recommend measures to prevent similar incidents in the future.

Meanwhile, Electricity Consumers’ Association (ECA) General Secretary Sanjeewa Dhammika disputed claims that the outage had been caused by the Upper Kotmale power plant.

Speaking to The Daily Morning, he said Upper Kotmale had a generating capacity of 140 MW and questioned whether the loss of a 75-MW unit could have caused the entire national grid to collapse.

He alleged that the Norochcholai plant was responsible for the outage and claimed that problems involving low-quality coal were behind its failure. 

Furthermore, the Energy Ministry’s special media briefing scheduled for 10 a m, yesterday (18) at the Government Information Department was cancelled. The Department stated the new date and time would be announced later.