The Norochcholai coal power plant will remain disconnected from the national grid for several days after being shut down as a precaution following Saturday’s (17) islandwide power failure, the National System Operator (NSO) Private Limited has said.
In a statement, the NSO said it was following standard safety procedures and would not reconnect the plant until the necessary steps were completed. The shutdown leaves the grid without 810 megawatts (MW) of generating capacity, and the company said it was taking steps to manage supply over the coming days to minimise the impact on consumers.
Weather is working in the grid’s favour. The NSO said prevailing rain had kept hydropower generation high, while electricity demand was expected to stay relatively low. Together, these factors should help maintain supply with minimal disruption.
How the system collapsed
The islandwide failure struck at around 11.43 a.m. on Saturday, after a generating unit disconnected from the national grid. The resulting imbalance caused the entire system to collapse in less than 30 seconds.
Restoration began soon after. Main hydropower units were brought back from around 12.11 p.m., and the system was restarted in four separate sections. The NSO said the process was complicated by small power generation sources that were not under the direct control of the system control centre.
Distribution feeders were reactivated from 12.37 p.m., and power to essential services, including major hospitals, water treatment plants and the airport, was restored by around 3 p.m. By 5 p.m., all grid substations had electricity, allowing supply to resume for most consumers.
Investigation under way
The NSO said the sudden disconnection of a generating unit is a normal safety occurrence at power plants. The collapse of the entire system after such an event, however, is not normal.
The company has launched an internal investigation into the sequence of events and the causes. NSO Chairperson Pradeep Priyadarshana said a formal investigation is under way, with a report due to the Public Utilities Commission of Sri Lanka and the Energy Ministry within a month. He told the media the report would also recommend measures to prevent a repeat.
Consumer group disputes the cause
Electricity Consumers’ Association (ECA) General Secretary Sanjeewa Dhammika disputed claims that the Upper Kotmale power plant caused the outage. Speaking to The Daily Morning, he noted that Upper Kotmale has a generating capacity of 140 MW and questioned whether the loss of a 75-MW unit could bring down the whole national grid.
He alleged that the Norochcholai plant was responsible, claiming problems involving low-quality coal were behind its failure.
Meanwhile, the Energy Ministry’s special media briefing, scheduled for 10 a.m. yesterday (18) at the Government Information Department, was cancelled. The Department said a new date and time would be announced later.
Source: Daily FT