The Ceylon Electricity Board (CEB) has attributed the recent nationwide power outage to the high penetration of non-synchronous solar photovoltaic (PV) energy, which reduced grid inertia and heightened vulnerability to faults. The imbalance between electricity generation and demand led to cascading disconnections, ultimately causing a total blackout.
CEB spokesperson Eng. M.H. Dhammike Wimalaratne explained in a media release that the power failure, which occurred on February 9 at 11:13 AM, originated from a disturbance at the 33kV Panadura Grid Substation. This triggered a sudden voltage drop across the network, destabilizing the system.
At the time of the incident, over 50% of the national electricity demand was being met by 800 MW of solar PV generation, supplemented by 470 MW from the Lakvijaya Power Plant in Norochcholai and 130 MW from hydropower plants. The dominance of solar PV, which lacks synchronous generation, resulted in low grid inertia, making it susceptible to voltage and frequency fluctuations. The initial disturbance caused multiple solar PV systems to disconnect, exacerbating the instability and ultimately leading to a complete outage.
The tripping of the Norochcholai Power Plant was an automatic protective response to system instability, preventing severe damage to the plant and avoiding prolonged power failures. Additionally, the “Sunny Sunday” effect—where weekend demand is significantly lower while solar PV generation remains high—further contributed to grid instability. With most industrial and commercial operations offline, the grid operated at reduced demand and inertia, making it highly vulnerable to sudden fluctuations.
Immediate Corrective Actions
To prevent future occurrences, the CEB has implemented urgent measures, including:
Maintaining synchronous generators at minimum output and operating selected gas turbines in synchronous condenser mode to enhance grid stability.
Curtailing ground-mounted solar PV generation during low-demand periods when necessary to mitigate instability risks.
Medium-Term Strategies
The CEB is also accelerating several initiatives to strengthen grid reliability:
Adjusting rooftop solar PV inverter settings to prevent unnecessary disconnections during minor faults.
Introducing special industrial tariffs for weekends and holidays to encourage industries to operate during low-demand periods, thereby supporting grid stability.
Promoting solar PV installations with Battery Energy Storage Systems (BESS) and introducing a dedicated tariff for customers using BESS-equipped solar PV systems.
Long-Term Grid Stability Solutions
As part of its commitment to modernizing the power grid and integrating more renewable energy sources, the CEB is investing in long-term solutions, including:
Deploying grid-forming inverters with BESS to provide synthetic inertia and frequency stabilization.
Installing emergency backup generators at the Norochcholai Power Plant to enable rapid reconnection in the event of future disruptions.
Accelerating the Maha Oya Pumped Hydro Project (a 600 MW storage facility) to enhance grid flexibility and energy security.
Advancing Smart Grid investments to improve real-time monitoring and control of renewable energy integration.
The CEB acknowledges the inconvenience caused to the public and remains committed to ensuring a resilient and reliable electricity grid. As Sri Lanka transitions toward a renewable energy-driven power system, the CEB is proactively implementing both immediate and long-term solutions to enhance grid stability and energy security.
