NISO blames tripping of 330kV lines for first national grid collapse of 2026

 

The Nigerian Independent System Operator (NISO) has attributed Friday’s national grid collapse to a system-wide disturbance caused by the tripping of multiple 330kV transmission lines and the disconnection of some power-generating units.

Data from NISO showed that load allocation to all 11 electricity distribution companies dropped to zero megawatts (MW) at about 1 pm, marking the first national grid collapse of 2026.

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In a statement on the incident, the operator said total power generation fell to zero at approximately 12:40 pm, resulting in a nationwide blackout.

“Preliminary operational reports indicate that the disturbance was associated with the simultaneous tripping of multiple 330kV transmission lines, alongside the disconnection of some grid-connected generating units,” NISO said.

“These events collectively contributed to the system collapse at the time indicated.”

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NISO said restoration efforts began shortly after the outage, with power supply already restored to several locations across the country.

“Following the outage, system restoration activities commenced at about 13:15 hours, in accordance with established grid restoration and recovery procedures,” the operator said.

“As of the time of this update, electricity supply has been successfully restored to Abuja, Osogbo, Benin, Onitsha, Sakete, Jebba, Kainji, Shiroro, and parts of Lagos, while restoration efforts are continuing progressively in other parts of the country.”

The operator added that investigations into the cause of the grid collapse are ongoing, noting that full restoration and stabilisation of the grid remain a top priority.