The Nigerian Independent System Operator has confirmed that Tuesday’s nationwide grid collapse was caused by a voltage disturbance at the Gombe transmission substation.

In a statement released on Tuesday, NISO provided updates on ongoing repair and restoration efforts.

The operator noted that the incident led to a partial system collapse, representing the second grid disturbance recorded in 2026.

NISO stated that electricity supply across the affected areas has been fully restored following prompt corrective measures by its technical teams.

The agency explained that the disturbance began at the Gombe transmission substation and subsequently affected other parts of the network.

NISO emphasized that the incident did not constitute a total system collapse, as some media reports had suggested.

“The national grid has been fully restored, and electricity supply across the affected areas has since returned to normal.

“The incident only affected part of the national grid, therefore not a total collapse.

“The event was accompanied by the tripping of some transmission lines and generating units, resulting in a partial system collapse,” NISO added.

The system operator said that restoration efforts began immediately after the disturbance and were completed within hours.

NISO disclosed that the voltage disturbance rapidly spread across the transmission network, impacting several substations.

According to NISO, corrective measures were promptly implemented to stabilise the system and restore normal grid operations.

Nigeria’s power grid has faced recurring disruptions in recent years.

In 2025 alone, the national grid experienced multiple collapses, with the most recent incident recorded on December 29.