The Nigerian Independent System Operator (NISO) has attributed recent changes in power allocations to Distribution Companies (DisCos) serving Lagos, Abuja and northern corridors to multiple transmission line outages.

NISO, in a statement issued on Sunday, said the outages affected available transmission capacity and the network configuration at different times.

The organisation said the adjustments were part of normal system operations aimed at keeping the interconnected network within safe operating limits.

“The changes in allocations occurred due to multiple transmission line outages that affected available transmission capacity and configuration of the network at different times,” the statement said.

NISO explained that generation availability alone does not guarantee that electricity can be delivered to a particular load centre.

It said power transfer depended on the availability and capacity of transmission infrastructure, as well as the prevailing configuration of the network.

The system operator said it continuously assesses available transmission capacity and network configuration to determine safe generation dispatch and load allocation.

NISO, as the Independent System Operator responsible for real-time monitoring, coordination, control and dispatch of the interconnected Nigerian Electricity Supply Industry, said the measures were necessary to maintain system security.

The statement reads In part, “Lagos Complex: The Lagos complex was affected by successive outages of the Olorunsogo–Ayede 330kV Line 1, Benin–Egbin 330kV Line 1 and Benin–Omotosho 330kV Line 1, in addition to the prolonged outage of the Osogbo–Ikeja West circuit.

“The cumulative loss of these critical circuits reduced the transmission transfer capability into the Lagos axis. Consequently, NISO reviewed and curtailed load allocations to Eko Electricity Distribution Company (EKEDC), Ikeja Electric Distribution Company (IE) and the Sakete international supply, in accordance with the prevailing network configuration and system-security requirements.

“Northern Corridor: The Northern corridor experienced tripping of Shiroro–Mararaba 330kV Line 1 from 24 to 26 August 2026.

“This affected load allocation to Abuja and the northern part of the country, as load was supplied solely through the remaining circuit.

More significantly, at 06:47 hrs on 27 August 2026, the Shiroro–Mando 330kV Line 2 and Mando–Jos 330kV Line 1 tripped simultaneously.

During that time, the Mando–Jos 330kV Line 1 was the only available transmission circuit serving the Jos and North-East areas.

“The alternative circuits, Apir–Lafia 330kV Lines 1 and 2, have been out of service for an extended period due to faults.

“The simultaneous outage resulted in a significant loss of transmission supply to the Jos and North-East areas.

The separation of the bus at the Mando Transmission Substation further altered the network configuration and constrained power transfer to the affected northern load centres.

“This condition necessitated the revision and curtailment of power allocations to Kano, Kaduna, Jos, Yola and other affected areas in order to operate the remaining network within secure limits. Abuja axis: At 03:55hrs on 29 August 2026, the Shiroro–Katampe 330kV Line 1 and Gwagwalada–Katampe 330kV Line 1 tripped simultaneously, temporarily constraining transmission supply to the Abuja axis.

“The circuits were restored at 07:25hrs and 07:20 hrs, respectively, following which the affected transmission capacity was recovered.

“The events described above demonstrate the interconnected nature of the Nigerian power system, where the outage of a critical transmission circuit can affect power transfer beyond the immediate geographical location of the outage.

“Generation availability does not automatically translate into deliverable power to Distribution Companies. Adequate transmission capacity and a secure network configuration are equally essential.

“Where transmission constraints or changes in network configuration affect the ability to safely transfer available power, NISO needs to temporarily redispatch generation, curtail load or revise DisCo allocations in order to maintain system security and prevent wider network disturbances.

“Accordingly, the recent changes in power allocations resulted from transmission line outages, constrained transmission capacity and system configuration prevailing at the respective times, rather than being attributed to generation availability.

“This clarification is intended to put the relevant facts on record and provide the public with a clear understanding of the circumstances surrounding the recent changes in power allocations.” (The Nation)