The Transmission Company of Nigeria (TCN) has announced a fresh Abuja blackout after a 100MVA transformer at the Apo 132/33kV Transmission Substation tripped in the early hours of Wednesday, September 9, 2026.
The incident has disrupted supply through four 33kV feeders serving customers under the Abuja Electricity Distribution Company (AEDC). TCN said its preliminary assessment pointed to oil spillage on the red-phase high-voltage bushing of the affected TR4 transformer.
TCN maintenance engineers have begun a technical investigation to establish the precise cause of the failure and determine the repairs required to return the transformer to service.
The latest incident adds to a series of power interruptions affecting parts of the Federal Capital Territory in recent days, including planned maintenance work at transmission facilities serving several Abuja communities.
According to TCN, the transformer fault has taken four 33kV feeders out of supply.
The affected circuits are:
- H31
- H33
- H35
- H37
These feeders distribute electricity to AEDC customers within parts of Abuja. The immediate impact on individual communities can vary depending on how AEDC manages available supply across its network.
TCN said its maintenance team is examining the transformer to determine the exact fault and carry out the necessary corrective work.
The company has not given a definite timeline for full restoration, meaning customers connected to the affected feeders may have to wait for the technical assessment and repair process to be completed.
TCN’s preliminary finding identifies oil spillage on the red-phase high-voltage bushing as a possible factor behind the transformer trip.
However, the company is still conducting a detailed investigation. It has therefore not presented the preliminary observation as a final technical conclusion.
The distinction is important because transformer trips can result from several electrical or mechanical conditions, and engineers normally need to complete testing before identifying the precise failure mechanism.
TCN said the investigation is intended to establish the cause and enable its engineers to proceed with repairs.
The company also assured customers supplied through the affected feeders that efforts were underway to restore bulk electricity transmission through the transformer as quickly as possible.
The latest Abuja blackout comes only days after TCN carried out several maintenance activities affecting different parts of the Federal Capital Territory.
On September 6, TCN completed planned work at the Apo Transmission Substation after carrying out work on the Katampe-Apo transmission lines. Power was restored at about 4:08 p.m. after the maintenance exercise.
On September 8, TCN also conducted annual maintenance on the 132kV Katampe-Gwarimpa Transmission Line 1. The exercise affected supply to parts of Dawaki, Dutse Alhaji, Gwarinpa, Kubwa, Bwari, Zuba, Madalla and surrounding communities.
The current Apo transformer problem is different because it resulted from an unplanned equipment trip rather than a scheduled maintenance shutdown.
Planned outages allow electricity distributors and consumers to prepare for temporary interruptions. Unplanned transformer failures, however, can disrupt supply without a fixed restoration timetable because engineers must first diagnose the equipment before repairs can begin.
That makes the current incident particularly significant for customers connected to the four affected feeders.
TCN said its maintenance crew is already working on the affected transformer and conducting a detailed assessment.
The immediate priorities are to:
- Establish the precise cause of the transformer trip.
- Assess the condition of the affected bushing and related equipment.
- Carry out necessary repairs.
- Restore the transformer to service.
- Enable AEDC to resume normal off-take through the affected feeders.
TCN apologised for the disruption and said its engineers were working to restore bulk power supply as quickly as possible.
The latest incident also highlights the importance of transformer reliability within Abuja’s electricity infrastructure. A failure at a major transmission substation can affect multiple distribution feeders simultaneously, extending the impact beyond the immediate location of the fault.
For affected Abuja electricity customers, restoration will depend largely on the outcome of TCN’s technical assessment and the condition of the transformer.
TCN has not announced a fixed restoration time. Until repairs are completed, AEDC customers supplied through H31, H33, H35 and H37 may continue to experience interruptions.
The development comes against a backdrop of repeated transmission maintenance and equipment-related disruptions in the capital. While some recent outages have been scheduled, the Apo incident demonstrates how equipment faults can create additional pressure on electricity supply even after planned maintenance has been completed.
TCN’s ability to diagnose the fault quickly and return the 100MVA transformer to service will therefore determine how soon normal bulk electricity supply can resume for the affected feeders.
