Current transformer explosion at Jebba substation disturbs Nigeria's national grid

What happened

On 19 October 2024 at 08:15, the bus section of a current transformer exploded at the 330 kV Jebba Transmission Substation. The Transmission Company of Nigeria said protection opened the busbars, preventing fire and further damage to adjacent equipment, and described the result as a temporary grid disturbance. National supply fell from 3,041.72 MW at 08:00 to 47 MW by 09:00, with seven of 11 distribution companies reported to have zero load allocation.

The regulator said the explosion triggered a cascade of power plant shutdowns and that supply had been significantly restored in 33 states and the Federal Capital Territory by 13:00. A separate report of vandalism on the Shiroro-Kaduna lines was also published; it was not identified as the cause of this explosion.

Contributing factors

The reported trigger was the explosion of a current transformer. The cause of that explosion was not stated. Protection isolated the fault but also disturbed the grid and was followed by a cascade of plant shutdowns.

Lessons learned

1. Protection that isolates a failed current transformer can prevent fire, but the same trip can disturb a tightly coupled grid.
2. After a busbar trip, operators need a rehearsed way to reconfigure and restore supply without waiting for the failed unit to return.
3. A single substation fault can cascade into widespread loss of load, so contingency arrangements should limit how far one trip takes generation offline.

Source

vanguardngr.com