Fire damages transformer at Egbin substation

What happened

The Transmission Company of Nigeria said a fire at Egbin Power Plc at about 6:30 a.m. on a Tuesday affected its 150MVA 330/132/33kV Inter-Bus Transformer II at the Egbin Transmission Substation. The fire started in a service transformer owned by Egbin Power and connected to the 33kV side of that transformer. Preliminary investigations traced the fire to a faulty 33kV instrument transformer (CT/VT) installed by Egbin Power. The incident damaged the TCN transformer, with oil leaking from a tear in its main tank.

A load of 47MW was affected. Bulk supply was temporarily reduced to the Ikorodu and Odogunyan 132/33kV substations and to Sagamu Lines 1 and 2 and Maryland Line 2 in Lagos State. The load was diverted to the substation's second 150MVA transformer, which was reported to be operating under strain, and load-shedding followed.

Contributing factors

TCN said preliminary investigations traced the fire to a faulty 33kV instrument transformer (CT/VT) installed by Egbin Power. The full cause has not been independently confirmed.

Lessons learned

1. Instrument transformers on the lower-voltage side of inter-bus transformers need regular inspection, because a fault there can damage the main transformer.
2. Isolation and protection between a power station's service transformers and transmission assets should be checked so a station-side fault does not cascade.
3. Spare capacity or a rapid replacement plan for a critical substation transformer limits how long customers face load-shedding.

Source

gazettengr.com