The central transformer at 128-KV Sub-station’s switch yard exploded and caught fire around 3am Wednesday, said the plants director Sajjadur Rahman.
The units are capable of producing 120MW of electricity.
Unit-2 with 64 MW capacity, GT-2 unit with 56 MW capacity, Unit-3 with 150 MW and 50 MW gas engine unit, shut down immediately.
Unit-3 and the gas engine unit were restored around 7am Wednesday but the remaining two could not be fixed until 1:30pm.
Rahman could not provide a cause for the explosion that led to the fire.
Ashuganj Fire Service duty official Shahidul Islam said oil from the exploded transformer led the fire to spread quickly.
The incident comes barely two weeks after the countrywide power outage on Nov 1.
The nine units at Ashuganj Power Plant shut down after the national grid dropped. The committee probing the incident has blamed on an ‘internal flaw’ at the National Grid for the eight-hour power outage.