An accident in the 500 MW seventh unit of Dr. Narla Tata Rao Thermal Power Station (NTTPS) near here on Tuesday, the second in less than a month, resulted in stoppage of power generation, thus continuing the teething troubles of the unit commissioned in April.

It was only on October 26 that a major blast occurred in the generation transformer of the unit, triggering a fire that could have blown up the radiator containing about 50,000 litres of oil but for the timely action.

Unit linked to grid

Since then the technical personnel of BHEL, which executed all the engineering works relating to the unit, as well as the officials of AP Genco have been struggling to bring the unit back into action.

Chief Engineer S. Anjaneya Rao told The Hindu that after several efforts the unit was linked to the grid a couple of days ago once all the tests were completed. Power generation from the unit was gradually scaled up to reach 361 MW on Monday.

On Tuesday morning, when the generation came down to 316 MW due to load variation, the accident occurred in the generation bush that links the transformer to the grid.

Incidentally, the problem occurred for the second time in the same transformer of all the total three generation transformers in the unit. He said the time required to bring back the unit into action will be known by Wednesday.

Mr. Anjaneya Rao said that the generation bush, which remains in oil, went off and triggered a fire for about 5-8 minutes but it was immediately brought under control due to the availability of fire tenders.

‘No full possession’

He said that the NTTPS had not taken full possession of the unit as it had not been able to generate 500 MW continuously for 72 hours, which was one of the conditions that the BHEL would have to meet.

The second blast in less than a month attracted much criticism, with local MLA Devineni Umamaheswara Rao (Mylavaram) of the TDP blaming the “poor track record” of BGR Energy that executed some of the works in the unit for the recurring problems.

He said the company was given works relating to not just this unit but in two other thermal power stations in the State as well in violation of several rules.

However, Mr. Anjaneya Rao asserted that BGR Energy executed only the civil works of the unit and the BHEL was responsible for any technical problem that would crop up in the unit.

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