Nim Dorji | Trongsa

More than nine months after Mangdechhu Hydropower Authority’s (MHPA) turbine unit three broke down, restoration work is expected to complete next week.

MHPA official said that the unit would resume power generation by August 20. The 720MW plant shut down its turbine number three on September 21 last year.

A flashover has resulted in the burning and carbonisation of stator (a stationary part of a rotary system) windings and other rotor components inside the generator causing an electric short-circuit.

Flashover is a kind of spark that may be caused due to vibrations or insulation failure, which has created carbonisation in the machines. Carbonisation is the phenomenon of dirtying of stator windings and other components, with dark dust, inside the turbine when there are sparks or flash thereby causing an electric short-circuit.

The same unit was shut down for three weeks in June last year due to a fault developed in the stator of the turbine.

An official earlier said that such incidents are not fundamentally and electrically very catastrophic.

Such problems, according to officials, were expected during the operation and maintenance period of any new hydropower plant.

A similar flashover followed by carbonisation occurred in one of the turbines before but it was restored within a month.

Lately, the officials have been working round the clock to fix Unit III. Each of the three groups has around 17 workers and they work in three shifts.

It was learnt that workers from different power plants who have experience in the operation and maintenance were brought in to help expedite the restoration work.

According to a project official, the restoration work is almost complete and only two major testings are left. “The open circuit and short circuit will be conducted in the next two days,” the official said.

If everything goes as expected the plant will be put on the grid on August 20.

As of yesterday, the three units generated around 593.12MW. Each unit is generating around 197MW, which is 10 percent additional power above their capacity.

MHPA was completed in 2020 within seven years at a cost of Nu 51.442 billion. Each of the four units generates 180MW of electricity. 

Edited by Tshering Palden