VietNamNet Bridge – Two transformers, AT1 and AT2, of the Hiep Hoa 500KV transformer station in Bac Giang Province, failed to operate for one week in mid-May, affecting sufficient electricity output to the capital city of Hanoi.

The information about the troubles occurring with the two transformers has raised big worries to businesses and residents in the capital city.

The transformers had oil leaking out which then led to serious trouble. They were disconnected from the network immediately for having problems. As a result, the Electricity of Vietnam (EVN) had to stop providing 1,000 MW of electricity to the capital city area.

The noteworthy fact was that both transformers were made in China and the problems occurred right after the maintenance period was completed.

At 9.20 am on May 14, AT1 suddenly had oil leaking out, resulting in an electricity cut to the transformer when it was receiving electricity from the 500KV electricity system at the capacity of 700MW. The trouble caused overloading to a series of arterial lines and  lower voltage in the area.

After the incident, EVN’s engineers had to isolate AT1 transformer to check and fix problems.

Just exactly one week later, on May 21, AT2 transformer also broke for the same reason.

EVN has not made any official statements about the serious incidents. However, people easily recognized the outage at some transformer stations in some provinces.

It is estimated that the unprecedented incidents caused a loss of 600MW of electricity in total. More dangerously, they threatened electricity supply to the capital city.

Phap Luat newspaper quoted its sources as saying that by late last week, the troubles still had not been fixed.

Experienced power experts have all affirmed that the incidents are really “worrying” for two reasons. First, this was for the first time since the day the 500KV transmission line was put into operation that such a serious problem had occurred successively at an important transformer station.

Second, both the transformers were made in China and the troubles occurred right after the warranty period ended.

“I know troubles may occur and risks always exist. But there should not be problems  at nearly the same time for two transformers,” an experienced expert said.

“What would you say about the reliability of the power system if two serious problems occurred just within one week?” he questioned, adding that as the outage occurred at Hiep Hoa Station, other transmission lines and stations suffered from overloading.

The expert said EVN sets European or US standards for the power sector. Most of the transformers (more than 90 percent) used for the national grid are sourced from Europe or prestigious manufacturers.

They have been operating very well over dozens of years. But EVN recently bought Chinese products.

“What do you want, a European expensive product worth VND100 billion which can be used for 30 years, or a cheap Chinese product worth VND60 billion which can be used for two years only?” he said, adding that he believes EVN knows well what the answer is.

Phap Luat