HKE makes big moves to avoid another power fail

Hongkong Electric has suspended all renovation in power supply facilities until it strengthens circuit labeling and maps in the aftermath of a Hong Kong Island blackout caused by human error last month.

A new review mechanism has been introduced to have at least two engineers doing on-site inspections together to avoid misjudgment.

The power giant yesterday submitted to authorities a report explaining the 48-minute power suspension in the early hours of April 19 that affected 44,000 customers, as well as improvement measures.

Speaking to the press, HKE general manager of transmission and distribution Ip Sung-tai said the company was carrying out renovation work and adjustments at Cyberport electrical substation where a spare cable was accidentally electrified, causing a voltage plunge that led to the blackout.

Ip said the engineer carrying out the adjustment was looking at an energy management system circuit diagram, which did not mark the spare cable.

"We require all engineers to inspect the cables on-site and the engineer did that, but there was a fireproof box under the electric switch. So he could not see the spare cable being connected to the switch," he said.

"We noticed that we did not have a review mechanism, meaning there should be two engineers inspecting the circuit diagrams and the situation on-site."

HKE has suspended all renovation works pending review and update of the guidelines, Ip said.

It has also inspected all electric systems and separated four spare cables from them. Labels have been put up marking spare cables on-site so that engineers can be aware of the situation.

Ip said the company has come up with seven improvement measures, including updating the guidelines on labels and circuit diagrams, separating all spare cables from the system, enhancing training for engineers and reviewing the work of its customer service center.

It will hire experts to review the incident, he said.

Operations director Francis Cheng Cho-ying apologized to the affected customers again.

"This is Hongkong Electric's first serious blackout accident in nearly 30 years. It is very rare," he said.

Cheng said the spare cable was marked on other circuit diagrams but not included in the energy management system circuit diagram, which was used by the engineer last month. It was installed a decade ago as the spare cable would not be used most of the time.

He added the engineer has followed guidelines, but did not notice the spare cable due to "a lack of alertness."

Cheng said: "If there is no cable connection, there shouldn't be a fireproof box. The engineer had a suspicion but did not prove it."

He said the engineer would not have to spend so much effort if the circuit diagrams and labels on-site were clear.

"If our management system did well, this accident should not have happened."

Cheng said the engineer has been transferred to a support section and can return to the previous position once he passes all assessment tests.

The Electrical and Mechanical Services Department said it is examining the HKE report with an independent third-party expert to evaluate "whether the identified cause is well founded and improvement measures are appropriate."

Legislator Edward Leung Hei said HKE might have violated the Electricity Ordinance.

wallis.wang@singtaonewscorp.com