Speed at which power was restored after recent blackout showed that system is working: Chan Chun Sing

SINGAPORE — Specific components used in the power generating units could be behind the massive pre-dawn blackout earlier this week, but there was sufficient capacity in the Republic's power system to restore power fully within 38 minutes in this instance.

The speed at which power could be restored islandwide following the blackout demonstrated that Singapore's power system is working as it should, said Trade and Industry Minister Chan Chun Sing on Friday (Sept 21). He was speaking to reporters on the sidelines of a press briefing on the nationwide roll-out of the Open Electricity Market initiative. 

"When the first system failed, the back-up system kicked in immediately. Even when the second system failed, we had sufficient capacity (that could be) started up (after) 15 minutes, and that was what happened. Hence, within 38 minutes, we were able to fully restore power to the entire system", he said.

Asked if there will be a penalty imposed on the electricity suppliers, Mr Chan said this is "premature", as the primary focus is to "get to the bottom" of the failure of the power generation units at Sembcorp Cogen and Senoko Energy.

On Tuesday, power trips at the generator units at the two companies caused a blackout which hit 19 estates across the island.

Mr Chan said the authorities were conducting further tests because some of the components in the affected generator units are also used by other power plants in Singapore as well as in other parts of the world.

"So we are working closely with the original equipment manufacturer to make sure that such things do not get repeated," he added.

The authorities also took the opportunity to review the backup power systems, and Mr Chan assured the public that these procedures are in place, based on preliminary investigations.

Tuesday's incident was the second major power outage in Singapore in three months. In June, more than 3,000 people were affected by a power outage in the Central Business District which lasted for 34 minutes.

HOW TUESDAY'S BLACKOUT OCCURRED

• The first generator (managed by Sembcorp) tripped, and the second generator (managed by Senoko) started ramping up additional supply as back-up, but it also tripped.

• If the two generators tripped more than 10 minutes apart from each other, the blackout would not have occurred, as the backup systems are able to ensure that there is spare capacity to restore power if only one generator tripped.

• But if the two systems trip around the same time, which was what happened on Tuesday, the authorities would take about 15 minutes to start up the fresh capacity.

• Hence, power could be progressively restored after 15 minutes following the power trip on Tuesday, with a total of 38 minutes taken to restore power to the entire power grid.

• Some buildings continued to suffer from intermittent power failure after that as they needed to reset the internal system unique to their buildings.

BACKGROUND TO THE BLACKOUT

• The blackout started a 1.18am on Tuesday, and ended at 1.56am.

• 19 estates across the island were hit: Boon Lay, Chua Chu Kang, Clementi, Jurong, Pandan Loop, Aljunied, Geylang, Tanjong Rhu, Mountbatten, Kembangan, Bedok, East Coast, Ang Mo Kio, Bishan, Thomson, Mandai, Admiralty, Sembawang and Woodlands.

• Nearly 147,000 households and businesses were affected.

CORRECTION: In an earlier version of the story, it was stated that Trade and Industry Minister Chan Chun Sing said the latest investigations revealed that the first generator unit that failed and its backup both shared the same components. He did not say this. We are sorry for the error.