Hawaiian Electric plans to replace a transformer but fears that more outages will occur
POSTED: 01:30 a.m. HST, Dec 24, 2010
LAST UPDATED: 02:46 a.m. HST, Dec 24, 2010
Hawaiian Electric Co. hopes to replace a destroyed transformer for Ala Moana Center by this weekend, but the utility fears there could be further outages as it slowly switches from shaky backup systems.
Since Sunday, four short circuits in three days have plunged dozens of stores into darkness at Hawaii's largest shopping center.
HECO hopes to avoid more outages on the day after Christmas—one of the most critical shopping days for retailers.
"You can imagine (Ala Moana is) very sensitive to the day-after-Christmas shopping day," said Colton Ching, HECO's vice president for system operation and planning. "It's a big day for them."
HECO crews have been working nearly nonstop to rewire normal backup power service in order to keep the lights and air conditioning running at the mall.
"Although we can provide power, the redundancy was lost," Ching said. "We never want to stay in that situation if we can avoid it. But we don't have other options for providing service."
Even after a permanent transformer is installed this weekend, Ching said, electrical service has to be delicately returned from the backup circuits or the risk of further outages increases.
The series of power failures that began with Sunday's downpour overwhelmed Honolulu's storm drains and damaged HECO's outdoor Makaloa 2 transformer at its Makaloa Street substation mauka of Ala Moana Center, Ching said.
Makaloa 2 supplies the usual power to the Diamond Head end of Ala Moana Center with another transformer—Makaloa 1—serving as its backup.
On Sunday morning at about 7:30 a.m., water seeped into Makaloa 2 and triggered an electrical fire that destroyed the transformer and its "switch gear," which is used to quickly transfer electricity during short circuits and other problems. It also shut down Makaloa 1.
Before HECO crews could rewire power to the Diamond Head end of Ala Moana Center, they first spent two to three hours pumping rainwater from manholes, then checking the underground air for possible contamination, Ching said.
HECO's underground power lines are designed to operate in normal rain but are not accustomed to being submerged. The water in the hole accumulated to a depth of 5 or 6 feet during Sunday's storm, Ching said.
Over the next few days, the rewired backup lines began short-circuiting—perhaps stressed by the unusual electrical demands on the system, Ching said.
CHING TOLD the Star-Advertiser yesterday that the events that began at the Makaloa Street substation were "extraordinary"—even for a utility company that has endured islandwide outages lasting more than 24 hours.
"Many, many things happened over the course of the last several days," Ching said. "You can all bring it back to the fact that we had a huge amount of rain that compromised the switching gear. We had a fire and rain and flooding that then impacted the cabling in terms of the different loads on the cabling while being immersed underwater. The combination resulted in the outages. Then delays were created because we had to pump out huge amounts of water before starting repairs."
Transformers at other substations around Oahu also suffered water seepage and power disruptions during Sunday's deluge, but did not catch fire, Ching said.
He could not immediately identify the substations or account for all of them, but said, "It was more than a couple."
He said HECO's metal transformers represent the latest technology in the industry and are designed to withstand normal weather.
"They're standard," Ching said.
As soon as the shopping center's main transformer went down, Ching and other HECO officials began planning for the possibility of other short circuits in Ala Moana Center's backup systems, which quickly began occurring.
Adding a second backup system is highly unusual and "an extremely costly thing to do" for most HECO customers, Ching said.
But some military installations on Oahu—which Ching declined to identify—have installed additional backup systems, he said.
"I can't go into details," said Ching, a University of Hawaii graduate who as a civilian nuclear engineer worked on Navy submarines.
In general, Ching said, "There's not enough money to make something failure-proof. ... There's no way we guarantee that something like this won't happen again."
Corporate representatives for some of Ala Moana Center's major tenants, such as Macy's and Sears, did not respond to questions yesterday about the Christmas sales they lost this week—or whether they plan to file claims for losses against HECO.
Ala Moana Center spokeswoman Jasmin Tso declined to comment on lost sales or possible claims against HECO by retailers.
But Darren Pai, HECO's spokesman said, "We understand it's an important time for Ala Moana."
Two transformers at the Makaloa Street substation—Makaloa 1 and Makaloa 2—provide power to the Diamond Head side of Ala Moana Center. Makaloa 2 is the primary source of power, and Makaloa 1 is the backup.
1. On Sunday at 7:30 a.m., rain seeped into the Makaloa 2 switch gear and caused a "flash over" short circuit that triggered an electrical fire. Makaloa 2 and its switch gear were destroyed, and the adjacent Makaloa 1 transformer shut down. Both the primary and backup sources of power to the Diamond Head side of Ala Moana Center were lost.
2. HECO crews began repairing the damaged Makaloa 2 transformer and switch gear, an involved process with multiple steps that takes days to complete. At 11 a.m., HECO restored the Makaloa 1 transformer, and power was returned to the Diamond Head side of Ala Moana Center using power from another backup source.
3. On Monday at 7:30 a.m., the backup circuit between the Makaloa substation to the Diamond Head side of Ala Moana Center failed, causing power to go out once again. In order to repair this short circuit, HECO workers engaged in the time-consuming process of finding the location of the short circuit by going into multiple flooded manholes.
4. By 1 p.m., HECO workers had initiated a contingency measure and tied the primary Ala Moana cable into a third circuit that serves the Ewa-makai side of the shopping center.
5. At 2:30 p.m., this third circuit was lost due to another short, causing a power failure at the Ewa-makai side of the shopping center. Working through the night, another set of HECO workers began a separate process of finding the location of the short on this third circuit.
6. Meanwhile, the location of the original short circuit was found within the Makaloa substation, and power was restored by 10 p.m. that night for the Diamond Head side of the shopping center.
7. On Tuesday at 2 a.m., HECO identified the location of the short circuit on the third circuit, and workers began work to repair the short along Kapiolani Boulevard but had to delay repairs at 5 a.m. to clear the road for morning contra-flow traffic.
8. By 2 p.m. Tuesday, power was restored to the Ewa-makai portion of Ala Moana.
9. On Wednesday at 7 p.m., the Diamond Head side of Ala Moana experienced a third outage due to another underground cable short circuit. Sears also lost power. Within an hour HECO had restored power for Sears and the Diamond Head side of Ala Moana Center. HECO crews worked through the night to find and repair this short circuit on the backup circuit.
10. On Thursday at 7 a.m., stores on the Ewa-makai side of Ala Moana were returned to their normal circuit. Stores on the Diamond Head end were returned to their normal backup circuit.
11. Repairs to Makaloa 2 continue, and normal service is expected to resume sometime this weekend.