The Oct. 15 outage that left 291,000 O'ahu households without electricity for most of the day could have been avoided had Hawaiian Electric Co. replaced several palm-sized switches with ones that are better suited for earthquakes.

The switches, once available at Radio Shack, gave false readings that a fluid was low and triggered the automatic shutdown of two of HECO's largest generators. That in turn caused other generators to shut down in a cascading effect until the entire island was left without power.

"The HECO system would have survived" if not for the shutdown of those two generators, concluded a 90-page report submitted to the state Public Utilities Commission yesterday.

According to the study, which was commissioned by HECO and conducted by Idaho-based Power Engineers Inc., "HECO personnel reacted to the circumstances in a reasonable, responsible and professional manner."

The $64,000 report blamed the blackout on the manufacturer-installed mercury switches at HECO's Kahe power plant and recommended replacing the switches "with a type less likely to give false indications under earthquake conditions."

HECO spokesman Jose Dizon said the company is in the process of replacing the mercury switches with dry contact switches that are less likely to give false readings.

Utility industry experts said mercury switches shouldn't be used in earthquake zones.

"Those mercury switches are perfectly fine ... 95 percent of (the time), but not in this case," said Stan Johnson, manager of situation awareness and infrastructure security at the North American Electric Reliability Council. Princeton, N.J.-based NERC is a quasi-regulatory body that develops and enforces reliability standards for the nation's utility industry.

"You don't use them in places that are prone to earthquakes," Johnson said.

Dizon said HECO hasn't encountered any problems with the switches in the past. He said the switches were installed in the Kahe power plant in the 1970s and 1980s.

"This is the first time we experienced a generation-related islandwide outage," Dizon said.

DAMAGE CLAIMS

Although the outage's economic toll was negligible, it caused major inconveniences for O'ahu residents.

Dizon said that the company has received damage claims from about 1,400 isle customers. He said HECO is awaiting the outcome of the PUC's investigation into the outage before it considers paying any damages. He added that awards will be made on a case-by-case basis.

The Oct. 15 blackout occurred after 6.7- and 6.5-magnitude earthquakes rocked the Big Island.

In its report, Power Engineers said two of HECO's largest turbines — the 142-megawatt Kahe 5 generator and the 142-megawatt Kahe 6 generator — automatically shut down after the mercury switches incorrectly indicated that the generator's fluid levels were low and that the generators could be severely damaged.

According to HECO, the shaking from the earthquake caused the liquid mercury in the switches to sway, resulting in the false reading.

The two Kahe power plants represent about 23 percent of HECO's capacity that was running at the time of the quakes.

In addition to replacing the mercury switches, Power Engineers recommend that HECO re-evaluate the lockout mechanism that prompted the shutdown of the two big generators.

"I see no reason why this couldn't have been avoided," said Kailua resident Roger Wickenden, a retired physicist. "The important thing is that it's avoidable next time we have a comparable earthquake."

HECO PRAISED

The report gave HECO relatively good marks for how it restored power to its O'ahu customers.

After electricity was lost, HECO engineers were able to restore power quicker by simultaneously restarting generators at Kahe and Waiau, the consultant's report said.

But the report recommended further study on how the utility restored power to critical customers such as hospitals and called for additional employee training for restarting HECO generators after they go down.

"HECO operated reasonably and in the public interest by following a systematic, orderly and methodical approach ... allowing adequate time to inspect the system for earthquake damage (and) stabilize the operations of generating units," the report said.

PUC officials will evaluate HECO's outage report.

State Consumer Advocate Catherine Awakuni will meet with HECO officials on Jan. 9 and both sides will conduct further study into the outage.

Officials at HECO's sister companies, Maui Electric Co. and Hawaii Electric Light Co., will file similar studies with the PUC on outages on their islands by March 30.

"While the report provides a vote of confidence in our system plans and the performance of our employees, it also points out potential areas for improvement," said Tom Joaquin, HECO senior vice president of operations, in a news release.

"We will seriously evaluate all of these recommendations. We learn from every major emergency response and we always want to do better."

Reach Rick Daysog at rdaysog@honoluluadvertiser.com.