Hawaiian Electric Co. might have been able to prevent last month's islandwide blackout by having more spacing between the wires that make up the company's major transmission lines.

HECO officials said Friday that the Dec. 26 outage occurred after its system was hit by at least five lightning strikes within a 20-minute span.

One of the strikes took out all three of the wires that make up the transmission line connecting HECO's two largest power plants.

The rare, three-wire short circuit delivered what HECO officials called a "knockout blow" to its system, cutting off tens of thousands of customers and triggering the shutdowns of seven power generators 10 minutes later.

Experts contacted by The Advertiser said utilities in Florida and other states where lightning strikes are prevalent typically space the wires on major transmission lines farther apart than HECO's wires.

Typically, wires to major transmission lines in Hawai'i run about 10 feet apart, whereas those in Florida are about 15 feet apart. The 5 feet of additional space makes it more difficult for lightning to hit three wires and set off a cascade of events that bring the whole system down.

"This is one of the techniques to protect the system from damage a lightning strike can cause," said Stan Johnson, manager of situation awareness 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.

HECO has said that it uses a number of protective measures against lightning, including metal shield wires that run above major transmission lines, and lightning arrestors that act like surge protectors on transmission lines and other equipment.

HECO spokeswoman Lynne Unemori said reconfiguring the company's transmission lines could be extremely expensive. It would require buying or leasing additional land and would increase HECO's maintenance costs for the lines, which often are in remote areas with limited access.

HECO also would have to invest in larger towers and other equipment.

"Ultimately, what we're talking about is the cost to the customer," she said.

PROBE CONTINUES

The Dec. 26 blackout — the second islandwide outage in about two years — left most of HECO's 294,000 customers in the dark for more than 12 hours, disrupted traffic throughout O'ahu and forced hundreds of Isle merchants to shut down early in what's one of the busiest shopping days of the year.

It drew international attention in part because President-elect Barack Obama and his family were vacationing on O'ahu at the time, and their beachfront home was left without power.

HECO officials said they are still studying the reasons for the outage and potential remedies. They said they plan to hire Mainland consulting firms to conduct a more in-depth study.

The state Public Utilities Commission and state Consumer Advocate Catherine Awakuni also are likely to conduct separate investigations.

State lawmakers will hold hearings this week.

In addition to lightning strikes, the inquiries likely will focus on how HECO's system reacted after the major transmission lines went down.

During a media briefing Friday, HECO said the transmission line short circuits cut off thousands of customers within seconds, sending voltage levels plunging.

That, in turn, triggered safety mechanisms to shut down generating units at the Waiau and Kahe power plants as well as those operated by independent producers AES Hawaii Inc., HPower and Kalaeloa Partners LP.

Company officials said they still are investigating what happened with those generators.

'SMART RELAYS'

Shmuel Oren, site director for the Power System Engineering Research Center at the University of California-Berkeley, believes that HECO could have benefited from having what's known as a "wide-area technology" when it was dealing with the events that resulted in the blackout.

Oren said such technology relies on special "smart relays" within its power grid and advanced computer software reacts to problems such as downed power lines much quicker.

In cases where there's too much generating capacity, systems can shed load much quicker. If voltage levels are too low on some transmission lines, the system can isolate affected lines much quicker.

But the costs could be too high given that the types of problems that occurred on Dec. 26 are extremely rare. Redesigning HECO's grid with smart relays and related equipment can cost millions of dollars, which would in turn be passed on to consumers.

HECO officials said the system already has the capability to do those functions but added that those functions probably would not have been enough to prevent the outage.

"It's like protecting against earthquakes. At some point, rather than protecting the system from outages, you have to think about what to do when it happens," Oren said.