Local News

KPU plans diesel generator test; short outage possible

During a system-wide power outage last month, a large diesel backup generator that Ketchikan Public Utilities has nicknamed “Old Faithful” lost all claim to its title.

KPU Electric Division has done some trouble-shooting since then, and plans to test the generator early Sunday morning. But utility officials warn that a short power outage is possible.

If your digital clocks are flashing Sunday morning, then Old Faithful still has some issues. But, KPU Electric Division Manager Tim McConnell hopes the test will be a seamless switch from hydro to diesel, and back again.

The problem is, they’re still not quite sure why the generator didn’t work. He said they performed some maintenance on a cylinder that wasn’t running quite up to speed, and looked at the controls, “and right now, we can’t really ascertain that there was anything wrong.”

“During the outage on the 18th, we had a lot of voltage fluctuation and a lot of frequency fluctuation, so the machine may well have been performing exactly as the relays and the other safety systems would dictate, but we don’t know.”

Doubt is not a good thing heading into Ketchikan’s fall storm season, which is why the utility scheduled Sunday’s test.

“The plan is to have our backup generation available at Swan, and we’ll also have our backup generator on at Bailey,” McConnell said. “If all goes well, we won’t even get a bump in the system, it’ll just be a smooth transfer. Then we’ll load it up and let it cook at its full 9 megawatts load, and then we’ll migrate back, turn the diesel off and go back to our normal hydro for the rest of the evening.”

If the generator trips off, the backups in place should mean that any resulting outage won’t last more than 10 or 15 minutes. And, McConnell said, personnel will be on scene and poised for action.

“And we’ll be able to zero in on any of the specific problems that we weren’t able to identify during the (June 18) outage, because so much was going on,” he said.

The10-megawatt generator tripped a couple times during that June 18 outage, leading to on-again, off-again power for many customers. Utility staff eventually had to double-team the smaller backup generators, and ask customers to unplug and turn off electric equipment, to reduce the load, before power could be stabilized.

That five-hour outage started at the Swan Lake hydroelectric dam when a switching order came through from the Southeast Alaska Power Agency. SEAPA owns that facility, although KPU operates it. McConnell said the switch wasn’t properly coordinated, and he accepts blame for the error.

The test is scheduled to run between midnight and 4 a.m. Sunday. KPU recommends that customers turn off or even unplug electronic equipment Saturday night, especially those that aren’t plugged in to a power strip. That will protect the equipment from potential power surges.

UPDATE: The test of the Bailey Unit 4 diesel generator was successfully concluded at 3 a.m. July 14. There were no system disturbances, and the unit has been declared reliable.

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