Diesel Progress North American

POWER GENERATION

When the normal supply voltage
returns, the system — after a preset
time delay — transfers all building
loads, in the selected transition mode,
back to the normal source. Once initi-
ated, the retransfer sequence occurs
in two stages. In the closed transition
mode, the 12. 47 kVA generators syn-
chronize with the utility power source,
close the 12. 47 kVA utility breaker,
transfer the load gradually to the utility
source and then open the 12. 47 kVA
generator tie breaker.
Once the 12. 47 kVA generators have
transferred the load, the switchgear
controls allow the 480 V transfer switch-
es to return to their normal position.
The engines will continue to operate
unloaded during a cool-down period. All
controls are then automatically reset in
readiness for the next operation.
The Russelectric switchgear can
also be programmed for base-load
peak shaving. Through an agree-
ment between Bassett Healthcare
and the regional power company, an
“interruptible power contract” gives
the utility permission to drop Bassett
from the regional electrical grid (with
advance notice) during periods of
peak demand. In return, the utility
pays Bassett for every megawatt
Bassett generates while offline, at a
much higher rate than what Bassett
pays for its normal grid power.

“It’s great for us,” said Middleton. “We’re off the grid for a few hundred hours a year, mostly in the summertime, when the power we generate is of higher quality than what we get from the

the Bassett Heathcare site, new controls for the paralleling and transfer gear were installed with two Caterpillar 2 MW medium-voltage ( 12,470 V) gen-sets capable of generating 12. 47 kVA. A primary bus was integrated, linked and parallel with the three 900 k W gen-sets.

With these upgrades, if the normal utility feed is not restored in five minutes, the Russelectric equipment transfers the load to the Bassett standby system. Special controls in the paralleling switchgear and transfer switches lock the equipment in the emergency position so it doesn’t roll back to normal. Then, when a breaker is closed, the system begins back-feeding through a 2000 kVA transformer (480 V secondary, 12. 47 kVA primary) to generate enough prime power to feed the entire Cooperstown campus.

“In a sense, we’ve spoiled people,” said Middleton. “Our employees have become accustomed to continuous full power — they become very anxious with any transient outages. We’re seriously considering adjusting the timing circuit to reduce the delay from five minutes to just two minutes.”

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utility. It’s rock solid, with stable frequen-
cy and voltage. But on the grid, with all
the air-conditioning demands, we see
large switching transients as new power
sources are switched in and out.”
Bassett also has the capacity to
export power to the grid, although
they have never been asked to do so,
Middleton said.

Approximately 45,000 gal. of fuel for the generators is kept on site. The two largest units consume 280 gph when operating (6720 gal. every 24 hours). Due to improvements by Caterpillar, Middleton said that Bassett’s two newest generators also produce fewer emissions.

“At Bassett, we look at utility infrastructure as the core support element for all our other initiatives,” Middleton explained. “If the infrastructure is flexible and adaptable, you can build on it. But to do that, you need to partner with a company whose systems are adaptable and reliable, a company that is nimble and service oriented. Russelectric is both. We depend on Russelectric field service for everything except routine daily maintenance.” dp