POWER October 2014 - 43

OPERATIONS & MAINTENANCE
5. Damaged blades. Compressor blade
damage can occur when water wash and
evaporative cooling systems leak. Unidentified
water leaks can form ice on the compressor
blades or compressor inlet, which can cause
damage to the airfoils. Source: POWER
a regulatory requirement. Winter preparation
surveys must be completed by generators,
as are emergency operations and
resource weatherization plans. Generators
must submit their severe weather preparation
plans by affidavit.
ERCOT also performs spot reviews of
generator plans, makes site visits to verify
plans, and conducts unannounced black start
unit testing. The surveys include information
on backup fuels available and how long a
unit can operate on the backup fuel. This is
855 PM Chevelle 050713_Layout 1 5/7/13 10:18 PM Page 1
an important consideration, as 89 of the 130
units with dual-fuel capability experienced a
trip, failure to start, or derate during the February
2011 severe weather event. Only four
units successfully switched to backup fuels.
The surveys also must identify primary and
alternate gas pipeline fuel supplies. Finally,
the surveys require generators to estimate derating
and forced outage rate based on two
extreme temperature scenarios. ■
-Dr. Robert Peltier, PE is POWER's
consulting editor.
may want to consider the following method of
sorting your list with your budget request.
The first category is specific equipment
that, when frozen, will prohibit the plant from
starting or restarting during the coldest expected
conditions or equipment that is likely
to cause a forced outage when frozen while
operating. Also identify equipment that,
when frozen, will cause equipment damage
or personnel safety concerns. Essential instrumentation
and sensing lines, exposed service
water piping, and fire protection pipes
fall into this category. So do employee emergency
shower stations typically found around
chemical storage and use areas.
The second category is equipment that, if
frozen, will cause an equipment malfunction
or even damage, but will not cause a forced
outage of an operating plant or prevent a start
or restart of a unit. Nonessential instrumentation
and sensing lines fall into this category.
For example, one utility that uses lake cooling
water requires the continuous operation
of one circulating water system screen wash
pump to ensure piping integrity. The suction
leg of the standby unit is drained to prevent
freezing. Frozen condensate drains from continuous
emissions monitoring systems may
also fall into this category.
The third and final category is equipment
that, if frozen, has the potential of reducing
the availability or reliability of the plant or
may temporarily reduce unit output. Multiple
cell, forced draft cooling towers and nonessential
water lines fall into this category.
Another example may be failed heaters or
heat tracing used to warm lubricating oil and
greases that can result in motor or pump vibration
and unit trips or runbacks.
ERCOT Makes Preparations
The next unexpected cold weather blast
should mean less bad news for ERCOT generators,
because in ERCOT, and all NERC
regions, winter preparation planning is now
October 2014 | POWER
1969 Chevelle SS
855 Series
Low NPSHa on your
vacuum receiver got you down? Fail to
resume pumping as suction levels resume?
You need Carver Pump 855 Series muscle!
Carver 855 Series are designed for use on
TYPICAL
RECEIVER
TANK
OVERHEAD
DRIVE
MOUNTS
DIRECTLY
TO TANK
FLANGE
vacuum receivers operating with up to 26 " Hg
vacuum. Flange mounted directly to the vacuum
receiver tank eliminates suction piping/NPSH problems.
Whether operating at a trickle or full flow, specially designed
impellers allow pumping to resume even after periods of
interrupted flow.
Capacities range to 600 GPM depending on discharge head
and speed of operation. Available in 6 sizes ranging from
1 " - 4 " , standard materials of construction include All Iron,
CD4MCu and Rubber Lined. The 855 Series features an
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in the stuffing box with mechanical seals as an
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V-BELT
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Carver
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Creating Value.
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2415 Park Avenue
Muscatine, IA 52761
563.263.3410
Fax: 563.262.0510
www.carverpump.com
CIRCLE 18 ON READER SERVICE CARD
www.powermag.com
43
http://www.carverpump.com http://www.powermag.com
POWER October 2014

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