SPECIFICATIONS FOR THREE PHASE PADMOUNT OIL-FILLED TRANSFORMERS
A.
DESCRIPTION
65 Degrees C rise Pad-mounted Transformer, three phase, OISC,
compartmental, type, 60 hz, HV loop-feed, dead-front type conforming w ith
ANSI C57.12.26-1987.
B.
ELECTRICAL
High Voltage:
Low Voltage:
12,470 Grd Y-7200 volts (95kv BIL)
As specified, 480 Grd Y/277 or 208 Grd Y/120 volt 3
phase, 4 w Y
Impedance:
Per latest ANSI standard (must be stated in bidder’ s
quotation)
HV – Std. 2-2 ½ % above and 2-2 ½ % below externally
operable, non-loadbreak
Taps:
Connections:
Core/Coil
Configuration:
AU Transformer Spec 5-21-13
HV loop feed (loop-in loop-out)
The core and coil assembly shall be w ound core type
w ith copper or aluminum w indings. The assembly shall
be designed to reduce losses and noise and provide
adequate short -circuit strength and heat dissipation.
Manufacturer shall design transformers such t hat tank
heating problems sometimes associated w ith w ye-w ye
connections are eliminated.
Internal leads shall be
insulated, carefully trained and anchored to prevent
phase-to-phase flashover. A tap changing mechanism
shall be provided for accurate voltage adjustment
w ithout opening the transformer tank. The tap changing
mechanism shall be externally operated and shall be for
de-energized operation only. The high and low voltage
compartments shall be located side-by-side separated
by a steel barrier. When facing the transformer, the
low voltage compart ment shall be on the right.
Terminal compartments shall be full height, air filled
w ith individual doors. The high voltage door f astenings
shall not be accessible until the low voltage door has
been opened. The low voltage door shall have a 3 -point
latching mechanism w ith vault type handle having
provisions for a single padlock. The doors shall be
equipped w ith lift -off type stainless steel hinges and
door stops to hold the doors open w hen w orking in the
compartments.
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Fusing:
C.
HV Bay-O-Net Oil Cutout (Current-Sensing Fuse) in
series w ith internal ELSP current back-up fuse; one per
phase (coordinated t o provide full range protection up
to 50,000A)
MECHANICAL
HV Bushing:
2 loadbreak 200 AMP epoxy bushings per phase, per
ANSI C57.12.26, interfaces w ith 200A Load-break, 15
kV, Elbow s. Total of (6) bushing w ells, (6) bushing
inserts, (6) parking stands. Elbow s furnished by others.
LV Busing:
4 epoxy bushings w ith min.16 hole NEMA tin-= plated
CU spades; Externally removable tank ground strap to
Xo bushing, per ANSI C57.12.26. Figs. 7 & 8 (a).
Provide additional insulated supports for each secondary
spade.
Enclosure:
Steel sealed-tank construction (+ 7.0 psig w ithstand
strength), tamper resistant, lift -off doors w ith stainless
steel hardw are and captive locking provisions, steel
barrier betw een HV & LV compartment, removable sill,
lifting eyes and jacking pads w ill be provided,
undercoated and painted minimum 3 mils dark bronze.
Color t o be Benjamin Moore 16362 or equal. Primary
compartment shall be minimum 36” w idth X 18” depth,
secondary compartment a minimum 26” w idth X 18”
depth. Minimum height to centerline of low est primary
bushing 26” minimum and secondary bushing 31”
minimum.
Accessories:
1.
2.
3.
4.
5.
6.
Lighting
Arresters:
AU Transformer Spec 5-21-13
1” Oil drain valve w ith sampling device
(installed in HV Primary compartment,
not LV secondary side)
1” Upper filter press and filling plug
Liquid level guage
Dial type thermometer
Pressure/vacuum gauge and pressure
relief valve
Nameplate in low -voltage compartment
Furnish (3) external 9 KV M.O.V. w ith interface to
loadbreak expoxy bushings, and st randed ground w ire.
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Grounding
Pads:
Provide tw o-hole grounded pads in both high and low
voltage compartments. Tw o ½ ” dia. threaded holes in
each, stainless steel.
Transformers shall be furnished w ith:
1.
2.
3.
4.
5.
Impedance in percent
Guaranteed no-load and load losses, expressed Watts at rated
voltage and full load at 60 Hertz, corrected to 85 degrees C,
per the latest revision of ANSI C57.12.00 par 8.1.1.
Dimensional data including the high and low voltage
compartment dimensions (w idt h, height , and depth) and the
total w eight of the shipped unit.
Insulating Oil shall be FR3 Fluid, as manufactured by Cooper
and shall be tested and certified in w riting and a letter
accompanying the unit as w ritten below :
The dielectric fluid in this unit, serial number _______
has been tested to determine the amount of
polychlorinated bipheny(s) PCB content. Manufacturer
certifies that based on the test sample, the fluid
contains less than 5 ppm PCB and is therefore classified
a non-PCB as defined in the August 25, 1982, Vol. 47
No. 165 of t he Federal Register.
Unit shall be labeled w ith a non-PCB sticker, conspicuously
located to facilitate the inspection by the regulatory
compliance officer or any other individual desiring to inspect
such equipment.
All Impedance, No-Load and Load Losses, and Dimensional Data shall be
given prior to the approval by the Ow ner of the construction of the
transformer. Failure to furnish Impedance, No-Load and Load Losses, and
Dimensional Data including high voltage and low voltage compartment
dimensions and w eight s of the transformer may result in rejection of the
transformer. Upon aw ard of the transformer, final payment for the unit w ill
not be approved until vendor has furnished t he certified oil test report as
listed in C.4. above.
Approved manufacturers are:
Square “ D” , How ard Industries, A.B.B.,
Cooper (RTE), CG Pow er Systems, and ERMCO.
AU Transformer Spec 5-21-13
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