Three-Phase Pad-Mounted
Transformers for Aclara’s TWACS® System
• The primary voltages offered by Prolec GE go from
3,800 to 34,500 V as described in the following table:
Line to line
Height
Line to line
Depth
(Volts)
(Wye-primary
(Volts)
(Wye-primary
in Volts)
in Volts)
3,800
4,000
4,160
4,400
4,620
4,800
6,600
6,900
7,200
7,620
8,000
8,320
11,500
12,000
Prolec GE offers a complete line of liquid-filled distribution
transformers that meet current applicable ANSI® / IEEE®
standards.
With voltages up to 34.5kV and ratings up to 5 MVA,
Prolec GE three-phase pad-mounted type transformers
are used in a wide range of utility, industrial and commercial
applications. High-grade materials, combined with state
of the art technology in our design and manufacturing
systems, are key elements of a transformer that will deliver
years of high reliability service.
Our compartmental type transformer offering now includes
the TWACS® ready transformer
This transformer is designed to operate 100% of the time
as a signaling transformer. Its loading consists of phase
controlled SCR shorting of the secondary windings either
phase to phase or phase to ground of the transformer.
This shorting will occur near the zero crossing of the
voltage sine wave. The maximum duration of a short for
a 60 Hz system will be sustained for approximately up to
2.78 milliseconds, starting 30 electrical degrees before
and terminating at 30 electrical degrees after the zero
crossing of the voltage sine wave. This shorting will occur
once every two cycles during signaling.
The entire transformer unit is constructed in accordance
with IEEE C57.12.28 and Aclara’s TWACS® specifications.
Standard features
• Prolec GE’s TWACS ready transformers offering starts
at 45kVA and ranges up to 500kVA with available
intermediate sizes 75, 112, 150, 225 and 300 kVA
2,190
2,310
2,400
2,540
2,670
2,770
3,810
3,980
4,160
4,400
4,620
4,800
6,640
6,930
12,470
13,200
13,800
14,400
16,430
17,000
19,900
20,780
21,600
22,900
24,000
25,000
34,500
7,200
7,620
7,968
8,314
9,475
9,815
11,490
12,000
12,470
13,220
13,860
14,400
19,920
None of the above mentioned transformers include tap changer.
• The secondary voltage is 480Y/277V at rated high
voltage and designed for 30 kV BIL
• All units are available with or without Unistruts, with
TWACS® Outbound Modulation Unit (OMU) cable tray,
with Low Voltage Fuse Disconnecting Switch (LVFDS)
and with Fuse Block (LVFB) and/or High Voltage
Disconnecting Switch (HVDS)
• Impedances are 1.8% and not exceeding 10% of this
value, namely within the range of 1.62% to 1.98%
• Prolec GE units are oil immersed, self cooled, 60 Hz,
dead front primary and designed for a maximum Basic
Impulse Insulation Level (BIL) of 200 kV phase to ground
on the primary winding
• The terminals on the HV side are provided with
removable stud bushing wells on units less than 25,000
volts and with 35kV large integral one piece bushings
on higher voltages
• The low voltage bushings are arranged in a “slant” or
“in-line” arrangement for transformers only with the
integrated LVFDS or LVFB according to customer
requirements, if not
required,
arrangement will be
“in line”. All stud
bushings are
supplied with a
four-(4) hole NEMA
spade as standard
• A switch is provided and mounted on
the interior of the outer wall of the low
side of the transformer cabinet, next
to the door and has provisions for
locking it in either the ON or OFF
position as shown in the picture
Approximate outline dimensions
• A fusible load break switch is provided
as part of our standard features and
located in the low voltage compartment
• Our cabinet has a solid top as our preferred standard
for increased rigidity to prevent doors from inadvertent
dislodgment from the hinge
Optional features
Top View
• Mounting Brackets are an optional feature that is selected
by customer specification according to their needs. They
are provided on the outside walls of the transformer
connection cabinet, on the right side of the low voltage
compartment, the ones for the TWACS® Outbound
Modulator Unit (OMU), and on the left side of the high
side compartment for the brackets for the TWACS®
Control and Receiving Unit (CRU)
• An interconnecting raceway is provided for conductors
between the low voltage fused disconnect switch or low
voltage fuse block and the TWACS® Outbound
Modulation Unit (OMU) whenever the OMU mounting
brackets are specified
Front View
• OMU Cabling is supplied whenever mounting brackets
and cable tray are specified. All of the connectors, and
phase cables from the TWCS® Outbound Modulation
Unit (OMU) side of the disconnect switch or fuse block
to the OMU and from the low side neutral bushing to
the OMU will be provided as a standard and will be
provided with means to protect them during shipping
• High Voltage Disconnect Switch (HVDS) is an optional
feature that will need to be specified by the customer
• A Low Voltage Fuse Block (LVFB) will be supplied when
High Side Disconnect Switch is requested. The fuse
block to be provided are 200-ampere rated for 45 kVA
to 150 kVA, or 400-ampere rated for 225kVA to 500
kVA units and mounted in the low voltage compartment
of the transformer cabinet
Our knowledge, experience, and quality solutions make
us the right team for your Smart Grid projects with the right
design for your needs.
Enjoy a new level of responsiveness
and reliability that only Prolec GE
can offer.
For more information contact your local GE Sales Representative or visit our website at www.prolecge.com
Phone: Toll free 1 800-437-7653 (US & Canada) / +52 (81) 8030-2341 (Mexico) / Fax: +52 (81) 8030-2323 or 2325
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