SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 1 OF 13
SPECIFICATIONS
For Wind Farm
Transformer Pads
-1-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 2 OF 13
SPECIFICATION FOR TRANSFORMER BOX PAD
1.0
TECHNICAL SCOPE
1.1. These specifications cover a transformer fiberglass box pad to be purchased by NextEra Energy
Resources (Purchaser) or its designated representatives, to be used to support a three phase pad
mounted distribution transformer and to be installed on wind farm generating sites or in related
substations.
1.2. The pads shall be designed and constructed to provide a serviceable life of 25 years when installed
outdoors in full sunlight and without any protection from the weather at any location in the
continental United States.
1.3. These specifications cover several different pad designs. Information on the specific pads to be
provided will be included with each inquiry or purchase order. Each pad design is intended for use
with several different transformers. The dimensions and weight of each transformer intended to be
used with each pad design are shown in Section 6.0.
1.4. The Supplier shall perform a type test on a prototype of each pad design to be provided. This
prototype must pass all required tests, and a certified test report shall be furnished to the Purchaser
prior to shipping production pads.
1.5. The Supplier shall design, construct, perform dimensional and quality control tests, and prepare the
pads for truck shipment. Shipping and delivery responsibilities will be defined in the project specific
purchase documents. The Supplier shall provide all necessary documentation as stated in this
specification.
2.0
PAD DIMENSIONS AND DESIGN
2.1. Dimensions shall be in accordance with the drawings in Section 5.
A. The manufacturer’s design dimensions may be modified slightly from the dimensions shown in
this specification to correspond with manufacturer’s standard offerings, as long as the final
product is suitable for installation of all of the transformers identified for use with that particular
pad design, and is in accordance with the following paragraphs.
B. The dimensions shown for the top surface of the pad are the minimum acceptable. The top
surface may be up to 4” larger in either or both dimensions.
-2-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 3 OF 13
C. The narrow (front to back) dimension of the cable opening is the minimum acceptable. Any
change in the cable opening dimensions must remain within the footprint of the cable termination
compartment of all transformers identified for use with the pad (including the pad attachment
feet).
D. The dimension shown for the height of the pad is the minimum acceptable, and may be up to 2”
higher than shown.
E. The radius of the end of the extension must be within +/-1.0” of the specified value.
F. The flange at the pad base must be a minimum of 4” wide and must extend around the entire pad
as shown on the drawing.
G. The manufacturer’s design dimensions must be approved by Purchaser prior to fabrication and
testing of the prototype pad.
2.2. When an extension from the pad to the turbine foundation for secondary cable installation is
included in the pad configuration, this extension shall be formed as an integral part of pad. Designs
utilizing a separate piece that must be bolted or clipped to the main pad are not acceptable.
2.3. All edges of the pad and the cable opening shall be formed with a smooth radius. The minimum
radius of the cable opening shall be 3/8”.
2.4. The pads will be installed by setting the pad in a concrete slurry mix having a minimum compressive
strength of 1000 psi, with the lowest three (3) inches of the pad wall and the base flange embedded
in the concrete.
3.0
PERFORMANCE AND CONSTRUCTION REQUIREMENTS
3.1. Pads shall be fabricated from reinforced fiberglass using fire retardant resin.
A. The fiberglass base shall be a combination of chopped glass with a minimum of one layer
throughout of 18 ounce or 510 gram woven roving so as to form a continuous filament from top
to bottom and from side to side. The laminate thickness shall be not less than 3/16” at any point.
B. The resin shall be polyester thermosetting and shall be classified as self-extinguishing when
tested for flammability under ASTM D635. In addition, the extent of burning when tested per
ASTM D635 must not be over 12mm and the average burning time must not exceed eighty
seconds
C. The exterior surface shall be coated with an Isophthalic base gel coat or surface coat that will
provide protection from UV light and weathering. The color shall be a uniform Dark Green
-3-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 4 OF 13
Munsel No. 7GY3.29/1.5. The coating must comply with one of the following tests to verify
durability and longevity.
1.
Tested in accordance with DSET Laboratories EMMAQUA Test Method, with the
equivalent of two standard ultra-violet light years; showing no change in Fiber Show or
Fiber Bloom and no worse than a “Good” rating on General Appearance and Color Change.
2.
Tested in accordance with ASTM-G-70; with a maximum change of 2.3 Macadam Units
after one thousand hours of exposure in a Model 65WR Atlas Weatherometer or equivalent.
exterior surface of all pads shall be coated with gel coat having UV stabilized pigments,
Dark Green Munsel No. 7GY3.29/1.5.
3.2. The tolerance of the dimensions of each fabricated pad compared to the manufacturer’s design values
shall not exceed the following. These tolerances apply to the pad as ready for shipping, when set on
a flat and level surface with no loads applied.
A.
All dimensions must be within +/-1/4” of the design values, except as stated below.
B.
The top surface of the pad must not deviate more than 1/4” from a true plane resting on the
highest points of the pad top surface.
C.
The radius of the end of the extension must be within +/-5.0” of the design value
D.
The end of the extension must not deviate from true vertical (defined as a plane with an angle of
90° from the top surface of the pad) by more than 1/8 inch.
3.3. Provisions must be included for lifting the pad by providing eyebolts or other lifting attachments
near each of the four corners of the pad, with a minimum opening of 1” diameter bolted to the pad or
the pad base flange. Eyebolt mounting holes must be adequately reinforced to avoid damaging the
pad and to provide an ultimate strength of at least five times the pad weight when the pad is lifted in
accordance with the manufacturer’s instructions. If spreader bars or other special lifting
configurations are required, this information must be shown on the pad drawings and installation
instructions.
3.4. Pads must be reinforced to maintain long term structural and dimensional stability.
A. Reinforcing may be any combination of fiberglass ribs or lips, or wood or other structural
materials embedded in the fiberglass. Any wood or other structural members that might be
affected by moisture or attacked by insects must be totally encapsulated with fiberglass.
B. The pad must be designed to support the weight and the simultaneous wind loading of any of the
transformers identified for use with each pad design. The wind loading shall be assumed to
-4-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 5 OF 13
consist of a horizontal force of 800 lbs acting uniformly over a flat surface 72” wide and 80” high
representing the four sides of the transformer. The Supplier shall determine and design for the
direction of the wind that will produce the greatest stress in the pad components.
C. Essentially all of the transformer weight is concentrated in the tank area and is transferred to the
pad along the portions of the transformer base flange that are actually in contact with the pad as
shown on the drawings. It shall be assumed that no weight is supported by the cable termination
compartment.
D. The deflection from the unloaded condition caused by placing a transformer on the pad shall not
exceed 1/8” after 24 hours and 3/16” after 5 days when tested in accordance with Section 4.0 of
these specifications.
4.0
TESTING AND QUALITY CONTROL
4.1. A prototype pad shall be fabricated and tested prior to shipping any production pads. This pad shall
be identical in materials, dimensions, and fabrication techniques to the production design.
4.2. A new prototype shall be fabricated and tested if any change is made in the pad dimensions or the
materials used for fabricating the pads.
4.3. The prototype pad shall be measured to show compliance with the tolerances specified in Section 3.2
of these specifications.
4.4. The prototype pad shall be loaded to simulate the most severe loading conditions for the pad. The
Supplier is responsible for determining which transformer design that is shown for use with the pad
will produce the greatest stress in the pad structure and the greatest deflection. A force equal to
105% of the weight of the transformer shall be applied to the pad. The force shall be uniformly
distributed over the limits of the transformer tank base flange contact surface shown for that
transformer. No force is to applied to the transformer cable termination compartment portion of the
pad. It is acceptable to utilize a rigid frame for application of the loads to simulate the structure of
the transformer base. The loading shall be maintained for 5 days.
4.5. The location of the maximum deflection shall be determined during the initial loading. The
deflection at that point, and at the center of the back edge of the cable opening shall be measured and
recorded as follows.
A. The load shall be applied in steps of 25%, 50%, 75%, and 100% of the ultimate value.
B. The initial 25% load shall be applied and held for one hour, with the initial deflection measured
at the end of that time.
-5-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 6 OF 13
C. The subsequent load steps of 50% and 75% shall be held for one hour, with deflection measured
at the end of each time period.
D. The final step of 100% load shall be held for five days. The deflection shall be measured after
one hour and subsequently at 24 hour intervals for the duration of the test.
4.6.
A certified test report shall be provided to the Purchaser at the conclusion of the prototype testing.
A. The report shall include the results of tests on the pad materials that verify compliance with the
flammability requirements of paragraph 3.1.B and the weathering requirements of paragraph
3.1.C.
B. The report shall include details of the prototype loading test, including the method used to apply
the force to the pad, the dimensions of applied force, all measured deflections, and any pertinent
observations made during the test.
4.7. The condition of each pad shall be verified prior to shipping.
A. Each pad shall be examined visually for surface condition and overall quality of construction
B. All dimensions shall be checked and verified.
C. The flatness of the top surface shall be measured to ensure compliance with paragraph 3.2.B of
these specifications.
5.0
APPROVAL DRAWINGS AND DATA SUBMITTALS
5.1. Submittals with the initial Proposal shall include the following.
A. An outline drawing showing all dimensions and the total pad weight of each pad design that the
Supplier intends to provide in response to the Request for Proposals.
B. A description of the materials and methods to be used in fabricating the pads.
C. Any exceptions to these specifications.
D. A schedule identifying the time required for prototype fabrication and testing following receipt of
a purchase order, and the time required for initial production following approval of the prototype
test report.
-6-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 7 OF 13
5.2. Supplier shall provide a certified test report as described in Paragraph 4.6 of these specifications
prior to the first production fabrication of each pad design purchased. This report must be approved
by Purchaser before any production pads are fabricated.
5.3. Electronic copies of the final dimensional drawings shall be provided in both pdf and AutoCad
format for incorporation into design drawings of the project.
6.0
PAD DIMENSIONS AND LOADINGS
6.1. The following pad designs are covered by these specifications. Each pad design shall be suitable for
use with any of the transformers indicated.
A. Pad Design A1
1. Pad to be used with a variety of transformer having a maximum weight of 9245 pounds.
2. Pad dimensions to be as shown in Figure A1.
3. Pad must be suitable for use with any of the transformers shown in Figure A1-2.
a. ABB 1000 kVA grounding transformer, outline drawing J801BVRO
b. ABB 1000 kVA grounding transformer, outline drawing J801BVSN
B. Pad Design B7
1. Pad to be used with a variety of transformers with a maximum weight of 15,864 pounds.
2. Pad dimensions to be as shown in Figure B6-1.
3. Pad must be suitable for use with any of the transformers shown in Figure B7-2.
a. ABB 1750 kVA, 575 volt, outline drawing J801BVP8
b. ABB 1750 kVA, 690 volt, outline drawing J801BVRR
c. ABB 1800 kVA, 690 volt, outline drawing J801BVQV
d. ABB 1800 kVA, 690 volt, outline drawing J801BVQ2
e. ABB 2600 kVA, 690 volt, outline drawing J801BVRU
f. ABB 2600 kVA, 690 volt, outline drawing J801BVS6
g. GE Prolec 1750 kVA, 690 volt, outline drawing RCN46001B801, Rev 3
h. GE Prolec 1800 kVA, 690 volt, outline drawing RDO46601B801, Rev 0
7.0
PAD DRAWINGS
7.1. Pad and transformer dimension drawings are included on the following pages.
-7-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 8 OF 13
FIGURE A1-1
-8-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 9 OF 13
FIGURE A1-2
-9-
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 10 OF 13
FIGURE B7-1
- 10 -
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 11 OF 13
FIGURE B7-2 (A)
- 11 -
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 12 OF 13
FIGURE B7-2 (B)
- 12 -
SPECIFICATION DETAIL
Transformer Pads
Specifications
Spec No. NX-TX-Pad 35
Revision No. 1.0
Date 10/13/11
PAGE 13 OF 13
8.0
TRANSFORMER OUTLINE DRAWINGS
8.1. Manufacturer’s transformer outline drawings associated with each pad design are included on the
following pages.
A. Pad design A1
1. ABB J801BVRO
2. ABB J801BVSN
B. Pad design B7
1.
2.
3.
4.
5.
6.
7.
8.
ABB J801BVP8
ABB J801BVRR
ABB J801BVQV
ABB J801BVQ2
ABB J801BVRU
ABB J801BVS6
GE Prolec RCN46001B801, Rev 3
GE Prolec RDN46601B801, Rev 0
- 13 -