®
SOUTHEASTERN PENNSYLVANIA
TRANSPORTATION AUTHORITY
1234 MARKET STREET
PHILADELPHIA, PENNSYLVANIA 19107
Title:
Standard Specification for General Purpose Distribution Transformers
Number:
SPEC00091
Revision:
001
I. General
A. Scope
1) This Specification applies to dry-type transformers for power distribution; typically 3phase, delta-wye, 13.2/4.8 KV primary, 480/277 V secondary, 60 Hz, 500 KVA. Any
deviation from these typical characteristics will be detailed in the Bid Request and
Purchase Order.
2) Transformers of Vacuum Pressure Impregnation (VPI) or Vacuum Pressure
Encapsulated (VPE) construction are anticipated. Open-wound "dip-and-bake"
construction is specifically prohibited.
3) This Specification covers the design, manufacturing, testing, and furnishing of all
materials, equipment, labor, transportation, permits, equipment, machinery, tools,
appliances, and all other facilities or incidentals necessary for the delivery of the
transformer.
4) SEPTA will prepare the site for the installation of the new transformer, including new
cabling, and will perform the installation of the new transformer.
5) SEPTA will electrically connect and perform in situ testing of the new transformer.
B. References
The design, manufacturing, testing, and operation of the transformers shall comply with
the applicable portions of the latest edition of the relevant standards and codes
promulgated by:
a) NEMA - National Electrical Manufacturers Association
b) ANSI - American National Standards Institute
c) IEEE - Institute of Electrical and Electronics Engineers
d) ASTM - ASTM International
e) NEC - National Electrical Code
f) NESC - National Electrical Safety Code
g) OSHA - Occupational Safety and Health Administration
h) EPA - Environmental Protection Agency
i) NETA - National Electrical Testing Association
j) AREMA - American Railway Engineering and Maintenance-of-Way Association
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
k) local codes
C. Vendor Qualifications
1) The engineering and manufacturing of the transformer shall be by a firm which is
certified to comply with an internationally-recognized quality management system,
e.g. ISO9001:2008.
2) The vendor shall have not less than five years' experience in the production of drytype distribution transformers. This requirement is waived if substantially identical
equipment has been furnished to SEPTA and has been in satisfactory service for a
minimum of two years.
D. Submittals
Submit the following to SEPTA's Engineer for review and approval. The review and
approval of a submission, in part or in whole, shall not constitute acceptance of any
errors, omissions, changes, or other deviations from this specification. Wherever
possible, submittals shall be text-searchable .pdf files. References or hyperlinks to
information on the internet are not acceptable.
1) Product data consisting of manufacturer's catalog sheets, descriptive literature,
specifications, diagrams and drawings in sufficient detail to clearly indicate
compliance with all specified equipment and standards.
2) Operation and Maintenance manuals.
3) A nameplate drawing showing all tap connections and required nameplate data.
4) Dimensions and weight of the transformer.
5) Electrical schematic drawings.
6) Results of all tests for the transformer.
7) The guaranteed core and winding losses at 50%, 75%, and 100% of full load of the
transformer. This information must also be submitted with the shop drawings.
E. Quality Assurance
1) Transformers shall be standard products, or equivalent to the standard products, of
manufacturers engaged in the production of such equipment for at least the past 5
years.
2) The transformer shall be designed and manufactured for a minimum 40-year life.
3) Any transformer that has been damaged during any testing will not be accepted.
II. Products
A. Technical Description
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
Unless otherwise specified on the Purchase Order, the transformer's ratings shall be:
1) Frequency of Operation: 60 Hz ±5
2) Primary Voltage: 13,200/4,800 VAC, 3 phase, delta
3) Secondary Voltage: 480/277 VAC, 3 phase, wye
4) Power Rating: 500 KVA
5) Efficiency: 99.4% minimum at rated KVA
6) Regulation: 3% maximum at 95% Power Factor
7) Taps: The transformer's High Voltage (primary) side winding shall be provided with
five sets of taps as follows. These taps are intended for operation only when the
transformer is de-energized.
a) for an input voltage 5% above nominal
b) for an input voltage 2.5% above nominal
c) for a nominal input voltage
d) for an input voltage 2.5% below nominal
e) for an input voltage 5% below nominal
8) BIL: The Basic lightning Impulse insulation Level (BIL) for the High Voltage
(primary) winding shall be 110 KV. The Low Voltage (secondary) winding shall have
a BIL of 45 KV.
9) The insulation class of the primary shall be 15 KV, and the insulation class of the
secondary shall be 600 V.
10) Design equipment to operate as a fully integrated system and within the space
limitation to provide protection and reliability of equipment and the system against
accidental system failures and mechanical or electrical failures. Minimum clearances
of live parts shall be shown on the shop drawings. The equipment arrangement and
equipment part locations shall be as shown on the drawings and schematics submitted
by the vendor. The clearances of the live parts and workspace of the supplied
equipment shall not be less than those on the drawings. The design of the equipment
shall provide features for the safety of personnel during installation, operation and
maintenance.
11) The transformer shall be suitable for both operation and storage, including
prolonged storage, at 100% humidity and at ambient temperatures from -30 °C to
+40 °C.
12) The average winding temperature rise shall not exceed +80 °C above an ambient
temperature of 40 °C at the rated KVA of the transformer. (The winding temperature
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
shall be measured by a rise-of-resistance method.) Any bus or wiring connection shall
have at least the same thermal limit characteristics as the transformer windings.
13) Percent Impedance (%Z): 5.5% ±0.4125, i.e.: 5.0875% ≤ %Z ≤ 5.9125%
14) Sound Level: The sound level shall not exceed the NEMA recommended value.
B. Equipment Components, Construction, and Painting
1) Except as otherwise indicated, provide the transformer of type, size, characteristics,
and ratings as indicated, which comply with manufacturer's standard design,
materials, components, and construction in accordance with published product
information, and as required for a complete and functional installation.
2) The transformer shall be suitable for indoor application (NEMA 1), finished with
ANSI #61 Gray paint over phosphatized surface. The structural framework and
enclosure shall be sufficiently rigid to withstand any stresses due to short circuit
currents or transformer weight during transportation.
3) Provisions shall be made for jacking, lifting, skidding, as well as anchoring the
enclosure to the foundation.
4) All iron parts of the core coil assembly, except the core itself, shall be hot-dipped
galvanized after fabrication, or shall otherwise be protected from corrosion.
5) Proper clearances shall be maintained between primary and secondary connections
and transformer core (grounded) to prevent any arcing or fault. The submittal of shop
drawings must indicate the specific clearances for the transformer. A separate copper
grounding bus section shall be provided.
6) Provisions shall be made for lifting the whole transformer by a crane.
7) The transformer shall include a winding temperature sensor, two stage, with Form C
contacts rated at 125 VDC, 1 Ampere, for separate and independent indications of
each stage.
8) Windings: Both high and low voltage windings shall be of copper conductors. The
estimated full load winding loss shall be quoted in the shop drawing submittal and as
information to the bid evaluation package. The transformer winding design shall take
into account the high voltage stresses caused on the insulation system due to lightning
and switching surges on the system. The winding insulation shall be adequate to
withstand the thermal and mechanical stresses which may be caused due to transient
and sustained overloads or short circuits.
9) Terminals and Connections:
a) Proper spacing and heights shall be maintained for entry and exit of the cable
connections. Proper clearances shall be maintained between primary and
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
secondary connections and transformer core (grounded) to prevent any arcing or
fault.
C. Nameplate: Nameplate data shall specify rated KVA, frequency, phase, taps,
manufacturer's serial number, style, form, polarity, impedance, decibel rating,
temperature rise, and weight of the transformer (total weight, core and coil weights). A
nameplate drawing shall be submitted with the shop drawings.
D. Factory Test / Performance Test Data
The vendor shall perform the following tests. The vendor's test procedures and test results
are subject to the approval of the Engineer. SEPTA reserves the right to send one
representative for witnessing actual factory tests at SEPTA's expense. Should SEPTA
elect to witness any tests, the vendor shall not increase the cost above that in the
quotation. The vendor shall notify SEPTA at least four weeks prior to the performance of
the tests. The tests below marked with an asterisk (*) shall be witnessed by SEPTA.
1) Ratio Tests - on all tap connections
2) Phase Sequence/Polarity Test
3) Resistance of all windings on the rated voltage tap connections
4) Excitation current at rated voltage and different tap connections, where applicable.
5) *No-load loss at rated voltage and rated frequency.
6) *Impedance and full load loss at rated current on the rated voltage tap connection and
rated frequency.
7) Insulation resistance test.
8) *Dielectric withstand test to demonstrate the adequacy of the transformer insulation.
The test shall be carried out for both:
a) Applied potential
b) Induced potential
9) *Impulse Test: The tests shall verify the BIL rating specified. The impulse test shall
be carried out for full wave, reduced wave, and chopped wave. The tests shall be
performed on fully-assembled transformer, complete with enclosure.
10) *Partial Discharge Test: This test shall be performed on a fully-assembled
transformer, complete with enclosure. This test may be performed in conjunction with
the Dielectric Withstand Test.
11) *Power Factor Test
12) *Temperature Rise Test
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
13) Percent regulation at 85%, 90%, and 95% Power Factor
14) Efficiency at 50%, 75%, and 100% loads. The vendor shall bear the responsibility
for any deviation from the quoted losses of the transformer. SEPTA reserves the right
to reject the transformer for any deviation exceeding the quoted losses.
E. Patented or Copyrighted Material
In the event that any equipment or system delivered to SEPTA under this specification
shall be protected by any patent or copyright, the manufacturer shall defend, indemnify,
and save harmless SEPTA from any and all suits, claims, judgments, costs, and causes of
action at law or in equity arising out of or related to the sale, purchase, or use of any such
article, which sale, purchase, or use is alleged to be in violation of any rights under a
patent or copyright.
F. Delivery
Delivery shall be to the address noted in the Bid Request and Purchase Order. The vendor
shall notify SEPTA at least two (2) working days before delivery.
G. Warranty
The vendor shall warrant the transformers supplied to be free from defects in
workmanship and material for a period of four years from the date of final equipment
acceptance by SEPTA. The warranty shall cover manufacturing and design defects, labor,
material, and the cost of replacement installation. During this period, the vendor shall
replace all items or components which fail, at no cost to SEPTA.
III. Execution
A. Installation
SEPTA will install the transformer per the manufacturer's installation instructions.
B. Field Tests
1) Prior to energizing, SEPTA will perform the insulation resistance (meggering) and
dielectric strength (hipotting) at the voltage level recommended by the manufacturer,
and will check primary and secondary terminations, and equipment grounding.
2) SEPTA will be responsible to check the proper operation of the transformer during
commissioning, within the specified parameters recommended by the manufacturer.
3) If any failure occurs during field tests, the vendor shall bear the full cost of retesting
the transformer.
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SOUTHEASTERN PENNSYLVANIA TRANSPORTATION AUTHORITY
Number:
SPEC00091
Standard Specification for General Purpose Distribution Transformers
Revision:
001
Title:
Revision Control:
Revision
Number
001
Description of Change
Original Release
Approved by:
Date:
David T. Montvydas
09/17/2015
002
003
004
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