SECTION 16320
MEDIUM VOLTAGE TRANSFORMERS (LIQUID FILLED)
PART I - GENERAL
1.01
SUMMARY
A.
Section Includes:
1.
B.
1.02
1.03
Liquid filled pad mounted transformers.
Related Sections:
1.
Section 02200 - Earthwork: Soil Compaction Requirements
2.
Section 03300 - Cast-in-Place Concrete: Pads for Transformer Support
3.
Section 16110 – Raceways
4.
Section 09900 – Painting
REFERENCES
A.
All characteristics, definitions and terminology shall be in accordance with the
latest revision of applicable ANSI and NEMA standards.
B.
American Society of Testing and Materials (ASTM).
C.
Institute of Electrical and Electronic Engineers (IEEE).
D.
Manufacturer must be ISO 9001 certified.
SUBMITTALS
A.
Require submittals under the provisions of Section 16010 - Basic Electrical
Requirements and Section 01300 - Submittals.
B.
Submit shop drawings indicating outline dimensions, connection and support
points, weight, specified ratings and materials.
C.
Submit product data indicating standard model design tests and options.
D.
Submit manufacturer’s installation instructions under provisions of Section
01300.
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UCB STANDARDS
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1.04
1.05
OPERATION AND MAINTENANCE DATA
A.
Submit operation and maintenance data under provisions of Sections 01700,
01730, 16010 Division I.
B.
Include procedures for cleaning unit and replacing components.
C.
Submit product data indicating standard model design tests and options.
D.
Submit manufacturer’s installation instructions under provisions of Section
01300.
QUALITY ASSURANCE
A.
1.06
Manufacturer: Company specializing in distribution transformers with three (3)
years documented experience.
DELIVERY, STORAGE, AND HANDLING
A.
Store and protect products under provisions of Sections 01600 and 16010.
B.
Protect transformers as instructed by the manufacturer.
PART 2 - PRODUCTS
2.01
MANUFACTURERS
Medium Voltage Transformers:
2.02
A.
ABB
B.
Cooper/Power Systems
EQUIPMENT
A.
Pad Mounted Oil-Filled Transformers:
1.
JULY 2015
Liquid-filled Transformer, FM labeled, UL listed:
a.
Three phase, pad mounted, self-cooled transformer unit.
b.
Indicate kVA capacity, secondary voltage. Transformers larger
than 1000 kVA shall not be used without special written
authorization from the Director of Utility Services.
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c.
Primary voltage 13.2 KV Three Phase Delta with wye secondary.
Specify with 2-2 ½% above and 2-2 ½% below normal primary
taps, with externally-operated no load tap changer. Secondary
voltage as required.
d.
Impedance: Per ANSI Standards.
Consult with the Director of Utility Services if the new transformer
can be paralleled with an existing transformer.
e.
Cooling and Temperature Rise: 65oC, self cooled.
f.
Accessories: All accessories shall be housed in a side accessories
cabinet having the full height of the transformer with a lockable
Penta-head cabinet door.
All gauges and pressure indication shall have remote alarm
contact.
g.
JULY 2015
i.
NSI tank ground pad
ii.
1” filling plug mounted on the tank wall within the side
accessory cabinet
iii.
Two (2) 1” Drain Valves with samplers. One shall be
located in the HV compartment and the other in the side
accessories cabinet
iv.
Tap changer handle
v.
Liquid level gauge
vi.
¼” NPT with vacuum/pressure gauge
vii.
Pressure relief valve
viii.
Liquid temperature gauge
ix.
Two (2) nameplates; one shall be installed in the LV
compartment and the other in the side cabinet.
Dielectric fluid shall be non-toxic, non-bioaccumulating and be
readily and completely biodegradable per EPA OPPTS 835.3100.
The fluid shall have a minimum open cup fire point (ASTM D92)
of 350 C and be FM approved, UL Classified less-flammable
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Envirotemp FR3, all in accordance with current NEC Section 45023.
h.
Primary Terminations:
i.
Specify six (6) ANSI/IEEE 386 600 dead break bushings as
specified by the Director of Utility Services for loop fed
application. Parking stands shall be provided. Specify
three (3) internal oil immersed, two-position load-break
switches to allow alternate circuit service and isolation of
transformer. The three (3) switches shall be wired as
shown in the diagram at the end of this section.
i.
Primary Overcurrent Protection: Two fuse system consisting of
Bayonet-type, oil immersed expulsion fuse in series with current
limiting backup fuse. Current limiting backup fuse to be mounted
inside the transformer under oil. The current limiting fuse should
be located as near as practical to the incoming primary bushing, on
the source side of the expulsion fuse. The two fuses shall be
coordinated so that the expulsion fuse clears low energy faults on
the secondary system and the current limiting fuse clears only high
energy includes overload protection, can be provided as an
alternate with approval from the Manager of Utilities Distribution.
All transformer fusing shall be coordinated with upstream phase
overcurrent devices.
j.
Copper windings or aluminum windings, as specified by Manger
of Utilities Distribution.
k.
Efficiency standard per DOE 2010, 10 CFR Part 431
l.
Cabinet to be sized to accommodate 600 AMP bushings.
m.
Provide three spare Bayonet fuses.
PART 3 - EXECUTION
3.01
INSTALLATION
A.
Require installation in accordance with manufacturer’s instructions.
B.
Require safety labels per NEMA, and provide code listed and label option for the
non-toxic dielectric fluid.
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C.
Transformer clearances shall comply with Xcel Energy requirements.
D.
Transformers shall be looped into the primary electric distribution system
E.
All secondary conductors shall be terminated utilizing compression type 2 hole
lugs.
F.
Transformer grounding per specification E16390 transformer installation.
G.
New transformer installation shall have fault indicator as per specification
E16366.
H.
Transformer ID tag marking: Contractor is responsible to install transformer
identification tag and cable ID on the new installed transformer. Install 2”x2” new
non reflective weather resistant transformer identification tags. Cables ID tags on
the transformer inside wall above each loop feed switch:
Cable ID XX
From XXX to
XXX
I.
3.02
Transformer start-up: The on site test shall be completed after it is set on it’s
permanent pad and grounded. The transformer will not be started until all tests
are complete and turned over to Owner and engineer (2 sets) for review and
approval.
FIELD QUALITY CONTROL
A.
Factory and field testing shall be performed under provisions of Section 01400.
All field tests shall be witnessed by the University. All test reports shall be turned
over to the University prior to transformer energization. Perform the following
tests:
1.
JULY 2015
Sample insulating liquid in accordance with ASTM 3612 D3613 and
perform dissolved gas analysis (DGA) in accordance with ANSI/IEEE
C57.104 and ASTM 3612. The oil shall be tested for:
a.
ASTM D-1533B Moisture in oil
b.
ASTM D-971 Inter Facial Tension
c.
ASTM D-974 Acid Number
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B.
d.
ASTM D-1500 Color Number
e.
ASTM D-1524 Visual Exam
f.
ASTM D-1816 Dielectec Breakdown
g.
ASTM D-924 Power Factor 25C
2.
Turns ratio test on all taps.
3.
Power factor test or dissipation factor test.
4.
Excitation.
5.
Require oil testing 48 hours after energization. Contractor shall submit
reports to University for keeping.
Factory test transformer to ANSI/IEEE C57.12.91 and provide University the test
results prior to setting the transformer.
Field test transformer to ANSI/IEEE C57.12.91. All field tests to be witnessed by
Owner. All test reports shall be turned over to Owner.
3.03
WARRANTY
The contractor or the manufacture shall provide a minimum of 12 months warranty from
installation date.
A. The University of Colorado Utility department will periodically do a dissolved gas
analysis and other tests to the transformer oil. If during the transformer warranty period
the dissolved gas values exceed those specified below, responsibility and cost for further
diagnosis, oil sampling, and testing shall transfer from The University of Colorado Utility
department to the manufacturer or contractor. The manufacturer or contractor shall,
under the original warranty, analyze the problem, take remedial action, and retest the
transformer with sufficient frequency and over a sufficient duration to prove the cause of
the gassing has been remedied and any internal damage caused in the transformer has
been repaired. For transformers filled with type FR3 oil the dissolved gases and other
test values shall be limited to the following amounts during the warranty period of the
transformer.
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Oil type
Hydrogen
Methane
Acetylene
Ethylene
Ethane
H2
CH4
C2H2
C2H4
C2H6
Carbon
Monoxide
Carbon
Dioxide
CO
CO2
To be
measured
and
trended
Soybean
118ppm
22ppm
1ppm
20ppm
247ppm
179ppm
High Oleic
Sunflower
45ppm
30ppm
1ppm
23ppm
84ppm
583ppm
Synthetic
82ppm
135ppm
33ppm
215ppm
362ppm
1526ppm
Water content ≤ 400ppm
Power factor ≤ 3%
Acid neutralization number ≤ 0.3
Color ≤ 1.5
Flashpoint ≥ 275°C
1.
2.
3.
4.
5.
B.
The University of Colorado Utility department will compare the trend in the
concentrations of dissolved gasses measured at each dissolved gas analysis test. In
particular only the trended values of CO2 are significant rather than the absolute
values. If the rate of accumulation of any of the gasses significantly increases, the
manufacturer or contractor will provide further testing under the warranty to determine
the cause of the change in gassing rate. The manufacture or contractor shall provide
any repairs necessary to remedy the cause of abnormal gassing. After remedying the
problem causing the increased gassing the manufacturer shall provide additional
testing to prove the problem has been remedied and provide a 6 months warranty
extension to analyze the results.
C.
If the manufacturer has made an attempt to remedy a problem in the transformer
causing high levels of dissolved gases or a significant increase in the rate of gas
accumulation, and the transformer continues to accumulate gas levels above those
specified or at an increasing rate the manufacturer shall replace the transformer under
the terms of the warranty at no cost to the University of Colorado.
3.04
ADJUSTING
Adjust primary taps to tap D on 13,200 volt nominal transformers.
END OF SECTION 16320
JULY 2015
UCB STANDARDS
16320-7