SECTION 16208
TRANSFORMERS - 115KV/12KV
203.01
GENERAL
A.
Manufacturer
Acceptable manufacturers shall be H.K. Porter or ABB.
B.
Materials
The materials and equipment used, in the construction of the
transformer covered by this specification, shall be new, of the highest
quality, and of the type recognized by the industry for use in this type
of equipment.
C.
D.
Additional Applicable Documents
1.
In addition to the documents referred to in Section 16201.02,
reference will be made in this section to specific Codes and
Standards where applicable.
2.
Equipment supplied shall comply with all applicable standards of
the Code of Federal Regulations, Title 29, Chapter XVII,
Part 1910 (OSHA).
Description
This section covers the design, manufacturer testing and delivery of
outdoor power transformers for use in a generating station and/or a
switchyard.
208.02
GENERAL REQUIREMENTS:
A.
Ratings
Ratings shall be as specified under Section 16208.03 “Electrical
Requirements”, or as otherwise noted on the drawings.
B.
C.
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Overload Requirements
1.
The overload capabilities of all auxiliary equipment (i.e. bushings,
current transformers, and other accessories) shall not be less than
the transformer overload rating.
2.
Short time, overload rating shall be in accordance with ANSI
Standard C57.92.
Short Circuit Capability
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December 2004
SECTION 16208
TRANSFORMERS - 115KV/12KV
D.
E.
F.
1.
The transformer, including its accessories such as but not limited
to, bushings, current transformers, and tap changers, shall be
capable of withstanding the specified short circuit requirements,
without mechanical deformation or impairing the electrical
capabilities.
2.
The thermal and mechanical capability of the transformer and its
accessories shall meet or exceed the requirements listed in ANSI
C57.12.00, Section 10.
Impedance
1.
Transformer impedance shall be within the tolerances specified by
ANSI Standard C57.12.00.
2.
Specific transformer impedance shall be as listed under Section
16208.03 “Electrical Requirements” unless otherwise noted on the
drawings.
Insulating Oil
1.
Transformers shall be furnished complete with oil, unless
otherwise specified.
2.
The oil shall be new mineral oil.
3.
No additives shall be permitted, except for inhibitors. Inhibitors
shall be non contaminating and meet any Environmental
Protection Agency requirements.
Bushings
1.
Bushing weather casings shall be ceramic, colored ANSI No. 70
Gray.
2.
Bushings shall meet ANSI Standard C76.1.
3.
Bushings shall conform to the following rating and class.
Insulation Class
Terminal
HV Ter. (H)
LV Term. (L)
LV Neut. Term (Xo)
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Voltage BIL
115KV
550KV
15
110
15
26
4.
High voltage bushings shall have a test tap.
5.
Oil filled bushings shall have an oil level gage.
6.
Terminal connectors shall be as follows:
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December 2004
SECTION 16208
TRANSFORMERS - 115KV/12KV
Terminal Connectors
HV Term. (H)
1 ½-12, 2" High Stud
LV Term. (L)
2 ½-12, 2 ½" High Stud
LV Neut. Term (Xo)
Adequate for a 500 MCM Co.
Conductor
G. Bushing Current Transformers
H.
I.
1.
Provide one (1) bushing current transformer on each high voltage
terminal.
2.
Current transformers shall be 1200/5A (multi-ratio) and conform to
relaying accuracy class C400.
Surge Arresters
1.
Provide station or zinc oxide arresters without counters for the
high voltage terminals.
2.
Arresters will be rated 120KV and their color shall be ANSI No. 70
Gray.
Instruments and Control
1.
The transformer shall be provided with, but not be limited to, the
following instruments in addition to those nominally considered as
standard:
a. Sudden pressure relay, manufacturer’s standard.
b. Temperature detectors and indicators:
One (1) RTD detector for winding hot spot detection.
One (1) RTD for oil temperature detection.
Necessary dial-type temperature indicators which shall be
mounted on the transformers.
c. Temperature Control:
Provide all the necessary temperature detectors, controls,
starters, fans and motors, pumps and motors, control panel
and other equipment for the operation of a cooling system for
an OA, FOA, FOA type transformer, or as required for other
type of transformers as noted on the drawings.
J.
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Auxiliary Power Supply
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December 2004
SECTION 16208
TRANSFORMERS - 115KV/12KV
The auxiliary power supply available for the transformer(s) shall be
120/208-Volt, 3 Phase, 4 Wire, 60 Hertz.
K.
L.
Transformer Taps
1.
Transformer taps shall be of the No-Load changing type for the
high voltage windings and of the load changing type for the low
voltage windings.
2.
See Section 16208.03 “Electrical Requirements” for electrical
ratings and operation.
Tap changer - No Load-Type
1.
Provide a no-load tap changer for the high voltage winding rate full
capacity at voltages specified in Section 16208.03.
2.
Tap changer shall be arranged to provide for inspection and
maintenance without untanking.
3.
Provide positive indication of the tap in use.
4.
The operating mechanism shall be designed to prevent
unauthorized operation and so located to be operated at grade.
M. Tap Changer - Load Type
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1.
Provide an automatic load tap changer for the low voltage
windings, complete with a liquid immersed arc tap switch, or tap
selector and arcing switch, motor driven mechanism and
automatic control devices for suitable remote operation..
2.
The mechanical and electrical requirements shall be in
accordance with ANSI Standard C57.12.30. Oil in the switching
compartment shall be isolated from the oil in the main transformer
tank.
3.
The tap changer shall be capable of withstanding, on any tap, the
maximum short circuit stress that can be imposed on the
transformer without damage in accordance with ANSI
Standard C57.12.00.
4.
Allowable transformer overload currents shall be acceptable to the
load tap changer.
5.
All current carrying parts shall be of sufficient size to limit the
temperature rise to 10C above adjacent bushing temperature
under full load.
6.
Load tap steps shall be as follows:
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December 2004
SECTION 16208
TRANSFORMERS - 115KV/12KV
a. Taps above rating shall be five-eighths (5/8) percent taps, with
sixteen (16) steps for a total of ten (10) percent below
208.03
ELECTRICAL REQUIREMENTS
A.
208.04
208.05
208.06
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Transformer shall have the following electrical/mechanical
characteristics unless otherwise noted on the drawings.
MVA
Phase
Cooling
Coolant
Temperature Rise
MVA (Supplemental - Cont.)
Temp. Rise (Supplemental - Cont.)
Hertz
Impedance
Allowable Sound Level
As Specified
3
OA/FOA/FOA
Air/Oil
55C
As Specified
65C
60
9.6 Nominal at 18 MVA
80 db
“H” Winding
KV Connected (2 1/2% Taps)
KV BIL
Material
KV BIL
Delta
120.75/117.875/115.0/
112.125/109.25
500
Copper
500
“L” Winding
KV Connected
KV BIL
Material
Angular Displacement
WYE
12.4/7.16+/-10% LTC
110
Copper
ANSI Standard
EQUIPMENT IDENTIFICATION
A.
Provide stainless steel nameplates, attached with screws to each piece
of equipment in a highly visible location.
B.
Transformer nameplate shall be in accordance with ANSI
Standard C57.12.00.
FINISH
A.
Painted surfaces shall have at least one (1) prime coat of rust inhibiting
non-lead containing primer.
B.
Finish coat shall consist of two (2) coats of ANSI No. 70 light gray
enamel.
TEST
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December 2004
SECTION 16208
TRANSFORMERS - 115KV/12KV
A.
Shop Test
1.
Transformer(s) shall be tested according to ANSI C57.12.00 and
C57.17.90, prior to shipment.
2.
Part failures shall be located and corrected, after which testing
shall be repeated to certify meeting of test requirements.
3.
Tests and construction are subject to witness and inspection by
the HGST representative. The manufacturer shall notify the
purchaser not less than five (5) days prior to test to allow HGST’s
engineer to inspect and witness required tests.
4.
Provide certified reports of tests performed in accordance with the
latest revised standards of IEEE, ANSI and NEMA. Assemble all
test data in booklets for submittal.
***END OF SECTION 16208***
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