|
|
VPI
Dry Type Transformers
Up to 10,000 KVA (34.5 KV
Class)
VPI -- Vacuum Pressure Impregnation
|
VPI
is a process which is a step above the conventional
vacuum system. VPI includes pressure in addition to
vacuum, thus assuring good penetration of the varnish
in the coil. The result is improved mechanical strength
and electrical properties. With the improved penetration,
a void free coil is achieved as well as giving greater
mechanical strength. With the superior varnish distribution,
the temperature gradient is also reduced and therefore,
there is a lower hot spot rise compared to the average
rise.
In
order to receive the best possible electric, thermal
and environmentally protected transformer, you as
a buyer should insist on vacuum pressure impregnated
unit. Neeltran is now utilizing a state of the art,
9 foot diameter, vacuum pressure impregnating system.
|
Ventilated
Dry Type Standard Features:
|
Copper windings. (Aluminum optional).
220 degree C insulation. 150 degree C temperature
rise for operation in ambients of 30 degree C average,
40 degree C maximum. Four (4) full capacity taps on
H.V. winding, rated 2.5 %, 2 FCAN 2FCBN, on all voltages
above 600 V class. Vacuum pressure impregnation (VPI)
with high temperature thermosetting varnish, (VPE
optional). Core ground strap. Provision for lifting
core and coil assembly. Provision for lifting enclosure.
Vibration-isolation pads. NEMA 1/Rodent-proof ventilated
enclosure constructed with 12 ga. steel frame and
14 ga. panels. Removable panel -- front and rear.
ANSI 61 gray paint. Complete production tests in accordance
with ANSI C57.12.91.
|
Testing
After
final assembly, the following tests are made on all transformers
before shipment from the plant. All tests are made in accordance
with the latest revisions of the ANSI C57.91 dry-type transformer
test code:
| • |
Induced
potential tests. |
| • |
Applied
potential tests. |
| • |
Resistance
measurements of all windings on the rated voltage connections
of each unit and at the tap extremes of one unit of
a given rating on an order. |
| • |
Ratio
test on the rated voltage connection and on all tap
connections. |
| • |
Polarity
and phase-relation tests on the rated voltage connection.
|
| • |
No-load
loss at rated voltage connection. |
| • |
Exciting
current at rated voltage on the rated voltage connection.
|
| • |
Impedance
and load loss at rated current on the rated voltage
connection of each unit and on the tap extremes of one
unit of a given rating on an order. |
| • |
BIL
(Impulse) Test available when requested |
| • |
Other
test available, consult factory. |
Industry
and customer specified qualification tests are performed
on new designs. Records of these tests are maintained at
the factory for transformers manufactured by Neeltran.
Typical
Specification Guide (Information Required for Ordering)
| • |
Rated
KVA through 5000. |
| • |
HV
through 34,500 V delta or wye. |
| • |
HV
Taps -- Quantity and steps above and below nominal voltage
at full or reduced capacity. |
| • |
LV
through 13,800 V delta or wye. |
| • |
Frequency
of 25, 40, 50, 60 or 400 hertz. |
| • |
1
or 3 phases. |
| • |
Wye
winding neutral -- full or half capacity -- solidly
grounded or with low resistance. |
| • |
Self
cooled (AA) average temperature rise not to exceed 80
degrees C, 115 degrees C, 135 degrees C or 150 degrees
C over an average 30 degree C (40 C max.) ambient. |
| • |
Special
environment -- higher ambient condition, high humidity,
conductive or corrosive dust, chlorine or sulphurous
fumes, elevation above 3300 feet sea level. |
| • |
Ventilated,
VPI, VPI-End Cap, Cast Coil, VPE. |
| • |
Copper
or aluminum windings. |
| • |
Impedance
per ANSI standard or other. |
| • |
Indoor,
outdoor, or TENV enclosure. |
| • |
Throat
or air terminal enclosure. |
| • |
Enclosure
color: ANSI 61 (light gray) is standard with other paint
options available including ANSI 24 and ANSI 70. |
Accessories
(Optional):
Automatic Fan Cooling Package
(FA), complete with temperature gauge, to increase rating
by 25% in order to handle overloads. Packages to increase
KVA by 33% or 50% are also available (with internal or external
power).
Fan
Package Features:
| • |
Monitors
the temperature of each coil. |
| • |
Hottest
phase temperature automatically displayed. |
| • |
Temperature
of any single phase can be indicated. |
| • |
Fan,
alarm, and trip functions controlled by hottest phase
temperature. |
| • |
Contact
is provided for trip circuit. |
• |
Normally
open, contact provided for alarm circuit. |
| • |
Fan
exerciser activates fans for one minute every six days
to guard against fan motor freeze-up. |
| • |
Future
Fan Provision (FFA), to enable fan components to be
added at a later date. |
| • |
Temperature
Gauges, (one or three) with multiple NC and NO contacts. |
| • |
NC
or NO Over Temperature Thermostat, in center coil or
in all three coils and wired to a Terminal Board. |
| • |
Externally
Operated Tap Changer, (de-energized operation only)
with Key interlock or Padlock provisions. |
| • |
Primary
and / or Secondary Switchgear. |
| • |
Surge
Arrestors, Distribution, Intermediate or Station Class,
to protect the transformer against line or switching
surges. |
| • |
Key
Interlocks or Padlocks, to coordinate HV switch with
enclosed panels. |
| • |
Space
Heaters, with thermostats to prevent condensation during
prolonged shutdowns. Power from external source. |
| • |
LV
Circuit Breaker, Metering and Relays. |
| • |
Ground
Fault Detection. |
| • |
Flex
Connectors on HV/LV, to simplify field connections. |
| • |
Lugs
for HV/LV cable termination sized per NEC sec. 70-158
Table 310-24. |
| • |
Electrostatic
Shields available. |
^Top
of Page
|
|
|
