Voltage Regulators from Siemens
Guideform Specifications – Voltage Regulators
A.
Three Phase (SFR) Voltage Regulators
1.0 General
1.1 This specification covers electrical, mechanical and safety features and
characteristics of outdoor, three phase, oil immersed, 50 or 60 Hz 55/65oC
temperature rise by resistance, self cooled and force-air cooled step-type voltage
regulators. The voltage regulators must be completely self-contained and
provide +/- 10% voltage regulation in thirty-two (32) steps of 5/8 % each.
1.2 The voltage regulator furnished under this specification shall be designed
and manufactured in accordance with ANSI standard C57.15, latest revision.
This standard shall be a part of this specification.
1.3 Voltage regulator rating(s) and operating voltage(s) shall be specified on the
inquiry. Standard taps of operation are as follows:
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13200 V – 13800 V, 13200 V, 12470 V
34500 V – 34500 V
*A price adder shall be included for other taps of operation.
1.4 The voltage regulator shall be furnished with ANSI Type II mineral oil per
ASTM
D-3487. The oil shall contain less than 1 part per million PCB’s at the
time of manufacture and this shall be stated on the voltage regulator nameplate.
2.0 Construction
2.1 The voltage regulators shall be designed such that they can be partially or
completely untanked for inspection and maintenance without disconnecting any
internal electrical or mechanical connections. After the unit is untanked, it shall
be possible to operate the voltage regulator mechanism and test the control
panel from an external 120 volt source without any reconnections between the
control and the regulator.
2.2 The voltage regulator shall have the necessary electrical and mechanical
provisions for future addition of forced air equipment.
2.3 The tap changing mechanism shall be of the motor driven, quick break type
and shall be completely oil immersed.
2.4 The voltage regulator shall have some means of venting combustible gases.
2.5 The external parts of the tank and control enclosure shall be painted ANSI
#70 gray. The voltage regulator shall be powder coat painted to comply with
ANSI C57.12.31.
2.6 The voltage regulators external hardware is to be stainless steel.
2.7 Core and coil assembly to be provided with patterned epoxy-coated
insulation paper with a minimum of two sheets of insulation between all
series and exciting winding layers.
3.0 Standard External Accessories
3.1 The BIL (basic impulse level) of the bushings shall be compatible with the
BIL of the voltage regulator and all bushings shall have a minimum creep
distance of 17 inches. The bushing designations (S, L, SL) shall be stamped or
embossed on the voltage regulator cover adjacent to the bushings. The S, L,
and SL bushings must be interchangeable with each other.
3.2 The voltage regulators shall be equipped with line terminals per the following
criteria:
Nameplate Line Current
Conductor Size Range Or
Rating
Threaded Size Range
151A to 300A
#2 to 477 MCM
301A to 668A
#2 to 800 MCM
669A to 1200A
1.125-12 UNF-2A
1201A to 2000 A
1.500-12 UNF-2A
3.3 All voltage regulators shall be provided with an external metal oxide varistor
(MOV) bypass arrester connected across the series winding.
3.4 An external oil sight gauge shall be provided which indicates oil level at 25oC
ambient and oil color.
3.5 All voltage regulators shall be provided with an oil temperature gauge.
3.6 An external position indicator which is mounted above the oil level of the
voltage regulator shall be included to indicate the tap changer position. The
position indicator shall be furnished with reflecting numbers and a plexiglass face
plate and shall be slanted at a 45-degree angle for ease of reading from the
ground.
3.7 Voltage regulators rated 1300 amps and below shall include the VARI-AMP
feature which will permit additional current carrying capabilities at reduced
voltage regulation as shown in the table below, but not to exceed 1300
amps. The VARI-AMP adjustment shall be located inside the position
indicator faceplate.
Regulation (percent)
Current (percent of 55oC
rating)
+/- 10.0
100
+/- 8.75
110
+/- 7.50
120
+/- 6.25
135
+/- 5.00
160
3.8 All voltage regulators shall have a cover mounted terminal block. The
terminal block housing shall have a removable gasketed cover to allow easy
potential transformer reconnections.
3.9 Mounting bosses shall be provided for the addition of lightning arresters to
the source (S), load (L), and source-load (SL) bushings. Mounting bosses shall
be fully welded around their circumference. Spot welding will not be acceptable.
3.10 All voltage regulators shall have a side inspection door for inspection and
maintenance of tap changer mechanism.
3.11 The voltage regulator unit shall have a base for skidding in any direction.
3.12 All voltage regulators shall be furnished with an oil sampling valve.
3.13 Voltage regulators rated 250 kVA and below shall be pole-mounted and
provided with welded-on hanger brackets. Voltage regulators rated 167 kVA and
above shall be provided with a base suitable for securing them to a pad or
elevating structure. All voltage regulators must be capable of being secured to
an elevating structure.
3.14 All voltage regulators shall be furnished with an oil sampling valve.
3.15 Every voltage regulator shall be provided with two laser-etched
nameplates. One nameplate will be mounted on the control enclosure and
the other mounted on the voltage regulator tank.
4.0 The following Voltage Regulator Accessories shall be provided when
selected
4.1 Remote Mounting Kit. Please specify at time of request. Extra length
control cable shall be provided for remote mounting of the control cabinet for
location at the base of the pole.
4.2 Adjustable steel elevating structures (sub-bases) to raise the voltage
regulator to meet safe operating clearances from ground to the lowest live part
5.0 Testing
All voltage regulators shall be tested in accordance with the latest ANSI C57.15
standards. Standard tests to include:
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Resistance measurements of all windings
Ratio tests on all tap locations
Polarity test
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No load loss at rated voltage and rated frequency
Excitation current at rated voltage and rated frequency
Impedance and load loss at rated current and rated frequency
Applied Potential
Induced Potential
Insulation power factor test