(Sample Specification)
New Vacuum Replacement
Circuit Breakers
For GE MagneBlast Air Circuit Breakers
1
General
This specification covers the design, testing and manufacturing requirements for new
replacement medium voltage vacuum circuit breakers. The breakers shall be a direct
mechanical and electrical replacement for GE MagneBlast with type MS or ML
mechanisms. The replacement vacuum circuit breakers shall be interchangeable
between different cells of the same voltage, MVA and ampere class without cell +
modifications.
2
Scope of Work
Provide all project management, engineering, supervision, labor, material, tools, rental,
test equipment and transportation as defined by this specification for a complete
vacuum breaker replacement of the existing medium voltage switchgear circuit breakers
listed in Section 3.0 “Equipment List”. The breakers may be 4.76kV, 8.25kV or 15 kV
class breakers as designated.
3
3.1
3.2
3.3
Increased MVA Ratings
Switchgear line-ups designated for new replacement breakers with increased
MVA levels shall have the bracing verified to comply with the new maximum fault
close and latch capabilities as well as the new breaker momentary ratings per
ANSI C37.09.4.6.2.4 and ANSI C37.20.2.5.2.4.
The contractor shall perform a study to determine the current bracing capabilities
and provide mathematical documentation to support his findings. The contractor
shall state that the switchgear is sufficiently braced to handle the new
ratings or supply the cost as a separate item to increase the bus bracing in
all cubicles in the line-up to comply with the increased MVA ratings.
Following the study and/or the bracing modifications, the contractor shall affix a
nameplate to the switchgear structure stating the new MVA rating, the contractor
name and the certification date.
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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4
Cubicle Modifications
The new replacement breakers shall be interchangeable with existing breaker of the
same continuous current and MVA ratings without modifications to the existing cubicles
or cell code plates unless specifically noted in these specifications.
Increased MVA ratings shall require a modification to the cubicle coding system to
prevent the insertion of lower MVA rated breakers or the existing breakers into the
cubicles intended for use with the new higher MVA class breakers.
5
Equipment List
The vacuum circuit breakers shall be utilized to replace the following breakers currently
in service at (Location or Substation):
Qty
6
CAT. Type
kV
Amps
5
5
5
7.5
7.5
7.5
15
1200
2000
3000
1200
2000
3000
1200
15
15
2000
3000
MVA
500
500
500
MOC
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No
Yes/No
Applicable Standards
All medium voltage replacement circuit breakers shall be designed, manufactured and
tested in accordance with the applicable sections of:
ANSI C37.59.1996
ANSI C37.55
ANSI C37.04
ANSI C37.100
ANSI C37.06
IEEE STD 4-1995
ANSI C37.09
ANSI/NFPA 70 (NEC)
ANSI C37.20.2
7
Materials
All materials shall be new and unused. No parts from the original circuit breaker shall
be reconditioned and reused in the new replacement breaker.
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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8
8.1
8.2
8.3
8.4
8.5
9
Contractor/Vendor Qualifications
The supplier or manufacturer, hereafter designated as “contractor”, must meet the
following qualifications to be considered for the award of the contract. The
contractor shall have a minimum of ten years experience in a combination of
performing vacuum conversions and/or the manufacture of vacuum replacement
circuit breakers.
A reference list, preferably of utility and large industrial projects, shall be supplied
with the bid for the breakers.
Contractor shall supply evidence of ANSI certification of the circuit breaker
element and the completed assembly prior to delivery.
Contractor shall have local switchgear service engineers. The contractor shall
have a minimum of 30 years experience in the maintenance of medium voltage
switchgear. Provide address and telephone number of the service office nearest
to the job site with the bid proposal.
All contractors are required to verify nameplate data, control wiring requirements
and cell-to-breaker interface. If the contractor requires a site visit, contact the
department issuing the request for bid to coordinate.
Vacuum Element Features
9.1 General
The retrofit or replacement breaker shall utilize one of the vacuum elements
manufactured by Siemens Power Transmission and Distribution. Acceptable
conversion units are types 3AF and 3AH. The breaker design shall use a common
operator design across all ratings, e.g. a “breaker family”. The operator design shall
include ratings of IEC and ANSI standards including ratings of 38kV/40kA and
15kV/63kA. In addition to the standard ANSI reclosing duties, multiple reclosing duties
of O-3min-CO-3min-CO shall be available for all ratings and extended reclosing duty of
O-0.3s-CO-15s-CO-15s-CO-15s shall be available for ratings up to 31.5kA.
9.2 Mechanical and Electrical Life
The breaker family shall include breakers suitable for frequent operation with
mechanical service life of up to 120,000 operations. The breaker element employed in
any retrofit under these specifications shall have a mechanical design life of at least
10,000 mechanical operations and the vacuum interrupters with a life of at least 10,000
full load current switching operations and at least 20 full fault current switching
operations.
The breaker shall be capable of up to 10,000 cycles or 10 years under normal operating
conditions without relubrication and readjustment.
9.3
Element Frame
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The vacuum element mechanism frame shall be welded and constructed of a minimum
of 3/16 (7 GA.) material to ensure strength, rigidity and dimensional stability over the life
of the breaker.
9.4 Common Pole Shaft
The circuit breaker mechanism shall open and close all three phases and any auxiliary
devices via a common operating shaft to ensure consistent and simultaneous operation
of the main contacts. The main drive shaft shall be connected to the individual vacuum
interrupters via insulated drive links. The drive links shall employ contact pressure
springs that transfer the closing motion from the pole shaft to the contacts through roller
bearings to ensure smooth operation. It shall be possible to move the pole shaft into
the closed and latched position employing a closing bar (i.e. slow close the mechanism)
to ensure smooth operation without evidence of binding or to check and adjust the
synchronization of the contacts.
9.5 Insulated drive links
The mechanism drive shaft shall be connected to each moving contact via an insulated
drive link. The insulated link material shall be non-hydroscopic and meet the flameretardant requirements as set forth in ANSI C37.20.2. The drive links shall be easily
removable with single pins at each end and spring retaining clips. Due to the extremely
long life specified, it shall be possible to adjust the length of the drive links for the
purposes of adjusting or balancing vacuum interrupter stroke over the life of the breaker
or should vacuum interrupter replacement be necessary.
9.6 Shock Absorber System
The mechanism shall contain a shock absorber system to dampen the opening force of
the circuit breaker. The shock absorber shall have sufficient resilience to prevent
contact bounce that could cause a restrike of the main contacts during the opening of
the circuit breaker. The element shall have a sealed replaceable shock absorber and
shall be capable of being adjusted if replaced or during initial mechanism assembly.
The shock absorber shall have a design life of 30,000 breaker opening and closing
cycles without the need for repair, replacement or adjustment.
9.7 Manual and Electrical Tripping and Closing
The mechanism shall have front accessible manual close and trip operators that are
independent of the electrical trip and close coils. The trip and close solenoids shall be
capable of hand operation with the front cover removed to check for binding or unusual
force. The mechanism shall be able to accommodate one closing solenoid and up to
three tripping releases -- two shunt releases and either an undervoltage release or a
low energy (0.1Ws) current transformer operated release.
9.8
Operations Counter
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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Each breaker mechanism shall have a five (5) digit non-resetting mechanical operations
counter connected to the operating shaft.
9.9 Spring Charged Indicator
Each operating mechanism shall be equipped with a visible indicator to show the state
of the stored energy mechanism. The indicator shall display the word ‘charged’ in black
letters on a yellow background when the spring is fully charged and ‘discharged’ in
black letters on a white background when the springs are discharged. Additionally, the
spring charged state shall be available through both an ‘a’ and a ‘b’ contact which are
independent of any other circuits.
9.10 Auxiliary Devices
The breaker shall have a low inertia, rotary operated auxiliary switch connected to the
main pole shaft assembly. The auxiliary switches shall have a continuous current
capability of 10A, making current of 50A, and a breaking capacity at 220 VDC of 2A
(T=2ms). Wiring shall be at least AWG 16-gauge class C halogen free and flame
retardant insulation. Terminations shall be either self-locking push on connectors or
ring tongue. If ring tongue terminations are used a positive method such as lock
washers shall be employed to ensure the ring tongue connections remains tight.
9.11 Corona Suppression
The element, to the greatest degree possible, shall minimize the possibility of corona
generation. Sharp edges, points and punched parts with burrs and points shall be
avoided. Where sharp edges or points cannot be eliminated, corona shields with
rounded edges shall be incorporated into the design to distribute and even out the
electric field.
9.12 Vacuum Bottle Assembly
The vacuum bottle assembly shall be constructed from virgin materials and shall be a
Siemens Product or engineer approved equal. The edges of the ceramic components
shall be “metalized” and fired prior to assembly. The components shall be inspected
and assembled in a class 1000 clean room prior to sealing the components. The
components shall be inserted into a vacuum heat chamber and sealed under vacuum.
A stainless steel corrugated bellows shall achieve isolation of the ambient air and the
vacuum. The vacuum interrupter shall have a visual method of identifying contact wear
(contact erosion) without the use of gauges or other devices.
9.13 Vacuum Interrupter Contacts
The contacts shall principally be composed of unalloyed chromium-copper contact
material. The contacts shall be machined to form spiral petal contacts to assist in the
swirling of the arc during interruption. Contacts up to 50kA interrupting shall use a
radial magnetic design, 50kA and higher interrupting shall employ axial magnetic
contacts.
Following assembly onto the breaker element, the interrupters shall be put through a
conditioning process to work harden the contacts and as assurance of bellows integrity
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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in actual operation. Contact erosion indicators shall not be affixed until after contact
conditioning. The conditioning process shall nominally consist of 300 cycles but may be
shortened if numerically controlled test equipment indicates that full conditioning has
been achieved.
9.14 Insulated Pole Assemblies
Pole assemblies shall be insulated from ground with non-hydroscopic insulating
standoffs. Construction of the pole assemblies shall be such that it shall be possible to
access all sides of the vacuum interrupters for cleaning and inspection. It shall be
possible to replace individual vacuum interrupters without the need of replacing an
entire pole assembly.
9.15 Current Transfer System
The current transfer from the vacuum interrupter moving stem to the breaker terminals
assemblies shall be via a non-sliding current transfer system consisting of a copper
stem clamp and silver plated copper leaf conductors. It shall be possible to verify the
adequacy of the moving stem connection and tighten or replace the assembly if
necessary. All connections in the primary current path shall be silver plated.
9.16 Trip Free Operation
The new circuit breaker operation mechanism shall be a “true Trip-Free” design. When
the trip function is mechanically engaged and held and the close function is initiated
either electrically or mechanically, the contacts shall not close. The contacts shall be
restricted to 10% of the total travel. Execution of the trip–free function shall not
degrade breaker life nor cause the closing springs to impact upon any components
other than snubbers.
9.17 Mechanical Status Indicator
Each new vacuum replacement breaker shall have a mechanical status indicator with
the word "CLOSED" on a red background when the breakers are closed and the word
"OPEN" on a green background when the breakers are open.
10 Replacement Breaker Assembly
10.1 Frame
The frames shall be constructed from steel. Bolted construction is preferred over a
welded configuration. All steel components used in the frame shall be painted with
powder coat paint, ANSI 61 light gray finish, or plated with Type II yellow zinc
dichromate.
10.2 Counterweights
The breaker shall be provided with sufficient counterweights such that is shall be stable
in the cubicle while being racked into position and shall not ‘hang’ in the cubicle during
removal should the cubicle not be equipped with ‘push down’ rods.
10.3 Wheels and Casters for Transport
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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Replacement breakers shall be supplied with a functional replacement of the transport
systems of the original design. The transport system shall conform to the requirements
as listed below:
Original Design
Replacement Breaker
Fixed wheels and dolly
Fixed wheels and dolly
Wheels and casters-no dolly
Wheels and casters-no dolly
Transport dolly/skid required
Wheels and Casters-no dolly or skid
10.4 Bushing and Interface Conductor Material
Primary and power frequency interface conductors shall be constructed of 100% IACS
electrical grade conductive copper. Conductors shall be silver plated to a thickness of
.0001-.0002 for non-sliding surfaces and .001-.015 for sliding surfaces.
The power frequency conductors shall be sized to carry the full load ampacity of the
circuit breaker without exceeding the temperature rise established in ANSI C37.20.2
10.5 Insulation Systems
Bushing insulation shall be phenolic resin with a cotton paper base with a typical
dielectric strength in excess of 500 V/Mil. Diameter of the insulation shall not exceed
the diameter of the original bushing insulation at any point.
Phase barriers shall be designed to isolate individual phase conductors. Openings shall
be minimized to reduce the possibility of ionized gas propagation between phases.
10.6 Primary Connections
Primary connections shall be new solid one-piece conductors for 1200 and 2000 A
ratings; 3000 A breakers may use a hollow multi-part conductor of brazed construction.
All conductors shall be designed to carry the full nameplate rating of the replacement
breaker without exceeding the allowable temperature rise as stated in ANSI
C37.04.5.4.2-1979. In addition, the primary connections shall be capable of
withstanding the full momentary/close and latch rating of the circuit breaker without
arcing or pitting the contact surface.
10.7 Ground Contacts
A silver-plated copper, self-coupling, separable grounding contact shall be supplied of
the same size as the original breaker. The ground contacts shall be adjustable via the
use of shims.
10.8 Control Circuit Wiring
Control wiring shall be SIS flame retardant switchboard wire, #16 AWG minimum
except for short runs such as coil and motor leads.
10.9 Stored Energy Discharge
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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The replacement breaker shall incorporate an automatic system to completely
discharge all stored energy before the circuit breaker is moved to or from the connected
position. The system shall require no modifications to ML or MS mechanism cells. No
cell modifications shall be allowed for the spring discharge system.
10.10 Secondary Contact Block
Control wiring connections between stationary structure and the removable breaker
shall be provided with automatic, self-coupling contacts for disconnection. The
secondary block shall be made of molded epoxy insulation with silver plated phosphorbronze contacts. The secondary block shall be a direct replacement for the original GE
secondary block.
10.11 MOC Operator
All breakers shall be furnished with MOC operators unless specified. The MOC
operator shall have sufficient power to operate a 10-stage single height switch or a 20stage double-height switch in the switchgear line-up without affecting the breaker’s
ability to completely close and latch. The height shall be adjustable. The stroke shall
be fixed. The MOC operator shall have been tested a minimum of 10,000 operations
using the maximum number of stages listed above.
10.12 Cell Coding System
A cell coding system shall be employed to match the existing cell interference
interlocks. The system shall prevent the accidental insertion of a breaker into a cell of a
different voltage, current, interrupting capacity or physical arrangement than the type
intended for the switchgear cell receiving the breaker. The system shall match the
existing system in the cell if it exists.
11 Design and Certification (Type) Testing
In accordance with ANSI C37.59-1996, replacement breakers that do not reuse some
portion of the existing equipment are considered new equipment and must be tested to
the appropriate standard. Replacement breakers that are qualified to the more relaxed
standards of ANSI C37.59 in lieu of C37.09 are not acceptable.
The vacuum breaker supplied shall have type tests performed on its base design.
Extrapolation of test values based on individual components is unacceptable. The tests
shall be performed on the complete assemblies. All type tests will be performed in the
actual switchgear cell or an equivalent structure where permitted by ANSI C37.09.
Written test reports, data logs and records of the tests performed are required to be on
hand for review by the buyer.
11.1 Required Tests
Non-compliance with these base type tests or the failure to produce evidence of such
test shall result in the immediate disqualification of the contractor without obligation to
the buyer.
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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11.1.1 BIL - <60KV for 4.76KV applications, 95KV for 8.25 and 15KV applications as a
minimum> crest with 1.2 sec x 50 sec x 50% wave shape per ANSI
C37.09.4.5.4. The tests shall be conducted per IEEE STD 4-1995. This test
shall be performed in a breaker cell or cell equivalent in an environmentally
controlled “semi-clean room” area with controlled humidity levels. No adjustment
shall be required for humidity. Corrections for barometric pressure and ambient
temperature shall be applied to the test parameters.
11.1.2 Mechanical operations tests of each breaker design shall be performed in an
actual switchgear cell if the mechanism is designed to operate MOC switches.
The maximum number of auxiliary MOC devices shall be installed in the
switchgear cell to insure that the vacuum breaker has sufficient power to operate
the auxiliary devices and that no fatigue or failure occurs. Testing shall be to the
full no-load mechanical life as specified in ANSI C37.06-1987 Table 8. Testing
to only the first scheduled maintenance point is not acceptable.
11.1.3 Momentary tests per IEEE/ANSI C37.20.2.5.2.4 shall be performed of the
completed vacuum replacement breaker including the vacuum breaker element,
bushings, primary disconnects, all bus in the breaker unit, and all insulators and
braces per ANSI C37.09, 4.6.2.4. This shall prove the mechanical strength and
integrity of the conductor and frame assembly of the complete new vacuum
replacement breaker. This test must be performed in a switchgear cell designed
to accommodate the circuit breaker being tested. Anti-rotation devices may be
added to the cell if required to prevent rotation. If anti-rotation devises are used
in the test breaker, then they shall be installed in all the switchgear cells intended
to accommodate the new breakers.
11.1.4 Because the primary conductors in a vertical lift type vacuum breaker normally
parallel the vacuum interrupter, and can magnetically affect the arc interrupting
capabilities of the vacuum interrupter, the manufacturer shall have conducted
interruption testing in the configuration supplied or a more limiting configuration.
11.1.5 Short Time current tests for three (3) seconds at K*I current shall be performed
to confirm the breaker’s I2t capability. The test shall be performed in a
switchgear cell.
11.1.6 Continuous rated current testing per ANSI C37.04-1979 without exceeding 65
degrees C hotspot rise with a maximum ambient not to exceed 40 degrees C.
This test shall be performed in a breaker cell or a cell structure of the same
equivalent volume, dimensions and ventilation as the original switchgear
structure.
11.1.7 Low Frequency Withstand - <19kV rms for 4.76kV applications, 36kV rms for
8.25kV and 15kV applications> per ANSI 37.09, 4.5.3.1
11.1.8 Interlock functional test per ANSI C37.20.2, 6.2.4
11.1.9 All production tests as stated in ANSI C37.09-1979.5.
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
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12 BID EVALUATION:
All bids will be evaluated on the following criteria. All items will carry equal weight.
12.1 Contractor Capabilities
12.1.1 Contractor experience and references: Supply a list with the bid.
12.1.2 Contractor shall have a minimum net worth of $100 million insuring financial
stability.
12.1.3 Manufacturing Facilities - The contractor’s facility shall be dedicated to the
fabrication and production of medium voltage switchgear and related
components. The facility shall be the production facility of the breaker element
used in the assembly. The buyer reserves the right to send a representative to
visit the contractor’s manufacturing facilities prior to the award of a contract. The
buyer further reserves the right to send representatives to the contractor’s
manufacturing facilities during the course of the project for inspection and
witness testing.
12.1.4 Quality Assurance and Total Quality Process: The contractor shall have in place
a functional Total Quality Process. The facility shall be ISO 9001 certified.
12.2 Technical Specification Compliance: Compliance with ANSI production and design
test requirements as stated in IEEE/ANSI C37.59-1996.
12.3 Compliance with requested delivery schedule. Provide the following schedules
with the bid proposal:

Drawings for approval (include review time)

Final factory drawings

Equipment delivery
 Final test reports
12.4 Total installed price.
13 Execution
13.1 The contractor shall utilize a factory trained and certified field engineer to perform
the installation of each breaker at the customer’s site. The field engineer shall be
familiar with vacuum replacement to the point that he/she can offer initial training
to the owner’s on-site operators and maintenance personnel.
13.2 The owner’s maintenance personnel will provide the necessary switching and
breaker operation to accommodate the requirements of the Vendor/Contractor to
perform the removal, and reinstallation of the breakers.
13.3 The contractor shall provide training on the vacuum technology and new
replacement breaker operation and maintenance.
Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591
www.usa.siemens.com/energy-services 800-347-6659
D:\106765234.doc
Rev. 11-20-98