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(Sample Specification)

New Vacuum ReplacementCircuit Breakers

forWestinghouse types

50-DH-150-1200 & 50-DH-150-200050-DH-250-1200 & 50-DH-250-2000

50-DHE-350-300075-DH-500-1200 & 75-DH-500-2000

150-DH-500-1200 & 150-DH-500-2000150-DH-750-1200 & 150-DH-750-2000

50-DHP-350-1200 & 50-DHP-350-200075-DHP-500-1200 & 75-DHP-500-2000

150-DHP-500-1200 & 150-DHP-500-2000150-DHP-750-1200 & 150-DHP-750-2000

150-DHP-750C-1200 & 150-DHP-750C-2000150-DHP-1000-1200 & 150-DHP-1000-2000

1 GeneralThis specification covers the design, testing and manufacturing requirements for new replacement medium voltage vacuum circuit breakers. The circuit breakers shall be a direct mechanical and electrical replacement for WESTINGHOUSE type DH AND DHP circuit breakers. The replacement vacuum circuit breakers shall be interchangeable between different cells of the same voltage, MVA and ampere class without cell modifications.

Siemens Power Transmission & Distribution, Inc. 7000 Siemens Road, Wendell, NC 17591

www.usa.siemens.com/energy-services 800-347-6659

/tt/file_convert/5ad94de57f8b9ae1768bb141/document.doc

Rev. 03-08-06

http://www.usa.siemens.com/energy-services%20800-347-6659

2 Scope of WorkProvide 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 circuit breakers may be 4.76kV, 8.25kV or 15 kV class circuit breakers as designated.

3 Increased MVA Ratings

3.1 Switchgear line-ups designated for new replacement circuit 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.

3.2 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.

3.3 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.

4 Cubicle ModificationsThe new replacement circuit 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 circuit breakers or the existing circuit breakers into the cubicles intended for use with the new higher MVA class circuit breakers.

5 Equipment ListThe vacuum circuit breakers shall be utilized to replace the following breakers currently in service at (Location or Substation):




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5.1 Replacement circuit breakers for type DH air magnetic circuit breakers.

Qty CAT. Type kV Amps MVA MOC Number of MOC Tiers(1, 2, or 3)

50-DH-250-1200 5 1200 250 Yes/No

50-DH-250-2000 5 2000 250 Yes/No

50-DHE-350-3000 5 3000 3000 Yes/No

75-DH-500-1200 7.5 1200 750 Yes/No

75-DH-500-2000 7.5 2000 750 Yes/No

150-DH-500-1200 15 1200 500 Yes/No150-DH-500-2000 15 2000 500 Yes/No150-DH-750-1200 15 1200 750 Yes/No150-DH-750-2000 15 2000 750 Yes/No150-DH-1000-1200 15 1200 1000 Yes/No150-DH-1000-2000 15 2000 1000 Yes/No

5.2 Replacement circuit breakers for type DHP air magnetic circuit breakers.

Qty CAT. Type kV Amps MVA MOC Number of MOC Tiers(1, 2, or 3)

50-DHP-350-1200 5 1200 350 Yes/No

50-DHP-350-2000 5 2000 350 Yes/No

75-DHP-500-1200 7.5 1200 750 Yes/No

75-DHP-500-2000 7.5 2000 750 Yes/No

150-DHP-500-1200 15 1200 500 Yes/No150-DHP-500-2000 15 2000 500 Yes/No150-DHP-750-1200 15 1200 750 Yes/No150-DHP-750-2000 15 2000 750 Yes/No150-DHP-750C-1200 15 1200 1000 Yes/No150-DHP-750C-2000 15 2000 750 Yes/No150-DHP-1000-1200 15 1200 1000 Yes/No150-DHP-1000-2000 15 2000 1000 Yes/No




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6 Applicable StandardsAll medium voltage replacement circuit breakers shall be designed, manufactured and tested in accordance with the applicable sections of:

ANSI C37.04 ANSI C37.55ANSI C37.06 ANSI C37.100ANSI C37.09 IEEE STD 4-1995ANSI C37.20.2 ANSI/NFPA 70 (NEC)

7 MaterialsAll materials shall be new and unused. No parts from the original circuit breaker shall be reconditioned and reused in the new replacement breaker.

7.1 Contractor/Vendor Qualifications

7.1.1 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.

7.1.2 A reference list, preferably of utility and large industrial projects, shall be supplied with the bid for the circuit breakers.

7.1.3 Contractor shall supply evidence of ANSI/IEEE certification of the circuit breaker element and the completed assembly prior to delivery.

7.1.4 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.

7.1.5 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.

8 Vacuum Element Features

8.1 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




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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.

8.2 Mechanical and Electrical Life

The breaker family shall include circuit 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 re-lubrication and readjustment.

8.3 Element Frame

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.

8.4 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.

8.5 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 flame-retardant 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.




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8.6 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.

8.7 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.

8.8 Operations Counter

Each breaker mechanism shall have a five (5) digit non-resetting mechanical operations counter connected to the operating shaft.

8.9 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.

8.10 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.




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8.11 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.

8.12 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.

8.13 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 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.

8.14 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.

8.15 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




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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.

8.16 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 or cause the closing springs to impact upon any components other than snubbers.

8.17 Mechanical Status Indicator

Each new vacuum replacement breaker shall have a mechanical status indicator with the word "CLOSED" on a red background when the circuit breakers are closed and the word "OPEN" on a green background when the circuit breakers are open.

9 Replacement Breaker Assembly

9.1 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.

9.2 Wheels and Casters for Transport

Replacement circuit breakers shall be supplied with a functional replacement of the transport systems of the original design.

9.3 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 0.0001 - 0.0002 inches for non-sliding surfaces and 0.001 - 0.015 inches 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




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9.4 Insulation Systems

Phase barriers shall be designed to isolate individual phase conductors. Openings shall be minimized to reduce the possibility of ionized gas propagation between phases.

9.5 Primary Connections

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.

9.6 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.

9.7 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.

9.8 Stored Energy Discharge

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. No cell modifications shall be allowed for the spring discharge system.

9.9 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 phosphor-bronze contacts. The secondary block shall be a direct replacement for the original Westinghouse secondary block.

9.10 MOC Operator

The MOC system shall not require any adjustment to ensure full interchangeability of circuit breakers between cubicles with various MOC switch arrangements.

The MOC operator shall use a bi-directional snubber and velocity control system to control the operating velocities of the MOC system.




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There shall be not disconnect between the circuit breaker stored energy system and the MOC operation.

9.11 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.

10 Design and Certification (Type) TestingIn accordance with ANSI C37.59-1996, replacement circuit breakers that do not reuse some portion of the existing equipment are considered new equipment and must be tested to the appropriate standard. The vacuum breaker supplied shall have type tests performed on its base design. 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.

10.1 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. 10.1.1 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.

10.1.2 Mechanical operations tests of each breaker design shall be performed in actual switchgear cell if the mechanism is designed to operate MOC switches (if part of original circuit breaker). The circuit breaker shall be interchangeable between cells with various numbers of MOC switches (one, two or three tiers of MOC switches) without adjustment.




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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.

10.1.2.1 Mechanical endurance operations tests (to minimum of 1000 operations of the total number of operations required by ANSI C37.06) shall be successfully completed without maintenance while operating one (1) tier of MOC switches. This ensures that the circuit breaker has sufficient power to operate within the circuit breaker’s vacuum interrupter operating characteristics (velocities, times, etc.) while operating the MOC one (1) tier system.

The MOC system with a single tier of MOC switches absorbs more of the energy supplied by the vacuum circuit breaker. The MOC system shall not fail due to the forces applied.

The circuit breaker operating characteristics shall be verified at the beginning and end of each set of operations while operating the MOC single tier system.

10.1.2.2 Mechanical endurance operations tests (to minimum of 1000 operations of the total number of operations required by ANSI C37.06) shall be successfully completed without maintenance while operating three (3) tiers of MOC switches. This ensures that the circuit breaker has sufficient power to operate within the circuit breaker’s vacuum interrupter operating characteristics (velocities, times, etc.) while operating the MOC three (3) tier system.

The MOC system with a three (3) tiers of MOC switches requires that additional energy be supplied by the vacuum circuit breaker. The circuit breaker and MOC system shall operate properly and without failure.




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The circuit breaker operating characteristics shall be verified at the beginning and end of each set of operations while operating the MOC three (3) tier system.

10.1.2.3 Mechanical endurance operations tests (to minimum of 50 operations of the total number of operations required by ANSI C37.06) shall be successfully completed without maintenance while operating three (3) tiers of MOC switches plus an additional marginal load. An additional margin shall be included and stated (reference C37.59-2002, Clause A.5).This ensures that the circuit breaker has sufficient power to operate within the circuit breaker’s vacuum interrupter operating characteristics (velocities, times, etc.) while operating the MOC three (3) tier system plus an additional marginal load.

The MOC system with a three (3) tiers of MOC switches requires that additional energy be supplied by the vacuum circuit breaker. The circuit breaker and MOC system shall operate properly and without failure.

The circuit breaker operating characteristics shall be verified at the beginning and end of each set of operations while operating the MOC three (3) tier system plus marginal load system.

10.1.2.4 The maximum number of auxiliary MOC devices shall be installed in the switchgear cell to ensure 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.

10.1.3 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 circuit breakers.

10.1.4 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.




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10.1.5 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.

10.1.6 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.

10.1.7 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

10.1.8 Interlock functional test per ANSI C37.20.2, 6.2.410.1.9 All production tests as stated in ANSI C37.09-1979.5.

11 BID EVALUATION: All bids will be evaluated on the following criteria. All items will carry equal weight.

11.1 Contractor Capabilities

11.1.1 Contractor experience and references: Supply a list with the bid.11.1.2 Contractor shall have a minimum net worth of $100 million insuring financial

stability.11.1.3 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.

11.1.4 Quality Assurance and Total Quality Process: The contractor shall have in place a functional Total Quality Process. The facility shall be ISO 9001 certified.

11.2 Technical Specification Compliance: Compliance with ANSI production and design test requirements as stated in IEEE/ANSI C37.59-1996.

11.3 Compliance with requested delivery schedule: Provide the following schedules with the bid proposal:

Drawings for approval (include review time)Final factory drawings




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Equipment deliveryFinal test reports

11.4 Total installed price.

12 Execution

12.1 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.

12.2 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 circuit breakers.

12.3 The contractor shall provide training on the vacuum technology and new replacement breaker operation and maintenance.




Rev. 03-08-06


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