SF6 Gas Insulated Switchgear Guide Specification



1. General

1. The intent of this specification is to have the manufacturer furnish the equipment and material specified herein complete and operable.

2. All standard accessories to the equipment specified shall be supplied even if not specifically mentioned in this specification.

3. Material used in the fabrication of the specified equipment shall be new, unused, and of the highest quality available.

4. A switched way is considered a 3-phase circuit entrance to the bus through either a loadbreak switch or a vacuum interrupter, or a combination of the two.

2. Scope

1. Work Included

1. Furnish SF6 Insulated Switchgear as detailed in Sections 3.0 through 13.0 of these specifications. Any drawings or data sheets attached to the inquiry shall be considered part of this specification. The equipment shall be complete and operable.

2. Provide production tests and inspections as detailed in Section 11.0 of this specification.

3. To reasonably prevent the possibility of shipping damage, the manufacturer shall prepare the equipment for transportation to the jobsite and monitor the load out of this material.

4. Guarantee the performance of the switchgear during a reasonable warranty period. This warranty shall, at a minimum, cover the equipment for eighteen (18) months from time of shipment or twelve (12) months from date of energization whichever occurs first.

5. Supply all drawings, documentation, and information detailed in Section 14.0.

2. Work Not Included

1. Field installation of switchgear, unless otherwise specified.

2. Connection of incoming cables.

3. Connection of outgoing branch feeder cables.

4. Connection of external control cables or wiring.

3. Applicable Codes and Standards

1. The applicable codes and standards listed below should be considered as part of this specification. The latest revision in effect at time of inquiry shall apply for all standards referenced.

1. ANSI/IEEE C37.71, Standard for subsurface dead front switchgear.

2. ANSI/IEEE C37.72, Standard for padmount dead front switchgear.

3. ASTM D2772-SF6 gas requirements

4. ANSI/IEEE C37.60 Switchgear

5. ANSI/IEEE C37.57.12.28-Standard for enclosure integrity.

6. ANSI/IEE Standard 386-Bushing and bushing well requirements.

7. National Electric Code (NEC)

2. It shall be the manufacturer's responsibility to be knowledgeable of these standards and codes.

4. Service and Environmental Conditions

1. Unless otherwise specified this equipment is intended for use in ambient temperatures that do not exceed a maximum of 40°C (104°F) or a minimum of -30°C (-22°F).

2. This equipment is intended for use in an area where the elevation is less than 3300 feet above sea level. Above 3300 feet a de-rating factor as prescribed by ANSI standards will apply.

5. Basic Construction

1. The switch tank shall be designed to withstand the mechanical stresses caused by rough handling during shipment in addition to the electrical and mechanical stresses that may occur during operation.

2. The switchgear tank shall be constructed of 1/4” mild steel braced to withstand 15 PSIG internal pressure.

3. The switchgear tank shall have a leak rate of 1 x 10-6 cubic centimeter per second, certified by the use of a helium mass spectrometer. The leak certification process shall be performed by internal pressurization of the switchgear tank with helium to a minimum of 10 PSIG.

4. The switchgear tank shall be furnished factory filled with an electrical grade of non-toxic, no-flammable SF6 gas and have a pressure gauge, which provides status of the insulating gas.

5. Lifting provisions shall be arranged on the tank to provide a distributed balanced lift in a vertical direction.

6. Painting

1. Upon compellation of welding the tank, all exterior seams will be filled and sanded smooth for neat appearance.

2. Before coating, the tank shall be completely prepared for paint by removing welding flux or splatter. Surfaces must be washed and prepared by a chemical such as zinc phosphate coating.

3. After pre-treatment, final protective coatings shall be applied that shall provide 1500-hour salt spray protection, and UV protects the steel enclosure.

4. After the tank is completely assembled and the components installed, the finish shall be inspected for scuffs and scratches. Blemishes shall be touched up by hand to restore the protective integrity of the finish.

5. The finish paint coat shall be ANSI-61 for the interior and exterior of the tank.

7. Loadbreak Switch Ways

1. The loadbreak switches shall be three-position or two-position gang operated ArcWhipper( Switches as specified on the data sheet(s) or 1-Line drawing(s).

2. Viewing of the contacts in either of the position shall be through a viewing window.

3. The switch shall be operated by a quick-make, quick-break mechanism, which utilizes two expansion springs to insure proper operation torque throughout the life of the mechanism.

4. OPTION: Provide the Powell Cock-N-Trip release mechanism to allow for remote close and open of the switch mechanism. The release mechanism shall be either mechanically or electrically operated as specified on the data sheet(s) or 1-Line drawing(s).

5. OPTION: Provide motor operator to electrically operate the loadbreak switch as specified on the data sheet(s) or 1-Line drawing(s).

6. Switches shall be provided with “provisions only” for keylocks or with keylocks factory installed as specified on the data sheet(s) or 1-Line drawing(s).

7. Interruption will occur in an SF6 environment. The prevent erosion of the current carrying components interrupting current shall be between the arcing spring and the arc horn.

8. To insure low contact resistance the moving contacts shall be coated with rhodium and the stationary contacts shall be coated with silver.

9. The switch shall be mounted in the switch tank in such a way to allow the switch to remain unaffected by minor tank wall movement.

10. Loadbreak switches shall have the following electrical ratings:

|RATINGS |

|Voltage Ratings |

|Maximum Design Voltage |15.5 kV |27 kV |38 kV |

|Frequency |50/60 Hz |50/60 Hz |50/60 Hz |

|BIL impulse withstand |95/110 kV |125 kV |150 kV |

|One minute AC withstand |35 kV |60 kV |70 kV |

|Fifteen minute DC withstand |53 kV |78 kV |103 kV |

|Corona extinction |11 kV |19 kV |26 kV |

|Open Gap BIL Flashover withstand |200 kV |200kV |200 kV |

|Current Ratings |

|Load interrupting and loop switching |600 A |600 A |600 A |

|Transformer magnetizing interrupting |25 A |25 A |25 A |

|Capacitor or cable charging interrupting |40 A |40 A |40 A |

|Asymmetrical momentary and 3 operation fault close |40 kA |40 kA |40 kA |

|Symmetrical one second rating |25 kA |25 kA |25 kA |

|Continuous current |600 A |600 A |600 A |

|Symmetrical 10 cycle phase to phase simulated internal fault withstand|25 kA |25 kA |25 kA |

|Mechanical Ratings |

|Ambient temperature range |-40 to +120 degrees F |

|Mechanical life |2000 operations |

|Corrosion resistance per ASTM B-117 |2000 hours |

|Maximum leak rate |10-6 cc/second |

|Normal gas pressure @ 68 degrees F. |6 psig |

|Maximum design gas pressure |15 psig |

8. Vacuum Interrupter Ways

1. Provide non-fused, non-reclosing, electric reset, vacuum interrupters consisting of vacuum bottles and a spring assisted operating mechanism. Each vacuum interrupter way shall utilize internally mounted current transformers and an electronic protection relay to provide 3-pole gang tripping for single-phase and three-phase faults. The specific relays that are required shall be indicated on the data sheet(s) or 1-Line drawing(s).

2. The fault interrupter shall be enclosed in an SF6 environment.

3. The fault interrupter shall be two-position, three phase gang operated V-Mag (Open-Close).

4. The fault interrupter shall a position indicator viewable though a viewing window.

5. Operation of the fault interrupter shall be by means of push button pendent switch or panel mounted toggle switch. Operator will not be required to come in direct contact with the switch tank in order to open or close the fault interrupter.

6. A power source shall be provided to one operating of the fault interrupter for up to twenty-four hours after loss of normal control power.

7. Vacuum interrupters shall have the following electrical ratings:

|RATINGS |

|Voltage Ratings |

|Maximum Design Voltage |15.5 kV rms |27 kV |38 kV |38 kV |

|Current Ratings |

|Continuous current |630 Amps |630 Amps |630 Amps |630 Amps |

|Short Circuit Breaking Current |12 kA |12 kA |25 kA |31.5 kA |

|Number of Operations |10,000 + |10,000 + |10,000 + |10,000 + |

9. Optional Fusing

1. Dry Well Current Limiting Fuses shall be provided when specified on the data sheet(s) or 1-Line drawing(s).

1. The dry well holders are submersible, dead front and corrosion resistant.

2. An interlock is provided to prevent fuse access when the fuse is energized.

3. OPTION: Provide the Powell anti-single phase feature to prevent single phasing of three phase loads.

4. Dry well current limiting fuses may be installed in either single or parallel configurations.

5. Dry well fuses are available per the following table, and will be provided as shown on the data sheet(s) or 1-Line drawing(s):

|Dry Well Fuse Selection Guide |

|Maximum Voltage |Fuse Size Single Holder |Fuse Size Parallel Holder |

|4.3 kV |18 Amp |36 Amp |

| |25 Amp |50 Amp |

| |35 Amp |70 Amp |

| |45 Amp |90 Amp |

| |50 Amp |100 Amp |

| |65 Amp |130 Amp |

| |75 Amp |150 Amp |

| |100 Amp |200 Amp |

|5.5 kV |6 Amp |12 Amp |

| |8 Amp |16 Amp |

| |10 Amp |20 Amp |

| |12 Amp |24 Amp |

| |18 Amp |36 Amp |

| |20 Amp |40 Amp |

| |25 Amp |50 Amp |

| |30 Amp |60 Amp |

| |40 Amp |80 Amp |

| |50 Amp |100 Amp |

| |65 Amp |130 Amp |

| |75 Amp |150 Amp |

|Maximum Voltage |Fuse Size Single Holder |Fuse Size Parallel Holder |

|8.3 kV |18 Amp |36 Amp |

| |20 Amp |40 Amp |

| |25 Amp |50 Amp |

| |30 Amp |60 Amp |

| |40 Amp |80 Amp |

| |50 Amp |100 Amp |

|15.5 kV |6 Amp |12 Amp |

| |8 Amp |16 Amp |

| |10 Amp |20 Amp |

| |12 Amp |24 Amp |

| |18 Amp |36 Amp |

| |20 Amp |40 Amp |

| |25 Amp |50 Amp |

| |30 Amp |60 Amp |

| |40 Amp |80 Amp |

| |50 Amp |100 Amp |

|23 kV |6 Amp |12 Amp |

| |8 Amp |16 Amp |

| |10 Amp |20 Amp |

| |12 Amp |24 Amp |

| |18 Amp |36 Amp |

| |20 Amp |40 Amp |

| |25 Amp |50 Amp |

| |30 Amp |60 Amp |

| |40 Amp |80 Amp |

10. Optional Instrument Transformers

1. Current Transformers (CT) shall be provided when specified on the data sheet(s) or 1-Line drawing(s) CT’s shall be provided per the following:

1. Current transformers shall be installed over the bushings inside the switch tank. All leads shall be brought out of the tank using a Ductorseal that is designed to maintain the leak integrity of the tank (1 x 10-6 cubic centimeters per second leak rate) and terminated at shorting type terminal blocks inside of a sealed junction enclosure.

2. Each current transformer shall be rated to withstand the thermal and mechanical stresses imposed by the short circuit rating of the switch.

3. Current transformers shall have a rated 5 ampere secondary current unless otherwise specified.

4. Accuracy classification shall be as specified in the data sheet(s) or 1-Line drawing(s) and shall be suitable for the connected burden.

2. Voltage Transformers (VT) and/or Control Power Transformers (CPT) shall be provided when specified on the data sheet(s) or 1-Line drawing(s) and shall be provided per the following:

1. CPT’s and/or VT’s and associated fuse assemblies shall be fixed mounted inside the switch tank and shall be readily accessible with a removable cover.

2. Transformers shall have 120 volt secondaries unless otherwise specified.

3. Transformers shall have an accuracy rating comparable to the metering equipment and a burden capacity equal to twice the initial load.

4. Current limiting fuse protection shall be provided on the primary side of each voltage transformer.

5. Transformers shall be designed to withstand the basic impulse level of the switchgear.

11. Control Wiring

1. Control wiring shall be SIS type #14 AWG, 41-strand extra flexible, stranded copper or larger.

2. CT secondary wiring shall be SIS type #12 AWG, 65-strand, extra-flexible, stranded copper or larger.

3. Current transformer secondary wiring shall terminate on shorting type terminal blocks.

4. All control wiring shall be UL listed and have a VW -1 flame retardant rating.

5. Exposed wiring shall be suitably protected against contact with sharp edges. Throughout the assembly it must be neatly bundled and secured with nylon wire ties. Where control wiring passes from enclosure to door it must be wrapped with suitable protection so as to prevent damage. Holes cut to allow control wires to pass from cubicle to cubicle will have a grommet for protection.

6. Splicing of control wire is not permitted. Control wiring must be a continuous length from terminal to terminal.

7. Each control wire shall be marked at both terminations to agree with wiring diagrams. Plastic wire markers of either the slip on or heat shrink variety shall be provided.

12. Switchgear Terminals

1. Terminals for load interrupter switches shall have 600 amp apparatus bushings or 200 amp bushing wells as specified on the data sheet(s) or 1-Line drawing(s). All bushings shall be welded to the switch tank.

2. Provide parking stands for each bushing if specified on the data sheet(s) or 1-Line drawing(s).

3. One ground boss shall be provided for each three phase set of bushings.

4. One ground-connection pad shall be welded to the tank and have a short circuit rating equal to the switchgear.

13. Nameplate

1. Affix a stainless steel laser engraved switchgear nameplate to the tank.

14. Inspection and Testing

1. Perform production tests on each switch to insure that each switch to ensure that design performance is maintained during production. Certified production test reports indicating satisfactory completion of all inspection and test procedures shall be available upon request.

2. Physical dimensions shall be checked against approved drawings.

3. Manufacturer shall have in place a system of recording, correcting, and verifying resolution of discrepancies discovered during the inspection and testing process. The manufacturer shall be ISO 9001:2000 certified.

15. Submittals

1. Shop Drawings

1. Shop drawings with sufficient information, clearly presented, shall be included to determine compliance with specifications. Drawings shall include electrical ratings, nameplate data, dimensions, weight, mounting details, termination information, connection diagrams, and accessories.

2. After the return of approval drawings or after any change made to previously approved drawings, the manufacturer shall submit a record copy of any and all drawings that contained revisions.

3. Digital files in AutoCAD 2007 “dwg” or Adobe “pdf” format.

4. Each drawing prepared by manufacturer shall show, at a minimum, the name, jobsite location, purchase order or contract number, and equipment identification number in addition to any information required by manufacturer

5. Manuals are to be submitted with shop drawings, including companion copies of maintenance and operation manuals.

2. Installation and Maintenance Manuals

1. At time of shipment the manufacturer shall provide one copy of the installation and maintenance instructions for the switch.

2. Manuals shall contain a table of contents to allow for easy reference.

16. Shipping

1. Switchgear must be placed on pallets to facilitate handling with forklifts.

For assistance regarding these specifications or with support questions, please contact Powell directly:

|Powell Electrical Systems, Inc. |330.966.1750 |

|8967 Pleasantwood Ave NW |Email: info@ |

|North Canton, Ohio 44720 |Website: |

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download