33_77_19.00_40.pdf

SECTION 33 77 19.00 40

MEDIUM-VOLTAGE GAS SWITCH

08/13

PART 1 GENERAL

Section 26 00 00.00 20 BASIC ELECTRICAL MATERIALS AND METHODS apply to work specified in this section.

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

ANSI C37.72 (1987) Standard for Manually-Operated Dead-Front Pad Mounted Switchgear with Load Interrupting Switches and Separable Connections for Alternating-Current Systems

ASTM INTERNATIONAL (ASTM)

ASTM A123/A123M (2013) Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products

ASTM A153/A153M (2009) Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware

ASTM D2472 (2000; R 2014) Standard Specification for Sulphur Hexafluoride

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE 386 (2006; INT 1 2011) Standard for Separable Insulated Connector Systems for Power Distribution Systems Above 600V

IEEE C57.12.28 (2014) Standard for Pad-Mounted Equipment

- Enclosure Integrity

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA)

RCBEA GUIDE (2004) NASA Reliability Centered Building and Equipment Acceptance Guide

1.2 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for Contractor Quality Control approval. When used, a designation following the "G" designation identifies the office that reviews the submittal for the Government.

Submit the following in accordance with Section 01 33 00 SUBMITTAL

PROCEDURES:

SD-02 Shop Drawings

Connection Diagrams

Load- Break Switches

SD-03 Product Data

SF6 Load-Break Switches

Mounting Frames

Accessories

SD-06 Test Reports

Basic Impulse Insulation Level (BIL); G

Withstand Voltage Rating; G

Momentary RMS Asymmetrical Rating; G

Leak Tests; G

Final Test Reports; G

SD-10 Operation and Maintenance Data

Switches; G

1.3 PREDICTIVE TESTING AND INSPECTION TECHNOLOGY REQUIREMENTS

This section contains systems and/or equipment components regulated by NASA's Reliability Centered Building and Equipment Acceptance Program.

This program requires the use of Predictive Testing and Inspection (PT&I) technologies in conformance with RCBEA GUIDE to ensure building equipment and systems have been installed properly and contain no identifiable defects that shorten the design life of a system and/or its components.

Satisfactory completion of all acceptance requirements is required to obtain Government approval and acceptance of the work.

Perform PT&I tests and provide submittals as specified in Section

01 86 26.07 40 RELIABILITY CENTERED ACCEPTANCE FOR ELECTRICAL SYSTEMS.

1.4 MAINTENANCE MATERIALS SUBMITTALS

Submit operation and maintenance manuals for switches, .

PART 2 PRODUCTS

2.1 EQUIPMENT

2.1.1 Switches

Provide detail drawings that show mounting details and configuration for load-break switches.

Provide gas insulated load-break switches of the pad-mounted type in accordance with ANSI C37.72 and IEEE 386.

Provide sulphur hexafluoride (SF6) gas in accordance with ASTM D2472.

Provide manually operated, load-interrupting type SF6 load-break switches, rated 15 kV 600 amperes, minimum, continuous and load break for operation on a 12.47 kV, 3-phase, 3-wire system.

Provide switch enclosures in accordance with IEEE C57.12.28 equipped with ground bus capable of carrying the rated fault current for one second for each way.

Provide each switch with pressure gage, position viewing window and fill plug.

Provide lockable incoming line position of switches to prevent unauthorized grounding.

Provide cable and cable terminations in accordance with Section 26 05 13.00 40 MEDIUM-VOLTAGE CABLES. Equip switches with 600 amperes and bushings with inserts to accept dead break elbows, as indicated.

Provide cable terminations from the fuse compartment that are preformed stress-cones or have deep-well apparatus bushings in accordance with

IEEE 386.

Provide provisions for padlocking each handle in any position.

Provide switch tanks that are constructed of stainless steel plate, fully TTG welded.

Provide operating mechanisms that are equipped with handles for manual operation and are operated by a non-teasible, snap-action, quick-make, quick-break. Make opening and closing of the main contacts totally independent of the speed or position of the operating handle. Secure operating handle to the shaft in a manner that ensures tightness and alignment.

2.1.2 Mounting Frames

Furnish all switches with stainless steel tank having dual certification type 304/304L. Provide a stainless steel enclosure manufactured to ANSI C37.72 and C57.12.29.Furnish mounting frames that are of angle-iron construction, for all pad -mounted switches and are manufactured from stainless steel with the same material as given above.

After fabrication, clean and paint all exposed ferrous metal surfaces of the pad mount enclosure.

Paint mounting frames in accordance with ANSI C37.72.

2.2 ACCESSORIES

Provide fittings, lifting eyes, insulators, and other required accessories with the switch as necessary.

Provide all corrosion-resistant metal operating parts of switch assemblies.

Provide switches with suitable attachments to permit closing and opening under full rated load current, without damage.

Provide switches with a visible break option that allows direct viewing of the switch contacts in the open and closed positions within the switch tank.

2.3 TESTS INSPECTIONS, AND VERIFICATIONS

2.3.1 Factory Information

Ensure switch has momentary rms asymmetrical rating of 22.5 kA and a close rms symmetrical rating of 12.5 kA for 1 minute 60 Hz withstand voltage rating of 35 kV and basic impulse insulation level (BIL) of 95 kV.

Provide the type of switch indicated, designed to show the internal wiring, indicating each switch position. Provide each switching way with 600A dead break bushings.

Provide test reports for the momentary rms asymmetrical rating, withstand voltage rating, basic impulse insulation level (BIL) in accordance with

ANSI C37.72.

2.3.2 Shipping

Prior to shipment, ensure leak tests are performed and submit certification the completed switch assembly has a leak rate less than 0.0000001 cubic centimeters per second by a helium mass spectrometer test. Seal and fill switches with SF6 to a nominal 10 psig positive pressure at 75 degrees F.

PART 3 EXECUTION

3.1 INSTALLATION

Install switches in accordance with the manufacturer's instructions.

Include in the installation all necessary hardware, insulators, and connections to line wire or bus.

3.1.1 Grounding

Solidly bond tanks, mounting frames, and operating mechanisms to the station ground counterpoise in accordance with ANSI C37.72 and Section

28 05 26.00 40 GROUNDING AND BONDING FOR ELECTRONIC SAFETY AND SECURITY.

Identify incoming line position with a warning tag that states "CAUTION:

INCOMING LINE, DO NOT GROUND."

3.2 FIELD TESTING

Perform PT&I tests and provide submittals as specified in Section

01 86 26.07 40 RELIABILITY CENTERED ACCEPTANCE FOR ELECTRICAL SYSTEMS.

Disconnect load break switch assembly from the power supply and feeder cables and ground the switch enclosure before conducting insulation and high-voltage tests.

Give load break switch assembly an insulation-resistance test with a 5000V insulation-resistance test set.

Apply all tests for not less than 5 minutes and until three equal consecutive readings one minute apart are obtained. Record readings every 30 seconds during the first 2 minutes and every minute thereafter. Minimum acceptable resistance readings are 100 megohms.

Upon satisfactory completion of the insulation-resistance test, subject the load break switch to a high-voltage, 60-Hz withstand test. Make test voltage equal to 75 percent of the factory test values and apply for one minute.

Upon satisfactory completion of the high-voltage, 60-Hz withstand test, give the switch assembly a second insulation-resistance test as before.

Provide results of the second insulation-resistance test that are within 5 percent of the first test values and that indicate no evidence of permanent injury by the high potential test.

Operate switch assembly in the presence of the Contracting Officer.

Provide final test reports to the Contracting Officer. Provide a cover letter/sheet with the reports clearly marked with the System Name, Date, and the words "Final Test Reports - Forward to the Systems Engineer/Condition Monitoring Office/Predictive Testing Group for inclusion in the Maintenance Database."

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