SECTION MEDIUM VOLTAGE CABLE

Transcription

1 SECTION MEDIUM VOLTAGE CABLE PART 1 - GENERAL 1.1 SUMMARY A. Related Documents: 1. Drawings and general provisions of the Subcontract apply to this Section. 2. Review these documents for coordination with additional requirements and information that apply to work under this Section. B. Section Includes: 1. Single conductor, medium voltage power cable. 2. Cable - Grounding. 3. Medium voltage cable splicing and terminations. 4. Testing of medium voltage cable, splices and terminations. C. Related Sections: 1. Division 01 Section "General Requirements." 2. Division 01 Section "Special Procedures." 3. Division 26 Section "Common Work Results for Electrical". 4. Division 26 Section "Electrical Conduit". 5. Division 26 Section "Cable Trays for Electrical Systems" 6. Division 26 Section "Medium Voltage Outdoor Metal-Clad Switchgear". 1.2 REFERENCES A. General: 1. The following documents form part of the Specifications to the extent stated. Where differences exist between codes and standards, the one affording the greatest protection shall apply. 2. Unless otherwise noted, the referenced standard edition is the current one at the time of commencement of the Work. 3. Refer to Division 01 Section "General Requirements" for the list of applicable regulatory requirements. 4. Refer to Division 26 Section "Common Results for Electrical" for codes and standards, and other general requirements. B. ASTM International: 1. ASTM B-3, B-8, and B American Society for Testing Materials. C. NFPA 70 - National Electrical Code. D. AEIC CS8 - Association of Edison Illuminating Companies. E. ICEA Publication No. S NEMA WC7 - Insulated Cable Engineers Association. F. IEEE 48 - Test Procedures and Requirements for High-Voltage Alternating-Current Cable Terminations

2 G. NEMA WC 8 - Ethylene-Propylene-Rubber-Insulated Wire and Cable for the Transmission and Distribution of Electrical Energy. H. National Electrical Safety Code (NESC) I. NETA National Electrical Testing Association J. Underwriters' Laboratories, Inc. (UL 1072). 1.3 SUBMITTALS A. Submit under provisions of Division 26 Section "Common Results for Electrical - Review of Materials" and Division 01 Section "General Requirements." B. The manufacturer's proposal shall include the following information: 1. Diameter of cable. 2. Weight of cable in pound per foot. 3. Complete description of cable, insulation production compound code number. 4. Trade name. 5. Written warranty. 6. Recommended splicing and termination methods. 7. Recommended bending radius. 8. Maximum length of cable on standard reel. 9. Net price of cable per 1,000 feet (305 m) delivered. 10. Additional price of reels, refundable on return to manufacturer. 11. Delivery date. C. Confirmation that the cable meets the requirements of Paragraph 2.2.G.1 shall be supplied with quotations. D. Manufacturer's Documentation: After approval by SFPUC of cable to be used, the cable manufacturer shall furnish the following: 1. Electronic copy of Certified Test Reports on tests required in Paragraphs 2.2.G.2 and 2.2.G.3 shall be provided for each cable. 2. Proof that cable has been manufactured within six months of its installation. 3. Two copies of the manufacturer's splicing and termination procedures for approval. E. Calculations: The Subcontractor shall provide pulling tension and sidewall pressure calculations for pulling in both directions of each cable pull. Include drawings of actual duct layouts indicating duct lengths, size and material and bend radius and degrees of arc between pulling points. F. Product literature and samples of materials for circuit labeling. 1.4 QUALITY ASSURANCE A. Manufacturer's Qualifications: Company experienced in manufacturing Products specified in this Section with minimum of 10 years. B. Cable Splicer Qualifications:

3 1. Workers' Competency: Submit high voltage cable splicer certification of competency and experience 30 days before splices or terminations are made in high voltage cables. Splicer experience during the immediate past three years shall include performance in splicing and terminating cables of the types and classification being provided under this Subcontract. In lieu of a certification of competency, a Subcontractor may demonstrate the qualifications of a proposed cable splicer through formal training and relevant experience in splicing cables of the type and class under this Subcontract. 2. A notarized listing of relevant projects completed by the proposed splicer during the past three years and completed formal training must be submitted to demonstrate qualifications. 3. Before assigning cable splicer to work covered by this specification, the Subcontractor shall provide the SFPUC with the names of the cable splicers to be employed, together with satisfactory proof that each splicer has had at least three years experience in splicing high-voltage cables and is experienced with the type and rating of cables to be spliced. In addition, each cable splicer may be required to make an approved dummy splice in the presence of the Project Manager in accordance with manufacturer's instructions, before the splicer is accepted to splice cable covered by this Specification. 4. Material for dummy splices shall be furnished by the Subcontractor. C. Factory Inspection by SFPUC: Following cable fabrication, the SFPUC reserves the right to have a factory inspection and witness testing of the cable. The Subcontractor shall notify the SFPUC in writing at least three weeks prior to factory tests. The SFPUC will provide the Subcontractor with a written waiver if a factory inspection and witness testing of the cable is not to be performed by the SFPUC. PART 2 - PRODUCTS 2.1 ACCEPTABLE MANUFACTURERS A. Cablec Industrial Cable Co., Southwire, Okonite Co., Pirelli Cable Corp., or approved equal. B. Substitutions: Under provisions of Division 01 Section "General Requirements", Paragraph E, Material and Equipment KV CABLE A. This Specification describes requirements for 15kV Class (133 percent Insulation level) aluminum, shielded power cable for use in power distribution. Cable provided must be single conductor, jacketed, and insulated with a high quality, heat, moisture, impact, ozone, and corona resistant thermosetting (ethylene propylene) rubber that shall be suitable for use in wet or dry locations in conduit, underground duct systems, direct burial, and aerial installations. B. Conductors: 1. Conductor material shall be aluminum in conformance with ASTM B Conductors shall be Class B stranded in conformance with ASTM B

4 C. Conductor Screen: 1. The conductor strand shield shall be both a 2.5 mil thick extruded semiconducting material in conformance with Paragraph 2.7, ICEA S , NEMA WC 74 or extruded energy suppression and stress control material having the necessary characteristics to perform the function of the semiconducting material. A nonmetallic semiconducting tape shield is not acceptable. D. Insulation: 1. Insulation shall be an ethylene propylene rubber compound rated at 105 deg C for normal operation, 140 deg C for emergency overload conditions, and 250 deg C for short circuit conditions. a. Other synthetic rubber based insulations are acceptable if they meet the above operating temperatures and are unaffected by ozone and electric discharge and proven by the insulation's ability to withstand continuous exposure to electrical discharge for more than 2,000 hours when energized at a test potential equal to 250 volts/mil of insulation thickness. The test procedure shall be that described in part 6 of ICEA S The insulation material shall meet the electrical and physical requirements specified in Part 3, ICEA S /NEMA WC The average insulation thickness shall be not less than 220 mils; the minimum thickness at any point shall not be less than 90 percent of the specified average thickness. E. Insulation Screen: 1. The insulating screen shall consist of semiconducting non-metallic, extruded covering, in conformance with Paragraph , ICEA S , directly over the insulation and a non-magnetic metal tape, in conformance with Paragraph , ICEA S , directly over the semiconducting covering. Substitution of a nonmetallic semiconducting tape for the extruded covering is not acceptable. a. Cables using the extruded energy suppression and stress control material for the strand shield may use the same material instead of the semiconducting material for the 15kV insulation shield. 2. The extruded covering shall be at least 2.5 mils thick and shall be in intimate contact with the insulation, but shall be removable without damaging the insulation; leaving no residue that cannot be readily removed. 3. The metal tape shall be of 5.0 mil bare copper with at least 10 percent nominal overlap. The tape shall be electrically continuous without joints, soldering, or brazing. F. Shield 1. Shield shall be bare copper tape, 5 mils thick, helically applied, with 12.5% nominal overlap. G. Overall Jacket: 1. A continuous, extruded, tight fitting, non-conductive, abrasion, moisture, heat, weather, solvent and flame resistant black thermosetting Chlorinated Polyethylene (TS-CPE) jacket shall be applied directly over the copper shielding tape, in conformance with Paragraph , ICEA S /NEMA WC The overall jacket shall be free stripping from the shielding tape. 3. The minimum average thickness of the overall jacket shall not be less than 80 mils, and the minimum thickness shall not be less than 80 mils. H. Electrical and Physical Tests:

5 1. Qualification tests in compliance with Section B, AEIC CS8 are required for each shielded cable furnished. 2. All materials used in construction of the cables shall be tested in compliance with the application paragraphs of ICEA S All completed cables shall successfully pass the following tests prescribed in ICEA publication S NEMA WC 74: a. Par Aging. b. Par Voltage. c. Par Insulation Resistance. d. Par Partial Discharge Extinction (Corona) Level. e. Par Discharge Residence. 4. Test methods and frequency of tests (for tests in G.2 and G.3 above) shall be as prescribed in Part 6 ICEA S I. Cable Identification: The following information shall be indicated, by means of a surface legend printed in compatible ink of contrasting color, at intervals not to exceed 24 inches over the entire length of the cable: 1. Manufacturer's name. 2. Conductor material. 3. Conductor size. 4. Maximum rated voltage. 5. Insulation material. 6. Letter designating cable type. 7. Shielded or non-shielded. 8. Date of manufacture. J. Reel Identification: Each reel shall have printed on the reel or a weatherproof (metal or plastic) tag firmly attached indicating: 1. Manufacturer's name. 2. Conductor material. 3. Conductor size. 4. Insulation type and thickness. 5. Jacket thickness. 6. Temperature rating. 7. Length of cable. 8. Manufacturer's type. 9. Voltage class. 10. Purchaser's purchase order number and item number. 11. Cable weight. 12. Reel weight. 13. Shielded or non-shielded. 14. Date of manufacture. K. Shipment: The cable shall be shipped in continuous lengths as specified by the Subcontractor. The shipment shall be made on carefully inspected non-returnable reels if possible. Cable ends shall be securely fastened to the reel using polypropylene rope ties. Metal ties shall not be used. Cable ends shall be completely sealed against moisture and contaminants. The cable on the reel shall be protected with plyboard or tekboard lagging held securely in place with steel banding. L. Conductor and Shield Continuity: Each length of completed cable shall be tested for conductor and shield continuity

6 M. Reports: Certified copies of Production Tests specified in Paragraph 2.2.F shall be furnished for each shipment of cable. 2.3 CABLE TERMINATIONS A. Manufacturers: 1. Raychem, Hot Splices, 3M, or approved equal. 2. Substitutions: Under provisions of Division 01 Section "General Requirements" and as recommended by the cable manufacturer. B. Description: IEEE 48; Class 1, molded rubber cable termination in kit form with stress cone, ground clamp, non-tracking rubber skirts, utilizing molded elastomer, wet process porcelain, pre-stretched, and heat-shrinkable terminations utilizing factory preformed components to the maximum extent practicable, rather than tape build-up. Terminations shall have a basic impulse level as required for the system voltage level. 2.4 CABLE TERMINATION ELBOWS A. Manufacturers: Cooper, Raychem, 3M, or approved equal. B. Substitutions: Under provisions of Division 01 Section "General Requirements" and as recommended by the cable manufacturer. C. Description: IEEE 386; 200A elbows shall be rated as a switching device. With pulling eye and capacitive test plug. Minimum 95 BIL. 2.5 CABLE SPLICES A. Manufacturers: 1. Raychem, Hot Splices, 3M, or approved equal. 2. Substitutions: Under provisions of Division 01 Section "General Requirements" and as recommended by the cable manufacturer. B. Description: IEEE 404 and 592; splice kits may be of the heat-shrinkable type, of the premolded splice and connector type, the conventional taped type, or the resin pressure-filled overcast tape type. 2.6 CIRCUIT LABELS A. Manufacturers: 1. Ametek Industries, Type E-Z -Tag; Seton; or equal. 2. Substitutions: Under provisions of Division 01 Section "General Requirements". B. Description: Cable circuit labels shall be 1-1/2 high, polyethylene, with black on yellow characters, in a polyethylene holder, attached to the cable by two nylon self locking ties. 2.7 FIREPROOFING TAPE

7 A. Manufacturers: 1. 3M, Plymouth, or equal. 2. Substitutions: Under provisions of Division 01 Section "General Requirements". B. Description: The tape shall be noncorrosive to cable sheath, shall be self-extinguishing, and shall not support combustion. The tape shall not deteriorate when subjected to oil, water, gases, salt water, sewage, or fungus. PART 3 - EXECUTION KV CABLE INSTALLATION A. Carefully protect cable from mechanical damage. Provide suitable mechanical protection for reels. B. Pull cable directly from reels into the ducts. It may not be laid on the ground or otherwise handled for cutting or sorting. Pulling lubricant, UL-listed and compatible with the cable being pulled, as manufactured by IDEAL, Y-ER-EAS, or equal, shall be generously applied. Pulling tension (lbs) not to exceed times the circular-mil cross-sectional area of the conductor. Cables shall not be pulled through more than one intermediate manhole on one pull. Cable ends shall be sealed against moisture after pulling. Pull ropes shall be non-metallic to prevent cutting of duct materials. C. Pulling tension and side wall pressure shall not exceed the manufacturer s allowable values. Pulling tension shall be continuously monitored during a pull by use of a dynamometer. The dynamometer shall have been calibrated within a year of its use on the project. If the pulling tension or sidewall pressure is exceeded during a pull, the cable shall be considered damaged and shall be replaced by the Subcontractor. D. Installation of Cables in Manholes and Handholes: Cable shall not be installed utilizing the shortest route, but shall be routed along those walls providing the longest route and the maximum spare cable lengths. Cables shall be formed closely parallel to the walls, shall not interfere with duct entrances, and shall be supported on brackets and cable insulators, spaced at a maximum of four feet. In existing manholes and handholes where new ducts are to be terminated or where new cables are to be installed, the existing installation of cables, cable supports, and grounding shall be modified as required for a neat and workmanlike installation with cables properly arranged and supported. E. Split wire-basket cable grips shall be used to restrain conductors in manholes, handholes, and pull boxes on downhill duct runs. F. Splicing of cable within manholes shall be as recommended by the cable manufacturer. The Subcontractor shall furnish for approval two (2) copies of the manufacturer's splicing and termination procedures. Splices shall be suitable for continuous immersion in water and shall be made only in accessible locations in manholes or handholes. Maintain existing phase rotation after splicing in the new sections of cables. G. Splicing shall be done by a qualified subcontractor specializing in high-voltage splicing and testing, using experienced cable splicers having experience specified in the Quality Assurance article above

8 H. Splices in Shielded Cables: Splices in shielded cables shall include covering the spliced area with metallic tape, or like material, to the original cable shield and by connecting it to the cable shield on each side of the splice. Provide a No. 12 AWG or larger solid copper ground connection brought out in a watertight manner and grounded to a 3/4 inch by 10 foot ground rod as part of the splice installation. Wire shall be trained to the sides of the enclosure in a manner to avoid interference with the working area. I. The 4/0 AWG bare copper-conductor ground wire shall be bonded to existing and new ground rods in manholes. J. Fireproofing (arc proofing) of cables in manholes, handholes, and vaults: Medium voltage cables, in manholes and handholes, shall be fireproofed. Strips of fireproofing tape, approximately 1/16 inch thick by 3 inches wide, shall be wrapped tightly around each cable spirally in a half-lapped wrapping, or in two butt-jointed wrappings with the second wrapping covering the joints in the first. To prevent unraveling, the fireproofing tape shall be random wrapped, the entire length of the fireproofing, with pressure sensitive glass cloth tape. The fireproofing tape shall consist of a flexible, conformable fabric having one side coated with flame retardant, flexible, polymeric coating and/or a chlorinated elastomer not less than inch thick and shall weigh not less than 2.5 pounds per square yard (1.436 k/m²). The tape shall be applied with the coated side toward the cable and shall extend one inch into ducts KV CABLE LABELING A. 15kV circuits shall have each phase tagged (A, B, or C) at termination points and on either side of each splice in a man hole, using plastic tie-tags. B. At each manhole, handhole or pull box, 15kV circuit labels, as shown on the drawings, shall be attached to each cable group. As the cable enters it shall be labeled to identify the source. As the cable leaves it shall be labeled to identify its destination. At approximately the center of the cable group it shall be identified with its feeder circuit designation. 3.3 TEST LABORATORY A. The Subcontractor shall provide the services of a recognized independent testing laboratory for the purpose of performing inspections and tests on the cable installation. The testing laboratory shall meet federal OSHA criteria for accreditation of testing laboratories, Title 29, Part Membership in the National Electrical Testing Association constitutes proof of meeting such criteria. The testing laboratory shall submit proof of the above qualifications through the Subcontractor to the SFPUC. The testing laboratory shall provide material, equipment, labor, and technical supervision to perform such tests and inspections. The tests and inspections shall determine the suitability, of the cable installation for energization kV CABLE TESTING IMMEDIATELY AFTER INSTALLATION A. Immediately after cables have been installed, the Subcontractor shall notify the testing laboratory and the SFPUC when the installation is available for testing. The SFPUC or its representative shall witness testing

9 B. Each conductor shall be individually tested with other conductors grounded. Shields shall be grounded. C. A DC high potential shall be applied in at least 8 equal increments until a maximum of 55kV is reached. DC leakage current shall be recorded at each step, allowing stabilization time for system charging current decay. A graphic plot shall be made of leakage current (x axis) versus voltage (y axis) at each increment. D. The tested conductor shall be raised to the maximum test voltage and held for fifteen minutes. Readings of leakage current (y axis) versus time (x axis) shall be recorded and plotted at thirty second intervals for the first two minutes and then at each minute thereafter. E. A shield continuity test shall be performed by the ohmmeter method. The ohmic value shall be recorded. F. The test laboratory shall maintain a written record of tests and, upon completion of the project, assemble and certify a final test report no later than ten days after completion of the tests. The SFPUC shall receive 3 copies of the final test report kV CABLE TESTING AFTER SPLICING AND END TERMINATION PREPARATION A. Immediately after cables have been spliced and cable ends prepared for termination, but not connected to equipment, the Subcontractor shall notify the testing laboratory and the SFPUC when the installation is available for testing. The SFPUC or its representative shall witness testing. B. Each conductor shall be individually tested with other conductors grounded. Shields shall be grounded. C. A dc high potential shall be applied in at least 8 equal increments until a maximum of 30kV is reached. Dc leakage current shall be recorded at each step, allowing stabilization time for system charging current decay. A graphic plot shall be made of leakage current (x axis) versus voltage (y axis) at each increment. D. The tested conductor shall be raised to the maximum test voltage and held for fifteen minutes. Readings of leakage current (y axis) versus time (x axis) shall be recorded and plotted at thirty second intervals for the first two minutes and then at each minute thereafter. E. A shield continuity test shall be performed by the ohmmeter method. The ohmic value shall be recorded. F. The test laboratory shall maintain a written record of tests and, upon completion of the project, assemble and certify a final test report no later than ten after completion of the tests. The SFPUC shall receive 3 copies of the final test report. END OF SECTION