STEAM EXPANSION PHASE 1PROJECT NO.: 9507400

UNIVERSITY OF CALIFORNIA, DAVIS

DAVIS, CALIFORNIA

SECTION 16135 – MEDIUM VOLTAGE CABLE (OVER 600 VOLTS)

PART 1 - GENERAL

1.1WORK

  1. Provide medium voltage cable complete with accessories.
  2. Cable rated 15 kilovoltfor use on 12.47 kV 3-phase, 60 hertz distribution systems.
  1. submittals
  2. In addition to the requirements of Section 01334 Shop Drawings, Product Data and Samples and Section 16010 General Requirements for Electrical Wire, the following shall apply:
  3. Shop Drawings:
  4. Cable manufacturer experience
  5. Cable shipping and handling protocol
  6. Certified test reports.
  7. Catalog cuts.
  8. Splice kit information.
  9. Separable load break connections.
  10. List of certified cable splicers.
  11. Pulling lubricant information
  12. Cable Pulling Plan including set-up arrangement
  13. quality assurance
  14. Refer to Division 1 and Section 16010 General Provisions for Electrical Work.
  15. Cable to have 40 year warranty from date of shipment
  16. delivery, storage, and handling
  17. Delivery: Deliver cable packaged in factory-sealed containers wound on NEMA cable reels. Each end of each length of cable shall be hermetically sealed and securely attached to the reel. The minimum diameter of the real drum shall be 14 times the overall diameter of the cable. A pulling eye shall be installed by the manufacturer for each length of cable supplied.
  18. Storage: Store cable in a clean dry space in original containers. Protect products from weather, damaging fumes, construction debris and traffic.
  19. Cable reels shall be stored and handled in a manner which will prevent physical damage to the cable. Cable reels shall be stored on a hard surface to prevent contact between cable insulation and earth due to sinking of the reel. Impact damage between reels shall be prevented by aligning reels flange-to-flange or by using guards across flanges. During storage, the ends of all cable rated 5 kilovolt and above, shall be protected with heat shrink end caps. Heat shrink end caps shall be installed at the factory prior to shipment, and in the field by the Contractor on all cut cable ends at all termination points in switchgear and manholes prior to installing termination connectors.
  20. Handling: Handle cable carefully to avoid abrading, puncturing, and tearing cable insulation and sheathing. Ensure that dielectric resistance integrity of cables is maintained. After installation, all cable sections shall be DC Hi-pot tested.

PART 2 - products

2.1single conductor shielded cables

  1. Overall cable rating of 105C normal, 140C emergency (1500 hours maximum), 250C short circuit operating temperatures, UL listed, type MV-105.
  2. Conductor: copper, Class B compact concentric stranded. #2/0 AWG for 200 amp feeders and 350 kcmil for 400 amp feeders.
  3. Conductor screen: Extruded semi-conductor thermosetting “EPR” compound with resistivity not less than 50,000 ohm-cm at temperature of 105 degrees C, compatible with both conductor and insulation with an operating temperature equal to that of the insulation.
  4. Insulation: Ethylene propylene with average thickness of 220 mils, 133 percent insulation level. Minimum thickness at any cross section not less than 90 percent of the average thickness.
  5. Insulation screen: Extruded semiconductor thermosetting “EPR” compound with resistivity not in excess of 50,000 ohm-cm at 105 degrees C. Average thickness; 30 mils.
  6. Conductor shield, insulation and insulation screen to be applied to conductor in single “triple extrusion” operation.
  7. Shield: Minimum five mil copper tape applied helically with a 12-1/2 percent minimum overlap.
  8. Outer jacket: Sunlight resistant extruded HMW-PE, CPE or PVC, for wet, dry locations in conduit, cable tray or direct buried.
  9. Cable must be free stripping without use of heat curing or need for machine removal.
  10. Factory testing: Completed cable shall be tested per AEIC CS6 to include AC withstand, IR, conductor resistance and partial discharge testing.
  11. Cable supports: Vertical or slopping runs shall be properly supported when conduit runs exceed 25 feet. Provide non-metallic tape to grip cable securely. Support vertical runs of cable at intervals not exceeding those noted in the Electrical Code.
  12. Manholes: Support cable in manholes with standard equipment fastened by concrete inserts, as follows:
a.Feeders: tie feeders to non-metallic supports or arms bracket mounted.

2.2cables, splices, and connectors

  1. General: Provide Underwriters Laboratories, Inc. (UL) listed single conductor stranded copper cable of sizes, ampacity, temperature ratings, and insulation materials as indicated on the drawings. Cables shall be manufactured and tested in accordance with latest editions of ICEA S68-516, AEIC CS6 and UL Standard 1072. Cable splice kits shall be manufactured and tested in accordance with IEEE 386.
  2. Insulation: Provide insulation level of 133 percent.
  3. Cable shall be manufactured by an extrusion process utilizing compounds which have been formulated and mixed at the manufacturer’s facilities.
  4. The extruded cable core shall be wrapped with a non-magnetic shielding tape with an overall PVC jacket.
  5. Splices and Termination Kits: Provide splice and termination kits containing factory formed parts.
  6. Kits shall be heavy duty, pressure type fittings, designed for proper size of cables and wires being spliced and terminated. Kits shall be rated for 15 kV system use and approved by the University’s Representative before installation.
  7. Splices and terminations shall not be less than the voltage rating of cable and shall include shielding and stress core material.
  8. Kits shall be suitable for interior, exterior, or submersible applications.
  9. Premolded rubber devices shall have a minimum of 0.125 inch semi-conductive shield material covering entire housing.
  10. Grounding of metallic shield shall be accomplished by solderless connector enclosed in watertight rubber housing.
  11. All final connections to equipment shall utilize non load break elbow connectors.
  12. All cable connections shall be made with a hexagonal compression connection sized as per manufacturer’s recommendation for the cable.
  13. Splice kits in manholes shall be rated and sized for cable installed.
  14. Heat shrink splices shall be Raychem HVS-1520S series or equal.
  15. Separable connector elbow splices shall be Elastimold 156LR series or equal including equipment bushings, dead end plugs, dead break junctions and grounding connections.
  16. Apparatus bushings: Universal busing well Elastimold K1601PC with approved shank or equal.
  17. Bushing insert: Elastimold 1501A1 or equal
  18. Elbow connector: Elastimold 156KR non-load break elbow with grounding adapter and bailing assembly or equal
  19. Fireproof tape: Provide tape fabricated of flexible, conformable fabric of organic composition coated on one side with flame-retardant elastomer.
  20. Tape shall be arc-proof, fireproof, self-extinguishing and shall not support combustion.
  21. Tape shall not deteriorate when subjected to water, gases, salt water, sewage, or fungus and shall not be resistant to sunlight and ultraviolet light.
  22. Provide securing tape fabricated of glass cloth electric tape not less than 7 mils thick and 3/4 inch wide.
  23. Grounding: Equipment grounding conductors are required for medium voltage (2.3 kilovolt and above) cable equipped with metallic sheath, or provided with ground conductor in cable interstices and bonded to non-current carrying metallic equipment at both ends.
  24. Shielding: Provide shielding as follows:
  25. Ethylene propylene (EP) or ethylene propylene rubber (EPR), single conductor cables shall be shielded for grounded and ungrounded neutral voltage ratings of more than 8,000 volts
  26. Cable Identification: Provide on each cable outer jacket showing the name of the manufacturer, the year in which the cable was manufactured, and a number for identification purposes. The information shall be closely grouped on the cable at standard intervals to permit complete identification and in accordance with AEIC CS6 and UL listed for type MV-90 cable.
  27. Flammability: Cables not enclosed in metallic conduit shall be tested for flammability. The assembly shall not support combustion for more than 3 seconds after application of flame or spark and shall not convey flame during or after application or flame or spark.
  1. manufacturers
  2. Medium Voltage Cable:
  3. Kerite.
  4. Okonite.
  5. Pirelli.
  6. Rome.
  7. Or equal
  8. Splice Kits:
  9. Raychem, or equal.
  10. Load Break Connectors:
  11. Elastimold, or equal.

PART 3 - execution

3.1installation of cable

  1. General: Install cable in accordance with applicable codes and manufacturer’s recommendation under observation of University’s Representative using approved pulling set-up and approved pulling plan with nylon or manila rope.
  2. Shielding: Provide continuous shielding in cable runs grounded at each end and at each splice.
  3. Personnel Qualification: The personnel involved in splicing and assembling medium voltage termination shall be qualified. Qualifications of cable splicers shall be submitted to the University’s Representative for review. Once a termination of spice has been started by a worker, the same person shall complete that particular splice. Each termination and splice shall be started and completed in one continuous work period.
  4. Splices and Terminations: Make splices and terminations as follows:
  5. Splices shall be kept to a minimum and shall be made in manholes except where cable terminations are specifically indicated. Splicing and terminating of cables shall be expedited to minimize exposure and cable deterioration.
  6. Cables shall be terminated as herein specified. Dry terminations with high voltage pennants, preformed, or pre-fabricated stress cones may be used for terminating cables.
  7. Terminations shall be field fabricated from termination kits supplied by and in accordance with the manufacturer’s recommendations for the type, size, and electrical characteristics of the cable.
  8. The installation shall include heat or cold shrink stress-relief cones at the terminals of all shielded cables and at the terminals of single conductor cables rated 15 kilovolt and above, ungrounded.
  9. Dielectric tests on insulators shall be conducted and certified by the manufacturer. Thermal and routing tightness tests on factory-assembled kits shall be in accordance with IEEE 48.
  10. Cable splices shall be field fabricated from splicing kits supplied by and in accordance with the cable manufacturer’s recommendations for the type, size, and electrical characteristics of the cable specified. Cable splices in manholes shall be located midway between cable racks on walls of manholes and supported with cable arms.
  11. Contractor shall provide equipment to allow for proper bailing to avoid premature connection failure.
  12. Cable manufacturer shall review connectors and methods proposed by Contractor. Cable manufacturer shall be notified by the Contractor prior to any terminations being performed, and at the discretion of the manufacturer, be present for all field terminations in order to assure that the warranty is maintained.
  13. Do not exceed manufacturer’s recommended maximum cable pulling tension during pulling. For cable pulls exceeding 200 feet, and/or exceeding two 90 degree bends,provide calculations of pulling tension. Pulling tension to be monitored via dynamometer during installation. Do not exceed pulling tension of 100 lbs or value of
    TM = No of conductors in run x cross section area of conductor in cmils x 0.008
  14. Use only pulling compounds recommended by the cable manufacturer.
  15. Cables shall be dressed around the perimeter of all pull boxes and manholes.
  1. certification
  2. Provide the following:
  3. Prior to installation of cable, deliver 4 certified copies of all factory tests required by referenced NEMA standards, including quality control. Tests on each length of cable shall include conductor resistance; thickness of lead sheath, where specified; ionization high voltage; and flammability, where specified. Tests on each sample of cable shall include mechanical integrity, bending test, high-voltage time test, dielectric power loss, and power-factor tests.
  4. Furnish 4 copies of manufacturer’s written certification that the products furnished for this project meet or exceed referenced NEMA standards and NFPA 70 requirements.
  5. After testing, submit 4 certified copies of each graph, specified hereinafter under field testing. Include adequate information identifying cable locations, types, voltage rating and sizes.
  6. After splices and terminations have been installed and tested, deliver 4 copies of certificate which includes the following:
  7. A statement that materials, detail drawings and printed instructions were those contained in kits approved for this Contract.
  8. A statement that each splice and each termination was completely installed without any overnight interruption.
  9. A statement that field made splices and terminations conform to these specifications.
  10. certified field tests after installation
  11. Perform visual and mechanical inspection after cable installation, splices, and terminations have been made, but before connection to equipment, as follows:
  12. Inspect exposed sections for physical damage.
  13. Verify cable is supplied and connected in accordance with single-line diagram.
  14. Inspect for shield grounding, cable support, and termination.
  15. Check for visual cable bends against ICEA or manufacturer’s minimum allowable bending radius.
  16. Inspect for proper fireproofing in common cable area.
  17. If cables are terminated through window-type CT’s make an inspection to verify that neutrals and grounds are properly terminated for proper operation of protective devices.
  18. Visually inspect jacket and insulation condition.
  19. Inspect for proper phase identification and arrangements.
  20. Contractor shall hire an Independent Testing Company to perform electrical tests prior to connecting equipment and in the presence of Quality Control Engineer hired by the Contractor. Contractor shall provide minimum of 7 work days notice before testing. University’s Representative shall also be present. Tests shall be as follows:
  21. Perform a shield continuity test on each power cable by the ohmmeter method. Record ohmic value.
  22. Shielding must exhibit continuity. Investigate resistance values in excess of 10ohms per 1000 feet of cable.
  23. Perform an insulation-resistance test utilizing a megohmmeter with a voltage output of at least 2500 volts and capable of measuring 2,000 megohms minimum. Individually test each conductor with all other conductors and shields grounded. Test duration shall be one minute. Minimum acceptable insulation resistance is 750 megohms.
  24. Perform a dc high-potential test on all cables. Adhere to all precautions and limits as specified in the applicable NEMA/ICEA standard. Perform tests in accordance with ANSI/IEEE Std. 400. Test procedure shall be as follows, and the results shall be recorded as specified herein. Test voltage shall not exceed 80 percent of cable manufacturer’s factory test value or the maximum test voltage in NETA ATS. Overpotential tests shall not be performed until insulation-resistance levels are above minimum values. If splices or terminations are included in the tested length, the accessory manufacturer is to be consulted for maximum permissible test voltages.
  25. Current-sensing circuits in test equipment shall measure only the leakage current associated with the cable under test and shall not include internal leakage of test equipment.
  26. Record wet-and dry-bulb temperatures or relative humidity and temperature.
  27. Test each section of cable individually.
  28. Individually test each conductor with all other conductors grounded. Ground all shields.
  29. Terminations shall be properly corona-suppressed by guard rings, field reduction sphere, or other approved methods as necessary.
  30. Ensure that the maximum test voltage does not exceed the limits for terminations specified in IEEE Standard 48 or manufacturer’s specifications.
  31. Apply a DC high-potential test in at least five (5) equal increments starting with initial voltage of 15 kV until maximum test voltage of 63 kV or splice or termination voltage limits is reached. No increment shall exceed the voltage rating of the cable. RecordDC leakage current at each stop after a constant stabilization time consistent with system charging current.
  32. Raise the conductor to the specified maximum test voltage and hold for five minutes. Record readings of leakage at 30 seconds and one minute and at one minute thereafter. Investigate any leakage current readings in excess of 10microamps for each 1000 feet of cable under test.
  33. Reduce conductor test potential to zero and measure residual voltage at discrete intervals.
  34. Apply grounds for a time period adequate to drain all insulation stored charge.
  35. For DC high-potential test:

1)Step voltage slope shall be reasonable linear.

2)Absorption slope shall be flat or negative. In no case shall slope exhibit positive characteristic.

  1. Maximum leakage current shall not exceed IL corrected to 60 degrees F where IL=E/KLOG p/d.
K = insulation specific resistance Megohm/MFT at 60 degrees F.
D = diameter over insulation.
d = diameter under insulation.
E = maximum test voltage.
  1. A log-log graphic plot shall be made with leakage current (Y-axis) versus voltage (X-axis) at each increment. The step voltage slops shall be reasonably linear. Graph shall include current vs. time recorded at 1 minute intervals after final voltage reached. Absorption slope shall be flat or negative. In no case shall slope exhibit a positive characteristic.
  2. Submit written report to University’s Representative. Each report sheet to include the following data:

1)Date

2)Name of test operator

3)Section of cable tested

4)Cable insulation type

5)Cable length

6)Nominal cable rating

7)Cable manufacturer and product identification

8)Conductor size

9)Test equipment identification

10)Test type

11)Each test report page shall be signed by the test operator and endorsed by the Contractor.

  1. Correct or replace cable testing below manufacturer’s standards at no additional cost to the University.
  1. inspection
  2. The Contractor shall hire a Quality Control Engineer to conduct periodic inspections of the installation of cable, and shall report in writing to the Contractor any deviations from good installation practice observed.
  3. On completion of cable installation, the Quality Control Engineer shall inspect the complete system and report in writing any installation errors or fault in the system that could affect the performance of the system.
  4. The Contractor shall submit a report to the University’s Representative including the Quality Control Engineer’s final report indicating all reported as properly installed or requiring correction, and include a report by the Contractor on steps taken to properly complete the work.

END OF SECTION 16135

April 13th, 2007MEDIUM VOLTAGE CABLE (OVER 600 VOLTS)

Revision: 016135-1