Secondary Unit SubstationsME- Building Group

SECTION 261116 - SECONDARY UNIT SUBSTATIONS

PART 1 - GENERAL

1.1RELATED DOCUMENTS

  1. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division01 Specification Sections, apply to this Section.

1.2SUMMARY

  1. This Section includes secondary unit substations, each consisting of the following:
  2. Incoming primary section.
  3. Transformer section.
  4. Secondary distribution section.
  5. Neutral grounding resistor(s).

1.3SUBMITTALS

  1. Product Data
  2. Short-time and short-circuit current ratings of substations and components.
  3. Ratings of individual protective devices.
  4. Time-current characteristic curves for overcurrent protection devices.
  5. Shop Drawings: Show details of equipment assemblies and indicate dimensions, weights, loadings, required clearances, method of field assembly, components, and location and size of each field connection for each substation. Include the following:
  6. Dimensioned plans and elevations showing major components and features.
  7. One-line diagram.
  8. Materials list.
  9. Nameplate legends.
  10. Size and number of bus bars and current rating for each bus, including mains and branches of phase, neutral, and ground buses.
  11. Current ratings of buses.
  12. Wiring Diagrams: Detail wiring for power, signal, and control systems and differentiate between manufacturer-installed and field-installed wiring.
  13. Product Test Reports: Indicate compliance of substations with requirements.

1.4QUALITY ASSURANCE

  1. Product Options: Drawings indicate size, profiles, and dimensional requirements of substations and are based on the specific equipment indicated.
  2. Listing and Labeling: Provide equipment that is listed and labeled.
  3. The Terms "Listed" and "Labeled": As defined in the National Electrical Code, NFPA 70, Article100.
  4. Comply with the following:
  5. NFPA70.
  6. IEEEC2.
  7. IEEEC37.
  8. IEEE C57.
  9. Color-coding convention for circuit breaker control and status indication:
  10. GREEN = OPEN
  11. GREEN color for lamps, status flags, or other indicating devices associated with the power circuit breakers indicates that the device is “OPEN”.
  12. GREEN color for pushbuttons, selector switches, or other devices associated with the power circuit breakers in the switchgear assembly indicates that operation will cause the power circuit breaker to open.
  13. RED = CLOSE
  14. RED color for lamps, status flags, or other indicating devices associated with the power circuit breakers indicates that the device is “CLOSED”.
  15. RED color for pushbuttons, selector switches, or other devices associated with the power circuit breakers in the switchgear assembly indicates that operation will cause the power circuit breaker to close.

1.5DELIVERY, STORAGE, AND HANDLING

  1. Store equipment in dry, enclosed locations.
  2. Furnish equipment in shipping sections that can be placed in electrical rooms by lifting through 8 foot by 12 foot floor hatch openings.
  3. Properly tag equipment with P.O. numbers and assembly numbers. Itemize on packing slips and properly tag with P.O. numbers and assembly numbers the contents of boxes, cartons, or crates shipped loose.

PART 2 - PRODUCTS

2.1MANUFACTURERS

  1. Manufacturers: Unless otherwise directed, provide products by one of the following:
  2. Cutler Hammer; Westinghouse Products.
  3. General Electric Co.; Electrical Distribution & Control Div.
  1. Siemens.
  2. Square D Co.

2.2480 VOLT UNIT SUBSTATIONS

  1. Arrangement: Indoor unit substation in single assembly.
  2. Primary Switch: Enclosed fusible load break switch.
  3. Transformer: Vacuum-Pressure-Impregnated.
  4. All unit substation shall be equipped with lightning arrestors.
  5. Secondary Distribution: Low voltage power circuit breaker switchgear, draw-out mounting.

2.3FABRICATION AND FEATURES

  1. Enclosure Finish: Factory-applied finish in manufacturer's standard gray finish over a rust-inhibiting primer on treated metal surface.

2.4INCOMING LINE: PRIMARY SWITCH

  1. Main-Bus Continuous Rating: 600A.
  2. Interrupter Switches: Stationary, gang operated, suitable for application to maximum short-circuit rating of integrated switchgear assembly.
  3. Rating: 600A, continuous duty and load break.
  4. Nominal System Voltage: 12,470 volts.
  5. Phase: 3.
  6. Number of Poles: 3.
  7. Frequency: 60 Hertz.
  8. Rated Design Voltage: 15,000 volts.
  9. BIL Impulse Rating: 95 kV.
  10. Fault-Closing: 61,000A asymmetrical (10 Hertz duration).
  11. Fault –Interrupting Rating: 750 MVA RMS symmetrical or as otherwise indicated.
  12. Switch Action: No external arc and no significant quantities of ionized gas released into the enclosure.
  13. Switch Construction: Supported entirely by interior framework of the structure, with copper switch blades and stored-energy operating mechanism.
  14. Phase Barriers: Full length of blades and fuses for each pole, designed for easy removal, allows visual inspection of switch components when barrier is in place.
  15. Protective Shields: Cover live components and terminals.
  16. Fuses: De-energized when switch is open.
  17. Mechanical Interlock: Prevents opening switch compartment door unless switch blades are open, and prevents closing switch when door is open.
  18. Primary Cable Terminals: Provide compression-type connectors for primary circuit conductors.
  19. Window: Permits viewing switch-blade positions when door is closed.
  20. Accessory Set: Tools and miscellaneous items required for interrupter switch test, inspection, maintenance, and operation. Include fuse-handling tool as recommended by switchgear manufacturer.
  21. Power Fuses: Comply with applicable requirements of NEMA SG2 and the following:
  22. Indicator integral with each fuse shows when it has blown.
  23. Mounting: Fuses are positively held in position with a provision for easy removal and replacement from the front without special tools.
  24. Continuous current rating coordinated to protect the transformer, yet service full fan rated secondary load and coordinate with secondary breakers.

2.5DRY-TYPE TRANSFORMER

  1. Description: NEMAST20, IEEEC57, IEEE C57.94, VPI-type, 2-winding, power transformer designed for operation with high-voltage windings connected to a 3 phase, 3 wire, 60 Hertz grounded-neutral distribution system.
  2. List and label as complying with UL 1562.
  3. Enclosure: Indoor, ventilated.
  4. Surge Arresters: NEMA LA1, distribution class; connected from each phase of the incoming primary circuit to ground.
  5. Cooling System: ClassAA/FA, air cooled with forced-air rating. Provide cooling fans, temperature-sensing devices, and controls, complete with housings, mounting devices, conduit, and wiring.
  6. Cooling Fan Operation: Automatically and sequentially controlled by temperature-sensing devices.
  7. Manually Operable Switch: Connected in parallel with automatic control contacts.
  8. Enclosure for Controls: Cabinets mounted on side of transformer at a height not more than 60 inches (1500 mm) above base.
  9. Cooling Fans: Propeller type, direct-drive, totally enclosed, fan-cooled motors.
  10. Motor Circuits: Individually fused or thermally protected.
  11. Fan Control: Thermally operated, windings’ temperature sensing devices. Provide a contact wired to a terminal block to permit remote monitoring of transformer fan operation.
  12. Temperature Monitoring: Provide a sensor in each transformer winding, connected to a local temperature indicating meter on the control panel. Provide wiring to a terminal block to permit remote monitoring of temperature.
  13. High-Temperature Alarm: Provide local audible and visual alarm. Provide a contact wired to a terminal block to permit remote monitoring of high temperature alarm.
  14. High-Temperature Trip: Provide a contact wired to a terminal block suitable to trip the secondary main circuit breaker upon reaching high temperature trip setting, and provide wiring from this contact to the remote trip circuit of the secondary main circuit breaker.
  15. Insulation Class: 220degC.
  16. Basic-Impulse Insulation Level: 95kV primary, 10 kV secondary.
  17. Full-Capacity Voltage Taps: 4 nominal 2.5-percent taps, 2 more than and 2 less than rated high voltage.
  18. Impedance:
  19. NEMA 4.50 percent for welding substations.
  20. NEMA 5.75 percent for all other substations.
  21. Continuous Ratings:

.

  1. 2500 kVA, 80 degree C rise above 40 degree C, without fans operating.
  2. 3375 kVA, 150 degree C rise above 40 degree C, without fans operating.
  3. 4150 kVA, 150 degree C rise above 40 degree C, with fans operating.
  1. Secondary connection:
  1. 480 volt, ungrounded Delta secondary connection for welding substations.
  2. 480Y/277 volt, solidly grounded Wye connection for all other substations.
  1. Sound Level: Not to exceed 70 dB with fans running.
  2. Provide means to minimize transmission of vibration from the transformer core and coil assembly to the primary section, the secondary sections and the floor.

2.6LOW VOLTAGE SWITCHGEAR

  1. Nominal System Voltage:
  2. 480 volt, ungrounded Delta secondary connection for welding substations.
  3. 480Y/277 volt, solidly grounded Wye connection for all other substations.
  4. Main-Bus Continuous Rating: 5,000A.
  5. Neutral Bus: Copper, 100 percent of main bus capacity.
  6. Ground Bus: Copper, 100 percent of main bus capacity.
  7. Short-Circuit Current Withstand Ratings of Bus: Match or exceed the ratings of the highest-rated circuit breaker in the switchgear assembly.
  8. Enclosure Material: Steel.
  9. Enclosure Finish: IEEEC37.20.1, manufacturer's standard gray finish over a rust-inhibiting primer.
  10. Section barriers between main and tie circuit-breaker compartments extend to rear of section.
  11. Bus isolation barriers arranged to isolate line bus from load bus at each circuit breaker.
  12. Circuit breaker compartments equipped to house power circuit breakers in draw-out mounting, and fitted with hinged outer doors.
  13. Circuit breaker load termination compartments with removable, hinged, rear cover door secured by captive thumbscrews, allowing access without use of tools.
  14. Auxiliary Compartments: Match and align with basic switchgear assembly. Include the following as required:
  15. Metering compartments.
  16. Bus transition sections.
  17. Hinged front panels for access to interior of metering, accessory, and blank compartments.
  18. Provide main bus connection between vertical sections and between compartments of the switchgear assembly with bus bars. Cable connections are not permitted for the main bus.
  19. Main Phase Bus: Uniform capacity the entire length of the assembly.
  20. Bus Material: Copper, with tin-plated connections.
  21. Use copper bus for connecting circuit-breaker line terminals to main bus.
  22. Feeder Circuit-Breaker Load Terminals: Tin-plated copper bus extensions equipped with compression-type connectors for outgoing circuit conductors.
  23. Neutral Disconnect Link: Bolted, uninsulated, 1/4-by-2-inch copper bus, arranged to connect the transformer neutral bus to the ground bus.
  24. Bus-Bar Insulation: Individual bus bars wrapped with factory-applied, flame-retardant tape or spray-applied, flame-retardant insulation.
  25. Bolted Bus Joints: Insulate with secure joint covers that can be easily removed and reinstalled.

2.7COMPONENTS

  1. Instrument Transformers: Comply with IEEEC57.13.
  2. Potential Transformers: Secondary voltage rating of 120V and NEMA accuracy class of 0.3 with burdens of W, X, and Y.
  3. Current Transformers: Ratios as indicated; burden and accuracy class suitable for connected relays, meters, and instruments.
  4. Where a breaker serves VAR compensation equipment, provide a current transformer in each phase for exclusive use by the VAR compensation equipment, coordinated with requirements of the manufacturer.
  5. Relays: Comply with IEEEC37.90, types and settings as indicated; with test blocks and plugs.
  6. Provision for Future Devices: Equip empty breaker compartments (spaces) with rails, mounting brackets, supports, necessary appurtenances, and bus connections requiring only the insertion of a breaker to activate.
  7. Control Power Supply: Control power transformer supplies 120-V control circuits through secondary disconnect devices. Include the following features:
  8. Dry-type transformers, in separate compartments for units larger than 3 kVA, including primary and secondary fuses.
  9. Control Power Fuses: Primary and secondary fuses provide fault current limiting and overload protection.
  10. Control Wiring: Factory installed, complete with bundling, lacing, and protection; and complying with the following:
  11. Flexible conductors for #8 AWG and smaller, for conductors across hinges, and for conductors for interconnections between shipping units.
  12. Manual Operating Mode Selector: Provide factory installed manual operating mode selection system consisting of relays, timers and wiring to accomplish the following:
  13. Three-position, rotary, maintained-contact selector switch, with “Open Main Left”, “Open Tie”, “Open Main Right” positions.
  14. The normal operating position is “Open Tie” where the Left Main and Right Main breakers are closed and the Bus Tie breaker is open.
  15. Selecting “Open Main Left” from the “Open Tie” position closes the Bus Tie breaker and then opens the Left Main breaker.
  16. Timer (0-30 seconds, set at 5) trips the Bus Tie breaker if the Left Main breaker does not open.
  17. Selecting “Open Main Right” from the “Open Tie” position closes the Bus Tie breaker and then opens the Right Main breaker.
  18. Timer (0-30 seconds, set at 5) trips the Bus Tie breaker if the Right Main breaker does not open.
  19. Selecting “Open Tie” from “Open Main Left” closes the Left Main breaker and then opens the Bus Tie breaker.
  20. Bus Tie breaker does not open if the Left Main breaker does not close.
  21. Selecting “Tie Open” from “Open Main Right” closes the Right Main breaker and then opens the Bus Tie breaker. The Left and Right Main breakers serve the load.
  22. Bus Tie breaker does not open if the Right Main breaker does not close.
  23. Breaker closing operation is blocked if breaker is tripped on fault.
  24. Communication and metering transformer secondary ports for main, tie, and feeder breakers will be located and accessible from the front of the breakers.

2.8CIRCUIT BREAKERS

  1. Description: Comply with IEEEC37.13.
  2. Ratings: Voltage and frequency same as for switchgear.
  3. Continuous Ratings
  4. Main and Bus Tie Breakers: 5,000 A.
  5. Feeder Breakers, Utility substations: 1,600 A.
  6. Feeder Breakers, Welding substations: 3,200 A.
  7. Interrupting Ratings
  8. Main, tie and Utility substation feeder breakers: 65,000 AIC.
  9. Welding Substation Feeder Breakers: 125,000 AIC using current-limiting fuses.
  10. Operating Mechanism: Mechanically and electrically trip-free, stored-energy operating mechanism with the following features:
  11. Normal Closing Speed: Independent of both control and operator.
  12. Slow Closing Speed: Optional with operator for inspection and adjustment.
  13. Stored-Energy Mechanism: Manually charged for feeder breakers, electrically charged, with optional manual charging, for main and tie breakers.
  14. Operation counter.
  15. Trip Devices: Solid-state, overcurrent trip-device system consisting of one or two current transformers or sensors per phase, a release mechanism, and the following features:
  16. Trip Functions
  17. Main and Tie Breakers: Long-time-delay and short-time-delay functions, independent of each other in both action and adjustment.
  18. Feeder Breakers: Long-time-delay, short-time-delay, and instantaneous-trip functions, independent of each other in both action and adjustment.
  19. Welding Substation Reverse-Power Trip Functions
  20. Main Breakers. Provide solid-state, reverse-power relay, ANSI Device 32, in addition to solid-state overcurrent trip device. Provide for time delay and pickup independent of each other in both action and adjustment. Provide separate current transformers if required.
  21. Temperature Compensation: Ensures accuracy and calibration stability from minus 5degC to plus 40degC.
  22. Field-adjustable time-current characteristics.
  23. Current Adjustability: Dial settings and rating plugs on trip units or sensors on circuit breakers or a combination of these methods.
  24. Three bands, minimum, for long-time- and short-time-delay functions; marked "minimum," "intermediate," and "maximum."
  25. Pickup Points: Five minimum, for long-time- and short-time-trip functions. Equip short-time-trip function for switchable I-squared-T operation.
  26. Pickup Points: Five minimum, for instantaneous-trip functions.
  27. Ground-fault protection with at least three short-time-delay settings and three trip-time-delay bands; adjustable current pickup for main, tie and feeder breakers of Utility substations.
  28. Trip Indication: Labeled, battery-powered lights or mechanical targets on trip device to indicate type of fault.
  29. Auxiliary Contacts: For interlocking or remote indication of circuit-breaker position, with spare auxiliary switches and other auxiliary switches required for normal circuit-breaker operation, quantity as required to accomplish all control and indications specified. Each consists of two Type "a" and two Type "b" stages (contacts) wired through secondary disconnect devices to a terminal block in stationary housing.
  30. Draw-Out Features: Circuit breaker mounting assembly equipped with a racking mechanism to position circuit breaker and hold it rigidly in the connected, test, and disconnected positions. Include the following features:
  31. Interlocks: Prevent movement of circuit breaker to or from the connected position when it is closed, and prevent closure of circuit breaker unless it is in the connected, test, or disconnected position.
  32. Circuit Breaker Positioning: An open circuit breaker may be racked to or from the connected, test, and disconnected positions only with the associated compartment door closed, unless live parts are covered by a full dead-front shield. An open circuit breaker may be manually withdrawn to a position for removal from the structure with the door open. Status for connection devices for the different positions includes the following:
  33. Test Position: Primary disconnect devices disengaged, secondary disconnect devices and ground contact engaged.
  34. Disconnected Position: Primary and secondary devices and ground contact disengaged.
  35. Arc Chutes: Readily removable from the associated circuit breaker when it is in the disconnected position and arranged to permit inspection of contacts without removing circuit breaker from switchgear.
  36. Padlocking Provisions: For installing at least three padlocks on each circuit breaker to secure its enclosure and prevent movement of draw-out mechanism.
  37. Operating Handle: One for each circuit breaker capable of manual operation.
  38. Electrical Interlocks: Provide an adjustable 2 minute time delay relay with a dial calibrated in and indicating intervals in seconds, and interconnecting wiring scheme such that if the substation tie breaker and both main breakers are simultaneously closed, then the substation tie breaker will trip open after the preset time.
  39. Manually Operated Breaker Trip and Close Devices: Capable of tripping or closing the breaker with the breaker cubicle door closed.
  40. Indicating Lights: LED push-to-test type.
  41. Circuit breaker open and closed for main and bus tie circuit breakers.
  42. Ground fault detection lights for each welding substation feeder breaker.

2.9METERING