DESIGN A/E NOTE - GUIDE SPECIFICATION CONVENTIONS
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Rev 19JUN09 j:\Projects\Active\com-deca_design_criteria_revisions-04071\Guide Specifications\TJG Innformation
SECTION 16271
MEDIUM-VOLTAGE TRANSFORMERS
Verify that Section titles referenced in this Section are correct for this Project's Specifications; Section titles may have changed.
PART 1. GENERAL
1.1 RELATED DOCUMENTS
1.1.1. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division1 Specification Sections, apply to this Section.
1.2 SUMMARY
1.2.1. This Section includes the following types of transformers with medium-voltage primaries:
Adjust list below to suit Project.
1.2.1.1. Pad-mounted, liquid-filled transformers.
1.3 SUBMITTALS
1.3.1. Product Data: Include rated nameplate data, capacities, weights, dimensions, minimum clearances, installed devices and features, location of each field connection, and performance for each type and size of transformer indicated.
Edit paragraph below to suit Project. Power, signal, and control wiring are applicable to forced-cooling systems of liquid-filled and dry-type transformers and to the high-temperature alarm of dry-type transformers.
1.3.2. Shop Drawings: Wiring and connection diagrams including power, signal and control wiring where applicable.
Retain first paragraph and subparagraphs below if required by seismic criteria applicable to Project. Coordinate with Division16 Section "Seismic Controls for Electrical Work" and with seismic-related requirements in Parts2 and 3 of this Section. Verify certification availability with specified manufacturers. See "Seismic Considerations" Article in the Evaluations.
1.3.3. Manufacturer Seismic Qualification Certification: Submit certification that transformer assembly and components will withstand seismic forces defined in Division16 Section "Seismic Controls for Electrical Work." Include the following:
1.3.3.1. Basis for Certification: Indicate whether withstand certification is based on actual test of assembled components or on calculation.
a. The term "withstand" means "the unit will remain in place without separation of any parts from the device when subjected to the seismic forces specified."
1.3.3.2. Dimensioned Outline Drawings of Equipment Unit: Identify center of gravity and locate and describe mounting and anchorage provisions.
1.3.3.3. Detailed description of equipment anchorage devices on which the certification is based and their installation requirements.
1.3.4. Source quality-control test reports.
1.3.5. Field quality-control test reports.
1.3.6. Follow-up service reports.
1.3.7. Operation and Maintenance Data: For transformer and accessories to include in emergency, operation, and maintenance manuals.
1.4 QUALITY ASSURANCE
1.4.1. Electrical Components, Devices, and Accessories: Listed and labeled as defined in NFPA70, Article100, by a testing agency acceptable to authorities having jurisdiction, and marked for intended use.
1.4.2. Comply with IEEEC2.
1.4.3. Comply with ANSIC57.12.28, IEEE C57.12.10, IEEEC57.12.70, and IEEEC57.12.80.
1.4.4. Comply with NFPA70.
1.5 PROJECT CONDITIONS
1.5.1. Service Conditions: IEEEC37.121, usual service conditions except for the following:
Select and revise unusual or extreme conditions below to suit Project; specify features required to provide satisfactory service. See Editing Instruction No.3 in the Evaluations for discussion of service conditions.
1.5.1.1. Exposure to significant solar radiation.
1.5.1.2. Altitudes above 3300 feet.
1.5.1.3. Exposure to fumes, vapors, or dust.
1.5.1.4. Exposure to explosive environments.
1.5.1.5. Exposure to hot and humid climate or to excessive moisture, including steam, salt spray, and dripping water.
1.5.1.6. Exposure to seismic shock or to abnormal vibration, shock, or tilting.
1.5.1.7. Exposure to excessively high or low temperatures.
1.5.1.8. Unusual transportation or storage conditions.
1.5.1.9. Unusual grounding-resistance conditions.
1.5.1.10. Unusual space limitations.
1.6 COORDINATION
Delete portions of first paragraph below that are not applicable to the project.
1.6.1. Coordinate installation of area drainage, downspouts, maintenance access, louvers, doors, spill retention areas, and sumps. Coordinate installation so no piping or conduits are installed in space allocated for medium-voltage transformers except those directly associated with transformers.
PART 2. PRODUCTSÉ
2.1 MANUFACTURERS
2.1.1. Available Manufacturers: Subject to compliance with requirements, manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following:
2.1.1.1. Acme Electric Corporation; Power Distribution Products Division.
2.1.1.2. Cooper Industries; Cooper Power Systems Division.
2.1.1.3. Cutler-Hammer.
2.1.1.4. GE Electrical Distribution & Control.
2.1.1.5. Hammond Manufacturing; Transformer Group.
2.1.1.6. Kuhlman Electric Corporation.
2.1.1.7. Pauwels Transformers.
2.1.1.8. Pioneer Transformers Ltd.
2.1.1.9. Siemens Energy & Automation, Inc.
2.1.1.10. Square D/Groupe Schneider NA.
2.1.1.11. Uptegraff, R. E. Mfg. Co.
2.1.1.12. Virginia Transformer Corp.
2.1.1.13. Insert manufacturer's name.
2.2 PAD-MOUNTED, LIQUID-FILLED TRANSFORMERS
In first paragraph below, retain stainless steel cabinet and sills for coastal installations.
2.2.1. Description: ANSIC57.12.13, IEEEC57.12.00, IEEEC57.12.26, pad-mounted, 2-winding transformers. Stainless-steel tank base, cabinet, and sills.
2.2.2. Insulating Liquid: Mineral oil, complying with ASTMD3487, TypeII, and tested according to ASTMD117.
If transformers have standard basic impulse level, retain paragraph below. If basic impulse level is other than standard, revise below or delete and note basic impulse level in schedule. See Editing Instruction No.5 in the Evaluations.
2.2.3. Basic Impulse Level: [30] [60] [95] kV.
Revise paragraph below if other-than-NEMA-standard taps are required. Coordinate with schedule.
2.2.4. Full-Capacity Voltage Taps: Four 2.5 percent taps, 2 above and 2 below rated high voltage; with externally operable tap changer for de-energized use and with position indicator and padlock hasp.
Select one of first two paragraphs below to suit transformer's high-voltage terminal arrangement. Coordinate switch rating with transformer rating, system fault currents, and basic impulse level for associated equipment.
Loop-feed arrangement below may be used for radial feed to provide an extra set of terminals for dead-front, insulated, load-break, connector-type surge arresters.
2.2.5. High-Voltage Switch: [200] [300] [400] A, make-and-latch rating of 10-kA RMS, symmetrical, arranged for loop feed with 3-phase, 4-position, gang-operated, load-break switch that is oil immersed in transformer tank with hook-stick operating handle in primary compartment.
Delete paragraph and subparagraphs below if primary fuse is specified in Division16 Section "Overhead Electrical Distribution." Select a primary fusing arrangement acceptable to organization that changes blown fuses and maintains the system. Coordinate fuse rating with transformer rating, system fault currents, and other protective devices; show characteristics on Drawings.
2.2.6. Primary Fuses: 15.0-kV fuse assembly with fuses complying with IEEEC37.47.[Interrupting Rating of current-limiting fuses shall be 50-kA RMS at specified system voltage.]
2.2.6.1. Current-limiting type in dry-fuse holder wells, mechanically interlocked with liquid-immersed switch in transformer tank to prevent disconnect under load.
For dead-front arrangement in paragraph below, specify insulated, high-voltage, load-break cable connectors in Division16 Section "Medium-Voltage Cables."
2.2.7. High-Voltage Terminations and Equipment: Dead front with universal-type bushing wells for dead-front bushing-well inserts, complying with IEEE386 and including the following:
2.2.7.1. Bushing-Well Inserts: One for each high-voltage bushing well.
Delete items below if not applicable.
2.2.7.2. Surge Arresters: Dead-front, elbow-type, metal-oxide-varistor units.
2.2.7.3. Parking Stands: One for each high-voltage bushing well.
2.2.7.4. Portable Insulated Bushings: Arranged for parking insulated, high-voltage, load-break cable terminators; one for each primary feeder conductor terminating at transformer.
2.2.8. Accessories:
Normally required. Coordinate with Drawings.
2.2.8.1. Drain Valve: 1 inch, with sampling device.
2.2.8.2. Dial-type thermometer.
2.2.8.3. Liquid-level gage.
2.2.8.4. Pressure-vacuum gage.
2.2.8.5. Pressure Relief Device: Self-sealing with an indicator.
Delete below if metering is not required at the transformer.
2.2.8.6. Mounting provisions for low-voltage current transformers.
2.2.8.7. Mounting provisions for low-voltage potential transformers.
2.3 IDENTIFICATION DEVICES
Coordinate this Article with Drawings.
2.3.1. Nameplates: Engraved, laminated-plastic or metal nameplate for each transformer, mounted with corrosion-resistant screws. Nameplates and label products are specified in Division16 Section "Electrical Identification."
2.4 SEISMIC RESTRAINTS
2.4.1. Design and fabricate transformers, and anchorage devices for them, to withstand static and seismic forces in any direction.
2.5 SOURCE QUALITY CONTROL
In first paragraph below, IEEEC57.12.90 applies to liquid-filled transformers.
2.5.1. Factory Tests: Perform design and routine tests according to standards specified for components. Conduct transformer tests according to IEEEC57.12.90.
2.5.2. Factory Tests: Perform the following factory-certified tests on each transformer:
2.5.2.1. Resistance measurements of all windings on rated-voltage connection and on tap extreme connections.
2.5.2.2. Ratios on rated-voltage connection and on tap extreme connections.
2.5.2.3. Polarity and phase relation on rated-voltage connection.
2.5.2.4. No-load loss at rated voltage on rated-voltage connection.
2.5.2.5. Excitation current at rated voltage on rated-voltage connection.
2.5.2.6. Impedance and load loss at rated current on rated-voltage connection and on tap extreme connections.
2.5.2.7. Applied potential.
2.5.2.8. Induced potential.
PART 3. EXECUTION
3.1 EXAMINATION
3.1.1. Examine areas and conditions for compliance with requirements for medium-voltage transformers.
3.1.2. Examine roughing-in of conduits and grounding systems to verify the following:
3.1.2.1. Wiring entries comply with layout requirements.
3.1.2.2. Entries are within conduit-entry tolerances specified by manufacturer and no feeders will have to cross section barriers to reach load or line lugs.
3.1.3. Examine walls, floors, roofs, and concrete bases for suitable mounting conditions where transformers will be installed.
Adjust 5-ohm value in first paragraph below to suit Project.
3.1.4. Verify that ground connections are in place and that requirements in Division16 Section "Grounding and Bonding" have been met. Maximum ground resistance shall be 5 ohms at location of transformer.
3.1.5. Proceed with installation only after unsatisfactory conditions have been corrected.
3.2 INSTALLATION
3.2.1. Install transformers on concrete bases.
If appropriate, retain subparagraph below for projects in areas of seismic activity.
3.2.1.1. Anchor transformers to concrete bases according to manufacturer's written instructions, seismic codes at Project, and requirements in Division16 Section "Seismic Controls for Electrical Work."
Edit subparagraphs below to suit Project. Consider indoor and outdoor transformer locations and seismic requirements, if any.
3.2.1.2. Construct concrete bases of dimensions indicated, but not less than 4 incheslarger in both directions than supported unit and 4 inches high.
3.2.1.3. Use 3000-psi, 28-day compressive-strength concrete and reinforcement as specified in Division3 Section "Cast-in-Place Concrete."
3.2.1.4. Place and secure anchorage devices. Use supported equipment manufacturer's setting drawings, templates, diagrams, instructions, and directions furnished with items to be embedded.
3.2.2. Maintain minimum clearances and workspace at equipment according to manufacturer's written instructions and NFPA70.
3.3 IDENTIFICATION
3.3.1. Identify field-installed wiring and components and provide warning signs as specified in Division16 Section "Electrical Identification."
3.4 CONNECTIONS
3.4.1. Ground equipment according to Division16 Section "Grounding and Bonding."
3.4.2. Connect wiring according to Division16 Section "Conductors and Cables."
3.4.3. Tighten electrical connectors and terminals according to manufacturer's published torque-tightening values. If manufacturer's torque values are not indicated, use those specified in UL486A and UL486B.
3.5 FIELD QUALITY CONTROL
Retain paragraph below to require a factory-authorized service representative to perform, or assist Contractor with, field inspections, tests, and adjustments. Retain one of two options to suit Project; delete both to require only an inspection before field testing.
3.5.1. Manufacturer's Field Service: Engage a factory-authorized service representative to inspect field-assembled components and equipment installation, including connections,and to assist in field testing. Report results in writing.
Retain one of first three paragraphs below.
3.5.2. Perform the following field tests and inspections and prepare test reports:
Retain subparagraphs below with either of last two paragraphs selected above. Edit to suit Project. Delete subparagraphs if testing will be performed by Owner-engaged testing and inspecting agency.
3.5.2.1. After installing transformers but before primary is energized, verify that grounding system at substation is tested at specified value or less.
3.5.2.2. After installing transformers and after electrical circuitry has been energized, test for compliance with requirements.
3.5.2.3. Perform electrical test and visual and mechanical inspection stated in NETAATS, Section7.2. Certify compliance with test parameters.
3.5.2.4. Test and adjust controls and safeties. Replace damaged and malfunctioning controls and equipment.
3.5.3. Remove malfunctioning units, replace with new units, and retest as specified above.
3.5.4. Test Reports: Prepare written reports to record the following:
3.5.4.1. Test procedures used.
3.5.4.2. Test results that comply with requirements.
3.5.4.3. Test results that do not comply with requirements and corrective actions taken to achieve compliance with requirements.
3.6 FOLLOW-UP SERVICE
3.6.1. Voltage Monitoring and Adjusting: If requested by Owner, perform the following voltage monitoring after Substantial Completion but not more than six months after Final Acceptance:
3.6.1.1. During a period of normal load cycles as evaluated by Owner, perform seven days of three-phase voltage recording at secondary terminals of each transformer. Use voltmeters with calibration traceable to National Institute of Science and Technology standards and with a chart speed of not less than 1 inch per hour. Voltage unbalance greater than 1percent between phases, or deviation of any phase voltage from nominal value by more than plus or minus 5 percent during test period, is unacceptable.
3.6.1.2. Corrective Actions: If test results are unacceptable, perform the following corrective actions, as appropriate:
a. Adjust transformer taps.
b. Prepare written request for voltage adjustment by electric utility.
3.6.1.3. Retests: After corrective actions have been performed, repeat monitoring until satisfactory results are obtained.
3.6.1.4. Report: Prepare written report covering monitoring and corrective actions performed.
3.6.2. Infrared Scanning: After Substantial Completion, but not more than 60 days after Final Acceptance, perform infrared scan of each transformer. Open primary and secondary front rear panels so joints and connections are accessible to portable scanner.
3.6.2.1. Follow-up Infrared Scanning: Perform an additional follow-up infrared scan of each transformer 11 months after date of Substantial Completion.
3.6.2.2. Instrument: Use an infrared-scanning device designed to measure temperature or to detect significant deviations from normal values. Provide calibration record for device.
3.6.2.3. Record of Infrared Scanning: Prepare a certified report that identifies transformer checked and that describes infrared-scanning results. Include notation of deficiencies detected, remedial action taken, and observations after remedial action.
END OF SECTION 16271
insert project name and location
June 2010
MEDIUM-VOLTAGE TRANSFORMERS
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