SECTION TRANSFER SWITCHES

Transcription

1 SECTION PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this Section. 1.2 SUMMARY A. This Section includes transfer switches rated 600 V and less, including the following: 1. Automatic transfer switches for standby applications between a utility and generator set. 2. Remote annunciation system. B. All transfer switches shall be furnished, set, and tested by the engine/generator supplier. 1.3 SUBMITTALS A. General: Submit the following in accordance with conditions of Contract. B. Product Data: Include ratings and dimensioned plans, sections, and elevations showing minimum clearances, conductor entry provisions, gutter space, installed features and devices, and material lists for each switch specified. C. Wiring Diagrams: Detail wiring for transfer switches and differentiate between manufacturer-installed and field-installed wiring. Show both power and control wiring. D. Single-Line Diagram: Show connections between transfer switch, power sources, and load. E. Product Certificates: Signed by manufacturer certifying that products furnished comply with requirements and that switches have been tested for load ratings and short-circuit closing and withstand ratings applicable to units for Project. F. Qualification Data: For firms and persons specified in "Quality Assurance" Article. G. Field Test Reports: Indicate and interpret test and inspection results for compliance with performance requirements. The RMH Group

2 H. Maintenance Data: For each type of product to include in maintenance manuals specified in Division 1. Include all features and operating sequences, both automatic and manual. List all factory settings of relays and provide relay-setting and calibration instructions, including software, where applicable. 1.4 QUALITY ASSURANCE A. Manufacturer Qualifications: Maintain a service center capable of providing emergency maintenance and repairs at Project site with a four-hour maximum response time. B. Source Limitations: Obtain automatic transfer switch and remote annunciator through one source from a single manufacturer. C. Electrical Components, Devices, and Accessories: Listed and labeled as defined in NFPA 70, Article 100, for emergency service under UL 1008, by a testing agency acceptable to authorities having jurisdiction. D. Comply with NEMA ICS 1. E. Comply with NFPA 70. F. Comply with NFPA 110. G. Comply with UL 1008, unless requirements of these Specifications are stricter. PART 2 - PRODUCTS 2.1 MANUFACTURERS A. Subject to compliance with requirements, manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following: 1. Conventional Transfer Switches: [Rev 1] a. Caterpillar, Inc.; Engine Division. b. Emerson Electric Co.; Automatic Switch Co. Subsidiary. c. Onan Corp.; Electrical Products Division. d. SpectrumStewart Stevinson (Detroit Diesel). e. Russelectric, Inc. f. Zenith Controls, Inc. 2.2 GENERAL TRANSFER-SWITCH PRODUCT REQUIREMENTS A. Indicated Current Ratings: Apply as defined in UL 1008 for continuous loading and total system transfer, including tungsten filament lamp loads not exceeding 30 percent of switch ampere rating, unless otherwise indicated. The RMH Group

3 B. Tested Fault-Current Closing and Withstand Ratings: Adequate for duty imposed by protective devices at installation locations in Project under the fault conditions indicated, based on testing according to UL C. Annunciation, Control, and Programming Interface Components: Devices at transfer switches for communicating with remote programming devices, annunciator, or annunciator and control panels have communications capability matched with remote device. D. Solid-State Controls: Repetitive accuracy of all settings is plus or minus 2 percent or better over an operating temperature range of minus 20 to plus 70 C. E. Resistance to Damage by Voltage Transients: Components meet or exceed voltage-surge withstand capability requirements when tested according to IEEE C Components meet or exceed voltage-impulse withstand test of NEMA ICS 1. F. Neutral Terminal: Solid and fully rated, unless otherwise indicated. G. Enclosures: NEMA 250, Type 1, complying with NEMA and UL unless otherwise indicated. H. Factory Wiring: Train and bundle factory wiring and label consistent with Shop Drawings, either by color code or by numbered or lettered wire and cable tape markers at terminations. 1. Designated Terminals: Pressure type suitable for types and sizes of field wiring indicated. 2. Power-Terminal Arrangement and Field-Wiring Space: Suitable for top, side, or bottom entrance of feeder conductors as indicated. 3. Control Wiring: Equipped with lugs suitable for connection to terminal strips. I. Electrical Operation: Accomplish by a nonfused, momentarily energized solenoid or electric-motor-operated mechanism, mechanically and electrically interlocked in both directions. J. Switch Characteristics: Designed for continuous-duty repetitive transfer of fullrated current between active power sources. 1. Limitation: Switches using molded-case switches or circuit breakers or insulated-case circuit-breaker components are not acceptable. 2. Switch Action: Double throw; mechanically held in both directions. 3. Contacts: Silver composition or silver alloy for load-current switching. Conventional automatic transfer-switch units rated 225A and greater have separate arcing contacts. 2.3 AUTOMATIC A. Comply with NFPA 110. The RMH Group

4 B. Switching Arrangement: Double-throw type, electrically and mechanical interlocked, and mechanically held in both positions. C. Manual Switch Operation: Under load, with door closed and with either or both sources energized. Transfer time is the same as for electrical operation. Control circuit automatically disconnects from electrical operator during manual operation. D. Signal-before-Transfer Contacts: A set of normally open/normally closed dry contacts operates in advance of retransfer to normal source. Interval is adjustable from 1 to 30 seconds. E. Digital Communications Interface: Matched to capability of remote annunciator. 2.4 AUTOMATIC TRANSFER-SWITCH FEATURES A. Automatic Controls: Transfer switches that are designed on the drawing as automatic shall be provided with a fully automatic control system, and provisions for manual operation as described in this section. 1. Control shall be solid-state and designed for a high level of immunity to power line surges and transients, demonstrated by test to IEEE Standard 587. The control shall have optically isolated logic inputs, high isolation transformers for AC inputs, and relays on all outputs. a. Solid-state undervoltage sensors shall simultaneously monitor all phases of both sources. Pick-up and drop-out settings shall be adjustable. Voltage sensors shall allow for adjustment to sense partial loss of voltage on any phase. Voltage sensors shall have field calibration of actual supply voltage to nominal system voltage. b. Controls shall be provided with solid-state overvoltage sensors, adjustable from % of nominal, to monitor all phases of both sources. Provide adjustable time delay of 0.5 to 2.2 seconds. c. Controls shall be provided with a solid-state over and under frequency sensor to monitor the normal source. Pickup bandwidth shall be adjustable from a minimum of +/-4% to a maximum of +/- 20% of nominal frequency. Dropout shall be +/-5% of nominal wider than pickup frequency bandwidth. Adjustable time delay shall be 0.1 to 15 seconds. Automatic controls shall signal the engine-generator set to start upon signal from normal source sensors. Solid-state time delay engine start, (TDES) adjustable from 0 to 5 seconds shall avoid nuisance start-ups. Battery voltage starting contacts shall be gold, dry type contacts factory wired to a field wiring terminal block. d. Provide Phase Sequence Monitor and Balance module to protect against inadvertent phase rotation hookup and monitor for voltage phase imbalance between phases. The RMH Group

5 e. The switch shall transfer when the emergency source reaches the set point voltage and frequency. Provide a solid-state time delay (TDNE) on transfer, from normal to emergency source, adjustable from 0 to 120 seconds. f. The switch shall retransfer the load to the normal source from the emergency source after a time delay, (TDEN) adjustable from 0 to 30 minutes. Retransfer time delay shall be immediately bypassed if the emergency power source fails. g. Controls shall signal the engine-generator set to cool down and stop after a time delay (TDEC), adjustable from 0 to 10 minutes, beginning on return to the normal source. h. Power for transfer operation shall be from the source to which the load is being transferred. i. The control shall include latching diagnostic indicators to pinpoint the last successful step in the sequence of control functions, and to indicate the present status of the control functions in real time, as follows: 1) Source 1 OK 2) Start Gen Set 3) Source 2 OK 4) Transfer Timing 5) Transfer Complete 6) Retransfer Timing 7) Retransfer Complete 8) Timing for Stop j. The control shall include remote transfer inhibit and area protection features. k. Transfer switches shall be equipped with field-adjustable program transition controls (TDN) to allow the operator to control the transfer switch operating time during switching in both directions. The controls shall control the time, the load is isolated from both power sources, to allow load residual voltage to decay before closure to the opposite source. The transfer switch operating speed control feature shall have an adjustable range of 0 to 7.5 seconds. Phase angle monitor is not acceptable substitute for this feature. 2. Panel Devices: a. The front door of the transfer switch enclosure shall be empty except for the nameplate. b. Provide devices mounted on cabinet inter-panel consisting of a key-operated selector switch to provide the following positions and functions: 1) Test - Simulates normal power loss to control for testing of generator set. Controls shall provide for a test with or without load transfer. 2) Normal - Normal operation position The RMH Group

6 3) Retransfer - Momentary position to override retransfer time delay and cause immediate return to normal source, if available 4) Switch-position Pilot Lights: Indicate source to which load is connected. 5) Source-available Indicating Lights: Supervise sources via transfer-switch, normal- and emergency-source sensing circuits. a) Normal Power Supervision: Green light with nameplate engraved Normal Source Available. b) Emergency Power Supervision: Red light with nameplate engraved Emergency Source Available. B. Accessory Items: Transfer switches shall be equipped with accessories as follows: 1. Meters: Provide an AC Voltmeter, an Ammeter, and a Frequency meter; 2.5 inch, analog, 2% accuracy. Provide a phase selector switch to read L-L voltage and current of both power sources. 2. Exerciser Clock: Provide solid-state exerciser clock to set the day, time, and duration of generator set exercise/test period. Provide a with/without load selector switch for the exercise period. 3. Manual Selector Switch: Provide a manual/automatic retransfer selector switch to provide either automatic retransfer after the retransfer time delay, or a manual retransfer when selected by an operator. 2.5 REMOTE ANNUNCIATOR SYSTEM A. Functional Description: Remote annunciator panel annunciates conditions for indicated transfer switches. Annunciation includes the following: 1. Sources available, as defined by actual pickup and dropout settings of transfer-switch controls. 2. Switch position. 3. Switch in test mode. 4. Failure of communications link. B. Annunciator Panel: LED-lamp type with audible signal and silencing switch. 2.6 FINISHES 1. Mounting: Flush, modular, steel cabinet, unless otherwise indicated. 2. Lamp Test: Push-to-test or lamp-test switch on front panel. A. Enclosures: Manufacturer's standard enamel over corrosion-resistant pretreatment and primer. The RMH Group

7 2.7 SOURCE QUALITY CONTROL A. Factory Test Components, Assembled Switches, and Associated Equipment: Ensure proper operation. Check transfer time and voltage, frequency, and timedelay settings for compliance with specified requirements. Perform dielectric strength test complying with NEMA ICS 1. Perform acceptance test to comply with NFPA TRANSFER SWITCH SETTINGS A. Coordinate this time delay setting of the standby automatic transfer switch with the Life Safety ATS. PART 3 - EXECUTION 3.1 INSTALLATION A. Floor-Mounted Switch: Level and anchor unit to concrete housekeeping pad on floor. B. Identify components according to Division 16 Section "Electrical Identification." 3.2 WIRING TO REMOTE COMPONENTS A. Match type and number of cables and conductors to control and communications requirements of transfer switches as recommended by manufacturer. Increase raceway sizes at no additional cost to the owner if necessary to accommodate required wiring. 3.3 CONNECTIONS A. Ground equipment as indicated and as required by NFPA FIELD QUALITY CONTROL A. Testing: Perform the following field quality control testing: 1. Before energizing equipment, after transfer-switch products have been installed: a. Measure insulation resistance phase-to phase and phase-toground with insulation-resistance tester. Include annunciation and control circuits. Use test voltages and procedure recommended by manufacturer. Meet manufacturer's specified minimum resistance. b. Check for electrical continuity of circuits and for short circuits. c. Inspect for physical damage; proper installation and connection; and integrity of barriers, covers, and safety features. d. Verify that manual transfer warnings are properly placed. e. Perform manual transfer operation. The RMH Group

8 2. After energizing circuits, demonstrate interlocking sequence and operational function for each switch at least three times. Coordinate all transfer switch testing with main switchboard and generator testing. a. Simulate power failures of normal source to automatic transfer switches and of emergency source with normal source available. b. Verify time-delay settings. c. Verify pickup and dropout voltages by data readout or inspection of control settings. d. Perform contact-resistance test across main contacts and correct values exceeding 500 microhms and values for one pole deviating by more than 50 percent from other poles. e. Verify proper sequence and correct timing of automatic engine starting, transfer time delay, retransfer time delay on restoration of normal power, and engine cool-down and shutdown sequence. B. Coordinate tests with tests of generator plant and run them concurrently. C. Report results of tests and inspections in writing. Record adjustable relay settings and measured insulation and contact resistances and time delays. Attach a label or tag to each tested component indicating satisfactory completion of tests. 3.5 CLEANING A. After completing equipment installation, inspect unit components. Remove paint splatters and other spots, dirt, and debris. Repair damaged finish to match original finish. B. Clean equipment internally, on completion of installation, according to manufacturer's written instructions. 3.6 DEMONSTRATION A. Engage a factory-authorized service representative to train owner s personnel to adjust, operate, and maintain transfer switches and related equipment as specified below: 1. Coordinate this training with that for generator equipment. 2. Train owner's maintenance personnel on procedures and schedules for starting and stopping, troubleshooting, servicing, and maintaining equipment. 3. Review data in maintenance manuals. 4. Schedule training with owner s Representative, with at least seven days' advance notice. 5. Provide a minimum of four hours of instruction. END OF SECTION The RMH Group