Section 263623 - ATS

Dubai Creek Harbour Development

District Cooling Plant DCP-01A

AUTOMATIC TRASNFER SWITCHES 26 36 23 – of 6

2016 APRIL- REV.0

SECTION 26 36 23

AUTOMATIC TRANSFER SWITCHES

PART 1 – GENERAL

1.01 RELATED DOCUMENTS

1.02 Drawings and general provisions of the Contract, including General and Supplementary Conditions

and Division 1 Specification Sections, apply to this Section.

1.03 SUMMARY

A. This section includes transfer switches rated 600 V and less. It includes the following items:

1. Transfer switch products, General.

2. Main Failure Automatic transfer switch (ATS), which is to be part of the “Main Distribution

Boards” as shown on the Drawings.

B. Related Sections: the following Sections contain requirements that relate to this Section:

1. Division 26 " Basic Electrical Requiremenmts ” and other sections apply to work of this

section."

2. Conductors for hard-wired connections between transfer switches and remote equipment are

specified in Division 26 Section "Low Voltage Conductors and Cables."

3. Division 25 “Integrated Automation System”

1.04 SUBMITTALS

A. General: submit the following according to Conditions of Contract and Division 1 Specification

Sections.

B. Compliance statement: Clause by clause full and compliance statement of specification shall be

submitted ,where a clear compliance is indicated as follows:

a. “ Yes” interprets full unconditional compliance.

b. “ No” interprets a deviation ( to be clearly indicated as remark or note in the dedicated

column).

c. “ Not Applicable” where the case is.

It should be noted that other comments like “noted “ or “partial compliance” are unacceptable and

will be interpreted as a non compliance.

C. Shop drawings or published product data for each transfer switch, including dimensioned plans,

sections, and elevations showing minimum clearances; conductor entry provisions; gutter space;

installed features and devices; and materials lists.

D. Wiring diagrams, elementary or schematic, differentiating between manufacturer-installed and field-

installed wiring.

E. Single-line diagrams of transfer switch units showing connections between automatic transfer

switch, bypass/isolation switch, power source, and load, plus interlocking provisions.




2016 APRIL- REV.0

F. Operation and maintenance data for each type of product, for inclusion in Operating and

Maintenance Manual 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.

G. Manufacturer's certificate of compliance to the referenced standards and tested short-circuit closing

and withstand ratings applicable to the protective devices and current ratings used in this Project, as

indicated and as specified in paragraph "Tested Fault Current Ratings."

1.05 QUALITY ASSURANCE

A. Manufacturer's Qualifications: firms are experienced in manufacturing equipment of the types and

capacities indicated and have a record of successful in-service performance.

B. Comply with IEC 60947-6, IEC 337, IEC 61439-1, IEC408, and IEC204-1.

C. Single-Source Responsibility: obtain ATSs, and required accessories from a single manufacturer that

assumes responsibility for all system components furnished.

D. Emergency Service: manufacturer maintains a service center capable of providing emergency

maintenance and repairs at the Project site with an 8-hour maximum response time.

E. Certification of Power Authority: items furnished under this Section are to be certified for

emergency service, by Power Authority or other Authorities/Institutes having jurisdiction.

PART 2 – PRODUCTS

2.01 MANUFACTURERS

A. Available Manufacturers: subject to compliance with requirements . Refer to list of approved

manufacturers /suppliers.

2.02 TRANSFER SWITCH PRODUCTS, GENERAL

A. Number of Poles, Current and Voltage Ratings: as indicated on Drawings. In general:

1. Units smaller than 600 amperes shall not have different current ratings for different classes or

mixtures of loads, including 100 percent tungsten filament lamp or 100 percent inductive load.

2. Units 600 amperes and larger shall have current ratings that apply to mixtures of loads including

30-percent-maximum tungsten filament lamp load.

3. The rating of any contact shall be a minimum of 1.5 times the rated load it controls.

B. Tested Fault-Current Ratings: closing and withstand ratings shall exceed the indicated available rms

symmetrical fault current at the equipment terminals based on testing according to IEC 60947-6-1,

conducted at full-rated system voltage and 20 percent power factor. Rate each product for withstand

duration time when tested for rated short-circuit current correlated with the actual type of circuit

protective device indicated for transfer switches as follows:

1. Molded-Case Circuit Breakers, Larger than 150 Amperes: 3 closing and withstand duration

cycles.

C. Connection to Integrated Automation System (SCADA/PLC): coordinate with the SCADA/PLC

supplier & provide all necessary interface devices, instruments, dry contacts, etc. for connection of

all required points to the SCADA/PLC as specified or indicated in the SCADA/PLC schedules.




2016 APRIL- REV.0

D. Solid-State Controls: repetitive accuracy of all settings shall be plus or minus 2 percent or better

over an operating temperature to 70 deg C.

E. Resistance to Damage by Voltage Transients: components to meet or exceed voltage surge

withstand capability requirements when tested according to applicable approved standards.

F. Four-Pole Switches: where 4-pole switches are indicated, provide full-capacity neutral switching.

G. Oversize Neutral: ampacity and switch rating of neutral path through units indicated are to be

double the nominal rating of the switch.

H. Enclosures: to IEC 60144 except as otherwise indicated.

I. Heater: within enclosure of units exposed to outdoor temperature and humidity conditions, connect

hydrostat within enclosure to control heater.

J. Factory Wiring: train and bundle factory wiring and identify consistently with shop drawings, either

by color code or by numbered or lettered wire and cable tape markers at terminations.

1. Designated terminals accommodate field wiring.

2. Power Terminals Arrangement and Field Wiring Space: Suitable for top, side, or bottom

entrance of feeder conductors as indicated.

3. Terminals: Pressure-type, bolted, suitable for copper or aluminum conductors of sizes

indicated.

4. Control Wiring: Equipped with lugs suitable for connection to terminal strips.

K. Electrical Operation: where indicated, accomplish by a nonfused, momentarily energized solenoid

or electric motor-operated mechanism, mechanically and electrically interlocked in both directions.

Switches using components of molded-case circuit breakers or contactors not designed for

continuous-duty and repetitive switching between active power sources are not acceptable.

L. Switch Action: mechanically held in both directions for double-throw switches.

M. Switch Contacts: use silver composition for switching load current. Contactors rated 225 amperes

and more shall have separate arcing contacts.

2.03 MAINS FAILURE AUTOMATIC TRANSFER SWITCH (ATS)

A. Type: wall or floor mounted, galvanized sheet steel cubicle, comprising two main contactors or

circuit breakers and controls necessary for automatic transfer of power supply from normal source to

stand-by source, voltage sensing control relay and time delay relays to signal generator start and

stop, auxiliary switches and indicating lights etc. as necessary for the required operation of the

system.

B. Automatic Unattended Operation (for utility-to-generator ATS): when voltage and/or frequency of

any phase drops below an adjustable setting (75% - 98%) of utility normal supply, for an adjustable

period of 0 - 300 seconds, power failure relay is to actuate generator starting control, whilst normal

mains contactor is to open. After an adjustable period of 0 - 10 seconds from sensing stabilized rated

voltage and frequency of generator at the ATS, the emergency contactor/CB is to close. Upon

restoration of normal mains supply to above 95% of rated voltage and/or frequency, for an adjustable

preset period of 2 - 30 minutes, emergency contactor/CB is to open and normal mains contactor/CB

is to close.

C. Mechanical and electrical interlocks are to prevent contactors/circuit breakers from being closed

simultaneously at any time. Transfer mechanism is to be powered from the source to which the load

is being transferred.




2016 APRIL- REV.0

D. The following selector switches are to be provided for utility-to-generator ATS’s:

E. Two position, maintained contact selector switch, marked “Auto”, “Test”.

F. Auto: the control is set for automatic unattended operation as described above.

G. Test: the control is to initiate test operation of the ATS by simulating a loss of the normal power

source, causing the generator to start and transferring the load to the emergency source if the

load/no-load selector switch is set on load position, otherwise generator is to run at no load.

H. Two position, maintained contact selector switch, marked “Load”, “No Load”:

I. Load: is to allow the generator to carry load during testing.

J. No Load: is to allow the generator to start and run but at no load.

K. Transfer Time Delay Bypass: two manual push buttons are to be provided to bypass the time delay

on the normal source (or source1) and the generator source (or source2).

L. Maintenance selector switch marked “ON”, “OFF”, is to be provided inside the ATS enclosure to

allow for disconnection of the control power to the transfer motor circuit in order to test the transfer

logic circuitry without initiating load transfer. Positioning the switch on “OFF” position is to isolate

the control logic circuit from the transfer motor, permitting manual operation of the ATS or testing

of the logic circuitry without load transfer.

M. Automatic Retransfer: if automatic retransfer from the emergency source (or source 2) to the normal

source (or source 1) is not required, a selector switch marked “AUTO”, “MANUAL” is to be

provided. On manual position, automatic retransfer is disabled, while it is enabled on auto position.

N. Motor disconnect switch is to be provided to disable the linear actuator (which is used to move the

contact assemblies between the normal and emergency power sources), for the purpose of servicing

and maintenance of the transfer equipment. It is to be located inside the enclosure.

O. Pilot lights are to indicate which contactor is on, green for 'normal source available'; red for

'emergency source available'. Engraved nameplates shall be provided accordingly.

P. Instruments shall include voltmeter and ammeter with phase selector switches.

Q. Contactors are to be to IEC 60947, 3-phase, 4-pole, magnetic type, 600 V rating, capable of

interrupting at least ten times rated current inductive or non-inductive loads under normal service

conditions and are to have replaceable main arcing contacts and arc quenching devices. Contactors

are to withstand, without welding or burning of contacts, an inrush current of 20 times normal rating

upon closing and the heaviest short-circuit of the system for the period required by upstream

protective switchgear to operate or a minimum of 0.1 second, whichever is greater. Three N.O. and

three N.C. spare SPDT contacts (10A, 230V a.c.) are to be provided on each contactor.

R. Circuit breakers used instead of contactors as transfer switches are to provide same functions as a

minimum requirement and are to be electrically and manually operated, non-automatic type.

S. Wiring: moisture and heat resistant, silicon rubber insulated, stranded copper conductors, modularly

and neatly arranged on master terminal blocks, with suitable numbering strips and appropriate

cartridge type fuses where required. Flexible wiring is to be used on all hinged/draw-out

components.

T. Connections are to be made at a front terminal block with no live metal exposed. Power cables are

to terminate on fixed insulated copper connectors suitably sized to receive specified cables. Cable

glands and gland plates are to be provided.




2016 APRIL- REV.0

U. Metal cases of instruments, control switches, relays etc. are to be connected by flexible protective

conductors, of not less than 2.5 mm2 section, to nearest earthing bar or terminal.

V. Earthing: earthing bus bar to be provided for connection of protective earthing conductors, using set-

screw or bolted anti-turn pressure terminations.

W. Ferrules: wire ends are to be fitted with numbered ferrules of approved type at each termination.

X. Incorporation into LV Switchboards: if it is required on the drawings to incorporate the ATS within a

LV switchboard, necessary coordination is to be carried-out with the LV switchboard supplier to

ensure full matching and compatibility between both products.

2.04 FINISHES

A. Enclosures: manufacturer's standard enamel over corrosion-resistant pretreatment and primer.

2.05 SOURCE QUALITY CONTROL

A. Factory test components, assembled switches, and associated equipment to ensure proper operation.

Check transfer time and voltage, frequency, and time-delay settings for conformance with specified

requirements. Perform dielectric strength test conforming to IEC 60947 requirements.

PART 3 - EXECUTION

3.01 INSTALLATION

A. Floor Mounting of Transfer Switches: level and anchor the unit to the floor (if applicable).

B. Identify components according to DIVISION 26 Section " Identification of Electrical Systems."

3.02 WIRING TO REMOTE COMPONENTS

A. Match the type and number of cables and conductors to the SCADA/PLC control points required for

the transfer switches. Provide necessary raceway to accommodate required wiring.

3.03 CONNECTIONS

A. Tighten factory-made connections, including connectors, terminals, bus joints, mountings, and

grounding. Tighten field-connected connectors and terminals, including screws and bolts, according

to equipment manufacturer's published torque tightening values. When manufacturer's torquing

requirements are not indicated, tighten connectors and terminals to comply with tightening torques

specified in Standards .

3.04 EARTHING

A. Make equipment earthing connections for transfer switch units as indicated and as required by

applicable Regulations/Codes. Refer to Section "Grounding and Bonding for Electrical Systems".

3.05 FIELD QUALITY CONTROL

A. Manufacturer's Field Services: provide services of a factory-authorized service representative to

supervise field tests.

B. Preliminary Tests: perform electrical tests as recommended by the manufacturer and as follows:

1. Measure phase-to-phase and phase-to-ground insulation resistance levels with insulation

resistance tester, including external annunciator and control circuits. Use test voltages and




2016 APRIL- REV.0

procedure recommended by the manufacturer. Meet manufacturer's specified minimum

resistance.

2. Check for electrical continuity of circuits and for short circuits.

C. Field Tests: give 7-day advance notice of the tests and perform tests in presence of Employer's

representative.

D. Coordinate tests of ATS with tests of generator plant and run them concurrently where ATS is

associated with a generator plant.

E. Tests: as recommended by the manufacturer and as follows:

1. Contact Resistance Test: measure resistance of power contacts for ATSs. Resolve values in

excess of 500 micro-ohms and differences between adjacent poles exceeding 50 percent.

2. Earth Fault Tests: coordinate with testing specified in DIVISION 26 Section "Low Voltage

Circuit Breakers" to ensure sensors are properly selected and located to optimize ground-fault

protection where power is being delivered from either source.

a. Verify earthing points and sensor ratings and locations.

b. Apply simulated fault current at the sensors and observe reaction of circuit interrupting

devices.

3. Operational Tests: demonstrate interlock, sequence, and operational function for each switch at

least 3 times.

a. Simulate power failures of normal source to ATSs and of emergency source with normal

source available.

b. Simulate low phase-to-ground voltage for each phase of normal source of ATSs.

c. Verify time-delay settings and pick-up and drop-out voltages.

F. Test Failures: correct deficiencies identified by tests and prepare for retest. Verify that equipment

meets the specified requirements.

G. Reports: maintain a written record of observations and tests. Report defective materials and

workmanship and retest corrected items. 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.

3.06 DEMONSTRATION

A. Training: furnish the services of a factory-authorized service representative to instruct Owner's

personnel in the operation, maintenance, and adjustment of transfer switches and related equipment.

Provide a minimum of 4 hours of instruction scheduled 7 days in advance.

END OF SECTION 26 36 23

Section 263623 - ATS

Documents

Transcript of Section 263623 - ATS