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الموضوع: مطلوب مواصفة لوحة توزيع ضغط منخفض رئيسية لمبني

  1. #1
    Junior Engineer
    تاريخ التسجيل
    Jul 2006
    الدولة
    Egypt
    المشاركات
    122

    مطلوب مواصفة لوحة توزيع ضغط منخفض رئيسية لمبني

    السلام عليكم ورحمة الله وبركاته
    ارجو من سيادتكم المساعدة في ايجاد توصيف لوحة ضغط منخفض main distribution board لمبني
    وتفضلوا بقبول فائق الاحترام والتقدير

  2. #2
    Junior Engineer الصورة الرمزية Wagdy Azzam
    تاريخ التسجيل
    Apr 2009
    الدولة
    Helwan
    المشاركات
    285

    رد: مطلوب مواصفة لوحة توزيع ضغط منخفض رئيسية لمبني

    PART 1 – GENERAL

    1.1 GENERAL

    The LV switchgear and controlgear is a combination of one or more LV switchgear devices together with associated control, measuring, protective and regulating equipment, completely assembled with all the internal electrical, mechanical interconnections and structural parts meeting the requirements of IEC 439 "Factory Built Assemblies" and comprising:

    Air Circuit Breakers to IEC 157
    HRC Fuse Switches to IEC 408
    On-load switches to IEC 408
    Heavy Duty Isolators to IEC 408
    HRC Fuse Cartridges to IEC 269
    HRC Fuse Units to IEC 269
    Miniature Circuit Breakers
    Moulded Case Circuit Breakers to IEC 947 Part 2
    Distribution Boards
    Motor Starter Panels
    Contactors to IEC 158

    1.2 MANUFACTURING AND WORKING DRAWINGS

    The manufacturer shall provide two sets of manufacturing and working drawings for approval. Any comments made thereon shall be incorporated and two further copies of the drawing shall be submitted for approval. Once approval has been given, by stamped notation by the Engineer, two sets of drawings shall be submitted, marked by manufacturer as “APPROVED FOR CONSTRUCTION”. No manufacturer of the panels shall commence until approval has been obtained. Should manufacturer commence prior to approval and modifications are required, these to be carried out at the manufacturer's risk, responsibility and cost. These fabrication drawings shall also be approved by SCECO prior to commencement of fabrication works.

    The drawing submission shall include but shall not be limited to the following:

    1. External panel construction: detailing all dimensions, method of construction, position of equipment meters etc.

    2. Internal panel construction : detailing position of equipment, mounting details, terminals, wireways, cabling, busbars and connection, indicating fixed and withdrawable components.

    3. Schematic Diagram: detailing system arrangement, equipment ratings, interlocks and instrumentation.


    4. Wiring diagrams: detailing system arrangement, equipment ratings, interlocks and instrumentation.

    5. Legend : Schedule of symbols and their functions.

    6. Schedule of components: Defining manufacturer, ratings, type or list numbers.

    7. Catalogues of various components such as ACB, MCCB, MCB, instrument etc.

    1.3 CONSTRUCTION

    Frames are to be constructed from folded steel angles strengthened by horizontal and vertical folded channels and corner gaskets. Frameworks are to be enclosed by cold rolled sheet steel of minimum thickness of 14 swg. Where joints or seams are welded to provide additional rigidity the welds are to be cleaned off and ground flush. Any grinding works are to be filled to prevent them from being visible after painting.

    For ratings greater than IP31 all parts of the framework, enclosures, doors, etc., are to be gasketted or shrouded to obtain a minimum of IP55. Gaskets shall form a seal when compressed under low pressure between rigid faces. When compressed the thickness of the gasket shall not be less than two-thirds of the uncompressed thickness. Gaskets shall be of 3/8" thickness butyl rubber of polychloroprene (neoprene) which shall be securely fixed by base hardened adhesive (Aeroldrite) or set into retaining channels. Shrouds shall be purpose made covers of a polycarbonate (Makrolan) transparent fixed to the steelwork by a minimum of 4xl/4" turn quick release screws with gaskets between surfaces.

    Enclosure fixings shall relate to the IP rating required to ensure ingress of dust and water does not occur. For larger panels the steelwork is to be manufactured so that it can be split into manageable segments for transporting to site. Each segment shall have lifting eyes fitted such that the weight is taken without distortion. Where lifting eyes are bolted to the enclosure suitable infills are to be provided so that the defined IP standard is not derated. The segments are to be bolted together and line up and all equipment fitted inside the various components are wired and tested at works. The fixing bolts used for bolting the segments together should be tied to the inside of the segments and their purpose clearly defined on a label attached to them. Wiring connections between segments to be made by means of kippon plugs and socket connectors which when plugged together are then fixed by means of screws into tapped holes.

    Each segment shall have provision in the base for fixing to a concrete plinth within the plant room/switchgear room.



    The switchgear panels are to comprise of separate compartments within the overall panel of steelwork to house the individual controls, instrumentation and switchgear. The individual compartments are to be sized to enable the components to be installed in accordance with the manufacturer (position of use, clearances to be observed for electric arc, for the removal of the arc chute, removal of contactor coils etc.). The apparatus, functional units mounted on the same support and the terminals for external conductors shall be so arranged to be accessible for mounting, wiring, maintenance, replacement and resetting.

    Where frameworks are bolted together the bolts shall be hexagonal head M6x25 zinc plated into tapped holes, hank bushes fixed to the main steelwork or nuts. Self tapping bolts or screws will not be permitted.

    The compartment doors are to be rigid horizontally and vertically stiffened to prevent any distortion, particularly when manual control and indication components are mounted on the door.

    The compartment doors are to be fitted with gaskets so as to protect the interior against the ingress of dust and water when the door is closed to meet the IP ratings.

    The hinges on compartment doors are to allow for the doors to be opened to greater than 90 Deg.C. movement without undue strain on the hinges and without causing the doors to distort.

    Where permanently fixed removable covers are fitted they are to be gasketted in the same manner as the doors. For coverplates over 600 x 600mm in addition to the four fixing screws at the corners, extra fixing screws are to be provided at not greater than 450ram centres to ensure the gasket is held in position. All fixing screws shall be countersunk shallow domes head M8 x 40 chromium plated brass with recessed collar. All cut-outs on compartment doors shall be accurately made using a template and all edges finished smooth and free from burrs and burns.

    The panel steelwork shall be protected against climatic conditions by degreasing acid etching the steelwork followed by one coat of rust inhibitor, then two coats of polyurethane primer followed by two coats of polyurethane top coats, final colour to be agreed.

    The interior compartment mounting plates shall be constructed from a minimum of 16 SWG flat sheet steel and are to be rigidly fixed into the compartment and stiffened by bending of the two longer edges into a 90 Deg.C.lip. The mounting plate shall be thick enough to enable a minimum of three full threads to be available when tapped holes are made for fixing the compartment components to the backplate. The mounting plates are to be removable from the front of the panel and must not deflect on the operation of switchgear mounted onto them or not set up vibrations when the switchgear is closed.


    It shall be the manufacturer's responsibility to ensure that the LV switchgear panels are constructed of materials capable of withstanding the mechanical, electrical and thermal stress as well as the effect of humidity which will be encountered in normal service. Information and certified test certificates will be required to indicate the mechanical strength of the enclosure and shall include:-

    a) Thickness of steel used in the construction.
    b) Impact strength test.
    c) Mandrel bending test.
    d) Cone bending test.
    e) Persoy hardness.

    The switchgear panel when fabricated will be dead flat, true and will be finished to a standard colour approval, primed, undercoated and top coated to give a final appearance entire free from blemishes, undulations, scratches or any defects whatsoever.

    The steelwork paint finish shall be subjected to corrosion resistance test at ambient temperature on coated sample of the sheet ****l enclosure. Duration of test will indicate corrosion resistance depending on ¬material coated and on surface condition.

    A 13 Amp. 3 pin, 220 volt switched socket outlet shall he installed within the kiosk complete with plug top. A ¬suitably rated and protected thermostat controlled anti¬condensation heater shall be fitted in the lower part of the general enclosure. A control switch shall be provided for the anti-condensation heaters with pilot ligh-¬indicator.

    Provision shall be made for earth bonding of all ¬components, cables and ****l framework.

    1.4 MOTOR STARTING EQUIPMENT:

    The type of starters contained within the panels shall be governed by the rating of the motors. Motors up to and including 3 KW being direct-on line started, and motors over 3 KW being auto star-delta or stator-rotor started. All starters for motors of 3 KW and above shall have power factor correction applied, by the inclusion of suitably rated capacitors, to better than 0.92 lagging a--operational loads.

    All motor starters, direct-on-line, star-delta, stator-¬rotor, etc. shall be of the automatic airbreak Contactor-¬type and shall be rated for not less than 15 starts per-¬hour up to 75 KW motor starters. Over this rating the Tenderer shall quote what starts per hour equipment he is proposing to supply unless specified otherwise herein.


    Each starter shall incorporate the following feature ¬unless specified otherwise herein:

    1. One TP & N isolator fully interlocking with the cubicle door to ensure that the starter is 'dead' when the door panel is open. The incoming connections from the bus-bars to the isolator shall be suitably shrouded.

    2. An adjustable current overload release, time lagged to cover the starting period, which when operated by excessive loading on any one or all phases shall cause the equipment to be locked out for inspection and the resetting of the release shall be by means of a suitable hand reset button. Single phasing protections shall also be included.

    3. A triple pole contactors, with under voltage release facility and timing device (where necessary) with inherent no volt release.

    4. Auxiliary contacts (at least 1 make and 1 break contact) for remote indication of motor running and to energize motor anti-condensation heater when not in operation.

    5. 3 HRC cartridge fuses for motor circuit protection.

    6. 1 HRC cartridge fuse for heaters circuits protection.

    7. 3 HRC cartridge fuses for motor circuit protection.

    8. 1 HRC cartridge fuse for heaters circuits protection.

    9. 1 HRC cartridge fuse for control circuit protection.

    10. A flush fitting ammeter of suitable range to be fitted on each direct-online, star-delta or stator-rotor starter, for motors of 0.75 KW and above.

    11. Green pilot light to indicate "Running".

    12. Amber pilot light to indicate "Motor Tripped".

    13. White pilot light to indicate "Heater On".

    14. A "running hours counter" meter of the cyclometer type registering up to 99,999 hours.

    15. A heating element of capacity adequate to maintain the temperature of the cubicle at notless than 100C toge-Lher with an overriding handswitch. The hand switch shall be a 2 position type giving "Heater Off" and "Heater On" working in conjunction with the white pilot light above.


    16. Terminais and wir-Lng to provide a 240 Volt supply, via the auxiliary contact above, to the motor anti-condensation heater.

    17. A rotary "Hand/Of f /Auto" switch where the motor is arranged for automatic control (i.e. switched "on or off" by contacts in automatic level, pressure, flow or sequence control equipment, etc.).

    18. Start/Stop push buttons.

    19. One de******ion label.

    Resistance type starters shall be provided with thermal cut-outs. The thermal cut-out shall be a hand re¬set type. For each stator-rotor type starter, the number of three phase rotor resistance short circuiting contactors shall be suitable for the maximum rotor current and an adjustable master timing devise shall be incorporated to energise the rotor contactor coils in a timed sequence.

    1.5 DEGREES OF PROTECTION OF ENCLOSURES (IP):

    Standards IEC 529, give a protection index IP which characterises the ability of equipment to withstand the external influences of solid bodies and water or NEMA Standards as indicated on drawings.

    The determination of the IP rating shall depend upon the location of panel which shall fall into three main categories:

    1. External : NEMA 3R

    2. Within a room enclosure classi-
    ¬fied as a plant area including mechanical
    rooms or electrical or a multi-service
    riser shafts : NEMA 1 or 2

    3. controlled environment for
    temperature, moisture, dust
    and maintenance factors as
    internal residential and
    office accommodation. : NEMA 1

    The manufacturer shall substantiate the protective index given to the equipment following a series of tests laid down in the respective standards. All kilowatt hour meters shall be provided in one row with the center of meter window at a height of 1650 +/- 10mm. The mounting arrangement of these meters shall meet SCECO requirements.


    1.6 METERS AND INSTRUMENTS

    All meters and indicating or recording instruments including ammeters, voltmeters, kilowatt hour meters, frequency meters and power factor meters will be of the flush mounted, square pattern and be in accordance with relevant standards. All kilowatt hour meters shall be provided in one row with the center of meter window at a height of 1650 +/- 10mm.

    Each instrument will have an accuracy of not less than that defined in relevant standards and will be subject to a high voltage test of 2KV for 1 minute and an overload capacity test of 10 times full load current for 3 seconds.

    Each current or voltage transformer used in conjunction with meters, instruments or protection relays.

    1.7 BUSBARS:

    Busbar and busbar connections shall be rated in terms of the following:

    a) Voltage
    b) Normal current
    c) Frequency
    d) Short time current either 1 sec. or 3 secs.

    Busbar and busbar connections shall be capable of carrying continuously their rated normal current w-Lth a temperature rise being taken into account. The limits of temperature rise shall be based on ambient temperature having a peak value not exceeding 45 Deg.C. and an ¬average value not exceeding 35 Deg.C- measured over a 24 hour period. The temperature rise of busbars and busbar -connections above the ambient temperature, when carrying rated normal current at rated frequency shall not exceed 50 Deg.C. If the ambient temperature exceeds that defined above, the permissible temperature rise shall be reduced by an amount equal to the amount of excess ambient ¬temperature. The busbar and busbar connections shall be hard drawn, electro-tinned, high conducting, hard copper ¬bar running the complete length of the panel. Flexible busbar and busbar connections will not be permitted. Busbar and busbar connections shall be sized to carry the normal current and withstand the fault (short circuit) current.

    Bends formed in the busbar shall be carried out in a cold state on a proprietary made mechanical or hydraulic bending machine. The busbar shall be bent over formers sized to accord with the thickness of the bar so that the mechanical, thermal and dielectric properties are not devalued. The distortion imposed on a busbar shall not exceed 2mm for 1 metre length of bar.

    The minimum clearances for open, indoor, air insulated busbars and busbar connections shall be 19mm betweern phase and earth and 25.4mm between phases.


    The busbars shall run the complete length of the panel and shall be supported by synthetic resin bonded paper or synthetic bonded laminated wood and shall be capable of safely withstanding stresses to which they may be subjected, including those due to short circuit and climatic conditions. Provision shall be made to allow for expansion and construction caused by temperature variation.

    Terminations onto and the jointing of the busbar shall be by bolting using M10 high tensile (8.8) steel bolts of sufficient length to give at a minimum two complete threads through the retaining nut.

    Hole tolerances shall be 11 mm diameter clean and free of burrs. All bolts shall be torqued tightened to 58.3 N/M to give a surface torque between conductors or not less than 25 NIM. All torque tightened bolts shall be clearly and permanently distinguishable by painting colours of which are coded to define the torque rating.

    Type test will be required to prove the performance of the busbars and busbar connections. The performance of the arrangement shall be substantiated by test data from a recognised testing authority (The Association of Short¬Circuit Testing Authorities - ASTA), and such data shall include drawings, diagrams, photographs, oscillograms and any other data that will enable the manufacturer to satisfy the Engineer that the arrangement tested and the arrangement offered are compatible. In the absence of such data, tests will be required to be carried out by the manufacturer under full laboratory conditions to include:

    a) Temperature test.
    b) Short-time current test.

    1.8 TEMPERATURE-RISE TEST

    The test of temperature rise for AC busbars and busbar connections shall be made with alternating current at an average frequency not below 95 percent of the rated frequency. For d.c. busbars and connections either alternating or direct current may be used.

    The test shall be arranged to produce conditions equivalent to those which would obtain in practice when one section of a busbar and typical busbar connections, together with any enclosures, are connected to similar adjacent sections on either side.

    Where the busbars and busbar connections are being tested, any busbar connections not carrying the test current shall have the lowest rating assigned to the connections for use with that busbar arrangement.

    The temperature-rise measurement may be made at normal room temperatures, as they are not materially affected by moderate changes in ambient temperature. Measurement shall be made using either thermometer or thermocouple.


    1.9 SHORT-TIME CURRENT TEST

    The test shall be arranged to produce conditions equivalent to those which would obtain in service when a section of busbars, including one joint, and typical busbar connections, carry fault currents.

    The r.m.s. value of the short-time current shall be not less than the rated short-time current, and the highest peak value of the major current loop during the first cycle of the test shall be not less than the rated making-capacity of any directly associated circuit¬ breaker or switch or fuse.

    Where, however, the characteristics of the test plant are such that the above requirements cannot be met, the following deviations are permitted provided that in (1) and (2) the product of the square of the short-time current and the duration is not less than the product of the square of the rated short-time current and the rated time.

    1. If the decrement associated with the test plant is such that the rated short time current cannot be obtained for the rated short-time duration without applying initially an excessively high current, the current may be permitted to fall during the test below the specified value and the duration of the test increased appropriately, provided that the initial value of both peak and r.m.s. current are not less than those set out above.

    2. If in order to obtain the required initial peak value, the r.m.s.,value of the short-time current is increased above the value of the rated short-time current, the duration of the test may be reduced below the rated short-time duration.

    For busbars and busbar connections used in direct association with a fuse or a circuit-breaker fitted with series trip-coils, or other overcurrent devices, the circuit shall be set to give a prospective current equal to the rated symmetrical breaking-capacity of the associated fuse or circuit-breaker, and the current shall be maintained for the total break-time of the circuit-breaker when set for a maximum time-lag, or the operating time of the fuse when fitted with the fuse-link giving the highest current rating of the size of fuse concerned. Three tests shall be made with intervals of three minutes between them.

    The short-time current shall not produce any mechanical damage, such as permanent distortion or burning of parts, and shall not cause a temperature rise that, added to the maximum temperature attained at rated normal current, would damage the insulation of the current-carrying parts.

    After the test the busbars and busbar connections shall be in a condition to comply with their rating when they are again at the ambient temperature.

    The busbar and busbar connections shall be tested in accordance with IEC 439 to withstand a fault level of 50 kA for 1 second.


    1.10 PROTECTIVE MEASURES WITH REGARD TO SHOCK:

    The following requirements shall be complied with. All external surfaces shall conform to the degree of protection for the particular panel defined under the previous heading of Protection Ratings. The distance between the mechanical means provided for protection and the live parts they protect shall be not less than the values specified hereafter for clearance and creepage distances unless the mechanical means are of insulating materials.

    Clearance - 19.0 mm minimum
    Creepage - 19.0 mm minimum

    Where it is necessary to make provision for the removal of barriers, opening of enclosures, or withdrawal of parts of enclosures (doors, casings, lids, covers, and the like) this shall be in accordance with ONE of the following requirements.

    1. Removal, opening or withdrawal shall necessitate the use of a key or tool.

    2. All live parts which can accidentally be touched after the door has been opened shall be disconnected before the door can be opened. This shall be achieved by interlocking the door with a disconnector so that it can only be opened when the disconnector is open and so that the disconnector cannot be closed when the door is open. If for reasons of operation, the panel is fitted with a device permitting authorised persons to obtain access to live parts while the apparatus is live, the interlock shall automatically be restored on closing of the door.

    3. The panel shall include an internal barrier or shutter shielding all live parts in such a manner that they cannot accidentally be touched when the door is open. This barrier or shutter shall meet the requirements for its IP rating and secure fixing as previously described. It shall either be fixed in place or shall slide into place the moment the door is opened. It shall not be possible to remove this barrier or shutter except by a key or tool. Warning labels must be displayed clearly on all such barriers or shutters.

    4. Where any part behind a barrier or enclosure need occasional handling (such as replacement of a lamp or fuse-link), the removal, opening or withdrawal without the use of a key or tool and without switching off shall only be possible if the following condition is fulfilled:


    1. A second barrier shall be provided inside the barrier or enclosure so as to prevent persons coming into accidental contact with live parts not protected by another protective measure. This barrier need not prevent persons from coming intentionally into contact by by-passing this barrier with the hand. It shall not be possible to remove the barrier except through the use of a key or tool.

    A protective circuit in the panel shall consist of a separate protective conductor running the complete length of the panel to provide protection against the consequences of fault within the panel and protection against the consequences of faults in external circuits supplied through the panel. The protective conductor shall be with dimensions not less than 50 x 6mm (2"xl/4") of hard drawn copper bar.

    Continuity of protection shall be ensured by effective interconnections either directly or by means of protective conductor.

    1. When a part of the panel is removed from the enclosure, e.g. for routine maintenance, the protective circuits for the remainder of the panel shall not be interrupted. Means used for assembling the various ****l parts of the panel are considered sufficient for ensuring continuity of the protective circuits if the precautions taken guarantee a permanent good conductivity and a current carrying capacity sufficient to withstand the earth fault current that may flow in the panel.

    2. When removable or withdrawable parts are equipped with ****l supporting surfaces, these surfaces are considered sufficient for ensuring continuity of protective circuits provided that the pressure exerted on them is sufficiently high. Precautions may have to be taken to guarantee a permanent good conductivity. The protective circuit of a withdrawable part shall remain effective from the connected position to the test position inclusively.

    3. For lids, doors, coverplates and the like, the usual ****l screwed connections and ****l hinges are considered sufficient to ensure continuity provided that no electrical equipment is attached to them.

    4. All parts of the protective circuit within the panel shall be so designed that they are capable of withstanding the highest thermal and dynamic stresses that may occur at the place of installation of the panel.

    5. When the enclosure of a panel is used as part of a protective circuit, the cross-sectional area of this enclosure shall be at least electrically equivalent to the minimum cross-sectional area specified.


    6. Where continuity can be interrupted by means of connectors or plug and socket devices, the protective circuit shall be interrupted only after the live conductors have been interrupted and continuity established before the live conductors are reconnected.

    7. Protective circuits within a panel shall not include a disconnecting device (switch, isolator, etc.) the only means permitted in the run of protective conductors shall be links which are removable with the aid of a tool and accessible only to authorized personnel (these links may be required for certain tests).

    8. All live parts of equipments shall be properly grounded.

    The connecting devices for external protective conductors grouped in a cable containing phase conductors shall be the same as those for the neutral conductors but not less than 16 sq.mm.

    The cross-section of protective conductors shall be as follows:

    - equal to that of the phase conductors if the cross¬ section of the latter does not exceed 16 sq.mm. if the protective conductors are made of a material different from that of the phase conductors, their cross-section shall be so fixed as to give the same conductivity;

    - equal to the value calculate with the aid of the formula indicated below or obtained by some other method if the cross-section of one of the phase conductors exceeds 16 sq.mm.

    Sp = I 2 t
    K

    Sp. Cross sectional area in square millimeters.

    I = RMS Value of a.c. fault current in amperes.

    t = Operating time of the disconnecting device in seconds.

    k = Factor dependent on the material of protective conductor, the
    insulation and other parts and the initial and the final temp.

    Values of K for insulated protective conductors not incorporated in cables or bare protective conductors in contact with cable covering:


    INSULATION OF PROTECTIVE CONDUCTOR OR
    CABLE COVERING.

    PVC XLPE/EPR/BARE COND. BUTYL RUBBER

    FINAL TEMP. 160 Deg.C. 250 Deg.C. 220 Deg. C.

    MATERIAL OF
    CONDUCTOR. k

    COPPER 143 176 166

    ALUMINIUM 95 116 110

    STEEL 52 64 60

    NOTE The initial temp. of the conductor is assumed to be 30 Deg.C.

    For fixing the cross-section of protective conductors, the following conditions have to be satisfied simultaneously.

    1. The value of the fault-loop impedance shall fulfill the conditions required for the operation of the protective device;

    2. The conditions of operation of the electrical protective device shall be so chosen as to eliminate the possibility of the fault current in the protective conductor causing a temperature rise that tends to impair this conductor or its electrical continuity. This is considered to be achieved if in the case of a fault arising which will produce maximum prospective short-circuit current, the temperature rise of the protective conductor does not exceed the following values:

    120 Deg.C. for insulated conductors
    180 Deg.C. for uninsulated conductors

    It is assumed that the starting temperature does not exceed + 40 Deg.C.

    Protective circuit not insulated from the exposed conductive parts - In the case of a panel containing structural parts, frameworks, enclosures, etc. made of conducting material, a protective conductor, if provided, need not be insulated from these parts.


    1.11 WIRING

    All small wiring shall be a minimum of 1.5 sq.mm PVC cable enclosed in plastic cable trunking with removable lids. The trunking shall be securely fixed to the mounting plates within the section compartments. Where small wiring is extended to components mounted on doors, the doors shall be protected by "looping' using plastic cable tee. Sufficient wiring shall be allowed to enable the door to fully open without putting strain onto the terminations. Both ends of all wires shall be identified with its circuit reference number using ‘0’ type cable markers.

    Terminations on the end of cables shall be by proprietary crimp connectors. Where two wires are made off into one terminal, both must have a crimp connector. Terminal and terminal boards for small wiring shall be accessibly located and so positioned as to minimize the number of small wiring connections impending access to other connections.

    1.12 PROTECTIVE DEVICES:

    Devices shall provide protection against overload current ¬and short circuit current and shall be capable of making or breaking any current up to and including the prospective short circuit current at the point where the device is installed. Such protective devices may be circuit breakers incorporating overload release, or fuses, or circuit breakers in conjunction with fuses. Protective devices shall have a rated breaking capacity of not less than the prospective short circuit current (fault level).

    The selection and settings of the protective devices shall be provided separately in a tabulated form listing circuit identification, IEEE device number, current transformer ratios, manufacturer, type, range of adjustment and recommended settings.

    1.13 LABELLING

    All components within the panel or those on the section compartment doors shall be identified with its circuit reference or function. The labels are to be manufactured out of white/black/white traffolyte labels and engraved with the appropriate information. These labels are to be fixed using a minimum of two self-tapping screws, adhesive labels will not be permitted. Minimum lettering shall be 10mm high characters.

    Adhesive film labels for phase marking shall be applied to all live conductors and shall be coloured for three phase RED, YELLOW, BLUE, BLACK for neutral WHITE for earth.

    Removable covers which expose conductors or terminals are to have danger flashes.


    1.14 FACTORY TESTS:

    Factory-built assemblies shall undergo a series of works tests at the manufacturer's premises in accordance with the tests stipulated in IEC 439.

    Factory tests to be carried out:

    1. Visual Inspection:

    Insulation-resistance on each bus section
    Cubicle structure.
    Bolt inspection.
    Wire check.
    Fuse rating and tightness.
    Current transformer rating.
    Phase clearances and earth clearance.
    All label and terminal identification.
    Cable entry/access and glands.
    Phase colour markings throughout.
    Shrouding terminal shields.
    Component voltages, currents and frequency.
    Paints.
    Quality of fabrication.

    2. Function Test:

    Switch gear insulation-resistance test voltage
    Phase sequence/polarity check.
    Remote switching and indication.
    Sequence and outputs.
    Electrical operation.
    Mechanical operation.
    Instrument readings.
    Current at each device
    Field over potential test voltage depend of the type to the switch gear (****l-clad switch gear, station type cubicle switch gear, etc.)

    3. Type Tests:

    Type test will be required to prove the performance of the panel and shall be substantiated by test dates from a recognized testing authority.


    The certification of data shall include drawings, diagrams, photographs, oscillograms and any other data that will enable the manufacturer to satisfy the Engineer that the arrangement offered is compatible. In the absence of such data tests will be required to be carried out by the manufacturer under full laboratory conditions.

    1. Verification of temperature-rise limits.
    2. Verification of the dielectric properties.
    3. Verification of the short-circuit strength.
    4. Verification of the continuity of the protective circuit.
    5. Verification of the mechanical operation.
    6. Verif ication of the degree of protection.
    7. Verification of interlock System

    1.15 DEFINITIONS OF TYPE TESTS

    A. Verification of Temperature-Rise Limits:

    1. General:

    The test shall normally be carried out at the values of rated current as defined in the sub-heading temperature-rise test using current on al apparatus with the apparatus of the panel installed.

    In certain cases, the test may be carried out with the aid of heating resistors of an equivalent power loss as defined in the sub-heading.

    The test shall be carried out in accordance with the type of duty for which the sample is designed.

    The temperature-rise test on the individual circuits shall be made with the type of current for which they are, intended, and at the design frequency. The test voltages used shall be such that a current equal to the current determined flows through the circuits. Coils of relays, contactors, releases, etc., shall be supplied with rated voltage.

    2. Arrangement of the Panel:

    The panel shall be arranged as in normal use, with all covers, etc., in place. When testing individual parts or constructional units, the adjoining parts of constructional units shall produce the same temperature conditions as in normal use. Heating resistors may be used.


    3. Temperature-Rise Test Using Current on all Apparatus:

    The test shall be made on one or more representative combinations of circuits so chosen as to cover with reasonable accuracy the worst condition for which the panel is designed.

    For this test, each circuit is loaded with rated current, taking account of the values of the diversity factor. If the panel includes fuses, these shall be fitted, for the test, with fuse-links as specified by the manufacturer. The power losses of the fuse-links used for the test shall be part of the test report.

    The size and the disposition of external conductors used for the test shall be part of the test report.

    The test shall be made for a time sufficient for the temperature rise to reach a constant value (but not exceeding 8 h). In practice, this condition is reached when the variation does not exceed 1 deg.C. per hour.

    In the absence of detailed information as to the service conditions, the cross-section of the external conductors shall be as follows:

    For values of test current up to and including 400 A:

    a. The connections shall be single-core, PVC insulated, copper cables or wires with cross¬ sectional areas as given in the following table;

    b. As far as practicable the connections shall be in free air;

    c. The minimum length of each temporary connection from terminal shall be:

    - lm for cross-sections up to and including 10 sq. mm.

    - 2m for cross-sections larger than 10 sq.mm.



    d. Standard Cross-Sections of Copper Conductors to the Test Current:

    Range of actual rated current 1) (A)
    ________________________________________ _______________________

    0 7.9 15.9 22 30 39 54 72 93 117 147 180 216 250 287 334

    7.9 15.9 22 30 39 54 72 93 117 147 180 216 250 287 334 400
    ________________________________________ _______________________

    Sq. mm

    1 1.5 2.5 4 6 10 16 25 35 50 70 95 120 150 185 240
    ________________________________________ _______________________

    Values of the rated thermal current 2) (A)
    8 16 40
    6 10 25 32 63 80 100 125 160 200 250 315 400
    12 20 50
    ________________________________________ _______________________
    1) The value of current shall be areater than the value in the first line and less than or equal to the value in the second line.

    2) These are standard recommended currents and are given for reference purposes only.

    e. For value of test current higher than 400 A but not exceeding 1600 A:

    - The connections shall be finished matt black copper strips of the sizes stated hereafter;

    - The connections shall be in free air and spaced not less than the distance existing between the terminal;

    - The minimum length of each temporary connection from terminal to terminal shall be 2m.



    f) Standard Test Connections for Test Currents Higher than 400 but not exceeding 1600 A 1):

    ________________________________________ _______________________
    TEST CONNECTIONS 2)
    TEST CURRENT (A)
    NUMBER DIMENSIONS 3) (mm)


    400 To 500 2 30 x 5
    500 To 650 2 40 x 5
    650 To 800 2 50 x 5
    800 To 1000 2 60 x 5
    1000 To 1250 2 80 x 5
    1250 To 1600 4 50 x 5
    ________________________________________ ______________________

    - The spacing between two parallel bars of the same polarity shall be approximately 5mm.

    - If the connection of the bars indicated to the terminals of the apparatus under test is not possible, the use of bars having the same cross¬ section but a width equal to that of the terminals is allowed.

    - The use of cables instead of bars is permissible. Standard values for cables are under consideration.

    Temperature-Rise Test using Heating Resistors with an Equivalent Power Loss:

    For certain types of enclosed panels with main and auxiliary circuits having comparatively low rated currents, the power loss may be simulated by means of heating resistors which produce the same amount of heat and are installed in suitable places inside the enclosure.

    The cross-section of the leads to these resistors shall be such that no appreciable amount of heat is conducted away from the enclosure.

    This test with heating resistors is considered to be reasonably representative of all panels using the same enclosure, even if they are equipped with different apparatus, provided that the sum of the power loss of the built-in apparatus, taking into account the diversity factor, does not exceed the value applied in the test.


    The temperature rise of the built-in apparatus shall not exceed the values given in Table hereunder. This temperature rise can be approximately calculated by taking the temperature rise of this apparatus, measured in the open air, increased by the difference between the temperature inside the enclosure and the temperature of the air surrounding the enclosure.

    Measurement of Temperature:

    Thermocouples or thermometers shall be used for temperature measurements. For windings, the method of measuring the temperature by resistance variation shall generally be used. For measuring the temperature of the air inside a panel, several measuring devices shall be arranged in convenient places.

    The thermometers or thermocouples shall be protected against air currents and heat radiation.

    Ambient Air Temperature:

    The ambient air temperature shall be measured during the last quarter of the test period by means of at least two thermometers or thermocouples equally distributed around the panel at about half its height and at a distance of about lm from the panel. The thermometers or thermocouples shall be protected against air currents and heat radiations.

    If the ambient temperature during the test is between +10 Deg.C. and +40 Deg.C.. The values given in the table given hereunder shall be the limiting values of temperature rise.

    If the ambient air temperature during the test exceeds + 40 Deg.C. or is lower than + 10 Deg. C., this recommendation does not apply and the manufacturer and the user shall make a special agreement.

    Temperature rise limits

    Parts of ASSEMBLIES Temperature rise (K)

    Built-in components. In accordance with the relevant requirements for the individual components, if any, or, in accordance with the manufacturer’s instructions, taking into consideration the temperature in the assembly.


    Terminals for external
    insulated conductors. 70

    Busbars and conductors,
    plug-in contacts of
    removable or withdraw¬able
    parts which connect to busbars. Limited by:
    - mechanical strength of
    conducting material:

    - possible effect on adjacent
    equipment:

    - permissible tempera¬ture limit
    of the insulating materials in contact with the conductor:

    - the effect of the temperature of the conductor on the apparatus connec¬ted to it:

    - for plug-in contacts, nature
    and surface treatment of
    the contact material.

    Manual operating means:
    - of ****l 15
    - of insulating material 25
    Accessible external
    enclosures and covers:
    - ****l surfaces 30
    - insulating surfaces 40

    Discrete arrangements of
    plug and socket-type
    connection. Determined by the limit
    for those components of the related equipment of which they form part.


    Temperature Rise of an Element or Part:

    a) For the temperature-rise test with the apparatus in the panel in place and the circuits being loaded with the specified current, the temperature rise of ¬an element or part is the difference between the temperature of this element or part measured as defined in heading "Measurement of Temperatures" and, the ambient air temperature outside the panel.

    Results to be Obtained:

    a) At the end of the test the temperature rise shall not exceed the values specified in Table II of BS 5486, Sub-Clause 7.3. The apparatus shall operate satisfactorily within the voltage limits specified for them at the temperature inside the panel.

    B. Verification of Dielectric Properties:

    General:

    This type test need not be made on such parts of the panel which have already been type tested according to their relevant specifications provided their dielectric strength is not impaired by their mounting.

    The test voltage shall be applied:

    1) Between all live parts and the frame of the panel;

    2) Between each pole and all the other poles connected to the frame of the
    panel.

    When the panel includes a protective conductor insulated from the exposed conductive parts, this conductor shall be regarded as a separate circuit, i.e., it shall be tested with the same voltage as the main circuit to which it belongs.

    The test voltage at the moment of application shall not exceed 50% of the values given hereafter for test voltage. It shall then be increased steadily within a few seconds to its full value defined hereafter maintained for 1 minute. The A.C. power sources shall have sufficient power to maintain the test voltage irrespective of any leakage currents. The test voltage shall have a practically sinusoidal wave form and a frequency between 50 Hz and 70 Hz.


    Testing of Insulated Enclosures:

    For enclosures made of insulating material, an additional ¬dielectric test shall be carried out by applying a test voltage between a ****l foil laid on the outside of the enclosure over openings and joints, and the interconnected live and exposed conductive parts within the enclosure located next to the openings and joints. For this additional test, the test voltage shall be equal to 1.5 times the values indicated hereafter.

    External Operating Handles of Insulating Material:

    In the case of handles made of insulating material, a dielectric test shall be carried out by applying a test voltage equal to 1.5 times the test voltage indicated hereafter between the live parts and a ****l foil wrapped round the handle. During this test, the frame must not be earthed or connected to any other circuit.

    Value of the Test Voltage:

    The value of the test voltage shall be as follows:

    RATED INSULATION VOLTAGE DIELECTRIC TEST
    VOLTAGE
    (a.c.)
    (r.m.s-l

    Up to 60 1000
    60 to 300 2000
    300 to 660 2500
    660 to 800 3000
    800 to 1000 3500
    1000 to 1200* 3500

    *for d.c. only

    For control circuits and auxiliary circuits which are indicated by the manufacturers as unsuitable for connection to the main circuit:

    Where the rated insulation voltage does not exceed 60V, the dielectric test voltage shall be 1000V.

    Where the rated insulation voltage exceeds 60V, the dielectric test voltage shall be twice the rated insulation voltage plus 1000V.

    Results to be Obtained:

    The test is considered to have been passed if there is no puncture or flash-over.


    C. Verification of the Short-Circuit Strength:.

    Testing:

    The panel or its parts shall be set up as in normal use. Except for tests on the busbars and depending on the type of construction of the panel it will be sufficient to test a single functional unit if the remaining functional units are constructed in the same way and cannot affect the test result. The tests shall be carried out as per relevant clauses of IEC standards.

    Results to be Obtained:

    After the test, the conductors shall not show any undue deformation. Also, the insulation of the conductors and the insulating parts shall not show any s-i-gns of deterioration.

    The earth fault indicating fuse shall remain intact. There shall be no loosening of parts used for the connection of conductors. The effectiveness of the protective conductors ensuring protection against electric shock in case of a fault shall not be impaired. Deformation of the enclosure is permissble to the extent to which the degree of protection is not impaired and the clearances are not reduced to values which are less than those specified. The apparatus incorporated in the panel shall be in a condition as prescribed in relevant specifications.

    D. Verifications of the Effectiveness of the Protective Circuits:

    1. Verification of effective connection between the exposed conductive parts of the panel and the protective circuit.

    2. It shall be verified that the different exposed conductive parts of the panel are effectively connected to the protective circuit.

    3. A measurement may be carried out to verify that the resistance between the terminal for the incoming protective conductor and the relevant exposed conductive part of the panel is sufficiently low.

    E. Verification of the Short-Circuit Strength of the Protective Circuit:

    1. A single phase test supply shall be connected to the incoming terminal of one phase and to the terminal for the incoming protective conductor. When the panel is provided with a separate protective conductor, the nearest phase conductor shall be used. For each representative outgoing unit, a separate test shall be made with a bolted short-circuit connection between the corresponding outgoing phase terminal of the unit and the terminal for the relevant outgoing protective conductor.


    2. Each outgoing unit on test shall be provided with that protective device of those intended for the unit which lets through the maximum values of peak current and I (sq. ) x t. The test may be made with the protective device located outside the panel.

    3. For this test, the frame of the panel shall be insulated from earth. The values of prospective current and voltage used shall be the single-phase values derived from the three-phase short-circuit strength of the pane

    4. Results to be Obtained:

    The continuity and the short-circuit strength, of the protective circuit, whether it consists of a separate conductor or the frame, shall not be impaired. Besides visual inspection, this may be verified by measurements with a current in the order of the rated thermal current of the relevant outgoing unit.

    Notes:

    1. Where the frame is used as a protective conductor, sparks and localized heating at joints are permitted, provided they do not impair the electrical continuity, and ¬provided that adjacent flammable parts are not ignited.

    2. A comparison of the resistance, measured before and after the test, between the terminal for the incoming protective conductor and the terminal for the relevant outgoing protective conductor gives an indication of conformity with this condition.

    G Verification of Clearances and Creepage Distances:

    It shall be verified that the clearances and creepage distances comply with the values specified in relevant IEC standards. If necessary, these clearances and creepage distances shall be verified by measurement, taking account of ooss'ble deformation of parts of the enclosure or of the internal screens, including any possible changes in the event of a short-circuit. If the panel contains withdrawable parts, it is necessary to verify that both in the test position and in the disconnected position the clearances and creepage distances are complied with.


    H. Verification of Mechanical Operation:

    This type test shall not be made on such devices of the panel which have already been type tested according to their relevant specification provided their mechanical operation is not impaired by their mounting. For those parts which need a type test, the satisfactory mechanical operation shall be verified after installation in the panel. At the same time, the operation of the mechanical interlocks associated with these movements shall be checked. The test is considered to have been passed if the operating conditions of the apparatus, interlocks, etc., have not been impaired and if the effort required for operation is practically the same as before the test.

    J. Verification of Degree of Protection:

    The degree of protection provided shall be verified in accordance with IE 529.

    Routine Tests:

    Routine tests are intended to detect faults in materials and workmanship they are to be carried out on every panel after its assembly or on each transport unit. The manufacturer shall declare the type of test equipment to be used and the Engineer will require a testing authority's certification to the accuracy of the test equipment.

    Routine tests shall include:

    A) High tension flash tests at 2-5 kV for one minute between all poles/neutral and earth.

    B) Injection test. Primary injection (whole current).

    The following information to be supplied by the manufacturer:

    - The manufacturer's name or trademark. (The final assembler of the switchgear is deemed to be the manufacturer).

    - Type designation, serial or identification number making it possible to obtain relevant information from the manufacturer.

    - Type of current (and frequency in the case of AC).

    - Rated operated voltage.


    - Rated insulation voltage.

    - Rated voltage of auxiliary circuit.

    - Limits of operation.

    - Rated current of each circuit.

    - Short circuit strength (ISC).

    - Degree of protection.

    - Measure for the protection of persons.

    - Service conditions for indoor use, outdoor use for special use, if different from usual service conditions.

    - Dimensions (height x length x depth).

    - Weight.

    - operation and maintenance manuals to enable site erection to be carried out and spares obtained.


    - END OF SECTION -

  3. #3
    V.I.P Member الصورة الرمزية رائد قوجا
    تاريخ التسجيل
    Feb 2008
    الدولة
    iraq
    المشاركات
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    رد: مطلوب مواصفة لوحة توزيع ضغط منخفض رئيسية لمبني

    شكرا بلرك الله فيك

  4. #4
    Junior Engineer
    تاريخ التسجيل
    Jul 2006
    الدولة
    Egypt
    المشاركات
    122

    رد: مطلوب مواصفة لوحة توزيع ضغط منخفض رئيسية لمبني

    السلام عليكم ورحمة الله وبركاته
    مهندس وجدي جزاكم الله خيرا
    وارجو ان كان متوفر لديكم توصيف باللغة العربية موافاتنا به
    وشكرا

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