TECHNICAL SPECIFICATION FOR LOW VOLTAGE SEGREGATED SWITCHBOARDS FOR MAIN DISTRIBUTION AND INTERNAL INSTALLATION -2- INDEX TABLE OF CONTENTS 1. SWITCHBOARD MAIN FEATURES 2. STANDARDS AND PRESCRIPTIONS 3. INTERNAL ARC (Optional) 3.1 Internal arc withstand rated values 4. MAIN FEATURES 4.1 Metal frame 4.2 Switchboard basic configuration 4.3 Bus bar area 4.4 Equipment area 4.4.1 Fix modules 4.4.2 Withdrawable modules 4.5 Power cables area 4.6 Instrumentation compartment 4.7 Equipment segregation 4.8 Accessibility 4.9 Switchboard earthing system 4.10 Power units connections 4.10 Interlocks 4.11 Painting 4.12 Designs upon request 5. EQUIPMENTS 5.1 Circuit-breakers 5.1.1 General features 5.1.2 Types 5.1.3 Design 5.1.4 Protection devices and measurements 5.1.5 Operating mechanism 5.2 Contactors 5.3 Switch-disconnectors 5.4 Metering devices 5.4.1 Transformers 5.4.2 Sensors 5.5 Auxiliary circuits 5.6 Auxiliary relays 6 PROTECTION AND CONTROL DEVICE 6.1 Circuit breaker 6.2 Drawers 6.3 Automatic network-unit transfer 6.4 Switchboard microprocessor-based multifunction device (MMD) 7. SWITCHBOARD ACCESSORY SELECTION 7.1 Terminals 7.2 Identification plates 8 SUPERVISION AND REMOTE CONTROL (option) 9. ASSET MONITORING (option) 10. TESTS AND CERTIFICATIONS -3- These technical specifications aim to define the project main prerequisites, the testing procedure and the provision of low voltage switchboards for the plant. All low voltage Switchboards / MCC shall be of the intelligent type and shall consist of independent and modular modules divided into cells, allowing enlargement on both sides. 1. SWITCHBOARD MAIN FEATURES - Rated insulation voltage : 1000V ac / 1500V cc - Rated voltage : 690V ac – 750Vdc - Rated impulse withstand voltage : up to 12kV - Overvoltage Category : II / III / IV - Frequency : 50/60Hz - Phase number :3+N - Rated voltage for auxiliary circuits : 230V ac - Rated voltage for protection relay : 24V dc - Industrial frequency test voltage for power circuits : 2.5kV/1 min - Industrial frequency test voltage for auxiliary circuits : 2kV/1 min - Rated short time withstand current for 1" : 100 kA - Rated peak withstand current : 250 kA - Internal arc withstand (Option) : up to 65 kA x 0,3s - Main bus bar rated current : up to 6300A - Distribution bar rated current : up to 2000A - Horizontal earthing bus bar cross-section : 200 sqmm min - Auxiliary circuit lead cross-section : 1.5 sqmm (signaling control) : 1.5 sqmm (voltmeter) : 2.5 sqmm (ammeter) - Power supply : from bottom / from top - Output : from bottom / from top - Installation : indoor - Designed temperature : 35° C - Segregation form : up to 4 - Degree of mechanical protection : Min IP 30 – Max IP54 2. STANDARDS AND PRESCRIPTIONS - Switchboard CEI 17.13/1 CEI EN 60439-1 IEC 60439-1 DIN VDE 0660 part. 500 BS 5846 UTE 63-412 - Circuit Breakers IEC 60947-2 - Switch disconnectors Norma IEC 60947-3 - Protection ratings Norma IEC 60529 - Internal Arc withstand tests Technical Report IEC 61641 -4- Standards and regulations laid down by Italian Legislation relating to accident prevention and EC Directives shall be complied with. 3. INTERNAL ARC (Optional) 3.1 Internal arc withstand sated values 50KA - Reference Technical Report Technical Report IEC 61641 (Criteria 1-5) - Rated voltage: 690 V - Expected arc withstand current: 50 kA - Expected arc time: 0,3 s Internal arc withstand rated values shall be ensured in any module or cell of the switchboard. 65KA - Reference Technical Report Technical Report IEC 61641 (Criteria 1-5) - Rated voltage: 690 V - Expected arc withstand current: 65 kA - Expected arc time: 0,3 s Internal arc withstand rated values shall be ensured in any module or cell of the switchboard. 100KA - Reference Technical Report Technical Report IEC 61641 (Criteria 1-5) - Rated voltage: 400 V - Expected arc withstand current: 100 kA - Expected arc time: 0,3 s Internal arc withstand rated values shall be ensured in any module or cell of the switchboard. -5- 4. MAIN FEATURES Main features include structural, mechanical protection, segregation, device accessibility, safety features and setting up of electrical connections inside switchboards. 4.1 Metal Frame Switchboards shall be made up of many successive vertical modules, so called panels, attached one another by means of bolts. In this way a frame to be lifted by special eyebolts will be created. The frame shall use rigid seal screw/bolt couplings (Eslock). This won’t require any future inspection or maintenance operation. Each panel shall be made up of an indeformable metal frame, with each frame made up of steel channels, provided with 25 mm spaced holes according to DIN 43660 Standards. The frame shall be totally enclosed in metal sheet, sides and top included. The front of the switchgear, that can be single or double, shall be made with hinged doors and equipped with a single keylock. Closing panels and sheets shall be equipped with one or more ventilation grids, so as to allow ventilation according to the degrees of protection. The degree of mechanical protection for guarding against foreign material shall be suitable for the installation environment. The above degree of protection shall be at least IP30 when the panel is closed. The switchboards shall allow future extension on both sides; this won’t require any special change or modification on the existing switchgear. The switchboards shall be provided with basic structures. The minimum Alu-Zinc (or similar material) structural work thickness is: - 20/10 mm for the main frame - 15/10 mm for the front panels 4.2 Switchboard basic configuration The switchboard basic configuration includes: - Bus bar area (main and distribution bus bars) - Equipment area - Power Cable area (inlet and outlet cables) - Auxiliary equipment including wiring 4.3 Busbar Area Main busbar are locate in the rear part of the switchgear; it shall be possible locate the busbar system in upper or lower position depending the cable incoming - outgoing layout, or have a double busbar system. Distribution bars shall be rectangular and treated (if necessary); shall have vertical disposition. It shall be possible to have different configuration or segregation in the same column -6- Busbar area (distribution and main) shall be segregated from equipment area with metallic or plastic partitions in order to reduce the effects and the propagation of faults. Where possible on the distribution bar extra insulation has to be provided in order to reduce the possibility to have an internal arc. The access to the main busbar for panel joint must be realize from the front of the cubicles Both switchboard ends can be later extended. This won’t require any special change or modification on the existing switchgear The bus bar will be sized so as to sustain the dynamic limit current and the symmetrical short circuit current for 1 second. Busbars shall lock with Eslock screw and bolts so further maintenance or closing torque control will not be needed. 4.4 Equipment area Thanks to the module structure, with its 25 mm spaced hole posts, different size modules can be put into the same column. 4.4.1 Fix Modules High performances compartment (typically Incoming & Bus Section) shall have fix connection to the busbars. Switch disconnectors (up to 3150A), MCCB (up to 1600A) and ACB (up to 6300A) can be installed in fixed, removable or withdrawable version. Cubicles with Air Circuit Breakers shall contain only one breaker located in central position; upper part shall be dedicated to low voltage equipment compartment. Soft Starter and variable speed drivers shall be installed with fix execution. 4.4.2 Withdrawable modules The withdrawable module technique as well as the mechanical design is based upon the standard grid dimension of E = 25 mm. The standard grid dimension of the withdrawable modules is 6E = 150 mm. The units comprise the withdrawable module and the frame mounted compartments. They are standardized for the sizes 6E/4, 6E/2, 6E, 8E, 12E, 16E, and 24E. For the size 6E/4 there will be 4 modules and for the size 6E/2 there are 2 modules in a horizontal arrangement at a width of 600 mm; it will not be possible to mix then in the same horizontal arrangement (Es n°1 6E/2 + n°2 6E/4 = Not possible). Modules full size 6E - 24E require the total equipment compartment width of 600 mm. Empty spaces, the area for the control cable trough at the cubicle top and the area for the PE/N bars at the cubicle bottom are provided with hinged sheet metal covers. With the module completely removed from the switchboard, the protection degree IP2X between the module cell and the busbar compartment shall be guaranteed without shutters or similar devices Full size drawers (6E – 24E) shall be complete metallic while the drawers 6E/4 and 6E/2 can be plastic. Drawers shall have an operating handle to control interlock, positions and operations; it shall be possible to lock the handle in safety positions with padlocks (minimum 3 padlocks are required) -7- The drawers shall have the following status Condition Drawer position Power and auxiliary circuits ON, Power and auxiliary circuits In cubicle Operating position connected OFF No-operating position Power and auxiliary circuits In cubicle Possibility to lock it; min 3 disconnected padlocks TEST Test position Power circuit disconnected and In cubicle Possibility to lock it; min 3 auxiliary circuits connected padlocks DISCONNECTED Isolated position Power and auxiliary circuits are In cubicle Possibility to lock it; min 3 disconnected padlocks MOVING POSITION Power and auxiliary circuits In cubicle / Removed Withdrawn position disconnected Drawers shall be equipped with status signaling leds as following - Running (green) - Stop (red) - Fault (yellow) - Ready (green) If need shall be possible to change signal/status associated to each led Control terminal block, and control cables, shall be located in the dedicate compartment segregated from the power cables. All the drawers of the MCC section has to be equipped with sensor for current and voltage measuring. To guarantee the efficiency of the drawers and the correct insertion Temperature monitoring on the power contacts of the withdrawable units shall be provided Withdrawable solution shall guarantee fast reply of the drawers when the switchgear is on service without disconnecting other drawers and without create safety risk for the operator. It shall be possible change the size/dimension of drawers of the same column depending from the needs; it shall be possible do it quickly without disassembling the structure of the cubicle and working in safety conditions also with the cubicle energized. 4.5 Power cables area It shall be a dedicate area for the power cables with minimum width of 300mm in order to guarantee: - Segregation from all the other operation compartments and auxiliary cables - Cable insertion from top/from bottom - Accessibility for the installation and further extensions 4.6 Instrumentation compartment It shall be a dedicate compartment for the control instrumentation with minimum width of 300mm in order to guarantee: the segregation from all the other operation compartments -8- 4.7 Equipment segregation For operation and safety reasons, whenever possible the vertical panels shall be divided into modules by means of metal plates, so as to segregate the main equipments (IP20 degree of mechanical protection). Particularly, the following segregations shall be provided: - instrumentation compartments - compartment with power equipments - busbar compartments - Power cables In this case segregation shall allow: - Module access, preventing any accidental contact with the bus bars or live parts. Segregation shall always comply with the required segregation form. 4.8 Accessibility You shall be able to carry out all everyday operations from outside the switchboard. Access for maintenance and cable termination shall be from the front of the switchboard / MCC. Power cable compartment and auxiliary cable compartment should be clearly separated and access should be protected by separate doors. When requested shall be possible install the switchgear against the wall; it means that all the operations and access to the equipments shall be possible from the front. 4.9 Switchboard earthing system Inside the switchboard there shall be a copper earthing bus bar, securely bolted to the metal frame. This bus bar shall have a 200 sqrmm minimum cross-section, or a correspondent cross-section as required by the switchboard short circuit withstand Standard. The whole frame and structural work shall be securely fixed by means of screws, in order to provide good contact between the parts. The doors including instruments shall be connected to the frame of the cubicle with a copper flexible plait minimum section 16sqrmm. During the withdrawing phase, pliers touching a copper plate and directly connected to the earthing bus bar will keep withdrawable air circuit-breakers earthed. All non-double or non-reinforced insulated main components shall be earthed. Both grounding bus bar ends shall be provided with holes for connection to the switchboard grounding system (earthing cable minimum section 16 sqrmm). 4.10 Power units connection -9- The main connections inside the switchboards shall be cable or bus bar connections, according to the actual power. Special insulating stands make these bus bars rigid. The bus bars shall be made up of electrolytic copper and shall be sized according to the related equipment rated current values. The 4-pole system shall be provided with a neutral bus bar, sized according to a load value not less than 50% of phase load. Moreover, the bus bars and their stands will be sized so as to sustain electrodynamic stress provoked by short circuit peak current. Power connection cables will be double insulated single-core cables with Uo/U=1.8/3kV rated voltage. These cables are flame-retardant, they have high mechanical strength and a treated copper core. 4.11 Interlocks The switchboard shall be provided with all interlocks necessary for preventing wrong operations affecting equipment efficiency and reliability, as well as the safety of the personnel in charge of plant operation. Air Circuit Breakers shall be equipped with mechanical interlocks to prevent incorrect operations like: - Any operation of the breaker if main contacts are welded after a short circuit. - Insertion or extraction of the breaker with power contact closed. - Opening of the shutters when the breaker has been removed from the cubicle. All the drawers “Full size” have to be equipped with safety interlock to prevent the fall of them during the extraction. On the Drawers shall be possible to with safety interlock to prevent to energize a feeder if the module inserted is not the correct one; the interlock has to work also in case the module has different scheme (Dol vs Star-Delta) but same mechanical dimensions 4.12 Painting In order to guarantee the highest wear resistance, all module metal panels shall be specially treated and coated with paint as follows: - Degreasing - Pickling - Bonderizing - Passivation - Drying - Oven epoxy enamel painting External surfaces shall have a fine orange peel texture. The finishing minimum thickness shall be 60 micron. 4.13 Design upon request - 10 - On request shall be possible to have anti-seismic & anti shock version according IEC 60068-2-6 / EN60068-2-6 (vibrations) and IEC 60068-2-27 / EN 60068-2-27 (single shock) according the following performances: - Anti-seismic execution (0,7 g) - Anti-shock execution(15 g) Depending on the electrical characteristics of the switchgear it shall be possible to have the following configurations: - Back to Back (with two independent busbars systems) - Duplex (with two independent busbars systems) 5. LOW VOLTAGE EQUIPMENTS The main equipments installed inside the switchboard shall be suitable for the project features, as stated in the wiring diagrams. These equipments shall comply with the following prescriptions. 5.1 Circuit-breakers 5.1.1 General features Circuit-breakers with the same load and features shall be totally interchangeable in order to provide maximum operation. For this reason, input and output circuit-breakers shall have the same breaking capacity. The coupling and the output circuit-breaker shall have the same features. 5.1.2 Types Transformer and generator set output circuit-breakers (current above 1250 A), together with their couplings, shall be air circuit-breakers. Input circuit-breakers shall be moulded-case circuit-breakers with current up to 1250 A. They shall be air circuit-breakers with current above 1250 A, unless otherwise specified in the single wiring arrangement. On the other hand, circuit-breakers with current below or equal to 630 A can be modular circuit-breakers. All Air circuit-breakers shall be provided with the fixed part made in metal. The circuit-breakers shall range from 800 A to 6300 A (effective in the switchgear) and shall have the same depth and height. 4-pole circuit-breaker neutral rating shall be 50% of phase rating. This rating can be changed to 100% for currents up to 3200 A. For higher current values the neutral rating can be set at 100% only with full size circuit breakers. For the sake of safety, circuit-breaker power circuit and control circuit shall be totally separated. Moreover, these circuit-breakers shall provide double insulation and phase segregation, and allow arc chamber and main contact inspection. In the case of current less than 4000 A, selective circuit-breaker Icw (short time withstand current) (1s) shall be at least 75% of Icu (ultimate breaking capacity under short-circuit). Moulded case circuit-breaker auxiliary and power circuits shall be electrically segregated. These circuit-breakers shall allow installation and inspection from the switchboard front side without removing the front panel. Power circuits and breaking chambers shall in turn allow inspection by removing the front panel for contact wear checking. After switchboard installation, all other devices can be assembled without any basic circuit-breaker and switchboard component replacement. In the case of limiting devices, Ics (rated ultimate breaking capacity under short-circuit) and Icu (ultimate breaking capacity under short-circuit) shall be 200 kA at 400 V. Modular circuit-breakers shall be provided with a flame-retardant enclosure certified to UL94 yellow card for maximum flame-retardant rating (V0 grade for 1.6 mm thickness) and they shall successfully pass the Darmstadt Institute inspection. Fume opacity and gas non-toxicity shall also - 11 - have been assessed. The circuit-breakers shall have a self-supporting structure, that is without any mechanical constraints between the enclosure and the internal mechanical components. All circuit-breakers can be fitted with the necessary locks and shall be provided with the accessories mentioned below. Withdrawable circuit breakers shall be "withdrawn" using the special tool provided. The switchboard panel shall be closed to ensure operator's safety. 5.1.3 Design All Air circuit-breakers shall be withdrawable. All withdrawable circuit-breakers can be operated as follows: - Racked-in: main power and auxiliary circuits are connected - Test: main circuits are disconnected while auxiliary circuits are connected - Racked-out: main and auxiliary circuits are disconnected 5.1.4 Protection devices and measurements All circuit-breakers shall be provided with maximum current protection for three-phases and for the neutral, when necessary. Particularly: • Air circuit-breakers shall be provided with microprocessor-based overcurrent releases. Circuit- breaker releasing behavior is based on the actual fault current. AIR circuit-breakers need no auxiliary power supply. The above releases shall have the following features: L protection range I1 = 0.4 1 In Tint t1 = 3s 144s with a fault current If= 3 I1 S protection range I2 = 0.6 10 In Tint t2 = 0.05 0.8 s with a fault current If= 10 In time-dependent/time-independent I protection range I3 = 1.5 15 In G protection range I4 = 0.2 1 In (I4 = 0.1 1 In with curve t=k/I^2 and external power supply 24V) Tint t4 = 0.1 1s with a fault current If= 4 In time-dependent/time-independent In case of short-circuit and constant specific let-through energy, it is possible to select the area so as to minimize non-operation condition. Air circuit-breaker releases can be fitted with an externally-powered dialog unit. On the switchboard front side there are mechanical dimension (springs, open, close, contact wear, etc.) and current values. • Moulded-Case circuit-breakers with continuous rated current above 160 A shall be fitted with electronic releases. In the case of limiting devices with short circuit breaking capacity of 200 kA at 400 V, Moulded-Case circuit-breakers with continuous rated current equal or above 250 A shall be provided with microprocessor-based overcurrent releases. Circuit-breaker releasing behavior is based on the actual fault current. Moreover, circuit-breakers with rated current above 400 A shall belong to class B, according to EN 60947-2 Standard. The above releases shall have the following features: - 12 - L protection range I1 = 0.4 1 In Tint t1 = 3s 18s at 6 I1 S protection range I2 = 1 10 In Tint t2 = 0.05 0.5 s at 8 In time-dependent/time-independent I protection range I3 = 1.5 12 In G protection range I4 = 0.2 1 In time-dependent/time-independent These protection relays shall be power-supplied by current transformers located inside the circuit- breaker, except measurement and dialog function modules, which can have an auxiliary power supply. In the case of moulded-case circuit-breakers with In equal or above 630 A, measurement and dialog function modules shall be installed inside the protection relay, as specified below. In the case of moulded-case circuit-breakers with In below 630 A, the modules can be installed separately (dimensions do not vary) and connected to the circuit-breaker by means of a special supply cable providing communication with the protection relay. Air and moulded-case circuit-breaker dialog function can be activated by means of the protection device. This function shall allow the fieldbus (RS-485 output with maximum baud rate of 19200) to receive all measurement information on the control and/or protection device, as well as all information concerning both circuit-breaker and release condition (prealarm/alarm/tripped relay). It shall also be able to receive from the central system all release parameters, as well as circuit-breaker opening and closing controls. Microprocessor-based protection relays shall comply with IEC 801/3 Standards concerning protection device electromagnetic immunity. • Moulded-Case circuit-breakers with rated current below 250 A shall be fitted with thermomagnetic overcurrent releases. The above releases shall have the following features: thermal protection range Ith = 0.7 ÷ 1 In (time-dependent) magnetic protection range 10 Ith (or 5 Ith) • Modular circuit-breakers shall be fitted with thermomagnetic protection relays. • If required by single wiring arrangements, both ordinary thermomagnetic moulded-case circuit- breakers and modular circuit-breakers shall be provided with residual current protection. In the case of moulded-case circuit-breakers fitted with a thermomagnetic release, the residual current protection can be either non-selective or selective. The following five options are available (see single wiring arrangements): a) Instantaneous residual current release for side-by-side mounting on 4-pole circuit-breakers and 125 A maximum rated current, with release thresholds IDn = 300 - 500 mA and class AC (suitable for simple harmonic current), fitted with a test button. The release acts directly on the releasing mechanism by means of a piston, and it is attached to the circuit-breaker body by means of a special linkage, which makes the circuit-breaker body integral with the residual current protection; b) Non selective electronic residual current release, with 0.03 - 0.1 - 0.3 A residual current adjustment. It can either be installed side by side or under the 4-pole moulded-case circuit-breakers. It can be single phase-powered. - 13 - c) Selective electronic residual current release, with 0.03 3 0 A residual current adjustment. Its operating time ranges from 0 and 1.5 s. It can either be installed next or under the 4-pole moulded- case circuit-breakers. It can be single phase-powered. d) Selective switchboard electronic release, having the following features: IDn1 = 0.03 ÷ 0.5 A with Tint = 0 ÷ 5 s IDn2 = 1 ÷ 30 A The pre-alarm threshold can be set from 25 to 75% of IDn matchable to many toroidal transformers (either closed or allowing opening) with a diameter ranging from 60 to 210 mm e) Residual current release, which is or can be built-in side by side the modular circuit-breaker body. The release is fitted with special locks in order to prevent any mismatching between the residual current release and lower rated current circuit-breakers. The two bodies are made integral by a special linkage. 5.1.5 Operating mechanism Air circuit-breaker operating mechanism shall be stored energy type, operated by pre-loaded closing springs. These springs are either automatically (by means of a motor) or, if necessary, manually loaded. Closing and opening operations shall be operator-free. This operating mechanism is automatic-release type, in order to provide main contact opening even if the opening command is given when closing operation is taking place. Starting with the springs loaded, you shall be able to perform the following cycle without any reloading necessary: - Starting with the circuit-breaker open and the springs loaded: closing-opening - Starting with the circuit-breaker closed and the springs loaded: opening-closing-opening Moulded-Case circuit-breaker operating mechanism shall be direct action motor type during opening and closing operation in the case of small circuit-breakers (In below 630 A). It shall be stored energy type, operated by pre-loaded closing springs in the case of big circuit-breakers (In equal or above 630 A). 5.2 Contactors Contactors having same load and features shall be totally interchangeable and shall allow installation of auxiliary contacts (that is subsequently insertable/withdrawable additional locks). Accessories shall be installed on the front side and shall be interchangeable according to the various contactor sizes, in order to reduce maintenance time. Terminal marking shall comply with EN 50012 Standard. Contactors shall either be wall or rail mounted (35 mm DIN rail). Thermal relays shall either be directly installed on the contactors or separately installed using a special tool, when necessary. They can be provided with: - Auxiliary contacts: - 1 NO auxiliary contacts 97 - 98 - 1 NC auxiliary contacts 95 - 96 - Test button - Automatic / manual reset selector Thermal compensation against temperature change is achieved by means of a bimetallic strip. 5.3 Switch-disconnectors - 14 - If required by single wiring arrangements, switch-disconnectors - built from the above-mentioned circuit-breakers - are available for the switchboard. These switch-connectors shall provide the same high strength and reliability, as well as be fitted with the locks as per Section 4.9.3 and with all necessary accessories. Switch-disconnectors shall have a closing capacity of no less than 3 kA. Alternatively, the switch-connectors shall have a rated current ranging from 25 A to 3150 A. They shall be available both as 4-pole or 3-pole types. Inside the switchboard, only those switch- disconnectors with rated current equal or above 800 A will be used. The switch-disconnectors are motorized, i.e. remotely controllable, they are fitted with the locks as per Section 4.9.3 and with all necessary accessories. Switch-disconnectors shall have a closing capacity of no less than 80 kA. 5.4 Metering devices 5.4.1 Transformers Current transformers shall be air-insulated ones and have the following features: - Maximum insulation voltage 690 V - Test voltage at 50 Hz/1 s 3 KV - Rated secondary current 1A - Accuracy class 10 VA for class 0.5 Current transformers shall have the same features as for current transformers, only with 400/100 V ratings. 5.4.2 Sensors All the MCC drawers has to be equipped with current and voltage sensors. 5.5 Auxiliary circuits Auxiliary circuits will mostly be made of 1.5 sqmm min. cross-section single-core cables, Uo/Uc=450/750V rated voltage. These cables are flame-retardant and connect equipments and terminal boards. At both ends of each lead there are two plastic identification rings; these rings are marked with the same lead identification number found in the diagram. Auxiliary leads will be driven through wide-sized closed lead holders, which are able to house at least further 50% cables. 5.6 Auxiliary relays If provided, auxiliary relays shall be installed on a special plate inside the instrument modules. Auxiliary relays multiply the number of contacts and enable further functions. 6. PROTECTION AND CONTROL DEVICE 6.1 Circuit breaker Circuit breakers protection and metering function has to integrated in to the breakers; see chapter 5.1.4 6.2 Drawers No separate protection panels are provided. All protection relays shall be programmable microprocessor, multi-characteristic, multi-function type. - 15 - The MCC protection relays shall use smart sensor measurements in contradiction to the traditional transformer measurement technique. Besides current and voltage measurement, the system shall be capable of providing temperature monitoring on the power contacts of the withdrawable units. For MCC part protection relays shall be located in the Auxiliary compartment. The setting of protection relays shall be via a dedicated port and laptop for uploading and downloading settings and interlocking using proprietary software. For MCC part Interface should be provided a touch screen for each bus section where all information will be collected. All relays shall have communication facilities to allow communication with the DCS through serial links. RS485 peer-to-peer communication (max 10MBps ) with a deterministic Master-Slave Real- time protocol will be used All data will be sent to DCS trought a device that provides connection and data filters for communication of essential information to higher-level systems. This device will contain time server / client functionality as an option to provide accurate time signal to all Motor Control Units. The time stamp of alarm and events is distributed to higher level Process Control System via OPC. Overcurrent relays shall incorporate facilities for selecting different types of inverse definite minimum time (normal, very and extremely) and definite time characteristics, and high-set instantaneous elements which can be set on infinity if not required. The following protection and warning functions shall be provided: - TOL (49) - Phase loss (46) - Phase current unbalance (46) - Stall (51LR) - Underload, no load (37) - Undervoltage (27), Underload cosphi (37) - Temperature PTC (49) - Earth leakage, min setting 2% of rated current (50G/51G) - Start limitation (66) - Failsafe - Contact temperature supervision The following measurement shall be provided: - Status - Phase Current (absolute and %) - Thermal Capacity - Time to trip - Phase Voltages - Power Factor - Active, Reactive, Apparent Power - Earth Fault Current - Frequency - Outgoing line temperature Diagnostic parameters or information available for DCS: - Time to overload trip - Percentage of thermal capacity utilized - Cause of previous trips - Trip levels - Warning levels - Time delays - Inputs and Outputs and status indication - Field I / O status such as ESD etc. 6.3 Automatic network-unit transfer - 16 - If "Automatic Network-Unit Transfer" is specified on the front panel drawing, the switchboard shall be fitted with an automatic network-unit transfer device. In this case, the same indication is to be found in every single wiring arrangement, next to 2 interlocked circuit-breakers to carry out the transfer. In order to carry out automatic transfer, both circuit breakers shall be fitted with opening/closing coils and shall be motorized. The automatic network-unit transfer device shall comprise two undervoltage relays (one on the network side and the other on the unit side), a PLC controller, a 4-position circuit-breaker (Aut., Emerg., Grid, Off), auxiliary relays and anything else needed to allow the following operation modes: Automatic operation mode: Turning the switch to the automatic position, standard line power supply is guaranteed and automatic transfer is enabled. While in the standard operation mode (standard supply voltage), the network circuit-breaker (Q2) is closed while the unit circuit-breaker (Q1) is open. In case of no standard supply voltage, a command for diesel generator turning on is issued and Q2 opens. Q1 closes when the diesel generator steady RPM is reached (i.e. when the voltage value set on the undervoltage relay on the unit side is exceeded). When supply voltage to the standard supply line is restored, Q1 opens, Q2 closes and a command for diesel generator turning off is issued. This restores the standard operation mode. Emergency power supply line mode Turning the switch to the emergency position, emergency line power supply only is guaranteed, irrespective of any standard supply voltage present. Q2 opening (if the circuit-breaker is closed) and diesel generator turning on commands are issued. The Q1 closing command is issued when the diesel generator steady state is reached (i.e. when the voltage value set on the undervoltage relay on the unit side is exceeded). Standard power supply line mode: Turning the switch to the emergency position, standard line power supply only is guaranteed, irrespective of any standard supply voltage present. Q1 opening (if closed), diesel generator turning off (if turned on) and Q2 closing commands are issued. OFF position operation mode: Turning the switch to the OFF position, the closed circuit-breaker opens, the diesel generator is turned off (if turned on) and the PLC controller is disabled. Only circuit-breaker operated controls are active. 6.4 Switchboard microprocessor-based multifunction device (MMD) for circuit breakers If the switchboard is to be fitted with MMD provided manual circuit breakers (as per single wiring arrangements), the MMD device shall be an independent and flexible module. It shall encompass protection, measurement, diagnostic, monitoring, communication, and automation functions so as to enable overall switchboard control. The MMD shall be provided with: - Optically-insulated binary inputs - Binary outputs suitable for devices chosen by the user - Analog inputs for current and voltage detectors - Serial communication The MMD front panel shall be fitted with a backlit LCD display and with a number of pushbuttons in order to provide a complete and user-friendly man-machine interface (MMI). Furthermore, the - 17 - panel shall be fitted with auxiliary LEDs with protection and diagnostic-alarm functions. The LEDs shall also provide information about any MMD-connected external unit. Particularly, the alphanumeric display shall show both general information (external unit condition, alarms, protections, self-diagnosis, etc.) and the single wiring arrangement related to the plant area the MMD is in, displaying the real-time position of the module operating devices. The MMD shall provide any of following protections, conveniently selected according to specific plant requirements: (Identification codes complying with IEEE C37.2-1996 Standards) - 25 (Synchrocheck) - 27 (Undervoltage) - 32P (Active power directional protection) - 37 (Underload) - 46 (Unbalanced load) - 49 (Thermal image) - 50 (Maximum instantaneous current) - 50N (Instantaneous constant specific let-through energy) - 51 (Trip time independent on the current) - 51IDMT (Trip time dependent on the current) - 51START (Motor starting) - 51LR (Locked rotor) - 51N (Inverse time ground fault) - 51NIDMT (Trip time dependent on the constant specific let-through energy) - 59 (Maximum instantaneous voltage) - 59 (Trip time independent on the voltage, 2 protection thresholds) - 59N (Trip time independent on the residual voltage, 2 protection thresholds) - 66 (Number of startups) - 67 (Trip time independent on the directional current, 2 protection thresholds) - 67 (Trip time independent on the directional constant specific let-through energy, 2 protection thresholds) - 68 (Transformer protection) - 81 (Frequency-check) - 87 (Transformer and/or Motor Differential protection) The DMM shall provide any of following measurements, conveniently selected according to specific plant requirements: - Phase currents - Constant specific let-through energy currents - Phase voltage - Line voltages - Residual voltage - 3-phase current average values (1 to 30 minutes time interval), maximum value recorded - Active power - Reactive power - Power factor - Frequency - Active energy - Reactive energy - External-impulse evaluated energy (max. 15) - Operation hours -Transfer cycles - Sum of discontinued voltages Furthermore, the MMD shall have main automation functions. This will allow the user to carry out such maintenance work as line section earthing or load breakdown safely. - 18 - Particularly, the device shall "control" interlocks between different operating devices and disable operations not allowed according to plant type. The interlock logic can be tailored to each user's needs, simply changing the configuration software. The MMD can also be used when automatic and manual transfer between two functional output units is required. Transfer time can range between 190 and 300 milliseconds (circuit-breaker operation time included). In case of no network voltage or temporary undervoltage, the MMD shall automatically turn the motors off and eventually prompt their automatic turning on. The MMD can also provide logic-type protections, which can find and isolate the fault by opening as few circuit-breakers as possible. The latest 100 events shall be automatically stored, together with their acquisition time. Transferring of the related data to a central control system shall be allowed. The stored events can be any of the following: - Protection enabling and, if necessary, activation - Binary inputs and outputs status change - Local and remote controls - Circuit-breakers and switch- disconnectors status change - Central unit switching on/off - Any attempts to issue a command not allowed by interlocks -Diagnostic alarms Moreover, the MMD shall monitor and process the following parameters: - Unit self-diagnosis - Power relay contacts - Opening coil winding - Circuit-breaker opening/closing spring loading -Number of mechanical operations - Gas pressure Communication with a central control system shall be provided by a SPABUS or LON, or or MODBUS/TCPIP and/or RS485 or Profibus or IEC61850 Intefaces. Up to 2 different protocol can be used.. 48 or 230V DC auxiliary supply options are available. Power consumption cannot exceed 30W. 7. SWITCHBOARD ACCESSORY SELECTION 7.1 Terminals The terminal boards shall be modular attached to a section. The terminal isolation class shall comply with IEC 85. The terminals shall be made of high conductivity brass, copper or any other high conductivity material and shall be slackproof. The terminal boards shall be provided with special plates in order to isolate different circuits. 7.2 Identification plates Each equipment shall have a plate identifying the corresponding circuit. This plate is to be found on the switchboard near the equipment. Moreover, on each equipment shall be found a series of letters, corresponding to the wiring arrangement. The plates shall be attached by means of screws or adhesive. Indicating plates for signalling and control equipment shall be found on the module panels. - 19 - The equipments inside the modules shall be provided with adhesive plates. On the switchboard is to be found a metal plate specifying the manufacturer name, the relevant Standards, the switchboard type, the manufacturing date, the reference project number, as well as technical data including rated voltage, frequency main bus bar rated current and short-time short circuit current. 8. SUPERVISION AND REMOTE CONTROL (option) Generally two different communication channels will be supplied. First one will be used for Electrical Control system (ECS) and second one will be used for Distribuited Control Sytem (DCS) . Normally Incoming and Bus Tie (PC Section) will be connected to ECS via MMD relays using appropriate protocol like IEC61850 or as an alternative Profibus/Modbus. MCC section will be connected to DCS via Fielbus protocol like Profibus and/or Modbus. In case system requirements ask for connection of MCC part to ECS otpion of OPCserver connection will be use according to simplified scheme shown below. DCS ECS Operator WorkStation Workplace 10/100Base-T Control Network Fieldbus Connectivity Server Process Controller OPC Server Fieldbus Switchgear Control Network PC Section = Incoming/BUS Tie MCC Section= Outoing Feeder/Motors MCC MCC MCC PC Section Section Section Section Figure 1 System Architecture Furthermore it should be possible, in case of System specification requiring , to supply each Switchboard/MCC with a dual redundant Data Concentrator/Coupler either using fibre optic cables ‘daisy chained’ or dedicated switchgear bus to the feeders intelligent controllers and 10/100 Base-T Ethernet network to upper systems with OPC technology. The communication between the Data Concentrator and Motor Control Units utilises a real time, master-slave protocol running at 10Mbps, which continuously polls all the MCU; the total internal system response time has to be equal to 300ms or less The DCS shall use this highway for “ON / OFF” control of motors. The DCS shall use this facility for SCADA communications either using Profibus and dual highways or 10/100 Base-T Ethernet network with OPC technology. Each intelligent controller shall be provided with an always active ‘STOP’ feature located on the controller section and directly acting on contactor coil for ESD purpose. - 20 - Setting and interrogation of protection relays or integrated intelligent protection on circuit breakers such as ACB shall be via a dedicated port and laptop for uploading and downloading settings, data and interlocking programming using proprietary software. It shall be possible to control the motors either from individual local control stations and Unit Control Panels (UCP) or from the plant Distributed Control System (DCS). The switchboards shall receive 24V d.c. pulsed signals to start and stop motors from either the UCP and start and stop signals via a serial link from the DCS. Status signals (running, stopped, tripped and available) shall be made available for either the UCP or DCS, either via a serial link facility or 10/100 Base-T Ethernet network with OPC technology. The field control will consist of emergency stop signals only; if needed. However, a remote start facility (enabled by the DCS or UCP) will be provided for test purposes at the switchboard. If requested manual trip facilities shall be provided on the switchboard. These shall be operable in all operating conditions. Test facilities (start / stop), at the switchboard shall be provided so that testing of the motor control circuit is possible. Each motor starter will be provided with equipment to receive an emergency shut down signal from the plant Emergency Shut Down system (ESD). This signal will be in the form of a powered 24V d.c. signal (de-energised to trip). The connection of the individual relays shall be taken via protected wiring to a marshalling / terminal box located within the switchboard. In case of lost of communication between the Intelligent MCC and supervision system shall be possible to set the reaction (disconnect, do not disconnect) of each feeder according the plant philosophy. 9. ASSET MONITORING (option) The intelligent MCC shall be able to supply all the information required for Asset monitoring. The Asset monitoring shall be focus on improving the “on service” time of the plant reducing as much as possible the period of shut down for fault or for maintenance. Maintenance time shall be reduce as quantity and duration as much as possible; per each fault it has to be available a report showing all the data till the fault and has to be issue a “Work order” suggesting the possible actions to fix the problem. With all the information available and the history of the equipment per each fault shall be possible to evaluate if it’s better fix o replace the damage equipment. It shall possible to store the data in order to have the “history” of the plant; the system shall be fully scalable and shall be engineered to suit additional requirements. 10. TESTS AND CERTIFICATIONS Switchboard acceptance and general tests – according to CEI/IEC Standards - shall be carried out at the manufacturer's facility. The customer or a customer's representative must also be present. The manufacturer shall show to be ISO 9001-certified. A compliance certificate shall be provided, together with the general test report. At proposal stage, passing of the internal arc withstand test is stated - according to IEC 61641 Technical report- (I.A. switchboard). When placing an order, a copy of the test-passing certificate is provided (I.A. switchboard). A copy of the papers relating to the type tests prescribed by the Standards is available upon request. The papers relating to type and internal arc withstand tests shall be issued by internationally accredited laboratories.
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