3.5 POWER GENERATOR PLANT
3.5.1 GENERAL
3.5.1.1 DESCRIPTION OF WORK
Standby/emergency power plant installation comprises the following:
- Engine generating set(s), with associated auxiliaries, exhaust system, start-up system, cooling system, fuel system, batteries and charger etc.
- Fuel storage and transfer system
- Instrumentation, protection and control equipment
- Mains failure automatic transfer switch
- Interplant cabling and wiring
- Earthing.
3.5.1.2 STANDARDS
Equipment and component parts are to comply with ISO 3046, ISO 9001, ISO 8528, IEC 34, IEC 85 and CISPR, or equivalent NEMA, ANSI, IEEE and DIN Standards and recommendations of ABGSM (Association of British Set Manufacturers) where such standards meet with or supersede the ISO and IEC Standards.
3.5.1.3 EQUIPMENT DATA:
Submit for approval full technical data of equipment including, but not limited to, the following:
- General description and characteristics of engine generating sets standards with which components comply, site rating and overload capability, overall efficiency and fuel and lubricant consumption at 100%,75%, 50% and 25% of rated load
- Description and operating criteria of engine; type, model manufacturer, fuel and lubricating oil types and specific consumption, starting conditions and starting periods from cold to full-load pick-up, governor and response characteristics due to sudden load changes, super-charger, fuel injection system, cooling system and radiator, air filters, fuel filters, oil filters and pumps
- Description and operating criteria of generator, exciter and voltage regulator, with loading response and short-circuit characteristics, insulation, cooling and accessories Dimensions, weights and forces, mounting methods, vibration protection etc.
- Battery type, make, charge/discharge characteristics, capacity and constructional features
- Battery charger, method of charging, equalizing and trickle charging
- Fuel tanks, pipes and accessories; materials and construction
- Exhaust system and silencers; materials and construction
- Control instruments, protection, alarms, cut-outs, indicating lamps indicating instruments and all other devices or components
- Automatic transfer switch including technical data
- Calculated noise levels in dBA at typical points within engine room and at various locations outside the room at 7m.
3.5.1.4 ROUTINE TESTS
Fully assembled plant or equipment is to be tested at the factory, before shipping. Complete performance tests are to be carried out under site simulated conditions, in accordance with the Standards and as described in the Specification.
3.5.1.5 SHOP AND CONSTRUCTION DRAWINGS:
Submit drawings for approval including, but not limited to, the following:
- Certified manufacturers' dimensional drawings, templates and installation instructions for equipment and accessories, showing weights and distribution of forces, location and size of cabling (power and control), piping connections to equipment, and other pertinent data
- Plans and elevations of all equipment
- Separate unit wiring diagrams, schematics and inter connecting wiring diagrams
- Constructional details of bulk fuel storage tanks and daily service fuel tank, including outline drawings showing piping arrangements, connections and dimensions
- Complete execution drawings of associated auxiliaries
3.5.1.6 SPARE PARTS:
Provide manufacturer's recommended spare parts for 1000 hours of operation of the standby plant. Provide list of manufacturer’s spare parts for 2000 hrs operation together with current prices.
3.5.1.7 TOOLS AND INSTRUMENTS:
Provide tools and instruments required for normal routine inspection, testing, operation and general maintenance, as recommended by the manufacturer.
3.5.1.8 APPROVED MANUFACTURERS
Obtain standard generator sets (ENGINE/ALTER.) from one of the following:
Caterpillar/Caterpillar (U.S.A.)
MAN /AVK (Germany)
Cummins / STAMFORD (UK)
3.5.1.9 WARRANTY
Provide one year warranty from startup date for all the unit and accessories specified in this Section with no limit on the number of operating hours.
3.5.1.10 LOCAL REPRESENTATIVE:
Provide evidence that proposed equipment manufacturer has a locally established and authorized organization which can be called upon for professional advice and maintenance as may be required, and which can immediately supply spare parts to support day to day and emergency maintenance requirements. Failure to satisfy the Engineer may disqualify a manufacturer.
3.5.1.11MAINTENANCE CONTRACT:
Obtain an undertaking by the equipment manufacturer and his authorized local representative to provide an annual maintenance contract, available after substantial completion of the work, covering routine service and emergency service by trained employees, and to ensure supply of necessary standard spare parts.
3.5.2 PRODUCTS AND SYSTEMS
3.5.2.1 PLANT DESCRIPTION
GENERATOR SET ASSEMBLY:
Compact package type, with all equipment mounted on one rigid steel bed frame suitable for skidding. Radiator is to be mounted on the set or remotely as shown on the Drawings. Design is to permit easy operation, maintenance and repair.
VIBRATION REDUCTION:
Is to be achieved by appropriate design and careful balancing at factory. Compact set is to have approved antivibration isolators of steel spring between rotating equipment and bed-frame, limiting transmission of vibration to building to a maximum of 0.04 mm amplitude throughout the operating vibration frequency range.
NOISE REDUCTION:
Is to be achieved by approved methods at source of noise, the over all noise level is not to exceed 70dB at 7mt. at 50Hz. for residential areas.
EQUIPMENT RATINGS:
Are to be as shown on the drawings or the next higher standard ratings provided by the manufacturer. Ratings are to be net continuous output to consumer, excluding fan and any auxiliaries, auxiliary drives and losses, delivered at specified frequency, voltage and power factor and under worst climatic conditions on site at 50oC with derating charts from the manufacturer to prove it.
DIESEL GENERATOR SET
Engine & Alternator are to be supplied by the same manufacturer. Set is to be basically consisting of diesel engine, brushless synchronous generator with direct flexible coupling to engine and single or parallel control cubicle as required and shown on the Drawings.
GOVERNING:
Is to be class A1 to ISO 3046/IV or BS 5514, using (electronic) type governor with the specified limits of speed control.
STARTING AND STOPPING:
When in the automatic mode, the set is to start and stop automatically by a signal sensed through an auxiliary contact in the load transfer switchgear. The set is to stop after an adjustable cool-down period of 2 - 15 minutes.
DUTY:
Transient response charts (volts, secs -volts/Hz-...) must be submitted to the consultant to be approved.
Plant is to reach full speed within 15 seconds from start impulse and accept immediately 100% of net rated output (load being mixed, steady and inductive, with motor starting loads as shown on the Drawings). Transient voltage variation is not to exceed 7% under any step-load application for which the system is intended, up to full rated load, recovering to within +/-2% within a few cycles.
FAILURE TO START:
Should engine fail to start following a start impulse, the system is to come to rest for a few seconds. Two further starting attempts are to be automatically made with intermediate periods of rest not exceeding 20 seconds each. Should the set fail to start after three attempts, an alarm is to sound and a 'start failure' signal illuminate.
HAND OPERATION:
Is to be possible for testing or normal operation through a test/manual/off/auto selector switch.
3.5.2.2 EQUIPMENT AND ACCESSORIES
DIESEL ENGINE AND AUXILIARIES:
DESIGN:
Diesel engine is to be designed for type of load and application required. Engine and governor are to be selected to meet operating requirements and response specified.
ENGINE TYPE:
Compression-ignition type with direct injection, turbocharged for ratings over 100 kW, water cooled with air- cooled radiator, 4-stroke cycle, in-line or V- type cylinder arrangement, 1500 rpm, operating on No. 2 diesel oil, suitable for direct coupling to driven machine. Flywheel is to be suitably sized for type of service and constraints specified, capable of being rotated at 150% of rated speed without failure. Torsional vibration dampers are to be provided.
ENGINE RATING:
Is to be such that alternator can deliver net specified continuous rated output, and is to withstand 10% overload for one hour in twelve hours continuous operation at full load, with temperature rise not exceeding rise allowed by the Standards.
ACCESSIBILITY:
It is to be possible to
- Remove rocker-box covers without disturbing fuel injection pipes or other components
- Remove and replace pistons and piston rods, liners, big and smalend shells and caps without dismounting engine (presence of witness holes for maintenance & inspection).
- Bar engine over by hand for spill timing check and adjustment
MEASURING INSTRUMENTS:
Engine mounted instruments are to include, at least, a water temperature gauge, lubricating oil temperature gauge and pressure gauge, tachometer and running time meter. It is to be possible to measure, with extra instrumentation, coolant temperature at lower end of radiator. Instrument accesses are to be normally sealed by threaded blanking caps.
COOLING SYSTEM:
Engine is to be water cooled with gear-driven water pumps. System is to be pressurized, with heavy-duty tropical radiator cooled by reverse flow fan. Fan coil and hand protection guard is to be fitted. Coolant temperature is to be controlled by one or more thermostats as determined by design of system. Radiator is to be sized for continuous performance at 110% rated load at worst operating ambient conditions with a 15 deg. C temperature differential. Radiator is to be non-ferrous metal, incorporating pressure valve, radiator cap and drain cock and with integral expansion tank. Direct acting modulating thermostatic diversion valve is to control engine cooling water temperature. Under normal operation, (by-pass is to be fully closed). Use treated or fresh cooling water and add anticorrosion additives.
COOLING AIRFLOW:
Check that obstructions in path of cooling air flow (openings, louvers, grilles, mesh, ducts, bends etc.) do not reduce air flow below that needed at full rated output and select fan and radiator characteristics accordingly. Advise if additional booster fans are required and provide necessary control gear for automatic operation.
CYLINDERS:
Are to have removable liners and spacer plates to separate between cylinder head & engine block. Wet type liners are to have witness hole between liner sealing rings of each cylinder for early detection of coolant or oil leakage. Each cylinder is to have drilled and tapped hole and valve for connections of pressure indicator.
LUBRICATING OIL SYSTEM:
Pressurized circulating type, using engine-driven, gear type lubricating oil pumps with full flow filters and replaceable elements and lubricating oil heat exchanger. Filter system is to have spring loaded by-pass valve to permit oil circulation if filters become clogged. Audible and visual alarms are to cut-in when valve starts opening. Lubricating oil cooler is to be shell and tube heat exchanger with water from engine radiator as the cooling medium. Direct acting thermostatic diversion valve is to control oil temperature. Under normal operation by-pass is not to be fully closed.
FUEL SYSTEM:
Is to have injection pump and injectors that are easily removable and replaceable for servicing. Engine is to have integral, gear type, engine driven transfer pump to lift fuel against a head of 2.5 m and supply it through filters to injection pump at constant pressure. Fuel filter elements are to be easily replaceable. Replacement or adjusting at site must not need a special tool.
EXHAUST SYSTEM:
Is to be complete with flanged, bolted, galvanized, seamless steel pipe sections, long sweep elbows, flexible expansion sections, clean-outs, critical silencer, wall thimbles and supporting steelwork. Silencer is to be independently supported. Indoor hot exhaust parts are to be insulated with aluminum foul, not less than 10 mm thick, with anti- condensation overlap and sheet metal covers to protect insulation. Exhaust system is to be designed to reduce backpressure to below maximum specified by the manufacturer, in relation to exhaust pipe length shown on the Drawings.
AIR INTAKE SYSTEM:
Plant room is to have heavy duty air-filter with pre-cleaner heavy duty of the locker panel, all metal, cleanable, viscous impingement type, complete with duct and frame, as shown on the Drawings. Engine air filter is to be dry filter with replaceable paper filter elements. Filters are to be capable of removing particles 10 microns and larger.
ELECTRIC STARTING SYSTEM:
Engine starting is to be manual by push-button or automatic through control system at control panel. System is to consist of heavy duty 24 V d.c.
STORAGE BATTERY:
As manufactured standard, complete with battery rack and intercell connectors. Battery is to have sufficient 110 over capacity to provide minimum four cranking periods.
To be 25% over-rated, solid state, full-wave rectifier type, adequate to fully recharge depleted battery in not more than 10:12 hours and to automatically control rate of charge (providing a high-charge rate to a depleted battery and reducing to a trickle-charge rate when battery is fully charged). Ammeter is to be provided to indicate charging rate, which is to be adjustable. Battery charger is to be mounted in control cubicle, unless otherwise approved.
ELECTRONIC GOVERNOR:
Is to provide isochronous governing, paralleling and load sharing of generator sets. Governor is to have zero percent (isochronous). System is to include power supply unit, magnetic speed pick-up, control module and actuator using fast response d.c.
Governor is to be designed for fast-response and high- precision of speed (frequency) control, automatic paralleling and load-sharing and is to include speed adjustment with remote control interface. Frequency deviation under 25% sudden load change is not to exceed 0.5 Hz, recovering to stable speed condition of +/- 0.1 Hz in 0.5 seconds.
GOVERNOR OVERSPEED TRIP:
Is to automatically close fuel pump racks in event of engine over speed. Device is to be separate and independent from governing mechanism.
PROTECTIVE SYSTEM:
Is to comprise automatic engine shut-down and generator trip with visual and audible alarm in event of over speed, low lubricating oil pressure, high cooling water temperature and over cranking.
GENERATOR (ALTERNATOR)
Type synchronous, low reactance, high efficiency, revolving field type, with brushless exciter and flexible coupling. Generator is to be sized to pick up effective load without exceeding transient and steady-state voltage deviation limits specified up to its full nominal rating and is to be designed for the performance stipulated under other subsections of this Specification.
LEADS AND CABLES:
Phase leads are to be brought out fully insulated to a terminal cable box of heavy gauge sheet steel, protection IP31 (NEMA 1A). Control and protection cables are to be brought out to a separate terminal box.
MAXIMUM VOLTAGE DIFFERENCE:
Between the three phases at 100% balanced load is not to exceed 1%. With unbalanced load up to 30% on one phase at unity power factor and zero load on other phases, the line- to-neutral voltages are not to differ by more than 5%.
CHARACTERISTICS :
number of phases : 3
rated voltage : 400
frequency : 50
Net rated output : AS SHOWN ON DRAWING
rated power factor : 0.8
winding connection : reconnect able with ends brought out and fully insulated unbalanced load current with none of the phase
Currents exceeding rated current : 30% mini rotor salient pole
excitation : brushless, with armature
voltage regulator: 3 phase automatic, with readily accessible controls for voltage level
insulation : class H
enclosure : drip proof and screen protected (IP31)
cooling : by built-in centrifugal fan .
3 PHASE SENSING VOLTAGE REGULATION:
Overall voltage deviation within normal speed variations is to be within limits specified from no-load to full-load, from hot to cold and with load power factor from 0.8 lagging to unity. Regulator is to automatically reduce voltage if load exceeds capacity of generator. Voltage build-up is to be positive and rapid even when full load is suddenly applied. Line-to-line voltage wave- form deviation factor is not to exceed +/-5%. Total harmonic content is not to exceed 5% and that of one harmonic not to exceed 2%. Radio interference suppression is to be within the limits set by the Standards, grade (N).
Telephone influent a factor (TIF) is to be less than 50. Regulation + 0.5%.
Solid state, volts/Hz type, utilizing silicon semi-conductor devices in control and power stages, with built-in electro-magnetic interference suppression and designed for single or parallel operation. Manual adjustment to +/-5% of regulated voltage level is to be possible by means of a potentiometer at control panel. All components are to be sealed, moisture and heat resistant, with a suitable environmentally protected enclosure. Voltage regulator is to automatically reduce voltage if load exceeds capacity of generator and is to sustain a 3-phase short-circuit current at the generator terminals for the period for which the short-circuit protection operates and at least for 3 seconds. Voltage regulator power is to be supported by generator voltage and current to maintain excitation field power.
EXCITER:
Exciter is to be permanent magnet type. Armature is to be 3-phase, directly mounted to generator shaft and connected to generator field windings through six solid states, hermetically sealed, silicon rectifiers, accessible for maintenance or repair. Exciter is to have field suppression system to eliminate any source of diode failure resulting from high inductive loads and surges. Exciter field windings are to be stationary. Exciter-regulator combination is to maintain output voltage within limits specified for any load up to 110% generator rating and under any sudden load changes specified.
TWO POSITION SWITCH:
Is to be provided for selection of manual or automatic mode of regulated voltage control.
CONTROL CUBICLE CONSTRUCTION:
Generator set mounted instrument and/or control cubicles are to be resiliently mounted, preventing transmission of vibration to the components.
Separately mounted instruments and control cubicles are to be self- supporting, floor mounted and free-standing. Cubicles are to be sheet steel construction, ventilated indoor type, vermin and dust-proof (1P31 to IEC 144), with lockable hinged doors and instrument panels. Inner and outer surfaces of steel enclosures are to be cleaned, phosphatized and given heavy duty rust inhibiting primer and two coats of enamel. Wiring is to be 600 V, modularly arranged, connections made at front terminal blocks with no live conductor exposed. Wires are to have approved numbered ferrules at each terminal. Printed circuit plug-in boards, where applicable, are to be of industry standards, accessible and withdraw able, mounted in standard racks.
GENERATOR CONTROL PANEL (deep sea 550 UK
Generator control panel shall include, but not limited to the following components and controls:
- Metering and protection relays
- Annunciation and shutdown system with 24 VDC control voltage
- Starting system control
- Automatic voltage regulator and voltage adjustment facility
- Governor control and speed adjustment facility.
- Emergency stop button
- Hour run meter
- Controls including switches, relays, etc required for controlling the relevant
Generator shall have the following metering collected to the generator control panel.
Generator voltmeter with selector switch (V & Vs)
Generator current with selector switch (A&AS)
Generator frequency( HZ )
All metering shall be sealed type.
All metering shall have 1% accuracy.
All metering shall be analogue type.
Protective relays
Generator control panel shall contain the following relays:
Testing of relays shall be through test blocks included in the panel. The annunciation for shutdown and alarm signals shall be collected to the generator control panel with the following minimum indicators:
- Over speed
- Over crank
- Low coolant temp
- Low fuel pressure
- Low coolant level (trip & warning)
- High coolant level (trip & warning)
- Low lube oil pressure (trip & warring)
- High temp (trip & alarm)
- Low lube oil level (trip & alarm)
- High stator temp (trip & alarm)
- High bearing temp (trip & alarm).
- Excessive vibration (trip & alarm)
- Emergency stop
- DC power available
- Prime mono shutdown
FUEL STORAGE AND TRANSFER:
Closed cubical steel, inclined at least 3 degrees from horizontal and fitted with drain plug, inlet and outlet pipe connectors and breather pipe.
FUEL STORAGE TANK (FST) CAPACITY:
Is to be sufficient for full load operation of plant for 15 days or as shown on the Drawings, whichever is larger.
FST CONSTRUCTION
Vertical cubical tank with long radius convex ends, of 6 mm thick high quality, black steel plate welded on internal and external seams and hydro-statically tested at factory to a pressure of one atmosphere for 24 hours with welds proven sound. Manhole 500 mm diameter with 6 mm sides and flanges is to be welded to top of tank. Manhole cover is to be fitted to flange with 1.5 mm asbestos composition ring gasket and long machine bolts and nuts equally spaced.
FST CONNECTIONS:
Female threaded, black forged steel pipe couplings, fitted through holes in top and sides of tank and welded all around inside and outside. Connections, except vent connection, are to extend inside tank to within 150ýmm of bottom and are to be seamless black steel pipes of same size as connection and braced to tank walls. Vent connection is not to extend inside tank more than 20 mm.
FST PROTECTION:
Tank including manhole and connection are to be cleaned of rust, scale, welding slag, oil, grease and foreign matter by sand blasting or wire brushing down to base metal and painted on outside with two coats zinc chromate primer and two coats acid and alkali resistant protective coating.
FST CONTROLS:
Tank suction pipe is to have horizontal swing check valve installed just after leaving tank to stop return of oil when pump is stopped. Tank is to have approved hydrostatic type remote reading tank level gauge with low level alarm contacts.
FUEL LINES:
Heavy gauge, black seamless steel, to ISO/R65 or equal, treated internally with corrosion resistant paint and with joints sealed with PTEE tape(plumber's twine or gasket sealing compound are not to be used). Changes in direction and branching and jointing are to be with regular pipe fittings (field fabricated and bent fittings will not be accepted).
Fuel feed line to day tank is to have float operated solenoid value and by-pass with stop-cock. Size of fuel return line from day tank to main fuel tank is to be to manufacturer’s recommendations.
Filling line of main fuel tank is to be at least 50 mm external diameter, entering tank at opposite end to drain plug. Main tank fill and sounding line connections are to have hinged, lockable caps.
EXPANSION JOINTS:
Stainless steel, pack less bellows type, suitable for working pressure and temperature of service, of same size as pipe on which installed, with screwed ends for pipe sizes not exceeding 50 mm and flanged ends for sizes over 50 mm.
VALVES GENERALLY:
125 psi steam working pressure rating and 200 psi cold water non shock pressure rating and type that can be repacked under pressure.
PIPE HANGERS AND SUPPORTS:
Galvanized steel.
EARTHING INSTALLATION:
Two diagonal copper bars to be fixed at generator set skid to receive the grounding network all grounding cables on the skid.
3.5.3 FIELD AND INSTALLATION WORK
3.5.3.1 INSTALLATION
EQUIPMENT BASES:
Ensure that concrete bases and sterpoer panels of thickness (5-10cm) are placed under contretr base foundations provided for installation of equipment are constructed in accordance with the approved shop and construction drawings and equipment manufacturers' drawings and that holes for fixing bolts and provisions for passage of cables etc. are provided as required.
BUILT-IN ITEMS:
Ensure that equipment supports, fixings and the like, and sleeves for passage of feeders and cables which are to be built into concrete foundations, bases or the building structure are provided as and when required and that they are properly installed.
TOOLS:
Use only tools recommended by equipment manufacturers for installations, particularly in making connections and adjustments.
SUPERVISION:
Carry out equipment installation under the direct supervision of a qualified technician, licensed by and trained at the factory. Final adjustments and putting into satisfactory operation are to be made by a specialist delegated by the factory.
INSTALL GENERATING SET:
To maintain alignment and minimize engine and generator stresses. Protect instrumentation and control equipment including engine mounted instruments from machine vibration.
Mountings and method of mounting are to be as recommended by the manufacturer and approved by the Engineer.
ENGINE EXHAUST PIPING:
Is to be slightly sloped away from engine to avoid condensation returning to engine and is to have drain plugs or clean-out at lower end as required.
ENGINE HOT-AIR EXHAUST DUCT:
Install approved canvas duct with metal frames between radiator and louvered opening provided in wall for radiator exhaust air. Air buffaloes are mounted on louvers opening feed to reduce air noise.
MAIN TANK PIPE:
Extend to nearest outside wall of building and carry up to at least 1 m above ground level with end at least 1 m away from any building opening. Slope vent pipe back to tank without traps and support securely. Provide replaceable dust filter and gooseneck bend or approved weatherproof vent cap in top of pipe.
PIPE HANGERS AND SUPPORTS:
Fasten securely to building structure with approved masonry expansion bolts, minimum 20 mm diameter and install in accordance with manufacturers' instructions.
3.5.3.2 INSPECTION AND TESTS ON SITE
EARTHING RESISTANCE TESTS:
Are to be carried out to verify specified requirements.
LOAD TESTS:
Are to be carried out at low loads to overload conditions, at various power factors. Measurements are to include voltage and frequency deviations and regulating time under various step loading conditions, temperature measurements and pressure measurements at various locations, and in accordance with an approved plan under conditions equal to worst site ambient conditions.
TESTS:
Are to include:
Full load test for 8 hours continuous, immediately followed by 10% overload test, without interruption for one hour.
- Insulation measurement
- Functional tests for voltage sensing, automatic start, protection metering and transfer of load
- Operation of engine shut-down and alarm signaling and indications under simulated fault conditions. Measurement of vibration transmission to building structure.
LOAD BANKS:
If actual loads are not made available at time of acceptance testing, provide load banks to carry out complete test cycle of the system under loading and switching conditions necessary to prove compliance with the Specification.
PIPING SYSTEM:
Using carbon dioxide or nitrogen from pressurized cylinder, test each system to 1.5 times normal operating pressure. Do not subject equipment, apparatus or devices to pressure exceeding prescribed test pressure obtained from nameplate data or from manufacturers' published data. Apply tests before connecting piping to equipment. Remove or disconnect and blank off relief valves, instruments and devices that might be damaged by test pressure. Maintain test pressure on system for 24 hours during which time there is to be no noticeable drop in pressure. Check for leaks using soap solution. Isolate source of pressure during testing.
End Of This Section
No comments:
Post a Comment