1.1.1. Basic Design Requirement - Electrical Equipment The electrical equipment consists mainly of: • Two horizontal shaft generators of 2.5 MVA each connected via 6.3 kV cables

to 6.3/11 kV step-up generator transformers • Auxiliary supply for all power needs of the power plant, intake area, spillway

and access road • Control and protection devices for all functions of the entire plant.

1.1.1.1. Generators Main characteristics of each generator are to be as under:

Item Unit Unit No. 1and2 Maximum Continuous Rating (mcr) MVA 2.53 Nominal Speed rpm 750 Runaway Speed rpm 2100 Nominal Voltage 6.3 kV/50 Hz Generator Efficiency % 97 Transmission gear efficiency % 98.5 Protection Class IP44 Insulation Class F Temperature Rise B Cooling Air/Water Power Factor cos φ 0.8 Life span of bearings Min : 100,000 h of

operation a. The generator shall be designed, constructed and tested in accordance with

IEC Publication No. 34 and other relevant parts dealing with rotating electrical machines.

b. The temperature of armature and field windings shall not exceed 130 oC

when delivering rated MVA continuously at rated voltage, power factor and frequency, and with a temperature of canal water of 30 oC and with only 75% of the cooling system working. The temperature of the armature winding shall be determined in operation, by means of resistance type temperature detectors embedded in the windings. The ambient temperature shall be taken as 50 o

c. The generator and all accessories shall be capable of withstanding all temperature changes and sudden three phase short circuit, at its terminal without damage to any equipment.

C.

1.1.1.2. Excitation and Voltage Regulation System The recommended excitation and voltage regulating systems shall be modern static type. However, the final decision would be taken by the Employer in coordination with the Contractor as regards the static excitation or the rotary excitation types. The voltage regulator shall have the following main functions: • Voltage regulation • Field current regulation • Field current limiter • Reactive compensation • Supervision and logic circuits • Following line voltage during synchronising • Under excitation limiter • Stator current limiter • Power system stabilizer • Power factor regulator • Active compensation

1.1.1.3. Transformers Two (2) main step-up transformers and two (2) auxiliary transformers shall be installed. The main transformers shall be coupled to the generating voltage of 6.3 kV and stepped up to 11 kV. The step-up transformers shall be installed in open air adjacent to the powerhouse and linked by cable to the 11 kV switchgear. The delta connected winding shall provide a closed circuit for third harmonics currents. The high voltage winding shall be Y connected with the neutral taken out on a separate terminal for connection to earth. Auxiliary transformers shall be installed for the power plant auxiliary supply system. Transformers installed outdoors shall be conventional oil immersed and hermetically sealed. Indoor transformers shall be dry – type. The high and low voltage transformer bushings shall be sealed by suitably designed terminal cover boxes and cable sealing ends so as to prevent ingress of moisture, insets and other objects to prevent possible short circuits and accidents.

Main Data Item Unit Main Transformer Auxiliary Transformers Function Step-up Step-down Rated output MVA 2.53 0.30 Rated voltage primary secondary

kV kV

6.3 11

11 0.4

Frequency Hz 50 50 Temperature rise 0 55 C Power Factor 0.8 0.8 Tap changer Off load Off load Vector group YN d11 Dyn 11 Tap range +10%,-5% in steps

of 2.5% ± 5% in steps of 1.25%

Cooling ONAN Dry type (if installed indoors) Rated BIL kV 95

1.1.1.4. Medium and Low Voltage Installations

Powerhouse The 11 kV metal clad switchgear shall be fed by the generating units through 6.3/11 kV step-up transformers. One 11/0.4 kV, 300 kVA transformer shall feed the 0.4 kV station auxiliaries, while another 11/0.4 kV, 300 kVA transformer fed from 11 kV line will serve as standby reserve in case of emergencies or shut down of the plant. Drawings, main single line diagram No. DO 16 and auxiliary power supply system diagram No. DO 17 show the general arrangement of 11 kV and 400 V supply systems. The Contractor shall perform short circuit calculations for the 11 kV & 0.4 kV systems to confirm the final determination of equipment ratings and proper selection of the protection devices. Medium Voltage (11 kV) Circuit breakers of SF6 or vacuum type enclosed in cubicles providing high personnel safety shall be provided. The rated maximum voltage Um

shall be 17.5 kV and the rated short circuit current (1s) will be 25 kA. The 11 kV switchgear shall also supply auxiliary power to the power plant. The switchgear shall be located indoors. The busbars and all main connections shall be of copper.

Low Voltage AC Supply (400 V) The low voltage AC distribution system shall be designed as a 400 V, 3 phase four wire plus protective (earth) conductor system. Normally the station service

bus shall be supplied by the station transformer connected to the 11 kV bus. In emergency cases, a standby diesel generating set shall start automatically and provide power to supply essential station loads as well as start-up load of one unit. A third source of auxiliary supply shall be from 11/0.4 kV, 300 kVA auxiliary transformer fed from 11 kV line. This supply will also serve for initial testing of the plant, commissioning tests and for essential supplies during canal closure. The 400 V circuit breakers of the auxiliary transformers and diesel generator shall be suitably interlocked to prevent mal-operation and to ensure smooth auxiliary supply. The changeover of supply from one source to the other shall be automatic as well as operator – initiated. The distribution system shall supply low voltage power to all plant service systems, lighting and battery chargers through local control cabinets with necessary starter motors and sub-distribution panels. From the battery banks, DC/AC power converters shall provide uninterrupted power to essential control functions. All motors shall be powered and controlled through motor starter units assembled in motor control centres (MCCs). The starters shall be of withdrawable design where each unit may consist of more than one starter. The 400 V bus bars and all connections shall be of copper. Low Voltage DC Supply The battery system shall provide a safe and reliable supply of power and control voltage to all primary functions. The system shall be independent of all other power systems and ensures reliable execution of the control functions, both for normal operation and during faulty conditions. For the powerhouse, the recommended direct current supply shall be based on a duplicated supply design. The two independent 110V battery systems, each with a separate main distribution switch-gear, shall both feed each of the DC distribution bus-bars. The double battery system shall mainly provide power to the complete Plant Control System (PCS), the Local Control System (LCS), the control voltage for the hardwired part of the system and DC equipment such as motors for black-start procedures. Telecommunication and some instrument protection devices or computer interfaces shall need 24 V or 48 V DC supply. AC/DC converters shall be used as necessary and separate 24 V or 48 V batteries shall be provided as required. The battery system for the spillway and intake shall provide power mainly to the Local Control System (LCS) and the control voltage for the hardwired part of the

system. Water level monitoring and gate control must remain operative. The powerhouse battery shall guarantee the function of all vital elements to bridge a timely limited power failure and to shut down and restart the plant safely. 110 V battery will be of about 300 Ah capacity. The battery charger should be capable of supplying the entire load normally along with charging the battery and have recharging time of 8 hours. The Contractor shall furnish calculations of actual DC requirements justifying the rating finally selected for the batteries for approval of the Employer.

1.1.1.5. Control System The powerhouse shall be equipped with a state of the art computerized control system consisting of the following elements: • One (1) unit of Plant Control System (PCS) • Four (4) units of Unit Control System (UCS) • One (1) unit of Data Communication System (DCS) Besides the fully automated computerized operation and control system, manual operation must be possible directly at the equipment, i.e. at the generating units, switchgear panels, motor control cubicles (MCC) etc., and all monitoring and control must then be done locally from the UCS mimic panel. The design of the local control panels must include equipment for indicating status and control of major parts such as generator, turbine, breakers, switches, control of alarm, level set-points, etc. Start, stop and other control of the generating units must also be possible by manual operation. The monitoring and operation shall be done by means of the control panels for the automatic voltage regulator (AVR) and the turbine governor as well as by manual operation of valves, switches etc. for manual operation together with local instruments. Also, an independent emergency stop function for the generating units shall be installed for use in the event of a severe fault, e.g. fire or flooding. The emergency stop function initiated by the emergency buttons shall be installed at selected locations. Plant Control System (PCS) The PCS shall be installed in the control room for an overall control and monitoring of the plant. System operation shall be based on three modes: • Load controlled operation with time-dependent function • Water level controlled operation, aiming to keep water level in the canal

constant to a defined level; used during normal operation • Operation on isolated grid; used in case of interruption of the national grid

Unit Control Systems (UCS)

The UCSs shall handle the process control, command procedures, interlocking routines, etc. for the following: • UCS1: Generating Unit 1 • UCS2: Generating Unit 2 • UCS3: Auxiliary System • UCS4: 11 kV and 400 V Switchboards Communication between the PCS and UCS shall be done by a fibre-optic cable system. The layout shall be either in bus, loop or star configuration.

1.1.1.6. Protection System

Protection Equipment Separate relay protection cubicles comprising modern electronic relays of proven design shall be installed. All relays shall preferably be from the same supplier to build a uniform modular system. The functioning of the protection relays shall not depend on the control system. The relays shall be organised in two groups so that one group provides back-up protection for the other group. Powerhouse main single line diagram No. DO 16 shows the protection and metering of generators, transformers and switchgear. Auxiliary power shall be taken only from the 110 V DC system. Separate circuits shall serve the two groups of relays in order to obtain maximum reliability. The relays shall be capable of operating properly with voltage variations of -20% to +10%. Generation Protection The generator shall be linked to the primary winding of the transformer by cables. To avoid the build-up of dangerous over-voltages in the event of an arcing earth fault, possibly due to the relatively high capacitance of the system, the generator neutral point must be earthed through an impedance to limit the earth fault current to a suitable value. The modern practice to use a distribution grounding transformer shall be followed. The secondary winding, designed for a voltage of 100 - 500 V, shall be loaded with a resistor of a value which, when referred through the transformer ratio, shall pass a suitable fault current. The resistor shall, therefore, be of low ohms value and shall be of rugged construction.

1.1.1.7. Telecommunications

A digital telephone network shall be installed in the powerhouse to cover the entire plant, powerhouse, intake, spillway and the residential colony. A PABX with 3 trunk lines for pubic network connection and 30 extensions shall be installed complete with telephone sets, modems, intercommunication equipment and DC uninterruptible power supply. Each generating unit shall include at least one telephone per floor. All cranes shall be connected to this communication system, as well as all the working and lay down areas. Suitable plug-in type weather proof telephone sockets with handsets shall be provided throughout the powerplant area for easy contact for routine operation and maintenance. A direct intercom link between central control and each unit control shall be provided. An internet facility shall be provided in the powerplant.

1.1.1.8. External Communication A system of telecommunication comprising pilot fiber-optic cable and radio telephone shall be installed for speech communication, intertripping and teleprotection between powerhouse and designated WAPDA grid station. The fibre optic cable shall be clamped on the 11 kV power overhead lines connecting the powerplant and the WAPDA grid station and shall be complete with terminal equipment at both ends including required interfaces. Speech communication shall be provided between the powerhouse and each pumping plant for lift irrigation located at a distance of approximately 10 km.

1.1.1.9. Lighting and Small Power

An adequate indoor and outdoor lighting with illumination levels of international standards shall be provided. Inside the power plant, an emergency lighting system powered from the station battery must be installed; the system shall instantly operate when the normal power supply fails.

1.1.1.10. Emergency Diesel Set In case of a breakdown of the WAPDA system simultaneously with a failure or standstill of all hydro generators, a 100 kVA diesel generator shall be installed at the power plant to take over the supply to a certain group of equipment to ensure and facilitate a safe shutdown or black start-up.

1.1.1.11. Earthing System

WAPDA operates its 11 kV system with the neutral solidly grounded. In case of any line to ground fault close to the powerhouse a fault current will pass through the neutral of each transformer. Proper combined earthing of all equipment at all voltage levels shall be carried out. The earthing resistance of the system must be less than 0.16 Ohm. A complete earthing system network for the entire powerplant area shall be designed using approved international standards, (ANSI, IEEE) for the safety of the plant and personnel to keep the touch and step potentials within allowable limits. The earthing mesh shall be designed and laid covering draft tubes, turbines casings, all embedded metallic parts and equipment in all powerhouse floors. Earthing meshes shall be laid beneath all buildings and structures using earthing rods where necessary. Copper conductors of suitable sizes will be used for the risers and meshes after required calculations are carried out. All the independent earthing systems shall be interconnected with conductor of proper size in the powerhouse, transformer area, switchgear rooms, diesel generators room, spillway etc. Conductor can be laid in conduits or covered cable trenches. The structural steel bars in the columns of buildings and structures shall be earthed suitably alongwith all conducting parts of the plant.

1.1.1.12. Lightning Protection All buildings and structures shall be provided with lightning protection equipment and apparatus including spikes, conductors and down conductors to protect against lightning. The lightning leads and conductors shall be connected securely to the main earthing system of the plant.

1.1.1.13. Transmission Lines and Interconnection with WAPDA For the purpose of dispersal of power, the Deg Outfall Hydropower station shall be interconnected through double circuit 11 kV overhead transmission lines with WAPDA/PEPCO power system at ICI Ataabad 132/11 kV grid station at a distance of approximately 6 km away. The Contractor shall be responsible for survey, design, construction and commissioning of the 11 kV transmission lines complete in all respects including steel lattice poles, insulators, hardware, steel reinforced (ACSR) conductor and any other material required. The lines shall be designed and constructed according to WAPDA specifications and standards. Land acquisition for the transmission lines will be done by the Employer; however contractor will provide

the land details, at least one year in advance to take up the construction of transmission line at site. The transmission line shall be aligned with the right-of-way (ROW) of UCC upto Sheikhupura – Lahore road and later on within the ROW of main roads upto the grid on Lahore – Sheikhupura road. Provision of switchgear, protection, control and synchronizing equipment for the transmission lines has been made in the power plant specifications at Deg Outfall. The Contractor shall study the existing facilities in the WAPDA/PEPCO grid station to access the additional requirement, if any, for interconnecting and proper interfacing of the new incoming 11 kV transmission lines for integration into WAPDA/PEPCO power system, to the approval of the Employer. The Contractor shall also carryout necessary system studies required for the dispersal of power from Deg Outfall hydropower plant and for system stability requirement during parallel operation of WAPDA/PEPCO system with Deg Outfall hydropower plant. The Contractor shall provide and install all necessary equipment in the WAPDA/PEPCO grid station for control, switching and operation of the 11 kV transmission lines. A reliable and accurate tariff metering of sale of power to WAPDA / PEPCO shall be ensured by the Contractor. High accuracy dedicated current and potential transformers, energy (kWh) and reactive power (kVArh) meters for this purpose shall be installed in suitable safe environment at the appropriate place in the power station. The accuracies of different components and meters shall be according to the highest class as per IEC or equivalent standards.

1.1.1.14. 400 V Distribution Line for Colony The Contractor shall design, supply, construct and commission a 400 V distribution line from the power house to the staff residential colony. The distribution line shall be constructed according to WAPDA specifications and standards complete in all respects.

1.1.1.15. Step-up Transformers and 11 kV switchgear Two 6.3/11 kV step up transformers shall be provided. The 11 kV side shall be connected to common 11 kV metal clad switchgear which shall be connected through two 11 kV lines to 132 /11 kV Grid Station of PEPCO / WAPDA as shown on drawing No. DO 16. Synchronization to the power system will take place at the power station at 11 kV bus.

1.1.1.16. 11 kV Circuit Breakers The circuit breakers and ancillary equipment shall conform to IEC standards. Circuit breakers shall be of in- door SF6 or vacuum types. The 11 kV circuit breakers shall be designed for the following ratings: • Nominal voltage 11 kV • Highest voltage Um

• Frequency 50 Hz 17.5 kV

• Phases 3 • B.I.L rating 95 kV • Power frequency withstand 38 kV • Bus Bar arrangement Single • Nominal current 1600A • Short circuit current 25 kA • Rated supply voltage for control and auxiliaries, DC volts 110

1.1.1.17. 11 kV Auxiliary Equipment

Auxiliary 11 kV equipment such as C.Ts, PTs, coupling capacitors, isolating switches etc. shall have the same matching ratings as of 11 kV breakers.

1.1.1.18. 11 kV Cabling 11 kV cables shall be rated 8.7/15 kV according to IEC with maximum (Um

) voltage of 17.5 kV.

1.1.1.19. Control and Protection Systems Power Plant Control System (PCS) The control system shall comprise the following control levels. a. The plant control level b. The local control level c. Manual control level The computerised PCS shall be designed for installation in an air-conditioned room. However, the equipment shall operate satisfactorily with the air-conditioning system out of operation. The protection relays shall be operationally independent of the local computer.

The Plant Control Level A computerized PCS shall be provided to allow overall control and monitoring of the power plant. However, no failure in the PCS shall interrupt the operation of the power plant. The operation of the system shall normally be carried out from the plant control room where PCS controls the entire process, including start up procedures, automatic control procedures, interlocking routines, etc. Basic design requirements: • Data acquisition from all LCCs, including status signals, alarms, analogous

measurements, etc • Determining and supervising the plant operation strategy • Transferring command and control outputs to the LCC • Alarm handling and event recording • Dynamic presentation of the start/stop sequence for each generator set • Database functions for periodical reports • Energy recording and reporting • Time synchronization and time tagging system • Post mortem review • Self-diagnosis and virus protection etc • Software for system configuration and maintenance

The Local Control Level There shall be four (4) local control cubicles as follows: • One for generating unit 1 (LCC 1) • One for generating unit 2 (LCC 2) • One for the auxiliary systems (LCC 3) • One for 11 kV and 400 V systems (LCC 4) In normal mode of operation when the Plant is being controlled from the Control room, the LCC manual control panel will be disconnected but all LCC indications shall remain active. The LCCs for the generating units shall be installed in the machine hall near the respective generating unit. The LCC for the 11kV and 400 kV systems shall be installed in the electrical switchgear room and the LCC for the auxiliary system shall be installed near the auxiliary equipment. Push buttons shall be provided at convenient places in the plant for emergency shutdown of the units.

Manual Control

The LCCs will normally perform all control functions automatically for the relevant device, e.g. the generating units, but in the “Manual Control” mode the LCCs will be put out of automatic operation. In this mode each operation is performed locally on each device. In addition, manual operation can be performed directly on the equipment, i.e. on the generating units, switchgear panels, motor control cubicles (MCC) etc., and all monitoring and control must then be done locally from the LCU mimic panel. The design of the local control panels must include equipment for indicating status and control of major parts such as generator, turbine, breakers, switches, control of alarm level set-points, etc. Start, stop and other control of the generating units must be possible by manual operation. Control Room Equipment The main components of control room equipment shall comprise the following: • Power control desk for synchronizing control and indications of the

generators, transformers and switchgear along with a mimic display behind

the desk, with indicators showing the position of circuit breakers, disconnect switches and earth switches, including metering of MW, MVA, Amps, Volts and power factor

• Hydraulic control desk which will accommodate all hydraulic controls and indications for the turbines and all gate equipment, headrace and tailrace levels equipment etc.

• One sequential events recorder • One Synchronizing Panel Main grouped alarms shall be annunciated on their respective control panels in the powerhouse control room with the detailed alarms being annunciated on a local panel. Power Supply Systems The PCS shall be supplied with 230 V AC via a DC/AC converter. 110 V battery will also be available as supply of the PCS equipment. Protection Systems

a. Protection Relays

Protection relays shall be provided to prevent or limit damage during faults or overloads and to minimize their effect on the remainder of the system. The system shall be divided into protective zones separated by circuit breakers. During a fault, the zone, which includes the faulted apparatus, shall be de-energized and disconnected from the system. Separate relay protection cubicles comprising modern electronic digital or numeric relays of proven design shall be installed. The functioning of the protection relays shall not depend on the control system. The relays are to be organized in two groups so that one group provides back-up protection for the other group.

Auxiliary power shall be taken from the 110 V DC system. Separate circuits shall serve the two groups of relays in order to obtain maximum reliability. The relays shall be capable of operation properly with DC voltage variations of –20% to +10%. Drawing No. DO 16 gives the outline of the proposed protection scheme for the powerhouse.

b. Generator Protection

The generator protection shall consist of:

• Over-/under voltage relay • Over/Under frequency relay • Over current/short circuit relay • Differential relay • Reverse power relay • Negative sequence current relay • Loss of excitation relays • Shaft current relay • Rotor (field winding) earth fault relay • Excitation transformer over-current relay • Stator earth fault relay • Rotational speed relay • Vibration and shaft movement supervision relay • Winding thermal relay • Generator - Transformer differential relay

c. Step-up Transformer Protection

The 6.3/11 kV step up transformer equipment protection includes:

• Three phase overcurrent relay • Three phase unit block differential current relay • Neutral point earth fault current relay • Restricted earth fault relay (REF) • Bucholz Relay • Pressure Relief Device • Winding temperature relay • Oil level low alarm

d. 11 kV Transmission Line (to WAPDA) Protection

The 11 kV transmission line protection comprises:

• Directional overcurrent relay • Three phase overcurrent relay • Earth fault relay • Synchro-check relay

e. 11 kV Feeder (to Colony and Pump Houses) Protection

• Three phase over current relay • Earth fault relay • Synchro-check relay

f. Busbar Protection

The 11 kV Busbar protection includes:

• Busbar earth fault relay • Busbar differential relay

g. Auxiliary Transformer Protection

Auxiliary transformer protection includes:

• Over current relay • Earth fault relay

h. Diesel Generator Protection The diesel generator shall contain the usual manufacturer & standard protection against damage. In addition, the following protections shall be supplied as a minimum: • Overload and earth fault protection • Reverse power protection • Over speed protection

i. Miscellaneous Protection

On certain faults e.g. breaker failure etc and other serious conditions in the powerplant, in addition to local trippings/shutdown, an intertripping signal shall be initiated to trip the remote end 11 kV circuit breaker in WAPDA’s grid station. The Contractor shall install suitable relays and necessary auxiliary equipment in the powerplant and in WAPDA’s grid station. The tripping signals will be transmitted over the fiber optic cable to be laid by the Contractor between the Plant and the WAPDA grid station.

1.1.1.20. Auxiliary Equipment

a. Low Voltage AC Supply

The low voltage AC Distribution shall be designed as a 415 V, 3-phase four wire system. Normally, the power station will be supplied by the station transformers 11 kV feeder from WAPDA shall be connected so as to provide the auxiliary supply for testing and starting of units during pre-commissioning of the plant and in case of complete shut down of the plant.

b. DC Supply

The battery system is to provide a safe and reliable supply of power and control voltage to all primary functions. The system is independent of all other power systems and ensures reliable execution of the control functions, both for normal operation and during possible fault conditions.

24V or 48V batteries or preferably the use of AC/DC converters may be necessary for instruments, protective devices and computer interfaces.

Direct current supply is based on a duplicated supply design. The two independent 110V battery systems, each with separate main distribution switchgear, feed each of the local DC distribution busbars.

c. Lighting and Small Power

Adequate indoor and outdoor lighting with illumination levels in accordance with recognized standards shall be provided. Inside the powerhouse, an emergency lighting system powered from the station battery shall be installed; the system shall operate through automatic AC/DC change over switch in case of normal supply failure.

AC lighting and small power socket outlets, for 240V, shall be single-phase, connected between phase and neutral of the 415V system.

Fluorescent light fittings are preferred everywhere indoor where it is feasible. For outdoor lighting, sodium floodlights with built-in gear for high pressure sodium lamps shall be provided. In order to reduce the number of equipment types and sizes which have to be stocked as spares, there must be standardization of both lamps and fittings. This will result in relatively few varieties.

Under normal conditions, both the emergency and normal lighting will be in operation. These two systems will have totally separate circuits with power supply as follows:

• Normal lighting: Powered from Unit Auxiliary Boards

• Emergency lighting: Powered from 415 V essential supply switchgear

Both systems have as a main concept, common distributed “on/off” switches. However, special considerations must be paid to areas containing “escape routes”.

• Normal lighting: It is recommended that the normal lighting

system shall be designed according to the following Design Requirement:

Type of area Illumination level Outdoor: Areas with common staff traffic and streetlight 50 lux Equipment rooms perimeter light 50 lux Transformers area light 50 lux Indoor: Offices, control rooms, switchgear rooms 400 lux Storage rooms, corridors, etc. 100 lux Equipment rooms 200 lux Machine hall, etc. 300 lux Workshop 300 lux The illumination requirement for the emergency lighting shall be at least 50 lux all over the related areas. Exit lights shall be installed above doors, staircases, etc. During blackouts these shall be powered from the batteries.

1.1.2. Other Facilities

Electrical and mechanical workshops and storage building shall be located in the powerplant which will also house the workshop equipment. Electrical workshop will comprise electrical laboratory for inspection, repair and maintenance of electrical and electronic devices. The Contractor shall supply suitable tools and plants for this purpose.

1.2. ELECTRICAL EQUIPMENT

1.2.1. Electrical Equipment Materials All materials incorporated in the equipment supplied shall be new and first class commercial quality free from defects and imperfections. Materials for heavy electrical equipment machines or assemblies shall comply with the requirements stated under the relevant sections of general specifications, for mechanical equipment. Copper used as electrical conductors shall be of the electrolytic type and comply with the respective ASTM or DIN standards.

1.2.2. Standardization of Equipment

The Contractor shall endeavour to standardize all small mechanical and electrical equipment materials and devices for the works. Such equipment devices fittings etc., shall comprise but not necessarily be restricted to the following: • Valves gauges, flow meters thermometers, etc • Electrical instruments and meters • Terminals and terminal blocks • Auxiliary relays • Contactors, fuses, miniature breakers • Control devices and control switches • Lamps, bulbs, sockets, plugs, etc • Lubricants Other outdoor installations and indoor installations in wet and damp rooms shall be hot dip galvanized if possible. Wherever galvanizing is not possible at least two coats of zinc rich paint shall be applied after perfect cleaning. The colour codes for cables pipe work etc., shall be adopted as per international practice.

1.2.3. Design and Construction a. General Requirements

Cubicles cabinets and similar enclosed compartments containing electrical equipment shall be specially treated on the exterior and interior surfaces to prevent corrosion and be adequately ventilated. All major or important compartments/panels containing electrical equipment shall be provided with internal lighting facilities. Anti condensation heaters shall be installed where required.

b. Switch Boards and Panels

LV switch boards and control relay and metering board/panels shall be of robust construction formed of a steel frame and covered with smooth steel plate. The steel plate shall be at least 2.5mm thick and properly stiffened to prevent distortion. Wherever required hinged steel doors with latches shall be provided, doors shall be lockable by means of approved keylocks.

Boards and panels shall be designed, constructed and tested in accordance with IEC Publication No. 439 Factory built assemblies of low voltage switch gear and control gear. Boards and panels shall be totally enclosed and the degree of protection according to IEC No.144/529 shall be:

Indoor minimum IP 42 Outdoor minimum IP 54

Unless otherwise specified or agreed upon all instrument apparatus and devices on the panel fronts shall be provided for flush mounting.

All cables control wiring and terminals shall be marked in a systematic manner, both on the drawings and on the cables, wires and terminals themselves. The markings shall be in accordance with a system presented and coordinated by the Contractor throughout the works.

c. Cable Laying and Routing

The final routing of HV and LV cables in indoor and outdoor installations shall be determined by the Contractor from the directives given in this section. All cable routing and arrangement shall be subject to the Employer’s approval.

For indoor installations and exposed outdoor installations cables shall be laid in covered cable trenches, plastic or steel ducts or depending on the available space on cable trays and racks. Cables on walls or ceiling shall be laid in conduits to protect against mechanical damage. LV cables shall be laid in covered concrete cable trenches with removable concrete covers with the exception of the cables connected to equipment, which shall be laid in conduits from the trenches to the equipment.

d. Electric Motors

For all electric power drives, 3-phase squirrel cage type induction motors shall be used. All motors shall be of the totally enclosed type (IP54, IP55 or better according to IEC publication 34.5). Winding insulation shall be class “F” throughout.

All motors shall have overload and short circuit protection.

All motors including all auxiliary and protective devices shall be capable of running continuously with full load at voltages ranging between 85% and 110% of the rated supply voltage.

e. Flexible Flanged Adapter

Flexible flanged adapter will be provided between inlet valve and inlet pipe (connected to volute casing) for dismantling the unit and to accommodate expansions/ Contraction due to temperature variation.

1.3. GENERATOR

1.3.1. General

Each unit shall be a three phase synchronous generator suitable for coupling to a horizontal turbine on the free end. The generator shall be supplied with suitable set of bearings which shall absorb loads and forces from both turbines and generators. If required, flywheel on the non-drive end to be installed for the required inertia of the rotating part shall be supplied with the generators. The flywheel shall be mounted onto the rotor shaft shrunk fit through oil pressure.

1.3.2. Generator (Structure)

• The generator offered shall be of well proven construction preferably selected from the Contractors existing range for similar climatic conditions as specified.

• The generator shall be of robust design made of high quality materials and shall be as far as possible maintenance free.

• The excitation system shall be of the static type or brushless by rotating diodes as agreed by the Employer.

• The generator and bearings shall be able to withstand transient and continuous runaway speed without any damages.

• The stator shall consist of frame, core and coil etc. the core shall be so designed in withstand extremely high temperatures due to any untoward incidents. The winding of stator shall be made of best quality copper. The generator reactance shall be kept as low as possible to minimize voltage drop and ensure stable operation.

• The rotor is composed of main shaft, magnetic yoke, poles and fan etc. the main shaft is made of forged steel. The yoke is shrunken on the main shaft to form an integral part

• The pole consists of pole core and field coils etc. The pole core shall be laminated with 16 mm steel plate and field coil is made of flat copper wires. The generator rotating parts shall be supported on well designed bearings.

• Temperature detectors (PT100 DIN or equivalent) i.e., minimum three (3) in the stator winding, three (3) in the cores and one (1) in each of the bearing shall be installed

• Anti condensation heaters in the stator shall be provided as per site conditions

• Speed monitoring device for rpm indication and over speed protection shall be provided. The device shall also send signals to the controlling equipment for shut down of the unit

1.3.3. Instruments

The control panel shall be equipped with the following instruments and devices: • kW meter (Digital) • A.C. Volt meter (Digital) • Frequency meter • Power factor meter • rpm meter • kVAR meter • kWH meter • Hour counter meter • DC volt meter • DC ampere meter • Thermometers (Digital) to indicate stator and bearing temperatures • Upstream and tail water level indicators • Synchronoscope

• Guide vane limit and guide vane position.