T3S - 31 - Specs_50 MVA_refurbishment

8/9/2019 T3S - 31 - Specs_50 MVA_refurbishment

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SPECIFICATION FOR

REFURBISHMENT OF SHORT-CIRCUIT MOTOR-GENERATOR AND ACCESSORIES

1.0 General

1.1 This specification describes the scope of work as regards the refurbishment of existing 50

MVA short-circuit Laboratory, CPRI, Bangalore.

1.2 It is preferred that the whole work of refurbishment is taken up by a single party. However if

it is not possible, the bidder may clearly state his scope among the five different sub-groups

identified for refurbishment.

1.3 Alternatively the bidder may also quote for entirely new set-up covering the scope of all the

sub groups. In this case, the set-up shall include a new generator in place of spare coils as

in clause 2.7.1 and shall meet the specifications of all the sub-groups.

1.4 The bidders are welcome to inspect the existing set-up in order to get any clarifications

and/or to obtain more details.

2.0 Out line of existing set-up and operation:

2.1 The 50 MVA short-circuit Laboratory, CPRI, Bangalore comprises a motor–generator set

with associated controls and accessories. There are two short-circuit transformers for

stepping down the voltage to required levels. There are three test bays where equipment is

mounted for testing. All the essential controls needed for testing are housed in test control

room. The generator excitation, initiation of short-circuit, test sequencing and test data

acquisition are all executed from control desk. The protection panels (relay) for motor-

generator and some specific operational controls are housed in machine (generator)

building.

2.2 The generator is used as a source for high current in short-circuit laboratory. The generator isthree-phase with 50 MVA short-time rating (0.2 sec) and 5 MVA continuous rating. More

details of the existing generator are given in Annexure-1. The windings are wound in two

sections for each phase with terminals brought out for external connections. The sections

can be connected in either series or parallel. The three-phase terminals can also be

connected either in star or delta. This gives flexibility in choosing full excitation voltages of

3.46, 6.0, 6.92 and 12 kV depending on the test requirements. The generator voltage may

be further stepped down using short-circuit transformers to suit the test requirements.



2.3 The generator is driven by a 750 kW slip-ring induction motor which is used to bring the

generator to full speed. The insertion of rotor resistors in drive motor just before the short-

circuit tests limits its supply current from the grid. The test current (short-circuit current) is

delivered therefore from the generator converted from the stored energy (moment of inertia)

in the rotating mechanical system. A 750 kVA, 550 V DC Generator coupled to the

generator-motor shaft is used as main exciter.

2.4 During testing, the equipment to be tested is mounted in the bay with its incoming terminals

connected to the generator output (often through the short-circuit transformer). A typical

short-circuit test involves initiation of short-circuit by closing a high-speed make switch. The

test parameters like currents & voltages are digitally acquired by transient recording system

through suitable transducers. The test current is terminated either by equipment under test

or back up circuit-breaker depending on the test specification. Since the duration of short-

circuit test is very short (in terms of ms or seconds), the entire test sequence is pre-

programmed in a sequencer. The sequencer gives signal for operation of different devices in

certain sequential order decided by the test engineer. The test engineer at control room

manages the entire test sequence. The Annexure-2 gives the single line diagram of the

existing short-circuit laboratory and general layout of the laboratory.

2.5 The existing set-up is now more than 40 year old. The reliability of some components is

becoming more suspect. The windings of generator, motor, exciter (DC machine) and short-

circuit transformer are very old and there is a concern that they may fail suddenly because

of long term insulation-degradation.

2.6 The main objective of refurbishment of the station is the replacement of aged components/

equipment/system with new one. It also involves augmentation/modernization of the facility

wherever required and desirable to suit present-day requirements of testing.



3.0 Detailed Requirements

Following are the scope of the work in five (5) different sub-groups involved in

refurbishment:

3.1.1 Generator

3.1.1.1 It is proposed to get the coils of the generator wound and stock them. In case of

eventuality, this would help in quickly taking up and completing the rewinding work and

bring down the down-time of the machine considerably.

3.1.1.2 The coils shall be wound with latest methods with all the care. Keeping in view the fact

that the coils are for a short-circuit generator, the coils have to be suitable for repeated

short-circuits resulting in thermal and mechanical stresses which should be withstood by

the windings.

3.1.1.3 There are 72 coils in stator winding. The coils need to be wound with at least class ‘H’

insulation.

3.1.1.4 The generator is a 6–pole machine (synchronous speed of 1000 RPM). These rotor coils

have to be wound with class ‘F’ insulation.

3.1.1.5 The coils shall be suitable for the existing generator in all respects ready for replacement

with reference to area of conductor, construction, end winding design, insulation,

dimension, etc.

3.1.1.6 Existing spare coils of generator are available for inspection and reference.

3.1.1.7 The drawing of the stator and rotor coils is given in annexure-3.

3.1.2 Fly wheel

3.1.2.1 The stored energy in the rotating system of the existing generator is sufficient to give rated

output for 0.2 second. This time is required to be increased to 1.0 second by increasing

moment of inertia (MI) of the rotating mass. Presently we are deriving the output for 1.0

second by super exciting the generator field. There is a considerable drop in frequency



during the tests (although the current magnitude is maintained by impulse excitation). It is

proposed therefore to add flywheel to the existing system in order to maintain the

frequency within the specified limit. Refer annexure 1 for more details.

3.1.2.2 The flywheel shall be suitably designed in order that the generator will be able to deliver

50 MVA at 0.25 power factor for 1.0 second with frequency tolerance of 50 Hz ± 10 %.

3.1.2.3 The supplier has to study the existing conditions of the machine and its capability and

present complete designing of suitable flywheel and its engineering including the mode of

fitting it to existing system. The flywheel shall be mechanically stable and balanced. The

bearings, couplings and other mechanical components have to be suitably designed and

integrated into the existing system. The scope of the work includes design, manufacture,

supply, erection and commissioning of the flywheel system. Any changes in the existing

set-up required to be made like extension of shaft, provision of extra bearings etc., shall

be included in the scope and clearly brought out in the bid.

3.1.3 Excitation system

3.1.3.1 The main exciter of the short-circuit generator is a 750kW, 550V DC generator coupled to

the main shaft which in turn is excited by a pilot exciter. The exciter not only supplies the

no-load excitation but also impulse excitation during short-circuit tests. During the short-

circuit tests (short-time withstand tests), the terminal voltage of short-circuit generator

tends to decrease rapidly, due to high magnitude of test current. This in turn tends to

decrease the test current. The test current needs to be maintained constant for the test

period (typically 1.0 second) using suitable dynamic compensation. This compensation is

provided by the impulse excitation system which has to respond quickly and inject

required higher field current in step with the test current. Unlike automatic excitation

scheme, the compensation is in manually fixed steps (four steps) which is preset

depending on the magnitude of the test current. The current control is therefore coarse

and not precise. It requires considerable empirical effort, sifting through past data to set

the controls for regulating the current within permissible limits. The existing excitation

scheme is given in annexure - 4 and 5.

3.1.3.2 The existing system is proposed to be replaced by static excitation scheme. It shall be

supplied complete with all the necessary accessories including source transformer,

thyristor panel, microprocessor based control, associated software etc. The feed-back



loop shall ensure automatic and dynamic regulation of test current (at any set value upto

full MVA level for set duration). Proposed excitation system shall provide an over

excitation facility upto 10% of the normal excitation with facility of impulse excitation for

suitable compensation of test parameters. The excitation controls and operation shall be

integrated with the existing system.

3.1.3.3 The excitation system shall include suitable provisions so as to supply no load excitation

and effective impulse excitation. The no-load excitation shall allow all the operating

sequence in accordance with the design of the rotor and especially the current level and

excitation duration. The system shall be such that the impulse excitation level will be

limited by the rating of the rotor and not by its own levels. The system shall ensure that all

voltage levels upto 12 kV + 10% are maintained with an accuracy better than 1%. The

generator terminal voltage and the excitation current shall be regulated in order to deliver

the preset reference voltage. The automatic device shall check the current and the

duration of excitation, and shall actuate the suitable protections, if needed. This system,

by its own constraint shall not limit the generator capacity. The impulse excitation system

will have to balance the armature reaction during short-circuits and to allow the machine to

comply with the ratings. The impulse excitation shall ensure that the magnitude of the

current is maintained within the limits specified for the various test requirements – typically

less than +5%. The impulse excitation shall be set in action by the synchronous sequence

processor (or a suitable a PLC) controlling the test sequence. The response of feed-back

system shall be as fast as possible to ensure better regulation of output current.

3.1.3.4 The system shall make stepless variation possible from no load to impulse excitation.

Prior to the test, the ceiling voltage ratio between the applied voltage on the field winding

during impulse excitation and the voltage necessary to maintain the no load rated voltage

shall be set in accordance with the magnitude and the duration of the current.

3.1.3.5 The harmonic contents generated shall be restricted by proper design (say by 12 pulse

rectifier) of the source. The total harmonic distortion(THD) shall be less than 8%.

3.1.3.6 De-excitation equipment shall be provided for rapid de-excitation of the generator field

winding. The function will be actuated either by the synchronous sequence processor or

by the protection system. (The function could be ensured by interchanging the function of

rectifier and inverter). However, an additional device shall connect a field discharge

resistance for rapid de- excitation in case of failure in the bridge power supply leading to

short-circuit of the bridge.



3.1.3.7 The scope of the work includes design, manufacture, supply, erection and commissioning

of the complete excitation system together with all the sub systems.

3.1.4 Motor and Drive

3.1.4.1 The 750 kW slip-ring induction motor which is the prime mover is old and to be replaced.

The controls are outdated. The no-load speed of the machine is less than synchronous

speed of 1000 RPM resulting in less than 50 Hz frequency. It is proposed to be replaced

by a machine with a suitable AC variable frequency /DC drive. The motor and the drive

shall be retrofitted with the provision of all the existing essential features. Additionally, it

shall be designed preferably for 50Hz as well as 60Hz operation. The insulation class shall

be at the least F. The details of the existing motor are given in annexure-6. The scope of

the work includes design, manufacture, supply, retrofit, erection and commissioning of

motor and the suitable drive. An option to provide braking arrangement to the motor may

also be quoted as optional extra (e.g. Regenerative/resistive braking – braking shall be

effective in rapidly bringing down the machine at full speed to halt.) The present timing is

about 50 minutes without braking arrangement. The supplier shall indicate the timing with

braking. All the auxiliaries like source transformer, drive panels and other equipment

required shall be included in the scope of supply. All the rotating machines and its

auxiliaries shall conform in the aspects of design, performance to IS 4722:2001 and IEC

60034 (relevant parts).

3.1.4.2 The manufacturer of the drive shall have at least ten (10) years experience in the

production of this type of equipment with ISO 9000, ISO 14000 and ISO 18000

certification. Since the down time in case of faults is very crucial, it is necessary that a

service centre is available for quick servicing with a cycle time of 24 hours near Bangalore

where this station is situated. All printed circuit boards shall be completely tested and

burned-in before being assembled into the completed drive. The Drive shall be subjected

to a preliminary functional test, minimum one (1) hour burn-in and computerized final test.

The burn-in shall be at 40°C, at full rated load, or cycled load. Drive input power shall be

continuously cycled for maximum stress and thermal variation.

3.1.4.3 In case of AC drive, the drive shall utilize efficient IGBT technology throughout the entire

power and Voltage range. Party must have experience in supplying and commissioning

test benches in India. Reference certificates/Orders to be furnished. The Drive shall be



rated to operate from 3-phase power input at rated voltage ±10 %, 47Hz to 53Hz. The

Drive shall employ a full wave rectifier to prevent input line notching and operate at a

fundamental input power factor of 0.97 at all speeds and loads. The Drive efficiency shall

be 98% or better at full speed and load. Suitable provisions may be made to reduce input

current harmonic content, provide protection from power line transients such as switchingtransients from power-factor correction capacitor and reduce RFI emissions. The over-

voltage trip level shall be a minimum of 30% over nominal, and the under-voltage trip level

shall be a minimum 35% under the nominal voltage. Output voltage and current ratings

shall match the adjustable frequency operating requirements of the standard 3ph, 50Hz,

motors. The drive shall be furnished with suitable enclosure rated for operation at ambient

temperatures between 0° and 40°C with a relative humidity less than 95% and no

condensation allowed.

3.1.4.4 The drive shall conform to IEEE 519 - Harmonic analysis for particular jobsite including

total voltage harmonic distortion and total current distortion. The Drive manufacturer shall

provide calculations, specific to this installation, showing total harmonic current distortion

(TDD), at the Point of Common Coupling. Prior to installation, the Drive manufacturer shall

provide the estimated total harmonic distortion (THD) caused by the Drive. The results

shall be based on a computer aided circuit simulation of the total actual system, with

information obtained from the power provider and the user. The acceptance of this

calculation must be completed prior to the manufacture of the drive. The THD shall not

exceed 8%.

3.1.4.5 The Drive shall be equipped with a front mounted operator control panel (keypad) with

back-lit alphanumeric display and a keypad with keys for Run/Stop, Local/Remote,

Increase/Decrease, reset, menu navigation and parameter select/save. All parameter

names, fault messages, warnings and other information shall be displayed in complete

English words or standard English abbreviations to allow the user to understand what isbeing displayed without the use of a manual or cross-reference table. The keypad is to be

used for local control, for setting all parameters, and for stepping through the displays and

menus. All the necessary parameters shall be able to be displayed. Serial communication

capabilities shall include, but not be limited to, run-stop control; speed set adjustment,

proportional/integral/derivative PID control adjustments, etc. A minimum of 15 field

parameters shall be capable of being monitored. A fiber optic communication port shall

also be provided for personal computer interface. Microsoft Windows®-based software

shall be available for drive setup, diagnostic analysis, monitoring and control. The



software shall provide real time graphical displays of drive performance. Monitors shall be

made available at two locations in the laboratory for supervisory information(Head of

maintenance and head of laboratory)

The drive shall include protection for over-load (motor), Over current , over voltage,Temperature, phase loss ( AC drive) and surge.

3.1.5 Operation and control

3.1.5.1 The existing controls of generator and motor and proposed controls of exciter-drive for

testing shall be integrated. During the tests, the input to the motor is blocked and the test

current is derived from the generator converted from the mechanical energy stored in the

rotating mass. Immediately after the end of test, the generator is to be de-excited and the

supply to the drive motor resumed. The controls needed during tests, like turning on and

off the thyristor to block the supply during short-circuit tests, impulse excitation controls,

de-excitation etc., shall be added to the programmable sequencer. The test sequencing

shall be automated with provision of suitable synchronous sequence

processor/programmable logic controllers (PLC). The manufacturer will preferably use

110V d.c. voltage level for control and automation. The connecting cables to be linked

with other parts of the station will be brought to a plug board and will comply as far as

possible with the above mentioned requirements, including the following but not limited to:

- The excitation and impulse excitation controls.

- The pilot generator signal.

- The protection signals for switching off.

- The interlocking lines coming from the test control room.

- The measurement transmission lines to the test control room

3.1.5.2 The test data is transient in nature and is captured by transducers at the test bay. The

outputs from these transducers are analog. These need to be converted to digital signals

using suitable Data-acquisition system ( DAS) and need to be transferred ( 24 different

signals) to the test control room where it is reproduced for analysis, stored and archived.

The DAS shall have 24 Single ended, isolated inputs. The resolution shall be at least 12

bits with a sampling rate of at least 1 MS/sec. (adjustable). The memory depth per channel

shall be 1 MB. The supplier has to build the system for reliable operation in high

electromagnetic noise- level environment prevailing in the laboratory particularly during the



actual transient test conditions. The supervisory and monitoring signals for the equipment

in general and the test data in particular needs complete noise immunity. The supplier

therefore has to use proven and reliable technologies of digital communication utilizing

suitable network protocol like Modbus / Profibus. However for acquiring test data, an

additional arrangement for analog signal transmission to the control room shall also beprovided as an option.

3.1.5.3 The supplier will have to state the main principles of proposed plans to use for the control

and monitoring system. The PLCs shall be of of reputed makes (Siemens, Rockwell, etc)

with open system architecture. The detail of each control loop and automatic device may

not be furnished in the bid. However, the manufacturer will have to comply with the

general requirements of this section and ensure that his proposal enables finalization of

the detailed control and monitoring system arrangement. The scope of the work includes

redesigning of the scheme, supply and commissioning of the new integrated control

system. The supplier shall propose further extension of the laboratory if any required for

the purpose like control room and indicate the size and requirements of the same.

The Annexure-6 gives the essential schematic of the existing motor-generator set.

4.0 Manufacture, Erection and Commissioning

4.1 The manufacturer shall follow documented quality procedures (QAP) during the manufacture

of equipment/module/component, a copy of which shall be made available once the order

is issued. The components/modules to be sourced from other manufacturers shall be

clearly brought out in a separate bill of materials. These bought-out items shall be of

reputed makes (with warranty clause). All the sheet-steel panels, enclosures shall be of 7-

fold construction (for e.g. Rittal make).

4.2 The supplier has also to indicate the schedule of manufacture for enabling stage

inspection to be planned wherever deemed necessary by CPRI. The schedule for stage

inspection and final inspection programs have to be agreed together with dispatch

clearance criteria. A set of pre-manufacture documents shall be submitted for approval

containing among other things GA drawings, foundation details (with static weight), Bill of

materials, Schematics, interconnection diagrams, single-line diagrams. Periodic review of

the project - one weekly and other monthly- shall be held between CPRI & the supplier to

monitor the progress. The supplier shall indicate the exact dates. The equipment and all



its components have to conform to the latest Indian/international standards. Tests shall

include all electrical, mechanical, pneumatic and hydraulic tests in the course of

manufacturing as well as the routine test after the completion of the manufacture. The final

tests on the completed equipment before dispatch shall be conducted as per the

procedures in the standards. The test report shall be submitted for approval beforedispatch.

4.3 Before the start of erection, the supplier has to submit for approval of CPRI, the program

of on-site test plan which shall include proving all the essential specification. The supplier

shall carry out tests at site in accordance with the on-site test plan. The supplier’s test

equipment shall be of satisfactory quality and condition with valid calibration.

4.4 At the time of erection, the supplier shall submit for approval fully detailed Installation,

Operating and Maintenance instructions. It will not be sufficient to incorporate the

manufacturer's standard brochures as part of the text unless they refer particularly to the

equipment supplied and are free from extraneous matter. Separate Operating & Maintenance

manuals are required for different modules. During the course of erection, the Purchaser

shall have full access for inspection of the progress of work and checking workmanship

and accuracy as may be required.

4.5 Initial energizing and subsequent “live” tests will be directed by CPRI and carried out

jointly by the CPRI and the supplier to ensure satisfactory performance to meet the ratings

of the generator system. The supplier shall remain responsible for his supply. The test

results can be used as a basis for maintenance test during the working life of the

equipment.

4.6 On completion of the erection work, prior to commissioning, all equipment shall be

inspected and tested to demonstrate that it is entirely suitable for commercial operation. A

general check of all the main and ancillary equipment shall be made and shall include a

check of the completeness, correctness and condition of earth connections, labeling,

clearances, painted surfaces, cables, wiring, pipe work, valves, and all other auxiliary and

ancillary items. A check shall be made that loose items which are to be handed over to the

Purchaser, e.g. tools, spares, are in order and are correctly stored or handed over.

4.7 The manufacturer will have to design the foundation complying with the requirements.

Necessary foundation details for the set wherever needed shall be presented. The design



of the special foundations shall ensure prevent the surrounding equipments from any

disturbing vibration, allow the generator to run without high strains and eliminate any

build–up of oscillations due to successive vibration pulses. The behavior during fully

asymmetrical single- phase tests shall have to be specially studied. Spaces for cabling

and air coolers shall be provided. The manufacturer will have to supply all the necessarytechnical documents for laying the foundation block: calculation notes, drawings,

specification for building material, etc.

5.0 Training and Documentation

5.1 The supplier shall arrange for comprehensive and detailed training programs for CPRI

personnel - both class room and on-the job. The number of personnel would be decided by

CPRI. The training shall cover all the aspects of operation/maintenance and basic trouble-

shooting. A special training would also be required for implementation of drive system (PCB

cards), control, communication systems, PLC aspects (operation and programming) of the

complete control scheme that the supplier chooses to use. This could be for example, the

bus systems, communication protocols, and other digital communication aspects.

5.2 The supplier shall submit complete documentation which shall be comprehensive. It shall

be reader-friendly with illustrations in suitable form like, schematics, graphs, pictures,

photographs, circuit diagrams, schedule and bill of material, spare part list, trouble

shooting procedures, etc. The documentation shall be supplied in both hard copy and

reproducible soft copy. Four copies of hard copy shall be submitted, printed and elegantly

hard bound. Three soft copies – one in PDF format and another in AUTOCAD format shall

also submitted.

6.0 General requirements

6.1 The bidder shall have to propose and quote for necessary/essential spares and tools. Two

separate lists, in accordance with the following requirements would be made:

6.2 The first list will include the so-called normal wear parts which are recommended to be

procured for first five years normal operation. This could include but not limited to for

example: brushes for rotor slip- ring, bearing linings, pump impellers, pump shafts,

bearings, gears, main screw and driven screws for the main lubricating pumps, pressure



reducers, filters, valves, pressure controllers, thermostats, probes, sensors, recorder

parts, protective relays etc.

6.3 The second list will include the spares which are not to be replaced in normal operation

but the failure of which will forbid tests to be carried out for an excessive duration takinginto account the delivery period. This could include but not limited to main electronic

devices such as: thyristors, complete electronic boards covering the main functions, PLC

modules etc.

6.4 The supplier shall propose all the necessary special tools needed for both routine and

major maintenance of the machine, its auxiliaries and ancillaries. The supplier shall

indicate the proposed maintenance schedule during the guarantee period and the life

period of the machine. The supplier shall also indicate the minimum life period of the

various equipments offered, when operated and maintained, in accordance with the

instructions of the manufacturers/ suppliers. The supplier shall offer to supply the spares

and tools for a period of at least 20 years.

6.5 The supplier also give the details of the changes he is making in the current set-up to

accommodate a new feature which may demand extra resources from CPRI like additional

/ larger space allocation, provision of higher electricity demands, etc.

6.6 The bidder shall give estimated time to complete the work of refurbishment. This is

important since the down-time of the machine affects the commercial interest of the

laboratory. Therefore it is expected that the bidder accurately estimates the time for which

the facility have to be shut down. This time would be factored in terms of loss of revenue

of the laboratory while calculating the total cost.

6.7 The bidder shall give list of his clients to whom he has supplied similar equipment with

contact details.

6.8 The bidder shall furnish the guaranteed technical particulars (GTP) as per the enclosed

format. The particulars shall include but not limited to the parameters specified in the

format. Simplified drawings of the main parts and layout of various equipment with their

details forming part of the “refurbishment package” may be given wherever necessary.



6.9 Warranty: The supplier shall offer a comprehensive warranty against the entire system to

be supplied by him for a minimum of three (3) years.

6.10 The price bid shall be given as following:

A. Refurbishment with replacement and modifications as per Item 2.7.1 to 2.7.5

A1 Main Parts (with detailed list)

A2 Spares (with detailed list)

A3 Training

Alternatively

B. Refurbishment with new set-up (covering all the scopes of 2.7.1 to 2.7.5)

B1 Main Parts (with detailed list)

B2 Spares (with detailed list)

B3 Training

XXXXXX

Encl: 1. GTP form

2. Annexures: 1, 2 , 3, 4, 5 & 6



Guaranteed Technical Particulars

The bidder is requested to give the information pertaining to but not limited to following particulars.

Sl.No.

Technical Particulars Requirement ReferenceClause

Complies(Yes/No)

Generator Coils

1 Stator coils

Rotor coils

72 no.s copper

6 no.s copper

3.1.1

2 Insulation class H for stator coils

F for rotor coils

3.1.1

3 Design and manufacture As per existing coil ;

(details in annexure 3;samples available)

3.1.1

Sl.No.


Complies(Yes/No)

Fly wheel

1 Type MS Fabricated 3.1.2.1

2 Construction Cylindrical ---

3 Moment of inertia Suitable to be fitted tothe specified

generator to give50MVA for 1.0 secondat 0.25 power factor

lag

3.1.2.2

4 Mounting Pedestal ---

5 Lubrication To be specified by thebidder

---

6 Type of Coupling To be specified by thebidder

---



Sl.

No.

Technical Particulars Requirement Reference

Clause

Complies

(Yes/No)Excitation System

1 Type Microprocessor basedStatic excitation

system

3.1.3.2

2 No-load & impulse excitationcurrent

Suitable for thesystem to give 50MVAoutput for 1.0 second.

To be specified by thebidder

3.1.3.3

3 Control system Closed loop feedback

to maintain theGenerator output

current constant withaccuracy better than

1%

3.1.3.3

4 Response time To be specified by thebidder

3.1.3.3

5 Number of pulse Preferably 12 pulse 3.1.3.4

6 Total harmonic distortion Less than 8% 3.1.3.4



Sl.No.


Complies(Yes/No)

Drive motor

1 Input voltage To be specified by thebidder

3.1.4.1

2 Rated output 750kW minimum 3.1.4.1

3 Type of motor variable speed 3.1.4.1

4 Insulation Minimum Class ‘F’ 3.1.4.1

5 Dimensions of motor To be specified by thebidder

---

6 Net weight To be specified by thebidder

---

7 Acceleration time Less than 1 minute ---

8 Output Torque To be specified by the

bidder along withspeed-torque curve

---

9 Losses at full load To be specified by thebidder

---

10 Type of cooling To be specified by thebidder

---

11 Source Transformer ratings (for motor)

To be specified by thebidder

---

12 Conforming to IS 4722:2001 & IEC60034 (relevant parts)

3.1.4.2

13 Quality assurance ISO 9001, ISO 14001 3.1.4.2

Drive for motor

1 Type Static 3.1.4.3

2 Total harmonic distortion Less than 8%;Compliance to IEEE

519 Harmonicanalysis

3.1.4.4

3 Input voltage To be specified by thebidder

---

4 Number of pulse To be specified by thebidder

3.1.4.3

5 Protection Over-voltage & surge,phase loss, overload,temperature etc.

---

6 Quality assurance ISO 9001, ISO 14001 3.1.4.2



Sl.No.


Complies(Yes/No)

Operation & control

1 Type PLC based 3.1.5.1

2 Communication MODBUS/PROFIBUS 3.1.5.3

3 Number of channels/control signals 24 (minimum) 3.1.5.2

4 Data acquisition system At least 12 bit

24 channel isolatedsingle ended ; 1 MS/s

3.1.5.2

5 Output of synchronous testprocessor ( sequence controller)

24 channels 6A 230VAC/DC

---

6 Noise immunity EMC & EMIcompatibility

3.1.5.2

7 Type of control PLC based viaComputer / self programmable

---



Sl.No.

Technical Particulars Requirement

Short-circuit Generator (If bidder quotes for new Short-circuit Generator)1 Maximum output voltage 12kV

2 Output power 50MVA for 1.0 second

3 Stator coil insulation Class ‘H’

4 Rotor coil insulation Class ‘F’

5 Dimensions of Generator To be specified by the bidder

6 Moment of inertia To be specified by the bidder

7 Type of rotor construction To be specified by the bidder

8 Synchronous speed To be specified by the bidder

9 Sub-transient reactance / time constant Suitable to give minimum 50MVA

output

10 Transient reactance/time constant Suitable to give minimum 50MVAoutput at the end of 150mS

11 Number of windings per phase (for series parallel connection)

Two

12 Stator winding connections 3.46kV, 6.92kV, 6kV & 12kV

13 Frequency 50 & 60Hz operation

14 Excitation voltage & current To be specified by the bidder

15 Field time constant To be specified by the bidder (asminimum as possible)

17 Type of cooling To be specified by the bidder 18 Weight of the rotor To be specified by the bidder

19 Lubrication To be specified by the bidder

20 Conforming to IS 4722:2001 & IEC 60034 (relevantparts)

21 Quality assurance ISO 9001, ISO 14001



Annexure-1

Technical details of existing 50MVA SC Generator

Three phase synchronous generator of enclosed self-ventilating design with horizontal shaft. On

the one end of the shaft rotor of the main exciter is mounted and the other end of the shaft is

coupled to he driving motor which is an induction motor. On the top of the generator a link board

for manual reconnection of the different voltages is mounted. The generator has the following data.

Make ASEA, Sweden

Output 50MVA calculated at the end of 0.2second short-

circuit and the recovering voltage of 12kV

Continuous output 5MVA, 12kV 241A

Standard BS 2613

Nominal voltage 12(star-series), 12/ √3(delta-series), 6(star-parallel) and

6/√3 kV (delta-parallel)

Frequency 50HzSynchronous speed 1000 rpm

Stator windings per phase Two

Nominal current 2410A in 12kV connection

Quantity of cooling air 360m3/min.

Moment of inertial 1550kgm2

Lubrication Self-lubrication

Runaway speed 1250 rpm

Stator insulation Class B

Rotor insulation Class A

Losses Approx. 2.5% of rated output

Total net weight 30 tons Net weigh of the stator 13.5 tons

Net weight of the rotor 10.9 tons

Time of retardation 34 minutes

Reduction of speed Speed reduction after a short circuit at nominal

charge and a duration of 0.2 sec. are;

at power factor less than 0.1 : 5%

at 0.12 pf : 6%

at 0.3 pf : 8%

Voltage at initiation of

short-circuit Not greater than 115% of the recovery voltage

Sub-transient reactance 1.7Ω in (star-series connection)

Transient reactance 2.22Ω

Synchronous reactance 14.3ΩExcitation voltage & current 550Vdc 1360A for 0.2 second



N

Annexure-2

Page 1 of 2

Layout plan of 50MVA SC test laboratory

Note:

G - Short-circuit generator with exciter

B - M-G set machine bed

M - Driving motor

T1,T2 - Short-Circuit Transformers

Note: All dimensions are in foot

131’

G M

Machine Control Room

Control Panels

26’

23’

17’

20’

45’

57’

B

Test Cell-3 Test Cell-2 Test Cell-1

T2 T1

Control Room

Handling bay



Annexure-2

Page 2 of 2

Single line diagram of the existing 50MVA SC Test facility





Annexure-3

Page 1 of 2



Annexure-3

Page 2 of 2



Annexure-4

Schematic of the existing excitation scheme for 50MVA SC Generator



Annexure-5

Schematic diagram of Generator-Motor-Exciter set



Annexure-6

Technical details of the existing driving motor

The driving motor is a 3Phase Slip Ring Induction motor of enclosed self –ventilating design

with horizontal shaft and flange for coupling to the generator. Following are its technical

particulars;

Continuous rated output 750kW

Speed 985 rpm

Synchronous speed 1000 rpm

Frequency 50Hz

Input voltage 3.3kV

Losses at full load 5kWRunaway speed 1250rpm

Efficiency at full load 94.3%

Net weight 3.7 tons

Acceleration / starting time 63 seconds

Type of starter Rotor resistance type (divided in to 3 steps)

Documents

T3S - 31 - Specs_50 MVA_refurbishment