gen testing schedule

7/28/2019 Gen Testing Schedule

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STATION: NTPC SIMHADRI BHEL REF NO : PS-DC-186-500-0020

NTPC REF NO: SIM/1/TS/ 2 / 008

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PLANT AREA : ELECTRICAL SYSTEM

TESTING SCHEDULE : GEN. TESTING PROCEDURE FOR FIRST SYNCHRONISING

1. PLANT DETAILS :

The 500 MW generator is coupled to the 500 MW KWUturbine. The rated parameters of the generator arelisted in plant details (Section-1) of Testing schedulefor generator protection and generator bay. The designand constructional features are outlined briefly below.Generator manual supplied by the manufacturer may bereferred for details of above.

STATOR BODY :

The stator body is a totally enclosed gas tightfabricated structure suitably ribbed internally to ensurehigh rigidity. Hydrogen coolers are housedlongitudinally inside the stator body. Rigid end shieldsclose the casing and support the fan shields.

STATOR CORE :

The stator core is made up of segmental varnish insulatedpunchings of cold rolled grain oriented silicon gel andis assembled in an interleaved manner on core bars.Steel spacers for ventilating ducts are provided forradial cooling of core by hydrogen. The core is heldpressed by means of heavy non-magnetic steel press ringswhich are bolted to the ends of the core bars.Additional support is provided to the teeth portion. Inorder to isolate the stator body and thus the foundationsfrom magnetic vibrations, the core bars are designed toprovide elastic suspension of the core in the stator

frame.

STATOR WINDING AND INSULATION:

The stator has a three phase, double layer short cordedbar type windings having two parallel paths. Each coilside consists of glass insulated solid and hollowconductors with cooling water passing through the latter.


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The elementary conductors are Rosbel transposed in theslot portion to minimize eddy current losses. The coilsides are firmly held in position by fibrous slot wedges.The overhang portion of the coil is securely lashed withglass chord to bondage rings and special brackets of non-magnetic steel, which are in turn fixed to the core pressrings.

DISTILLATE HEADERS:

Ring type water headers, made of copper are providedseparately for distillate inlet and outlet in the statoron turbine side. The headers are supported on insulatorsand isolated from stator body. The winding ends aresolidly soldered into the coil legs which are thenultrasonically tested. Individual bars are provided withwater inlet/outlet connections made of P.T.F.E Hoses, Thebar heads are insulated by fiber molded covers.

TERMINAL BUSHINGS:

Water cooled terminal bushings are housed in the lowerpart of the stator on the slip ring side, Porcelaininsulators are provided to insulate the terminal barsfrom the stator body. Effective sealing is providedbetween the terminal bushings and the stator body toavoid any possible leakage of hydrogen. Terminal bushingsare housed inside a chamber made of non-magnetic steelplates. Three phase terminals and three neutral terminalsare brought out. The terminal plate of the end terminals,where bus bar connections are made is silver plated.

ROTOR

The rotor is of cylindrical type; the shaft and bodybeing forged in one piece from chromium nickel molybdenumand vanadium steel. The rotor with all the detailsassembled is dynamically balanced to a high degree ofaccuracy subjected to 20% over speed for 2 minutes.


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FIELD WINDING:

The field winding is made from hard drawn silver bearingcopper. The winding is held in position and by non-magnetic rotating ring in the overhang portion. Gappickup method is used for direct hydrogen cooling ofrotor.

The main slot insulation is of glass cloth impregnated

with Epoxy resin. The inter turn insulation consists oflayers of prepped glass cloth glued to the bottom of eachconductor. The end windings are packed with blocks ofglass laminates to separate and support the coils and torestrict their movement under stress. The end windingsare insulated from the retaining rings with the help ofglass epoxy molded segments.

SHAFT MOUNTED FANS

For circulating the cooling gas inside the generator two

propeller type fans are shaft mounted on either end ofthe rotor body. Fan hubs are made of alloy steel forgingand are a shrunk fit on the rotor shaft. The alloy steelcast fan blades are machined in the tail portion to suitthe fan hub and held in position with the help of conicalpins. The blades can be easily removed from or assembledin the fan hub. Fan shields fixed to the end shieldsguide the gas flow.

RETAINING RINGS:

The end windings are held in position by retaining ringsof floating type shrunk fit on the rotor body. The ringsare screwed to prevent axial movement by locking nuts.


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SLIP RINGS:

The slip rings consists of helically grooved alloy steelrings shrunk on the rotor shaft and insulated from it.They are mounted on a single, common steel bush, whichhas an insulating jacket pre-molded on it. The completebush with sliprings are provided with inclined holes forself ventilation. The helical grooves cut on the outersurface help improve the brush performance.

FIELD LEAD:

The slip rings are connected to the field winding throughsemi-flexible copper leads and current carrying bolts,placed radially in the shaft. Two semicircular hardcopper bars insulated from each other and from the rotorshaft are placed in the central bore or the rotor joiningthe two sets of current carrying bolts with specialprofiled precision conical threads.

GAS COOLERS

Four longitudinally mounted gas coolers are mounted inthe stator body. They are made out of admiralty brasswith coiled copper wire wound on them staggered form soas to expose maximum surface area to hydrogen.

BEARINGS:

Generator bearings are of pedestal type with sphericalseating to allow self alignment and are supported on aseparate pedestal on slip ring side and in the L.P casing

on the turbine side, Bearing bush is of cast steel linedwith white metal. Oil catchers and deflectors areprovided to prevent axial leakage of oil. To preventshaft currents slip ring side bearing and connectingpipes are insulated from earth.


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SHAFT SEALS:

In order to prevent leakage of hydrogen from thegenerator casing radial thrust type shaft seals areprovided on either side where the shaft extends out fromthe generator. The seal consists of seal liner withbabbit pressing against the shaft caller of the rotor.

Seals are defined in testing schedule of seal oil system.


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NAME PLATE DETAILS

RATED DATA & O/P TURBO GEN. MAIN EXCITER PILOT EXCITERAPPARENT POWER 588 MVA ------ 65 KVAACTIVE POWER 500 MW 3780 KW ------

CURRENT 16166 A 6300 A 195 AVOLTAGE 21 + 1.05 KV 600 V 220 + 22 VFREQUENCY 50 HZ ------ 400 HZ

PF 0.85(LAG) ------ ------STATOR WDG CONN YY ------ ----HYDROGEN PRESS 3.5 BAR ----- -----CONT PERM UNBAL

LOAD8 % ------ ------

RATED FIELDVOLTAGECURRENT

340 V4040 A

------ -------


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2. TESTING OBJECTIVE :

TO TEST THE GENERATOR AND MAKE IT READY FOR SYNCHRONIZATION.


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3.0 PROPOSAL

3.1 Tests as detailed in item-8 shall be carried out on

generator, confirming the manufacturers test reports.

3.2 Generator short circuit test will be carried out and the

values will be recorded.

3.3 The current based relays will be dynamically tested for

their function and the values will be recorded.

3.4 Generator open circuit test will be carried out and the

values will be recorded.

3.5 The voltage based relays will be dynamically tested for

their function and the values will be recorded.

3.6 The synchronizing circuit will be checked and the phasing

out will be carried out.


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4. SERVICES REQUIRED

4.1 Laboratory equipments/test sets for measurement ofelectrical parameters required.

4.2 Illumination at required locations.

4.3 240 V A.C power supply for testing.

4.4 Communication facility at test area.


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5.0 S A F E T Y PRECAUTIONS:

5.1 The test area shall be clearly defined and cordoned

off.

5.2 The test team leader is fully aware of the nature,

location, and probable duration of the tests.

5.3 The other agencies working in the test area areinformed about the test in progress.


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6. EMERGENCY PROCEDURE :

6.1 Shock treatment chart and first aid box shall beavailable.

6.2 Emergency telephone numbers of fire and hospital shall beprominently displayed near by.

6.3 The test in progress shall immediately be stopped and allline apparatus disconnected and equipment suitably earthedin case of a accident or abnormality. Such instructionwill be received from the team leader.

6.4 The test team is fully aware of measures to be taken inthe event of injuries to any personnel / damage to anymachinery.


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7. STATE OF PLANT :7.1 Generator Erection complete and satisfactory. All

erection test results/log sheets available for thefollowing :

- Mounting of embedded parts and foundation plates.

- Erection of stator.

- Gas tightness and Hydraulic tests.

- Measurement of insulation resistances of various

parts of generator, D.C. resistances and impedances.

- Continuity, D.C. resistance and IR checks of RTDs.

- Purge tests of rotor ventilation canals.

- Rotor insertion tests.

- Bearing adjustment tests.

- Alignment or generator rotor.

- Inclination or shaft journal test results.

- Coupling alignment results of generator and LP rotor.

- Magnetic Axis adjustment results.

- Fan and shield clearance results.

- DTI checks on generator rotor.

- Shaft seal adjustment results.

- Temperature monitoring system.

- Centering and offset-setting of brush gear.

- Fixing of brush holder and brushes.


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7.2 Following Testing/Commissioning schedules completedsatisfactorily and results/records available :

- Generator Gas Tightness Test.

- Hydraulic test and oil flushing of seal oil system.

- Seal Oil System Circulation

- Hydraulic test and flushing of primary water system.

- Generator test schedule

- Generator, generator bay protection test schedule

7.3 All the systems mentioned in 7.2 are in totally normalisedcondition and available for generator testing.

7.4 Fire protection system (CO2 system) is made available.

7.5 For carrying out short circuit test, short generatortransformers HT terminals R,Y,B together at 400 KV side byearth switch or by the links capable of carrying 1500Acurrent. Isolate 400 KV supply and earth.


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1. The following measurement circuits to be made through formonitoring and taking readings :

a. Generator Voltage RY, YB, BRb. Generator Current R, Y, Bc. Excitation Voltage

d. Excitation Currente. Active Powerf. Reactive Powerg. Power Factorh. Energy meter

Synchronising circuits and protection circuits also to bekept ready alongwith recommended settings set in theprotection relays.

2. Testing / measuring equipments to measure PMG Voltage(3

Phase AC), main exciter Voltage (DC) and PMGs phasesequence in AVR are to be kept ready.

3. Excitation Circuit :

Fuses of PMG input to AVR and main exciter input from AVRoutput are to be checked for their healthiness.

Cables of PMG and main exicter are to be cnfirmed that theyare properly connected and are free from earth shortor any other faults.

Winding resistances of PMG and main exciter are to be takenonly to check their healthiness.

Healthiness of stroboscope and DAVR to be checked. No tripshould come from DAVR.


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4. Ensure that Gen PTS are racked in and Gen bus duct are inpressurised condition.

5. Systems :

i. Stator water cooling system is to be kept on line.ii. Rotor cooling is to be confirmed by parameters of H2

temp.iii. Seal oil circulation in service is to be confirmed.iv. All RTDs are to be monitored in control room.v. Busduct pressuring unit must be in service.vi. Rotor earth fault circuit to be made ready and kept

on line.vii. Operation of UT-A&B-11KV breakers and GCB are to be

checked and found OK. UT-A & B breakers are to beput in test position.

6. Following modifications to be carried out and to benormalised after synchronisation of generator.

i. Excitation system on manual

ii. Auto channel in blocked condition.iii. Field breaker closing from ATRS inhibited.iv. Auto synchronised isolated from circuit.v. Turbine trip from generator trip removed.

GRP TB3 9 & 10

GRP TB3 11 & 12

7. LBB LINKS to be kept out

8. Interlock between switchyard isolated and field beaker to

be defeated.

9. GT differential protection to be disabled by shortinginput CT Sec. Links.

At 3000 rpm Measure PMG voltage frequency and phase sequence .


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7.6 Excitation system panels are kept in ON condition.

7.7 The steam turbine run to 3000rpm after following thestart-up procedure.

7.8 The spill currents in the CT terminals in the relaypanel,control panel& AVR panels are first checked when themachine is at 3000rpm.


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8.0 TEST METHOD :

8.1 Short circuit characteristics test :8.1.1 AVR in manual mode.8.1.2 FB is off and no trip from tripping relays and AVR.

Hence, FB close permissive available.8.1.3 Close GCB in dead circuit.8.1.4 Measure CT secondary current of GT CT at switchyard.

Control room.8.1.5 Switch on the excitation

8.1.6 Slowly raise excitation till generator current reaches500 A and note the readings of field voltage,current, generator excitation current, terminalvoltage and stator currents in three phases.

8.1.7 Slowly raise excitation and measure the aboveparameters at diff. Stator currents till the ratedstator current.

8.1.8 Draw a graph between field current and gen. Current.

S.No Gen.Field

Current(Amps)

Gen.

current

Exciter

fieldvoltage

Exciter

fieldcurrent

Gen.

TerminalVoltage

AVR

controlVoltage

01.02.03.04.05.06.07.08.09.

10.11.12.13.14.15.16.17.

500 A1000 A2000 A3000 A4000 A5000 A6000 A7000 A8000 A

9000 A10000 A11000 A12000 A13000 A14000 A15000 A16000 A


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9 Find overall short circuit ratio of Generator and GeneratorTransformer.

8.2 PROTECTION CHECKING:

1. Proving of Rotor Earth Fault protection (64E) :

At machine stand still condition, connect the ground faultdetection brush to earth and ensure that rotor earth faultrelay operates (Refers 3-562-006-0357 / Rev.2, Sheet-37).

Either TE or EE side (TB1-40 OR TB1-41 to be earthed).

2. When GCB closed and , the following checks can be carriedout.

a. Proving of negative phase sequence (46G).

Change the polarity of anyone phase of 3Phases currents by interchanging relay terminals A5and A6 or A7 and A8 or A9 and A10 (sheet 36).

i. Ensure that the relays flags are reset.ii. Close field breaker and slowly raise excitation tillthe current is about __________ alarm will appearafter 5 Seconds trip will occur at K1 times operatingtime. Operating time depends on the current settingI23 .

iii. Reduce excitation and switch off FB.iv. Normalise wires on relays terminals.

b. Proving of Generator field failure protection (40G1 &40G2).

i. Set K1K5 to the maximum setting.ii. Check K3 + K4 = K2.iii. The Voltage across terminals 7 & 8 of the relay and

current through terminal 6.iv. Close FB and slowly raise the excitation. Check

relay operates at Vs = 2I (K1K5 + (K3+K4)


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v. Record Vop = Volts

Iop = Apms.

vi. Reduce the excitation and trip FB.

C. Proving of Generator Trasnformer DifferentialProtection (87GT R,Y,B)

Keep Relay setting in the minimum value so as to avoid

generator to run in fault condition for a long time and for themaximum fault current

R phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP 7 TB1-1&4 (wire nos.A411, A470) and monitor differential current at relay terminal27. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP 7 TB1-2&4 (wire nos.A431,A470) and monitor differential current at relay terminal27. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

PHASE OPERATING CURRENT GENERATOR CURRENT

RYB

D. Proving of Generator Differential Protection (87G1)

R phase: with machine in de-excited condition, blockcontribution of current to differential relay by short-


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circuiting CT secondary wires on GRP1 TB1-1&4 (wire nos.A11,A70) and monitor differential current at relay terminal 6.Switch on excitation & slowly raise till generator current isaround 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP1 TB1-2&4 (wire nos.

A31,A70) and monitor differential current at relay terminal 8.Switch on excitation & slowly raise till generator current isaround 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

B phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP1 TB1-3&4 (wire nos.

A51,A70) and monitor differential current at relay terminal 10.Switch on excitation & slowly raise till generator current isaround 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

E. Proving of Gen. Trf HV winding Diff Protection (87HV)

R phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP2 TB1-22&25 (wire nos.

A511,A570) and monitor differential current at relay terminal6. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay by


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shortcircuiting CT secondary wires on GRP2 TB1-23&25(wire nos.A531, A570) and monitor differential current at relay terminal8. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

B phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP2 TB1-24&25 (wire nos.

A551,A570) and monitor differential current at relay terminal10. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

F. Proving of Generator Differential (87G 2R,Y,B)

R phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP6 TB1-1 & 4 (wire nos.

A111,A170) and monitor differential current at relay terminal27. Switch on excitation & slowly raise till generator currentis around 2000A. Record the values of operated current andGenerator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP6 TB1-2&4 (wire nos.A131, A170) and monitor differential current at relay terminal27. Switch on excitation & slowly raise till generator current

is around 2000A. Record the values of operated current andGenerator current . Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

B phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP6 TB1-3&4 (wire nos.A151, A170) and monitor differential current at relay terminal27. Switch on excitation & slowly raise till generator current


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is around 2000A. Record the values of operated current andGenerator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

G. Proving of GT overhead connection Diff (87TL R,Y,B)

R phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP2 either TB1-1 & 4(A211,A270) or TB1-6&9(A221&A280) or TB1-11&14(A311&A370) or

TB1-16&19 (A321&A380) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP2 either TB1-2 & 4(A231,A270) or TB1-7&9(A241&A280) or TB1-12&14(A331&A370) orTB1-17&19 (A341&A380) and measure differential current at relay

terminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker.Normalise TB wirings and relay settings.

B phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP2 either TB1-3 & 4(A251, A270) or TB1-8&9(A261&A280) or TB1-13&14(A351&A370) orTB1-18&19 (A361&A380) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generator

current is around 2000A. Record the values of operated currentand Generator current . Switch off Excitation and trip fieldbreaker.Normalise TB wirings and relay settings.

H. Proving of Unit Transformers Differential (87 UTAR,Y,B & 87UTB R,Y,B)

UNIT TRANSFORMER - A


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R phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-1 & 4(A111A, A170A) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-2 & 4(A131A,A170A) and measure differential current at relayterminal 27. Switch on excitation & slowly raise tillgenerator current is around 2000A. Record the values ofoperated current and Generator current. Switch off Excitationand trip field breaker. Normalise TB wirings and relaysettings.

B phase: with machine in de-excited condition, block

contribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-3 & 4(A151A, A170A) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

UNIT TRANSFORMER - B

R phase: with machine in de-excited condition, block

contribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-16 & 19(A111B,A170B) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.


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Y phase: with machine in de-excited condition, blockcontribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-17 & 19(A131B, A170B) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

B phase: with machine in de-excited condition, block

contribution of current to differential relay byshortcircuiting CT secondary wires on GRP3 either TB1-18 & 19(A151B, A170B) and measure differential current at relayterminal 27. Switch on excitation & slowly raise till generatorcurrent is around 2000A. Record the values of operated currentand Generator current. Switch off Excitation and trip fieldbreaker. Normalise TB wirings and relay settings.

I. Proving of Backup Impedance(21GRY,YB,BR)

Excite the machine and slowly raise the current till therelay operates. Measure current at relay terminal 5 & voltageacross 7 & 8. Note the values of Operating current andVoltage.

iii) Normalise Generator Transformer HT terminals. OpenGenerator Circuit Breaker.

8.3 Open Circuit Characteristic Test

1. Keep DAVR in manual

2. Ensure that no trip from protection panel as well asDAVR are not present.

3. Field breaker close permissive is available4. Close field breaker5. Excite slowly upto Generator Terminal Voltage reaches 2

KV. Note down the values of Field voltage,fieldcurrent,Generator field current and Generator currentagainst Generator terminal voltage.


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6. Increase the excitation in steps of stator terminalvoltage 2 KV and note down the above values.

7. Tabulate the values noted and draw a graph betweenGenerator field current Vs Generator terminal voltage.

8. Find Characteristic impedance of Generator

Gen.Terminal

voltage

Exciterfieldvoltage

Exciterfieldcurrent

Gen.current

S.No. Gen.FieldCurrent

(Amps)

AVRcontrolVoltage

2000 v4000 v6000 v8000 v10000 v12000 v14000 v16000 v18000 v20000 v21000 v

01.02.03.04.05.06.07.08.09.10.11.

8.4 Proving of Stator earth fault (64G1 & 96G)

64 G1

1. Earth any one of the phases at 400 KV side.2. Keep stator Earth fault relay settings at minimum

value.3. Close FB and slowly raise the excitation. Note the

values of voltage operated and current flown throughearthed phase when relay operates.

4. Normalise the earth and relay setting connectionafter reducing excitation and tripping FB.

96G :


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1. Earth the point where neutral groundingtransformers and generator neutral connectedtogether.

2. Set the relay setting in minimum in order to avoidover strain of generator.

3. Close FB and slowly raise excitation fill relayoperateds note the values of current operated.

4. Reduce excitation, trip FB and then normalise theearth connection made for testing as said in point

No.1.

a. Proving of Over voltage(59G) & under voltage (27G1,27G2)

Excite the machine & reach the rated terminal Voltageacross Generator stator terminals i.e.21 KV . Measure thevoltage across 9 & 10 of 27G1 & 27G2. Reduce the voltage to theset value percentage of the above relays and check that therelays are operated.

Increase the terminal voltage further above rated voltageby 5 or 10 %. Check over voltage relay 59 G1 operated

CAUTION: KEEP AS MINIMUM SETTINGS AS POSSIBLE SO THATGENERATOR STATOR TERMINALS WILL NOT OVERSTRAIN FOR SUDDENVOLTAGE FLUCTUATIONS DURING TESTING.

8.5 Proving of Under frequency Protection(81G1)

1. Short GRP4 TB1-11 &12 to bypass GCB close temporarily.2. Increase the relay setting above 50 HZ for testing so

that it senses normal frequency as under frequency.3. Excite the machine and maintain rated terminal voltage4. Once terminal voltage is reached, underfrequency relay

will operate.5. Normalise TB shortings and relay settings as

recommended.

b. Proving of Gen overfluxing (99G)


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1. Keep the setting to minimum of 1.o2. Excite the machine such that the secondary voltge of

PT at the relay terminals is 110V.3. Relay will operate. After that reduce exdcitation

and trip field breaker.

8.6 SYNCHRONISING:

Now set all the relays as per the recommended values.The following are the steps for synchronizing the

generator to the Grid:8.6.1 Excite the generator to the rated voltage.8.6.2 Switch the synch.selector switch to Manual position

and also switch on the synchroscope.8.6.3 By monitoring the double voltmeter, match the generator

voltage by raising or lowering the excitation. Thegenerator in coming voltage to be marginally greaterthan the running bus voltage.

8.6.4 No check that the phase sequence of the running bus andthe incoming bus are same.

8.6.5 Now raise or lower the speed such that the

synchroscope pointer rotates in the clockwisedirection at a rate such that the check sync. Relayoperates when the pointer is about 12 O clockposition.

8.6.6 Close the generator breaker, when the Check sync inlamps glows.

8.6.7 Now, manually load the generator to 5 % of the ratedload by giving raise command to the speed reference.

8.6.8 Further loading of the generator is done from theturbine control panel.


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9. COMPLETION CRITERIA:

9.1 THE RECORD VALUES OF TESTING CARRIED OUT ON GENERATOR

ARE COMPLETED AND KEPT ALONG WITH THIS TESTING

SCHEDULE.

9.2 GENERATOR AUX SYSTEM FOR RUNNING GENERATOR ARE LISTED AND

KEPT ALONG WITH THIS SCHEDULE.

9.3 GENERATOR IS READY FOR SYNCHRONIZATION.


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10.APPENDICES

Drawings :1. Schematic Diagram of Gen, GT & UT protection (3-562-006-0357) Rev.02

2. Schematic diagram Electrical control panel-1. (3-659-0050610) Rev.

3. Line 1 & line 2 diameter circuits isolatorinterlock (3-562-006-0296) Rev.02.

4. Schematic diagram of 400 KV bus-1&2 protection(TBDG 1865100101/02)

MANUALS : 1. Relay manuals (Volume I to Volume IV)

2. 500 MW Turbo Generator O&M manual.

GENERATOR SYNCHRONIZATION CIRCUIT

Sl

No.

Source location phases values Phase

sequenc

e1 400 KV

Bus 1

ECP1

TBG-23a & 24a

TBG-24a & 25a

TBG-25a & 23a

R - Y

Y B

B R

2 400 KV

Bus 2

ECP1

TBG-27a & 28a

TBG-28a & 29a

TBG-29a & 27a

R Y

Y B

B R

3 Generator

VT

GRP1

TB1-23 & 27

VT 2 (LV

SIDE)


30/30



SHEET 30 OF 30



TB1-27 & 31

TB1-31 & 23

GRP8

TB1-36 & 38

TB1-38 & 40

TB1-40 &36

ECP1

TBG-31a & 32 a

TBG-32a & 33a

TBG-33a & 31a

R - Y

Y B

B - R

VT 4 (HV

SIDE)

R Y

Y B

B R

R Y

Y B

B R

`

gen testing schedule

Documents