commissioning of hydro.ppt

7/28/2019 commissioning of hydro.ppt

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COMMISSIONING

HYDRO POWER STATION


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Dam

Reservoir

Power intake (Penstock)

Power house

Turbine

Draft tubeMain inlet valve

Generator

Bus Duct

Field Excitation System

Governing System

SCADA System

Station Transformer

Balance of PlantProtection system & switchgear

LV/ HV distribution

DC, UPS Battery

Switch Yard

Following are the main components of a Hydroelectric Power Plant

INTRODUCTION


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Dome

Stator

Rotor

Generator Shaft

Turbine Shaft

Spiral Casing

Stay Ring

Runner

Draft Tube


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COMMISSIONING

Definition

Testing of new equipments to checkits conformity with contractualspecifications, as well as operation ofthe equipment until formallyaccepted by the Customer.

Commissioning usually occurs afterfirst erection of a new unit.


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Commissioningactivities consistof various tests:

Pre-commissioning tests

Prior to filling waterways

After filling waterways

Initial Run test

Test Run

COMMISSIONING


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READINESS CRITERION

Commissioning activities in hydro project begin with the filling of waterways on

the down stream side (common tailrace) and up stream side (Head Race or

Penstock) of the machine. This implies readiness of hydro set which broadlycomprises of following equipments and their readiness criteria :

1. Draft Tube and Liner, Spiral casing, Tail Race Channel, Penstock and gates etc. for

their erection and checks from the point of view of cleanliness, civil grouting work for

the hollow portions between metal and concrete contact surfaces etc.

2. It is to be ensured that there is no impediments in the free flow of water from any

projecting lumps of concrete/reinforcement rods etc.

3. The grouting plugs have been welded and flush grinded as per Drawing requirement

and no obstruction exists from any local bending of metallic liners etc. in the water

path.

4. Painting work of underwater parts with black anticorrosive paint has been completed.


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The Machine itself has been made ready mechanically along with its auxiliaries. This will

include the following major equipments/systems/works and other preparations :

Turbine & Turbine Pit :

1. Runner blade and chamber clearances have been checked and found OK to ensure that

no rubbing is likely to occur during start up and running.

2. Air inflated repair seal of Turbine shaft is OFF and cooling water to working seal willbe available when CW system is charged.

3. Turbine bearing oil is at proper level neither too high nor too low let the drawing be

followed at this stage. Keep record of pumping holes in the skirt if provided-whether

plugged and how many.

4. Manual/Auto greasing of guide vanes etc. has been done for smooth operation.

5. Easy mobility along with sufficient lighting both AC/DC provided in the pit.

READINESS CRITERION


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6. Dry stroking of guide apparatus/ MIV have been done upto full rated oil pressure of

OPU through governor. Record Opening/Closing and damping times.

7. Dowelling work etc. of bearing housing etc. has been completed.

8. Fulfillment of all requirements given in O&M manuals/check lists of the project to

be ensured.

9. De-watering of draft tube checked twice by closing the draft tube gates.

10. Turbine top cover drainage system is operational and in Auto to avoid turbine pit

flooding during first filling of TRC and subsequently during penstock filling etc.

Preferably additional pumping arrangement, not dependent on Electric Supply (i.e.

Air Operated) be provided as quantity of leakage water from shaft, Guide vane cup

seals, etc. is not known at this time. This is more necessary when starting a machineafter a long delay after erection.

READINESS CRITERION


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Generator & Generator Barrel :

1. Generator and its sub assemblies have been fully erected as per drawing and cleaned

with dry compressed air/cloth. Check top and bottom air guide clearances whichshould be at least 8-10 mm ( as per drawing requirement) from the rotor fan blades.

2. Stator/Rotor gap must be free from any foreign object which is usually checked by

taking a rope all around the gap along the full height of the stator core.

3. Check and ensure that Generator barrel/bracket areas are free from foreign objects,hanging wires/cables, loose electrical connections, loose clamps etc.

4. Bearing vapour seal segments may not be assembled in position during initial runs to

avoid likelihood of rubbing until performance in terms of vibration and wobble is

proved up to full speed (This is not applicable for vapour seals of wool felt type).

5. Initial bedding of slip ring carbon brushes, cleaning of slip rings etc. has been done.

Carbon brushes to be kept disengaged from the slip rings, during initial runs as no

excitation is to be given during this time. Should be in for proper bedding .

READINESS CRITERION


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6. Dowelling of stator frame/brackets etc. has been done and secondary concreting of

Stator and lower bracket foundations have fully cured. Epoxy grouting of foundationbolts to be ensured. Tightening of all bolts and their locking particularly of the

rotor/rotor lead clamps/pole to pole joints etc. to be carefully checked.

7. Generator Barrel water mist Fire Extinguishing system commissioned and kept ready in

manual/Auto mode, which is to be switched on prior to voltage build up/

synchronisation/loading.

8. Brake system is already tested for reliable lifting and release 10 times from HP

compressor/pressure reducer air system or L P air system along with Limit Switch

operation for indication/control. Free operation of brakes to be ensured. Auto operation

of Brake is to be disabled during initial period (Brake Air Pressure should be adjusted

for 4-5 Kg/cm2

). Brakes should be applied at a speed as given in design which is usually20 to 25% of rated speed). Required oil should be filled up in air filter unit.

READINESS CRITERION


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9. Generator bearings oil should be at proper level as per Drawing and this should be

marked in gauge glass. Operation of low/high level float switches should be checked.

10. Performance of HS Lube system to be proved. Check lifting of Rotor from HS lube

pressure by 4 dial gauges placed at X and Y positions i.e at 4 points to know

amount and uniformity of lift all around. The HS Lube pressure should not exceed

specified design value. Safety relief valve to be adjusted depending on the pressure

required for jacking. HP lub oil pressure switches/gauge to be adjusted for normal &

low pressure. Ensure no loose connections in the electrical circuits to avoid sparking

and consequent fire hazard in these enclosed spaces.

READINESS CRITERION

PRE REQUISITES FOR


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1. 440 V 3 Phase AC supply

2. 240 V 1 Phase A.C. supply

3. 220 V DC or 110 V D.C. Power supply system

4. 48 V DC Power supply system

5. Dewatering, Drainage and leakage collection system and their pumping arrangement.

6. 11 KV or 13.75 KV along with cable etc. for commissioning of excitation system.

7. 24 V DC power supply system.

8. The intake gates, draft tube gates and butterfly valves are tested for safe and reliable

operation and equipped with operator personnel and telephonic connection .

9. Oil supply system.

10. Compressed air system.

11. Completion of cable laying , termination @ earthing

12. 240 V AC UPS supply.

PRE- REQUISITES FOR

COMMISSIONING

PRE REQUISITES FOR


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13. Readiness of water conducting system .

14. Civil works in the vicinity of active and sensitive electrical and mechanica

machinery/equipment are finalized. Floors are clean and dry.

15. Station earthling system is in full and reliable condition.

16. Main fire fighting system for the power house cavern in safe operating

condition, including the portable fire extinguishers.

17. Ventilation, illuminations, communication, and Air-conditioning available

on a permanent base.18. Readiness of protective covers, guards ladders and covering of floor holes

and pits.

PRE- REQUISITES FOR

COMMISSIONING

PRE COMMISSIONING


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PRE-COMMISSIONING

TEST/CHECKS

Pre-commissioning

Tests:

Test between completion oferection of the equipment andinitial run.

Tests/Checks prior to filling

waterways Tests/Checks after filling of

waterways

TEST/CHECKS PRIOR TO


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TEST/CHECKSPRIORTO

FILLINGWATERWAYS1. Inspection of all the turbine waterways and removal of all

foreign or loose objects.

2. Calibration of scales for wicket gate opening and whereapplicable, for runner blades, needles and deflectorsincluding their cam relationships; and also measurementof clearances.

3. Operation of pressure oil units, MIV, governors, automaticand manually operated starting and stopping devices andsignaling devices.

4. Oil levels and pressures in governing system; Condition ofall oil filters.

TESTS/CHECKS PRIOR TO


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TESTS/CHECKSPRIORTO

FILLINGWATERWAYS

5. Protective devices such as oil level and temperature alarms and

relays, with adjustment if needed.

6. Times of opening and closing of governing elements, i.e. wicket

gates, runner blades of turbines with movable blades, needles

and deflectors of impulse turbines.

7. MIV opening and closing times.

8. Bearing and seal clearances and functioning of hydrostatic

lubrication system.

TESTS/CHECKS PRIOR TO


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TESTS/CHECKSPRIORTO

FILLINGWATERWAYS

9. Operation of drainage pumps and dewatering pumps.

10. Oil, grease and water supply to all bearings and seals

requiring lubrication or cooling.

11. Operation of braking system of the unit.

TESTS/CHECKS


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TESTS/CHECKS

AFTERFILLINGWATERWAYS

1. The Tail water gate shall be opened first after filling the draft

tube and spiral case up to tail water level through a fillingvalve of the draft tube gates. Check for leaks is to be made.The whole waterway should be filled slowly and manuallythrough a bypass valve of the penstock.

2. Operation of emergency protection devices which actuatesthe intake gate/MIV and closure of guide vanes and stoppageof machine is to be checked.

3. If the protective devices and emergency closing system work

satisfactorily, and no unusual leakage or deformation isobserved, Initial run of the Machine can be initiated.


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INITIAL RUN

After the permission for initial run, locking devices and brakes are

released and the turbine wicket gates or needles are openedunder manual control, slowly as per manufacturersrecommendations and bring the speed up to at least the minimumstated value.

If any noise, scraping or other abnormal phenomena is observed,the unit should be shut down immediately and thorough inspectionis to be carried out to find out the cause of the problem and rectifythe same.


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Time

Unit speed

Servomotor stroke

Temperature of bearing

Shaft run out

MeasurementsItems:

Tachometer

Dial indicatorInstruments to

be used:

INITIAL RUN

TEST RUN


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TEST RUN

Mechanical Spinningwithout Excitation

Spinning with Excitation

Synchronization with thegrid

Load run and LoadRejection Tests

Test

Runconsistsof :

MECH SPINNING WITHOUT


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MECH. SPINNINGWITHOUT

EXCITATION

1. The unit is kept under manual control at or above starting

speed until bearing temperatures are stabilized.

2. If any temperature is excessive or increases too rapidly, the

unit shall be shut down and the causes of this phenomenon is

to be investigated and corrected.

3. If all goes well, the unit speed shall be increased in

prearranged steps up to the rated value, remaining at each

successive speed until the rate of rise of all bearing

temperatures is satisfactory to the manufacturer'srecommendation.



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During each speed step of test run, at least the followingmeasurements / observations should be made:

1. Deformation of covers and bearing supports

2. Noise or vibration in the turbine and/or generator

3. Operating conditions for the oil pressure and other pumps.

4. Condition of oil in the bearings and pressure oil systems. If

water is observed in oil, the leaks shall be located andeliminated. If oil foaming is observed, the cause shall belocated and eliminated.

5. Temperatures of bearings and lubricating oil.

6. Shaft run out at turbine and generator bearings and axialdisplacement of rotating parts is measured.

7. At some agreed speed value, the action of braking systemshall be checked.

M C . S GW OU

EXCITATION



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Tachometer

Vibration meter (Structure)

Dial indicator

Thermometer

Instrumentsto be used:

. SEXCITATION

SPINNING WITH EXCITATION


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SPINNINGWITH EXCITATION After bearing run, the machine is prepared for short

circuit test.

For this test, we do three phase shorting at generator

terminal then the excitation is increased from zero up

to the full load stator current.

During this test, operation and stability test of

differential protections are also checked.

After SCC test, we go for high voltage test for statorwinding.

BASIC TESTCIRCUITFOR SCC TEST

SCC TEST


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SCC TEST

A

B

SCC TEST


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C

SCC TEST

SCHEMATICCONNECTIONDIAGRAMFOR


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SCC TEST

HV TEST FOR STATOR WINDING


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HVTESTFOR STATORWINDING Used for testing the dielectric strength of generator

stator winding insulation.

For less than 10MW, test voltage (r.m.s.) shall be1000V+2*Rated voltage; subject to minimum of 1.5kV.

For machines with a rated voltage 6 kV or greater,

when power frequency equipment is not available, then

by agreement a DC test may be carried out at a voltage

1.7 times the r.m.s. values to be chosen in case of ACtest.

For more than 10 MW, Test Voltage (r.m.s.) shall be

For voltage less than and equal

to 24kV

2*Rated voltage + 1000 V

For voltage more than 24kV Subject to agreement

OCC TEST


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OCC TEST

After successfully completing the HV test, OCC test is

carried out.

In OCC test, excitation cable is restored and voltage isbuild up to rated voltage in steps of 1KV. Then, Open

Circuit Characteristic Curve is drawn.

Operation of Stator earth fault protection is also checked by

creating actual earth and performance test of all voltage

relays is also carried out .

BASIC TESTCIRCUIT

FOR OCC TEST

SCHEMATICCONNECTIONDIAGRAMFOR


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OCC TEST

SYNCHRONIZATIONWITHTHE GRID


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Phase sequence of Generator voltage and Gridvoltage must be the same.

Two voltages must be equal, i.e. IV1I - IV2I=0.

The generator frequency must be nearly equal tothe Grid frequency, i.e. f1- f2 0.

At the instant of synchronizing, the two voltagesmust be almost co-phasal, i.e. 12 0.

The

followingconditionsmust besatisfied:

Finally the machine is synchronized with the grid at

the partial load.

SYNCHRONIZATIONWITHTHE GRID


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The degree of criticality of these parameters are in thefollowing order:

,V,f.

The inertia of the incoming machine being very smallagainst that of the grid, even with considerable f, themachine will easily be pulled into synchronism.

Voltage difference, if large, can result in heavy exchange ofVAR and can result in voltage fluctuations, if large enoughleading to instability.

Large can result in heavy exchange if MW, often goodenough to cause torsional damage to the shaft system.

LOAD RUN ANDLOAD REJECTION TESTS


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LOAD REJECTION TESTS

When the generator and switching equipment has been

declared ready for operation , the unit is synchronized.

During the load rejection tests, all necessary precautions shallbe taken to ensure that rated values of penstock andturbine stresses will not be exceeded. Such precaution

may include setting governor timing.

When adjustments are made on governor or regulating devicesall tests which might be affected by the adjustment shallbe repeated.



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To check the output of the unit with an agreedaccuracy.

To check the unit for instability, vibration orcavitations in the range of guaranteed loads.

To check the functioning of governor andregulating devices, as well as that of the entireunit.

To determine the momentary pressure and speedvariations of the unit and to find their extremevalues. To adjust the closing times of the wicketgates, needle valves and deflectors to minimizeover speeding of the unit within the permissiblelimit of pressure variation

To permit testing of the operation of otherhydraulic and electrical equipment, includingprotection and other automatic devices.

PURPOSES:




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PROCEDURE:

The load shall be increased in steps and load rejection test made at

successively higher loads up to the maximum expected to be placedon the unit. For example: rejections may be made at 25%, 50%, 75%and 100% of the rated load as well as from the maximum load thatmay be agreed upon.

Two rejections shall be made at each load. One rejection is made

under governor control to no load gate or needle opening, the othermay be an emergency shutdown by stop solenoid.

If specified, load rejection tests shall be made by means of theemergency valve or by any other emergency device.

After the completion of each load rejection test, the pressure rise andturbine speed rise data shall be analyzed to ensure that the specifiedsafe limits will not be exceeded during the next higher load rejectiontest.




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Observations, Measurements and Recordings:


Head and tail water level

Generator output.

Wicket gate or needle opening (where applicable)

Pressure at turbine inlet and outlet

Pressures and levels in oil pressure systems

Operating times of oil pressure pumps.

Temperatures in bearings.

Noise levels, if values are specified in thecontract.

Abnormal noises if any.

Vibration and other displacement of rotating andfixed parts.

Action of air-admission devices if any.

Applicablefor SteadyState

Operation:



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Observations, Measurements and Recordings:


Head and tail water levels Generator output

Strokes and closing times of wicket gates orneedles where applicable.

Pressure at the turbine inlet and outlet.

Level variations at intake and surge tanks

Pressure drop in the oil pressure system in theprocess of governing, and variation of level inthe oil pressure reservoir.

Noise levels, if values are specified in thecontract.

Abnormal noises, if any.

Vibration and other displacement of rotating andfixed parts.

Action of braking jets in case of Pelton turbine.

Load

rejectionand

subsequenttests:

COMMERCIAL RUN


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COMMERCIAL RUN

After meeting all the

contractual requirements of

operation, the machine canbe declared ready for

Commercial Run.


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ILLUSTRATIVE

PHOTOGRAPHS

Generator Barrel & Turbine Pit


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STATOR SECTION


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GENERATOR

ROTOR

LOWERING OF ROTOR


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DRAFT TUBE

ERECTION


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STAY RING

SPIRAL CASING


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HYDROSTATIC

TESTING

TURBINE RUNNER


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TURBINESHAFT


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TOP COVER & TURBINEASSEMBLY


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ASSEMBLY

LOWER BRACKET


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LOWER BRACKET

ASSEMBLY OF MIV


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BUTTERFLY TYPE SPHERICAL TYPE


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Documents

commissioning of hydro.ppt