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4.1 PREPARATION OF OIL SYSTEM.===========================

4.1.1 Check the quality of the oil in the oiltank by analysing chemically a portion of the oil

taken from oil tank. Drain off the sludge fromthe oil tank and the filters with the help ofcompressed air. Every time the oil tank should becovered Irith its cover to avoid entering ofundesirable matter.

4.1.2 Check the oil level in the tank. Zeroreading on the oil level indicator corresponds tolowest admissible oil level in the tank which is 520mm from the cover of the tank. The highest permissi-ble oil level in the tank is equal to 140 mm fromthe cover of the tank.

4.1.3 Make sure that the float of the oil levelindicator does not seize and check that theelectrical signals are appearing in UCB at correctoil level ljmits.

4.1.4 It is necessary to have an extra quantity ofoil in reserve for making up the losses of the oilsystem.

4.1.5 Check that the gate valves and non-returnvalves on the oil pipe lines are in order.

4.1.6 Open the following gate valves on pipe linesand lock them in that position on the suction lines

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of starting, stand by and emergency oil pumps(OL-1, OL- 3 and OL-2) and at the inlet andoutlet of four oil coolers OL-13 to OL-16 andOL-18 to OL-21. The remaining one oil coolershould be kept as standby.( For valve numbers please refer the drawingNo. STE/FES-014).

4. 1.7 Check that the pumps are fully primed byopening the air cocks. Check that the bearingsof oil pumps and of the electric motors have goodlubrication.

4.1.8 Check that the gate valves OL-6, OL-5 andOL-4 on the delivery side of the pumps are closed.Open the stop valve OL-11 and lock it in openposition.

4.1.9 De-interlock the stand-by oil pump andemergency oil pump.

4.1.10 Now switch on the standby oil pump. Slowlyopen the gate valve OL-5 on delivery line. Within

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(gauge). In this case emergency oil pumpshould start automatically.

d) Switch off both the lubrication oil pump andbring back the valves to their original positions.Barring gear should not start when the oilpressure in lubrication line drops to 0.3 kg/cm2

(gauge) and that can be checked while startingthe turbine and before giving steam to thesealings.

e) The above checking of automatic starting of thelubrication oil pumps should be carried out

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once before every starting of the turbineand once in a week when turbine is running

on load.

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4.2 CHECKING OF THE GOVERNING===========================AND PROTECTION SYSTEM.======================

4.2.1 Set a turbine control gear in its "0"position as per its scale. Start the starting oilpump. By opening the gate valve OL-6 on its delivery

line, raise the pressure to 20 kg/cm2 (gauge).Ensure all the servomotors of emergency stop valvesof HPT, interceptor valves of IPT and control valvesof HPT and IPT should be closed.

4.2.2 Set the load limiter to "0" position as perits scale.

4.2.3 Main steam gate valves before the emergencystop valve and its by passes should be tightlyclosed.

4.2.4 By rotating control gear hand wheel inanticlockwise direction, open the emergency stopvalves of HPT, interceptor valves of IPT and controlvalves of HPT and IPT. Check that their openingshould be smooth.

4.2.5 While rotating the control gear hand wheelin anticlock-wise direction from its "0" position,check the following.:

a) Emergency stop valves servomotors begin toopen when reading on the control gear scale

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is about 5.5 mm and it should be fully openedwhen the reading on the control gear scaleis about 6.7 mm. So 1.2 mm travel of controlgear corresponds to the full opening ofemergency stop valve servomotors.

b) Interceptor valves servomotors begin to open

when the reading on the control gear scaleis about 4.6 mm. Servomotors should be fullyopened when the reading on the control gearscale is about 6.00 mm. That means the 1.4 mmtravel of control gear as per its scalecorresponds to full travel of interceptorvalves servomotor.

c) Control valve servomotor begins to open whenthe reading on the control gear scale is about9.6 mm. It should be fully opened when thereading on the scale of control gear is about

12.8 mm. That means 3.2 mm movement ofcontrol gear should correspond to the fulltravel of control valves servomotor.

4.2.6 Bring back the control gear to in zeroposition as per its scale and ensure that closingof the servomotors and valves are smooth.

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4.2.7 By means of control gear, fully open the

emergenct stop valves, interceptor valves andcontrol valves as per their respective scales.Press the knob of turbine shut down switch andensure that all the valves are fully closedwithout any delay.

4.2.8 Check that, after the operation of protectionsystem, the return of the turbine shut down switchto its original position does not cause theopening of any valves. To reopen the valves,bring back the control gear hand wheel to zeroposition as per its scale and ensure that theprocess of emergency governor pilot charging occur.After charging of emergency governor pilot, valvescan be opened as described above.

4.2.9 Check the protection system by energizing theelectromagnet of turbine shut down switch andensura the turbine tripping with a signal inunit control board.

a) From remote control by operating the turbineshut down switch.

b) From axial shift transducer (by shifting

the transducer either side by a hand wheelprovided for the purpose at the middlebaaring pedestal).

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c) From pressure drop relay by dropping thepressure in lubricating line to 0.3 kg/cm2(gauge).

4.2.10 Check that, emergency stop valves close whenthe oil pressure in the governing system drops to10 kg/cm2 (gauge) and when it drops to 6 kg/cm2(gauge) interceptor valves also close.

4.2.11 After erection, inspection or capital repairsit is necessary to draw the characteristics ofelements of governing system on stationary turbine.

4.2.12 Before starting the turbine the control gearshould be brought to "0" position after finalcheck up of the governing system.

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4.3 PREPARATION AND STARTING OF CONDENSING====================================;=AND AIR EJECTION EQUIPMENT============================

4.3.1 Inspect the condensers and see that waterlevel indicators and vacuume gauges are in order.

4.3.2 Close all the valves on condensate and steam

side of the condensers. Check that manhole coversare closed.

4.3.3 Fill the condenser with condensate orchemically treated water upto 2/3rd of water levelindicators. Open valve MC-55.

4.3.4 Before starting the condensate pumps, thegate valves on the main condensate line at inletand outlet of main ejectors and on inlet andoutlet of all LP heaters.should be opened. In otherwords, the following valves as per piping schemeNo.32800009C should be opened: MC-14, MC-15. MC-16,MC-17, MC-22, IvlC-23, MC-25, MC-26, MC-28, MC-29,MC-31 and MC-32, MC-20, MC-21 and MC-35. Checkthat gate valves for by passing these equipmenti.e. valve No. MC-24, MC-27, MC-30 and MC-33 arein close position.

4.3.5 Globe valves Nos. MC-18, MC-19, and MC-34 onthe condensate line by passing Main Ejectors, Glandsteam Cooler and gland cooler respectively shouldbe closed.

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4.3.6 Ensure that isolating gate valves for controland recirculation valve (CRV) i.e. MC-20, MC-21 and

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MC-35 are in open position and by pass valves MC-37and MC-38 are in closed position. Check thatcontrol and re-circulation valve MC-36 is inworking order.

4.3.7 Prepare for starting the condensate pumps,check motors and their lubrication. Check gland

sealings of pumps and open the cocks for supplyingcondensate to their gland sealings. Open thedeaeration valves Nos. CA-16, CA-17 and CA-18.Valve provided on the discharge nozzle of condensatepump for priming should be opened and closedsubsequently after priming. Unless primedcondensate pumps should not be started.

4.3.8 Before starting the c.ondensate pumps opengate valves MC-1, MC-2 and MC-3 on their suctionlines.

4.3.9 Start one condensate pump. Slowly open thegate valve on the discharge line of the pump. Checkthe gland sealings and temperature of bearings.Follow ammeter reading so as to avoid over loading.Pump should not be operated with closed dischargeline for more than a minute.

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4.3.10. See the condensate level in the condensatehotwell and check if it is within permissiblelimit and the level controller operation is normal.

4.3.11 Condensate level in the condensate hotwellshould be 200 mm lower than the condenser shellwhich corresponds to zero of level indicator. Thecondensate level should be maintained within+/- 200 mm W. C.

4. 3.12 In case the CRV is not functioning properly,maintain the condensate level in the hotwellwith the help of by pass valves MC-37 and MC-38.

4.3.13 Check the operation of all the condensatepumps one after another following the aboveprocedure. Make sure that pumps operate withoutundue noise, and ammeter show normal currentcorresponding the normal operation of condensatepump. Keep one condensate pump in operation.

4.3.14 Supply cooling water to condenser and thenswitch on the barring gear as per specialinstructions, described elsewhere.

4.3.15 Start the main and starting ejectors asfollows:

a) Open the gate valves CA-1, CA- 2, CA- 3 &

CA-4 on the air suction lines from condenser.

b) Open the valve MC-62 on the line supplying

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condensate to sealed gland valves. Regulatethe condensate flow with the help of pressurereducing valve MC-89 and isolating valvesprovided near the respective sealed gland

valves. The pressure down stream of preseurereducing valve should be 1 to 2 kg/cm2(gauge).

c) Open the drain valves DW-46, DW-47 and DW-48,DW-49 from the steam space of ejectors to thedrain expander and condenser respectively.

d) Open the motorised valve CA-5 on the air linebefore the starting ejector. Ensure that thevalve CA-6 provided for vacuum breaking istightly closed.

e) Open the inspection valve DW-42 and DW-43with a view to drain out the collected water,if any, from the steam admission pipes of IPCand HPC respectively. After draining closethese valves tightly.

4.3.16 Start the starting ejector by opening thevalve AS-1 and motorised valve No. AS-4 on the steamline. If necessary, start the main ejectors also byopening the motorised valves AS-2 & AS-3. Steamunder the se circumstances would be required fromauxiliary source.

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4.3.17 Ensure that valves AS-10 thru' AS-15 onsteam supply lines to turbine glands are closod.Open the valve DW-2. Drain the pipe line for airsteam mixture to gland steam cooler by openingvalve DW-52 and close subsequently.

4.3.18 Open the valve MC-56 for filling 15 M syphonand close subsequently.

4.3.19 Drain the sealing header and heat the supplypipe line and sealing header by opening valves AS-7and DW-28. Close valve DW-28 after this operation.

4.3.20 Supply steam to the gland for suction of airsteam mixture from the sealings by opening valve AS-9.

4.3.21 Put in operation pressure regulating valveAS-5 by closing the valve AS-7 and opening the valvesAS-6 and AS-8. Check thepressurc in the headerwhich should be 1.15 to 1.20 kg/sq.cm(abs) so as toensure a sealing steam pressure of 1.01 to 1.03kg/sq.cm(abs) in the gland sealing chamber of theturbine.

4.3.22 Supply steam to gland of the turbineby opening valves AS-10, AS-11, AS-12, AS-13, AS-14

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and AS-15. The temperatura of the steam should be130 oC - 150 oC. Ensure that steam does not leakinto atmosphera from sealings.

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NOTE : Supply of steam to the sealings before-------- =============================starting the barring gear is strictly prohibited.==================================

4.3.23 When vacuum in the condenser reaches 600 mmof mercury column, stop the starting ejector,first by closing the motorised valve CA-5 on theair line and then the motorised valve AS- 4 on steamline. Keep one of the main ejectors operative andshut down the other by closing valves on steam andair side. Valves on condensate side shall remain

open.

4.3.24 Check the operation of the vacuum droprelay (VDR) after the vacuum in condenser is above650 mm of mercury column, in the following manner.

a) Slowly open the vent cock of the vacuum droprelay to drop the vacuum locally. If neededthe cock connecting the vacuum relay to thecondenser may be partially closed. Continueto adjust the position of these two cock sothat vacuum in the VDR drops gradually.

b) Check that the pre-trip annunciation flashesat vacuum of 650 mm of Hg column.

c) Check that signal "Turbine tripped due to lowvacuum" flashes at vacuum of 550 mm ofHg column.

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4.4. PREPARATION OF REGENERATIVE SYSTEM=====================================

4.4.1 Prepare the deaerator for operation.

4.4.2 Check all the supervisory and measuringinstruments of regenerative system.

4.4.3 Make sure that condensing and air ejectionsystem has been put into operation.

4.4.4 Put the drainage system into service bycarrying out the following operations - (For valvenumbers please refer drawing No. 32800009C) .

a) Open the drain valves DW-16, DW-17, DW-18, DW-19

and motorised valve DW-41 for draining thesteam admission pipes of HPC

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b) Open the drain Valves DW-33, DW-34, DW-35, DW-36and motorised valves DW-37 for draining thesteam admission pipes of IPC.

c ) Open the drain valves DW-12, DW-11, DW- 21 ,DW-15 and motorised valves DW-4 for drainingtho high pressure drain collector.

d) Opcn the drain valves DW-13,:DW-25, DW-26DW-27 and motorisod valve DW-38 for drainingthe intermediate pressure drain collector.

e) Drain the air suction pipes of heaters throughdrain valves Nos. DW-53, DW-54, DW-55 andclose them subsequently.

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f) Open drain valves DW-20, DW-50, DW-14, DW-22,

DW-23, DW-24 and motorised valves DW-39,DW-40 for draining the extraction lines afternon return valves. Also open drain valveDW- 3 for draining the leak off steam pipelines to gland cooler.

4.4.5 Open the valves CA-8, CA-9, CA-12 and CA-13on air suction pipes from heaters to the condenserand ensure that the valves CA-7, CA-10 and CA-11are closed.

4.4.6 Commission the system for operation ofextraction non-return valves in following

manne r :-

a) Open the valves MC-58, MC-59 and MC-60. Alsoopen the valves MC-42 and MC-43 before thefilters. Open valves before MC-48 and MC-49 beforethe orifice and valve MC-50 after the orificealso open the valves MC-40 and MC-41 locatedafter the solenoid operated valves MC-53and MC-54.

b) Remove the air from the system with the helpof vent valve MC-51 & MC-52, and thereafterclose them.

c) ManUally open and close the solenoid operated

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valves MC-53 and MC-54 alternatively andensure simultaneous and quick operation ofall hydraulically operated non-return valves.

4.4.7 Open the valves MC-44, MC-45 and FW-4.Check the operation of hydraulically operated by-

pass valves of HP heaters remote manually.

4.4.8 Check the propar functioning of control

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valves HD-1, HD-2, HD-3, HD-4, HD-5, HD-22, HD-23,HD-24 installed in drain lines for HP heaters, LPheaters and gland coolor. This may be done infollowing manner.

a) Put the switch of remote control column inmanual position.

b) Change the position of control valvesclosed or open by 2--30%.

c) Return valve switch to the position"Automatic" and mako sure that the valvesreturn to the original position.

4.4.9 Check the drain level in the heaters, whichshould not exceed 1/2 scale of water levelindicator.

4.4.10 Prepare for starting the drip pump forheater No.2.

a) Supply water to gland soalings.

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b) Open gate valves HD-6, HD-7, HD-12, HD-13,HD-14 on suction and discharge lines.

c) Open the cock CA-14, CA-15 on the air suctionline of drip pumps.

d) Check remote operation of the pumps.

4.4.11 During operation of the turboset, regularlycheck the readings of measuring instruments,mounted directly on the heaters and in theregenerative system.

4.4.12 After ensuring the, flow of condensate intube sides of heaters, commission the low pressureregenerative system, on steam side by opening theelectrically operated valves ES-12, ES-13, ES-14.Open the drain lines of condensate of heatingsteam in such a manner that condensate cascadesfrom heater No. 4 to 3, from heater No.3 to 2 andfrom heater No.2 to condenser i.e. open valvesHD-15, HD-18, HD-16, HD-17, HD-8 and close valvesHD-19, HD-9.

4.4.13 High pressure heaters ,should be switched ononly after the turbine has picked up a load of60-70 MW. Valves Nos. HD-25, HD-26 and HD-27should be kept closed. The opening or closingof electrically operated valves HD-29, HD-30,

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HD-31 and HD-21 are interlocked with the

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pressure in heaters 5 and 6. The valve HD-20should be kept closed under normal operativecondition.