35 THINGS YOU SHOULD KNOW DURING COLD STARTUP OF TURBINE:-
Heii power plant engineers today we discuss about a very important topic which is “35 THINGS YOU SHOULD KNOW DURING COLD STARTUP OF TURBINE ” in this topic we learnt about the very important things about the cold start up of turbine . cold start up of turbine is very critical operation of turbine in which all things is closely monitored during the start up if we are not take this serious and doing faulty operation a serious damage could be happen . so during the turbine cold start procedure all things which i tell about further in this topic should be followed for safe start up procedure of turbine .
STEAM TURBINE START UP SEQUENCE
1. Put Power, cooling water and air in service..
2. Check all valves of pressure gauges, pressure switches, level switches if they are open.
3. Ensure Oil level in MOT (Main Oil Tank) is Healthy i.e. above 30%.
4. Start Oil Vapor Extraction Fan and raise the Oil Temp to 40-42°C, if required
5. Start the Auxiliary oil pump, and put the Emergency oil pump in AUTO.
6. Put the TG set on barring gear and keep the selector switch in AUTO mode.
7. Keep the position of changeover valve of Oil Cooler to be taken into service. Starting the water side of Oil Cooler charging after ensuring ACW Pump is in service (open cooling water I/L valve 100% and open the cooling water side vent. Then open cooling water O/L valve as required based on the Oil Temperature after ensuring water is coming out from the water side vent and then close the vent valve.). Ensure water side drain valves are closed. Check out all the water side drain & vent valves of stand by Oil Cooler should be closed.
8. Open the shell side vent of Oil Cooler to release the air entrapped inside the shell and ensure drains of shell side are closed. Check out shell side all drain & vent valves of stand by Oil Cooler are closed for emergency use. After ensuring oil is coming out from shell side vent of Oil Cooler, vent is to be closed.
9. Open the Lube Oil Filter vent to release the air entrapped inside the Filter & ensure drain of Lube Oil Filter is closed. All drain & vent of stand by Lube Oil Filter are closed. After ensuring oil is coming out from vent of Lube Oil Filter, vent is to be closed.
10. Ensure Lube Oil Header Pressure is 2.0 kg/cm2.
11. Ensure Lube Oil Outlet flow through Sight Glasses provided in Alternator.
12. Check the mobility of the main stop valve and throttle valve as follows:
- Check that the Trip solenoid valve is not in tripped condition.
- Turn the hand trip lever to “RUN” position.
- Slowly operate the ESV by hand wheel until the valve is fully open.
- Turn the hand trip lever to “TRIP” position and ESV should fall to the closed position.
13. Ensure the drains of GSC are cleared without any choke.
14. Ensure all the steam drains, warm up vent are in open condition, use trap by- pass in line during warm up of steam line.
15. Open all the Turbine drains as follows:
- Nozzle drain
- Chest drain
- Casing drain
- ESV drain
- Gland sealing drain
- Ejector steam line drain
- Warm- Up line drain
16. Open Boiler MSSV by-pass at 20 Kg/cm2 also partially open the isolation valve for both Ejector PRDS and turbine inlet for line heating.
17. Open the Boiler MSSV at 40 Kg/cm2 by throttling all the drains in view of equalizing the pressure before and after the MSSV.Once the Boiler MSSV is opened fully, close the MSSV By-pass valve.
18. Close the Trap By-pass and take steam trap in line once it is ensured that all the condensate is removed from the system.
19. Open fully the isolation valve of ejector PRDS and Turbine inlet stop valve at HP header.
20. Charge the gland sealing once the required pressure 8 kg/cm2 and temperature above 250 °C. is achieved.
21. Maintain the gland sealing pressure at 0.10-0.20 Kg/cm2g and Temperature of 250 °C.
22. Pull the Vacuum once the required Aux. Steam pressure of 8 Kg/cm2 and Temp. Above 250°C is achieved.
23. Once the all the parameters achieved as mentioned below:
- Turbine Inlet Steam Pressure- 64 Kg/cm2.
- Turbine Inlet Steam Temperature-455°C.
- Vacuum Achieved – (-0.80 Kg/cm2g)
24. Reset the Trip from Wood ward 505 governor panel, also after resetting push run button in the governor panel governor will automatically take the pre-settled set point i.e.6000 RPM.
25.Ensure that after resetting all the alarms a SOV reset LED in the TCP panel will glow.
26. Push the reset knob on the L.P. oil trip valve and hold the same for 5-10 seconds. Knob will be released automatically once you release your hand.
27. If throttle valves do not open, slowly lift the governor output arm to its uppermost position raising the relay cylinder pilot valve.
28. Crack open the Turbine inlet steam stop valve near to ESV slightly in such a way to follow the start up curve.
29 .Crack open the ESV valve by rotating the hand wheel to anticlockwise position slightly in such a way that turbine should start rotate.
30 .Now slowly open both the above valves in such a way to achieve the 6000rpm following the speed rising curve. Also ensure that at this governor should take over.
31. Ensure the barring gear should stop at 600 rpm. Also MOP will take over at 6500 rpm AOP should stop manually after achieving the Turbine speed 7000 rpm.
32. Once the governor takes over i.e. at 6000 rpm open the ESV handle wheel fully also the Turbine inlet isolation near to ESV.
33 .Operate from the governor panel to achieve the rated speed (7545 rpm) of the machine.
34 .After synchronizing increase the load according to start-up graphs by pushing the corresponding keys on the WOODWARD Do not allow exhaust steam temperature to exceed 105°C.
35 . after that all steam temperature and pressure are maintained increase the load manually / from DCS gradually
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