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INTRODUCTION TO GOVERNING
SYSTEM
By : SURAJ KUMAR 16PG047
Content :
1. Governing System.2. Types OF Governing System.3. Features Of KWU Turbine Governing System.4. Turbine Oil System Interlocks.5. Main Elements of Governing System.6. Different Oil and there Colour Codes in KWU Turbine Governing.7. Automatic Turbine Testing ( ATT).8. Conclusion.
What is a governing system ?
To govern means to control and regulate certain parameters to achieve expectedfunctional requirements.
In the context of thermal power plant, Governing system of steam turbine can bedefined as a control and regulatory mechanism whose objective is to enable turbo generator unit to produce quality power with safe operation and to achieve functional requirements of turbo-generator operation by controlling and regulating steam turbine input parameters viz. inlet pressure and mass flow rate of steam.
Types Of GOVERNING SYSTEMOn the basis of steam admission method governing system of utility steam is classified into the following types:-1. Nozzle Governing.2. Throttle Governing.
Most of the LMW turbine have Nozzle Governing and Maximum of KWU turbine have Throttle Governing.
The throttling Governing in KWU Turbine is taken palace by regulating the opening and closing of the CONTROL VALVES present at the inlet of Turbine.
This throttling is taken place by the help of regulating oil pressure.
At the initial start of the Turbine Governing oil which is also known as Control Oil is supply by the Auxiliary Oil Pump ( from 0 RPM to 2800 Rpm) and after 2800 Rpm this control oil is supply by the Main Oil Pump mounted on the Turbine shaft.
Cont.
Features Of Governing SystemThe Turbine Governing System meet the demand of precise control with high response and safety.• Safe operation of turbine during load change period.• Throttling method is used to regulate steam flow a/c to the load demand. Throttling
is done at Control Valve of HP or IP Turbine.• Automatic Turbine Tester is provided to check the operation of protective devices
and closing of ESV, CV while machine in service.
Turbine Oil System interlocks
BARRINGGEAR ON
BARRINGGEAR VALOPEN
BARRINGGEAR OFF
JOP-1 Start & Oil Pre > 150 kg/cm2If Oil Pre falls < 150 kg/cm2 for 7 Sec JOP – 2 will Start
BARRINGGEAR ON
Oil Pre < 4.8 ksc – AOP – 1 StartOil Pre < 4.5 ksc – AOP – 2 StartOil Pre < 1.1 ksc – EOP - 1 Start
JOP OFF
SOAKING600 RPM on 250 MW
120 RPM
< 510 RPM
> 240 RPM > 540 RPM > 2850 RPM& Oil Pre > 7 kg/cm2
< 210 RPM120 RPM
AOPOFF
SYNCRONIZATIONSPEED 3000 RPM
WHEN TRIPPED
MOP @ 9 ksc
AOP - 2 Nos – AC - Oil Pre @ 7 kg/cm2 JOP – 2Nos – JOP-1- AC & JOP-2 - DC - Oil Pre @ 178 kg/cm2EPO – 2 Nos - EOP-1- DC & EOP-2 – AC – Oil Pre @ 2.3 kg/cm2
OIL Grade - SERVO PRIME - 46
Emergency Oil Pump Jacking Oil Pump
Emergency Oil Pump ( EOP). Two numbers of pump of
2x100% capacity. 1 AC and 1 DC. Discharge Oil pressure is
approx. 2.3 Kg/cm2 Mainly used a backup
pump.
Jacking Oil Pump ( JOP). Two numbers of pump of
2x100% capacity. 1 AC and 1 DC. Discharge Oil pressure is
approx. 170 Kg/cm2 Mainly responsible for
lifting of Turbine shaft and lubricating of Turbine shaft in initial condition before 540Rpm
Auxiliary Oil Pump
Auxiliary Oil Pump ( EOP). Two numbers of pump of 1x100% capacity. Both are AC pump. Discharge Oil pressure is approx. 6-7
Kg/cm2 Mainly responsible for supplying
CONTROL OIL ( From 0 – 2850 Rpm), Lifting of turbine shaft (after 540Rpm) and Lubrication.
Main Oil Pump
Main Oil Pump ( MOP). One number of pump of
1x100% capacity. Mounted on Turbine shaft. Discharge Oil pressure is
approx. 8-9Kg/cm2 Mainly responsible for
Lubrication and Control Oil Supply ( >2850 Rpm).
Main Elements in GOVERNING SYSTEM
THE MAIN ELEMENTS OF THE GOVERNING SYSTEMS ARE AS FOLLWS:-
1 . REMOTE TRIP SOLENOID VALVES2 . MAIN TRIP VALVES3 . STARTING AND LOAD LIMITING DEVICE ( SLLD )4 . SPEEDER GEAR ( HYDRAULIC GOVERNOR)5 . HYDRAULIC AMPLIFIER6 . ELECTRO-HYDRAULIC CONVERTER 7. AUX FOLLOW UP PISTON VALVES 8. FOLLOW UP PISTON VALVES 9. HP/IP CONTROL VALVE SERVOMOTOR10. HP/IP STOP VALVE SERVOMOTOR11. SEQUENCE TRIMMING DEVICE12 . OVERSPEED TRIP DEVICE13. TEST AND CHANGE OVER VALVES
S.No Name of Oil Source & pressure Purpose Colour Code
1. Control Oil MOP/AOP ( 7-8.5 Kg/cm2) To establish Trip Oil, Aux Trip Oil, Trip Oil, Start-up Oil, Aux Start-up Oil, Aux Secondary Oil, Secondary Oil, Primary
Oil, Etc2.
Trip OilMain Trip Valve (4.8-6 Kg/cm2) To reset , Open & Trip stop valve
3. Aux Trip Oil Main Trip Valve (4.8-6 Kg/cm2) To trip Hydraulic Trip Device
4.Start-up Oil
Starting Device ( 5.5 Kg/cm2) To assist Resetting & Opening Stop Valves
5.Aux Start-up Oil
Starting Device ( 5.5 Kg/cm2) To Reset Main Trip Valve & Hydraulic Trip Device
6.Aux Secondary Oil
Speeder Gear ( 2.3-4.8 Kg/cm2) Input Signal to Hydraulic Converter
7. Secondary Oil (HP/IP)
Hyd/Electro-Hyd Converter ( 0-6 Kg/cm2)
To govern HP/IP Control Valve opening
8. Primary Oil Primary Oil Pump ( 0-2.3 Kg/cm2) Feedback speed signal for HG
9.Test Oil
Over Speed Test Device ( 2.0 Kg/cm2) To test Over Speed Test Device
10. Drains
Different oils, their colour codes, sources and purpose in KWU Governing System
1. REMOTE TRIP SOLENOID VALVES
Cont.
These are Four in numbers, connected before the Main Trip Valves(MTV) in the governing rack.
The Main function of the RTSV to supply the CONTROL OIL to the MTV .
Whenever the Turbine got trip these RTSV gets energized and stop the flow of CONTROL OIL to the MTV.
2. MAIN TRIP VALVES
Cont.
These are two in numbers present in the series connection with the RTSV.The main function is to generate TRIP OIL and AUXILIARY TRIP OIL.The Function of trip oil is to reset or open the Stop valves and to work as the source for the HYDRAULIC AND ELECTRO-HYDRAULIC CONVERTER.The Function of Auxiliary trip oil is to trip the Hydraulic device.
3. STARTING AND LOAD LIMITING DEVICE ( SLLD )
Cont.
The Main function of SLLD is to reset the protective device and latch the HP & IP Stop valves. At SLLD opening of 42 % HP SV Open and at 56% opening IP SV open.
Working:Control oil is supplied to SLLD which generates AUXILIARY START-UP OIL and START-UP OIL for protective device and stop valve.
4. SPEEDER GEAR ( HYDRAULIC GOVERNOR)
Cont.
Also known as adjusting gear, used to manual or motor operation of reference speed setter and SLLD.
5. ELECTRO-HYDRAULIC CONVERTER.
Cont.
The main function of the Electro-Hydraulic converter is to convert the TRIP OIL to the SECONDARY OIL for the Opening and Closing of the HP CV and IPCV.
It is the main source of Secondary oil for the HPCV and IPCV.
IP CV control oil HP CV control oil
Cont.
6. HYDRAULIC CONVERTER.
Follow UP-Piston
Cont.
The main function of the Hydraulic converter is to convert the TRIP OIL to the SECONDARY OIL for the Opening and Closing of the HP CV and IPCV.
It is the backup source of Secondary oil for the HPCV and IPCV besides Electro-hydraulic converter.
IP CV control oil HP CV control oil
Cont.
7. TRIM DEVICE
Cont.
The main function of the TRIM DEVIVE is to cut the flow of the IP Control Oil and reduce the opening of the IPCV.
8. HP ESV/ CV9. SERVOMOTOR
Cont.
10. CHANGE OVER VALVE
Cont.
11.OVERSPEED TRIP DEVICE
Cont.
GOVERNING SYSTEM
Automatic Turbine Testing(ATT)
ATT plays a vital role in the Governing System. ATT is responsible for the safety and proper working of the elements of the Governing System .Its unable us to test the safe operation of the turbine by testing different elements of the Governing System such as : 1. ESV .2. CV.3. MTV.4. Over Speed Trip devices.
ConclusionThe Governing System act as the Back Bone of any Turbo Generator Unit as it not only control and regulate the steam parameters according to the load but also responsible for the safety and safe operation of the Turbine.