INTRODUCTION TO GOVERNING

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.