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Governing System Presentation Transcript
1.GOVERNING SYSTEM
To regulate the speed of the Turbine at various loads in a isolating set
To regulate the load as per the frequency demand when working in a grid network.
To prevent and protect the turbine from over speeding.
To allow on line testing of various safety protections .
To enable the tripping of TG set in the event of actuation of protections.
Safe and healthy loading of the TG Set
2.TYPES OF GOVERNING-I
Nozzle Governing
Throttle governing
Bypass Governing
Governing is effected by varying the amount of steam which is further done by changing the positions of control valves.
Any Throttling of Steam will lead to losses . In governing system along with the change of quantity of steam the quality of the steam also changes. Therefore Throttling should be minimum.
To regulate the speed of the Turbine at various loads in a isolating set
To regulate the load as per the frequency demand when working in a grid network.
To prevent and protect the turbine from over speeding.
To allow on line testing of various safety protections .
To enable the tripping of TG set in the event of actuation of protections.
Safe and healthy loading of the TG Set
2.TYPES OF GOVERNING-I
Nozzle Governing
Throttle governing
Bypass Governing
Governing is effected by varying the amount of steam which is further done by changing the positions of control valves.
Any Throttling of Steam will lead to losses . In governing system along with the change of quantity of steam the quality of the steam also changes. Therefore Throttling should be minimum.
3.BYPASS GOVERNING
It is employed in small capacity turbines running on high pressure conditions and with small blading dimensions.
Here the loading up to appx 80% ( Economic loading ) is met by normal control valves feeding the First stage. For higher loading , to supply more steam which is not possible due to small blading dimensions ( can lead to operational problems) the extra quantity of the steam is fed to the intermediate section of turbine bypassing the initial high pressure stages.
It is employed in small capacity turbines running on high pressure conditions and with small blading dimensions.
Here the loading up to appx 80% ( Economic loading ) is met by normal control valves feeding the First stage. For higher loading , to supply more steam which is not possible due to small blading dimensions ( can lead to operational problems) the extra quantity of the steam is fed to the intermediate section of turbine bypassing the initial high pressure stages.
4.TYPES OF GOVERNING-II
Constant Pressure Mode: Here pressure upstream of control valves is kept constant and change is made by changing the position of control valves.
Variable Pressure mode:Here control valves are in full open position and pressure upstream of control valves varies proportionately with the load requirement.
Response of Constant pressure Mode is much faster than Variable pressure mode, but Constant pressure leads to more losses.
Constant Pressure Mode: Here pressure upstream of control valves is kept constant and change is made by changing the position of control valves.
Variable Pressure mode:Here control valves are in full open position and pressure upstream of control valves varies proportionately with the load requirement.
Response of Constant pressure Mode is much faster than Variable pressure mode, but Constant pressure leads to more losses.
5.TYPE OF GOVERNING -III
Mechanical: Transducer is mechanical centrifugal speed governor which actuates controls valves through mechanical linkages.
Hydro mechanical: Here transducer is a centrifugal speed governor .It is connected to a Hydraulic system where the signal is amplified so that Control valves servomotor can be actuated.
Hydraulic: Here speed transducer is a centrifugal pump whose discharge pressure is proportional to square of speed. This signal is sent to hydraulic converter which generates
Mechanical: Transducer is mechanical centrifugal speed governor which actuates controls valves through mechanical linkages.
Hydro mechanical: Here transducer is a centrifugal speed governor .It is connected to a Hydraulic system where the signal is amplified so that Control valves servomotor can be actuated.
Hydraulic: Here speed transducer is a centrifugal pump whose discharge pressure is proportional to square of speed. This signal is sent to hydraulic converter which generates
6.a signal which is proportional to valve opening/Closure is required. Before applying it to control valves servomotor this signal is suitably modified.
Electro Hydraulic:Here transducer can be electrical or Electronic. The generated signal after processed electronically and electrically is fed to a Electro- hydraulic converter which converts electrical signal into Hydraulic signal.Hydraulic signal before applying to control valve servomotor is suitably amplified.
Electro Hydraulic:Here transducer can be electrical or Electronic. The generated signal after processed electronically and electrically is fed to a Electro- hydraulic converter which converts electrical signal into Hydraulic signal.Hydraulic signal before applying to control valve servomotor is suitably amplified.
7.Regulation % of Turbine is defined as
(No load Speed - Full Load speed) X 100 %
It varies from 2.5% to 8%
Normally it is 4 to 5 %
Turbine having less regulation will be more sensitive in the grid and hence will share more load and vice versa
Normally base load plant has high regulation and Peak load plant has small regulation.
(No load Speed - Full Load speed) X 100 %
It varies from 2.5% to 8%
Normally it is 4 to 5 %
Turbine having less regulation will be more sensitive in the grid and hence will share more load and vice versa
Normally base load plant has high regulation and Peak load plant has small regulation.
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