The power scarcity caused when the load of the generator increases suddenly is overcome by the kinetic energy which is stored in the rotating system. When the kinetic energy decreases, the turbine speed slows down due to the which the frequency of generator also falls down. This variation in the speed is overcome by turbine speed governor which brings the speed to a new steady state by adjusting the input valve of the turbine to vary mechanical power output.
Thus, this device plays a vital role in controlling the output of the alternator. It is present between the output of boiler and input of steam turbine to control the steam input to the turbine.It controls the real power flow in the power system. It is a primary tool for load frequency control.
The main parts of turbine governing system are
Thus, this device plays a vital role in controlling the output of the alternator. It is present between the output of boiler and input of steam turbine to control the steam input to the turbine.It controls the real power flow in the power system. It is a primary tool for load frequency control.
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- Fly ball speed governor
- Linkage mechanism
- Hydraulic amplifier
- Speed Changer
Fly-ball speed Governor:
The speed governor is the heart of the system. It senses the change in speed i.e; error. The mechanism in it provides upwards or downwards motion proportional to the increase or decrease in speed.As the speed
increase, the fly balls move outwards and as the fly balls move inwards the fly balls move inwards.
Linkage Mechanism:
Depending on the speed whether to increase or decrease, the links align themselves for compensating the error.
Hydraulic Amplifier:
It consists of main piston and pilot valve. With this arrangement of pilot valve and main piston Hydraulic amplification is achieved, which is nothing but the process of converting low power pilot valve movement to high power level piston valve movement. Hydraulic amplification is necessary to operate the steam valve i.e; to open or close the steam valve against high pressure steam.
Speed Changer:
This plays an important role in the whole speed governing system. It enables the speed governor system to adjust the speed of turbo generators and provides a steady state output setting for the turbines. When the speed changer moves in upward direction, due to which the upper pilot valve opens and high pressure oil will rush on the main piston and main piston moves in downward direction. Thus opening the steam input to the turbine increases due to which the mechanical power also increases. The reverse action occurs for the downward movement of the speed changer.
Though this seems to be quite efficient, it doesn't operate fast. The power system has to bear the change in frequency till the speed again reaches to the normal value i.e; rated speed of turbine. Now-a-days these are replaced by automation.
Hydraulic Amplifier:
It consists of main piston and pilot valve. With this arrangement of pilot valve and main piston Hydraulic amplification is achieved, which is nothing but the process of converting low power pilot valve movement to high power level piston valve movement. Hydraulic amplification is necessary to operate the steam valve i.e; to open or close the steam valve against high pressure steam.
Speed Changer:
This plays an important role in the whole speed governing system. It enables the speed governor system to adjust the speed of turbo generators and provides a steady state output setting for the turbines. When the speed changer moves in upward direction, due to which the upper pilot valve opens and high pressure oil will rush on the main piston and main piston moves in downward direction. Thus opening the steam input to the turbine increases due to which the mechanical power also increases. The reverse action occurs for the downward movement of the speed changer.
Though this seems to be quite efficient, it doesn't operate fast. The power system has to bear the change in frequency till the speed again reaches to the normal value i.e; rated speed of turbine. Now-a-days these are replaced by automation.
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