Steam Turbine Governing System. Prepared by: Nimesh Gajjar. DEFINITION OF GOVERNING “A SYSTEM WHOSE PURPOSE IS TO CONTROL A PRIME MOVER ” OR GOVERNOR IS A DEVICE TO CONTROL SPEED /LOAD TO A SET POINT. Why Governing is required?.
Prepared by: Nimesh Gajjar
“A SYSTEM WHOSE PURPOSE IS TO CONTROL A PRIME MOVER”
GOVERNOR IS A DEVICE TO CONTROL SPEED /LOAD TO A SET POINT.
*Constant speed at variable loads.
* Constant speed at varying steam inlet parameters.
*Constant speed at varying extractions and exhaust
SHAFT DRIVEN BY TURBINE SHAFT
EXHAUST TO CONDENSER
To produce more power ( when on over load) additional steam may be admitted a by-pass valve to the later stage of the turbine.
Suppose, if the load on a turbine is suddenly reduced, the machine begins to speed up. When the speed reaches a certain value, the governor comes into operation and due to this the steam supply is considerably reduced with the result that the speed drops well below the normal value. Again the governor acts after a period of time, which depends on a number of circumstances such as friction, sensitiveness etc. and the steam supply is suddenly augmented. Again the speed rapidly rises and the cycle begins a new.
Fluctuating loads or a sudden change of load especially in case of reduction of load, are more likely to produce hunting, but in other cases it will persist even at fairly steady loads.