PROBLEM OF HIGH FLUCTUATION IN SPEED DUE TO REDUCTION IN EXTRACTION STEAM FLOW

Turbine governing is designed for maintaining given speed on desired load or variation of load. When the power generation/speed fluctuates from its desired value or governor not able to maintain turbine speed, plant operation becomes unreliable to the operators. So the maintenance of any governing system is a tedious job which requires very wise full decisions for its component overhauling and replacement, it requires vast practical knowledge and equipment behavior. After one start up of plant, taking a shutdown is very costly affair to afford huge cost of loss of primary content for a big process industry due to a very minute problem, is not easy to justify. After observing any problem in the system, it is not easy task to identify the correct cause of the problem because there are so many linking of the parameters to each other. Problem of hunting of control valves and hunting of speed is faced by many industries in the past years and now they have sufficient knowledge about it but high oscillation in speed after a fix point of reduction in extraction steam is new type of problem. Variation in speed around 200 rpm creates fluctuation in compressor discharge flow and pressure due to which all the parameter deviates from its normal value so either plant to be tripped or plant load should be reduced.