Power Plant Guruji

Governor Issues Lead to Turbine Hunting If Turbine does not maintain the load as per set load, then this condition is called load hunting.  Following are the some potential reasons for load hunting 1- Problems associated with actuators: These are related to leakages in actuators, piston stuck up, oil holes elongation etc. Because of these issues there will interruption or fluctuation of secondary oil flow through actuators, this creates the problems of actuator miss- operation & eventually load hunting. 2-Improper calibration of actuators: This results into mismatch of actuator opening & given set point or valve demand 3- Lower control oil pressure than required: Actuators are designed for specific pressure of control oil, if the control oil pressure at actuator inlet becomes less, then there will be more chances of mal function of actuator. 4-Fluctuation of control oil pressure/flow: Fluctuation of control oil pressure or flow due to malfunction of pump or line PRV may lea...

WATER HAMMER The very large CCW flow rate results in huge kinetic energy of the flowing water, and hence it promotes severe water hammer during CCW pump start up, shutdowns and trips. How to Minimize Water Hammer To minimize water hammer the following general operating practices are used during CCW pump start up and shutdown. 1. A sufficient time delay before the next pump Is started up or shut down. This allows the energy of pressure waves in the system to destroy before the system is subjected to another flow surge. Time delay : About 5 minute 2.Proper position and slow opening / closing of the CCW pump discharge valve during pump start up and shutdown a)       Each CCW pump is started against its discharge valve fully closed or slightly pre-opened (depending on the plant) and then the valve opens gradually. b)       During normal pump shutdown first the discharge valve closes gradually and when it is fully closed (or nearly fully cl...