Three generators (1000KVA,800Kw,415V)are running in parallel almost on 500Kw each,but generator A is variating form 50 to 1500Kw when it runn on 400Kw (this was measured on recorder,it measures the both min & max vales) while the actuator voltages are constatnt.Please tell me the cause of load hunting.

When 'A' is hunting, are the other two gens compensating by picking up excess load?
How are you accounting for load sharing among the three gens?

No,two other generator pick up load only when speed drops of any one,there is no variation in speed,i already told that actuator voltage of A are constant.load sharing is controlled by 2301A woodward speed sharing and load control unit.

[This message has been edited by luckyali (edited 07-08-2004).]

If you have studied the Woodward instruction book and not resolved the problem, you might contact their technical-support group. From a distance, it is hard to tell whether it is a configuration problem or one internal to the Woodward components.

Sounds to me like a synchronising issue - definitely a sharing/control matter. Speed variation in gennys? Hmm. If a diesel set hunts its generally an injection pump governor problem, or the same for petrol but on the carb. However, this would result in cyclic problems and a host of other evils - and dropping like flies of breakers.

Several years ago I got up one morning to find the lights fluctuating from about 50% to full on roughly 2.5cps. The tv didn't like it at all!! This lasted about ten minutes before we had a 30 second outage then back to normal. A few days later I saw our chief utility troubleshooter in the village and asked him what it was about. His reply was that it was something that theoretically couldn't happen; the ( at that time ) two alternators supplying our region ( we were disconned from the national grid for repairs over the weekend ) had got out of sync with each other; the control system had crashed. I never stopped to work it out, but I guess it is theoretically possible, especially if balancing/motive force is not up to scratch.

Call up the load-box suppliers