How the load will be p.u by gen. set to different speed droop control

[mns15451]

If number of gas-turbine generating units having same capacity but set to different speed droop setting i.e. 4% and 5% are running and connected to large system. Upon sudden demand of load (due to the tripping of larger unit on the system) how the load will be picked up on these units keeping in view the droop setting. What I mean is which of the two machines i.e. 4% or 5% droop will p.u more load and why?

 

[GTstartup]

Droop of 5% means that for a 5% increase/decrease in frequency a 100% increase/decrease in load will result (or proportional quantities, e.g. 2.5 delta freq = 50% load response). So the Unit with 5% droop will pick up (or shed) 20% less load.

 

[waross]

When the 4% droop set is fully loaded the 5% droop set will be 80% loaded. Any further load increase will overload the 4% droop set.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[mns15451]

Thanx for the response.
It speaks that one having 4% droop will p.u more load as compare to the unit having 5%. I conclude that reverse i.e. the shedding of load is also true with regards to the droop setting? If thats right then can we say that the p.u or shedding off the load is inversly proportion to droop setting?

 

[waross]

In this instance yes, but I would be uncomfortable with that as a general statement. It is a little misleading as it does not apply to a standalone generator, and it applies more to load sharing than load pickup.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[mns15451]

Perfect. I understand.
Thank U very much indeed.