What is Governor Droop In electric generators? Why Governor Droop Required?

What is Governor Droop?

>Governor droop is a governor function which reduces the governor reference speed as fuel position (load) increases.

> It allows the engine to run at lower speed when the load increases and at rated speed at no load
>Droop is expressed as a percentage of the original speed
setting from no load to full load. The normal recommended percent of droop is 3% to 5%.

% Droop = [ (No Load Frequency - Full Load Frequency) / Full Load Frequency ] x 100%

Why Governor Droop Required?

> Consider a system without droop, as the load increases speed decreases
>Governor will respond by increasing the fuel until the engine has returned to the original speed.
>Due to the combined properties of inertia and power lag, the engine speed will continue to increase beyond the original speed setting, causing an overshoot in speed.
> The governor again will respond to decrease speed to correct for the overshoot.It will over-correct the speed in the other direction causing an undershoot.
>This over correction of speed in both directions (instability) will amplify until the engine trips out on over-speed. This can be eliminated by the introduction of droop

Why Droop Governor Is Fitted Only on  Auxiliary diesel Engine Generators?

For generators, governors are droop governors with constant speed in order to maintain frequency, while Main Engine's Governor needs to be able to run the engine at varying speeds. Generator Governors use 'Droop' for load sharing, whereas Main Engine is usually directly driving the Propeller and load sharing is not required.

If you have better Idea about Droop plz share your views in comment box

>> Discussion is an exchange of knowledge It Make the Mariner Perfect.... Please Discuss below...

1. you have done a great wrk...

2. great jobe done, thanx for posting,can u tell me what is governor reference speed??

1. Its the rated speed of your AE

3. normally droop is about 3 to 5%

1. can we define the droop as how much sense the gevorner will respond accourding to the load change? sp that at the droop of 3% will be more sense that 5%?

what about zero droop? I read that it can be used when we have a largee number of small consumers so the frequency will not have a big change.

4. can we define the droop as how much sense the gevorner will respond accourding to the load change? sp that at the droop of 3% will be more sense that 5%?

what about zero droop? I read that it can be used when we have a largee number of small consumers so the frequency will not have a big change.

1. what i understood is 3% droop means it will reduce the reference speed as 3%..... you can use zero droop if there is not much load variation and frequency variation....

5. It can be taken as while 2 gen. Are running with 2% and 5% droop .
5% droop can be considered as 5% change in frequency the load will change to 100% and same if 1% frequency change occurs than proportionaly 20% load will increase on the gen.
And if load is more on alternator than frequency will decrease and both gen. Will Act accordingly.
Let say 1% frequency decrease due to increased load than
5% droop gen. Will increase the load by 20% by increasing the fuel
2% droop gen. Will increase the load by 50% .
Thats how the sharing takes place

1. well said.... thanks for your great information....

6. shouldn't it be = { ( no load - full load ) / NO LOAD } x 100%

7. Well said bro...keep it up...

8. Well said bro...keep it up...

9. thank you for valuable information,
i have one question, the droop setting important in grid parellel power plants or captive power plants(industry load based)? can you please reply

10. How will adjust the droop ??

11. a system without droop, a load increase will cause the engine to slow down.
Can any one explain this line???

1. actually i mean that as the load increase speed get reduced slightly. suddenly your governor comes in action and which shall copup the speed

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13. Dude perfect ans...as I was searching....

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