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Kuncoro
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Join Date: Aug 2008
Posts: 31

Electrical Governor Settings

09/02/2009 2:30 AM

Dear All,

Could you please explain about the setting of electrical governor and when we use the setting below for paralelling betwen generator and generator or generator and power grid

1. Isochronous

2. Droop

3. Droop-droop load sharing

4. Isochronous load sharing

5. Droop-Isochronous

And what is the consideration use above governor setting

We will look forward your answers for all of the participants

Thanks and regard,

-kun-
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PWSlack
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#1

Re: Electrical Governor setting

09/02/2009 3:10 AM

Surely there must be copious advice in the User Manual that comes with this thing?

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msamad
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Location: Houston, USA
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#2
In reply to #1

Re: Electrical Governor setting

09/03/2009 10:15 PM

There are two prime mover speed control (governor) methods for controlling the frequency of the generator sets:

• Isochronous mode – When operating in isochronous mode the generator will vary its power output as power demand changes to fix the frequency constant.

• Droop mode – Multiple generators can share the responsibility of generator/load balance by operating in droop mode. The generator control in droop mode looks at the power system frequency, and adjusts the output of the generator from its nominal set point depending on the extent of the system frequency variation from the target value.

Droop = (No Load Speed - Full Load Speed) x 100 / No Load Speed

For paralleling generators, only one generator (it is also called swing generator) shall be in isochonous mode and all others must be in droop mode. If the generator runs with utility, it must be in droop mode. If the load increases, isochronous generator increases its power to maintain the frequency, while droop generators maintain their power. If two generators are in Isochronous, they must have load sharing function, otherwise two isochronous generators will be unstable. All generators can be in droop, but load change will result in frequency change in this case.

See the previous posting:

http://cr4.globalspec.com/thread/35000

Hope it helps.

- MS

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Kuncoro
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Join Date: Aug 2008
Posts: 31
#3
In reply to #2

Re: Electrical Governor setting

09/03/2009 10:31 PM

Dear msamad,

Thank you for your explanation, clear understood. But I have more question, as follows:

1. Why the generators have to set in droop mode if parallel with utility? What is the consideration

2. I have read saome article, If two generators are set up in droop and isochronus so the frequency follow the isoch? Could you please explain the concept.

3. You stated : If all generator are in Isochronous will be unstable. Why

Thank you

-kg
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msamad
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#4
In reply to #3

Re: Electrical Governor setting

09/03/2009 11:01 PM

I don't know why you made it 'Off Topic' and asked the question again.

1. Why the generators have to set in droop mode if parallel with utility? What is the consideration

In this case, the utility is infinite and it controls the frequency. If the generator is set in isochronous, the generator also attempts to control the frequency. Both utility and generator set attempts to control the frequency and the generator becomes unstable.

2. I have read saome article, If two generators are set up in droop and isochronus so the frequency follow the isoch? Could you please explain the concept.

The Isochronous generator controls the frequency of the system by sharing the change of load in the system. If the system runs with 10 MW and 2 MW load is added to the system, the system frequency attempts to slow down. The isochronous generator then attempts to keep the frequency constant. So, it will increase the input power to the prime mover and increases the speed, hence shares the load. As the system frequency remains same, the droop generator load is not changed.

3. You stated : If all generator are in Isochronous will be unstable. Why

Same as 1 - just think the other generator as utility.

- MS

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Kuncoro
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Join Date: Aug 2008
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#5
In reply to #4

Re: Electrical Governor setting

09/04/2009 12:16 AM

Hi MS,

One more question, case study actually i.e.

Station A has 8 unit diesels plant rated power @ 4 MW, station B has 4 unit diesels plant rated power @ 4 MW and station C has 20 unit diesels plant rated @ 4 MW as well. Station A, B, C were parallel.

On the other hand there is a coal fire plant 3 units @ 65 MW. Station A, B, C parallel with coal fire station and was connected by transmission line.

So, my question is:

1. What is your opinion about the govermnor setting in between A station and B station, B and C, A and C. (Droop-droop load sharing, Droop-Isoch, Isoch-Isoch)?

2. What is the governor setting in between station (A, B, C) and coal fire plant?

Thanks in advance,

-kg
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msamad
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#6
In reply to #5

Re: Electrical Governor setting

09/04/2009 11:38 AM

In this case, I would suggest you to consult a specialist and get advice. I am not a specialist in this field. However, my advice is to set one of the coal fire generators in isochronous mode and all others are in droop mode. I also would suggest using a separate load sharing device (such as Woodward EGCP-3 LS etc.) in this case. But again consult an expert first.

Thanks,

-MS

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Maint
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Join Date: Oct 2010
Posts: 1
#7
In reply to #4

Re: Electrical Governor setting

10/29/2010 9:16 AM

Please For example :

we have 3 generator are running can explaine if we put ischo. or droop mode.

and if the load increase which generator will take the load .

Thank you i hope somebody help with load with imagine number .
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