800 kVa Caterpillar Natural Gas Generator Unstable Frequency

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JONE Member Join Date: Oct 2014 Posts: 5	800 kVa Caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 12:03 PM
	dear all, could any body give me some idea on why our 800 kva caterpillar gas engine 3500 speed is unstable with no load(1600 rpm to 1300 rpm)frequency(46HZ-54HZ)problem started when we stop it for oil change. history, actuator replaced by new one carburetor replaced by new one linkage checked ok magneto replaced turbo charger checked ok 2301A speed control Woodward replaced magnetic pick up checked ok altronic box replaced gas regulator checked ok I wish anyone of our members can help us with his ideas and solutions. thanks
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This discussion was "closed" on 10/12/2014 8:24 PM. No new comments are allowed.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#1 Re: 800 kVa caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 12:50 PM
	These systems are not designed to be run at low or no load conditions.... NatGas fueled generators typically have transient stability issues....they don't have the same power and loading characteristics of a diesel....this should be taken into account when designing the system.... ..." Even at the steady state condition (no load change), you will often see less frequency stability on a gas unit when compared to a diesel. This is not all to say that gas packages can't be successfully applied in island mode applications, but it is important to understand the application and manage expectations."... https://forums.cat.com/t5/BLOG-Power-Perspectives/Operating-Gas-Generator-Sets-in-Island-Mode/ba-p/945 __________________ All living things seek to control their own destiny....this is the purpose of life
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JONE Member Join Date: Oct 2014 Posts: 5	#2 In reply to #1 Re: 800 kVa caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 1:24 PM
	Hi SolarEagle, Thanks for your response,the problem that we are facing now is to put the generator on share with others(synchronize mode),due to hunting we can not do it.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#3 In reply to #2 Re: 800 kVa caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 2:40 PM
	Are the other generators Natgas fueled or diesel...? You should have similar generators for synchronized operation....or at least similar loading characteristics....You can improve your response with injector systems instead of carburetors...You might vary your loading methods for experimentation....Is there any possibility of converting to diesel? __________________ All living things seek to control their own destiny....this is the purpose of life
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RAMConsult Guru Join Date: May 2007 Location: NYC metropolitan area. Posts: 3230 Good Answers: 444	#4 In reply to #3 Re: 800 kVa caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 2:50 PM
	If you are having hunting issues then you should be looking at governor setup; things like gain, droop, damping, time constants, etc., in order to tune the feedback loop. Gain is probably set too high, damping too low, and/or droop not set/enough. If the reactive power is unstable then look at the the VAR droop or cross current compensation settings. __________________ “Tell me and I forget. Teach me and I remember. Involve me and I learn.” Ben Franklin.
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Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#5 Re: 800 kVa caterpillar Natural Gas Generator Unstable Frequency 10/12/2014 4:19 PM
	Duplicate thread alert. __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
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This discussion was "closed" on 10/12/2014 8:24 PM. No new comments are allowed.
Message from admins:

Duplicate thread. See original at http://cr4.globalspec.com/thread/97911

These comments received enough positive votes to make them "good answers".

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JONE (1); RAMConsult (1); SolarEagle (2); Tornado (1)

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