Generator parallel operates with Invertor Output
Generator parallel operates with Invertor Output
(OP)
I have a project, need to parallel a generator set with an invertor output.
Generator; 20KW, 600V 3 Ph. 60Hz at 1800 rpm.
- Governor,Electronic always runs at constant speed 1800 rpm, no load to full load.
- Voltage regulator, Digital, self excited, constant output 600V, no load to full load.
Looking for advises from whoever have experience for this application.
Generator; 20KW, 600V 3 Ph. 60Hz at 1800 rpm.
- Governor,Electronic always runs at constant speed 1800 rpm, no load to full load.
- Voltage regulator, Digital, self excited, constant output 600V, no load to full load.
Looking for advises from whoever have experience for this application.





RE: Generator parallel operates with Invertor Output
I hope you don't really believe that, because it certainly isn't true. There will be deviations, and there are time constants that limit how fast it can get back to the "constant" value. And it's probably all too slow for a grid interactive inverter to stay paralleled.
RE: Generator parallel operates with Invertor Output
Let me know when the SMOKE clears !
RE: Generator parallel operates with Invertor Output
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If we learn from our mistakes I'm getting a great education!
RE: Generator parallel operates with Invertor Output
If a change-over, I think you stand a chance but you need synchronising relay, filters, contactors and more hardware plus something to control the drive or generator to synch to the other party.
I quickly searched the forum and found this thread where this has been discussed before but there may be more.
http://www.eng-tips.com/viewthread.cfm?qid=278446
I have successfully paralleled an inverter and the mains for this purpose of a change-over of the connected motor from the drive to the mains so that the drive could start another motor.
What is your application?
RE: Generator parallel operates with Invertor Output
It's possible that block-loads could be an issue paralleling a grid-tied inverter to a genset. However a grid-tied inverter must be designed to work with weaker grid connections so it might not be an issue. Other than that, I wouldn't expect any extra issue compared to using utility power. The grid-tied inverters protect themselves fairly well against variations in the power source and shut-down when necessary.
RE: Generator parallel operates with Invertor Output
In this project, there are three sources; Utility, Inverter( grid-tied type ) and generator. We are the generator supplier.
There is an intend to parallel all sources together.
I am planning to add; a synchronizer, a Load Shar Module ( LSM ) to provide droop and control the output active power (KW) of the generator, a new AVR with doop and addition KVAR/PF controller to control the reactive output.
Will it work?
Please advise!
RE: Generator parallel operates with Invertor Output
The grid will hold the generator frequency stable. All you need is a droop governor and set it over speed to pick up a base load.
eg: If the governor has 3% droop, and you set the speed 3% fast, the generator will be fully loaded and stable.
You still have to control the excitation. The grid will set the voltage but PF control may be used to control the excitation.
The grid will pick accommodate load swings.
The invertor will be connected to the grid and will not see frequency variations.
BUT, what else have you forgotten to tell us??
Bill
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"Why not the best?"
Jimmy Carter
RE: Generator parallel operates with Invertor Output
RE: Generator parallel operates with Invertor Output
- Utility only
- Utility with Inverter
- Utility with Generator
- Utility with Inverter and Generator
- Inverter only
- Inverter with Generator
The most difficult for me is the Inverter with Generator. What should I be carefull and take precustion?
Looking for advise and suggestion!
RE: Generator parallel operates with Invertor Output
Two solutions;
1> The inverter must be frequency agile and able to track generator frequency variation.
2> Accept that the inverter may not play well with the generator.
With a very steady load at 60 Hz (or 50 Hz) the inverter may work with the generator. Any load swings may cause the inverter to drop out.
If the inverter drops out on a reduction in load the system may become unstable.
You may have to change the excitation control from PF control to voltage control when going from parallel operation to island operation.
Bill
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"Why not the best?"
Jimmy Carter
RE: Generator parallel operates with Invertor Output
Thank you for your advise. I will run the generator governor in isochrous mode and short-cct the droop CTs on the AVR when I run the generator in islanding.
RE: Generator parallel operates with Invertor Output
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Generator parallel operates with Invertor Output
RE: Generator parallel operates with Invertor Output
I have the same concerns as LionelHutz.
-JFPE
RE: Generator parallel operates with Invertor Output
Bill
--------------------
"Why not the best?"
Jimmy Carter