Synchronize 2 generater with plc

Does anybody has experience about control (synchronize)2 generater
by plc?
Thanks a lot

Are the power wires connected to the same place? I know on large scale applications (Generator to a Power Grid) the generators will synchronize themselves

Alternators WILL not synchronize themselves. That is why you have a synch scope, synch lites and operator OR automatic synch.

I have synched alternators 100's of times so I think I am qualified. A trainee paralleled almost 180 out - kind of exciting. Hawaii Power and the Shipyard were not pleased.

AFTER they are paralleled THEN they will always run synchronously.
Dan Bentler

Thanks for the clarification.

leitmotif said:

AFTER they are paralleled THEN they will always run synchronously.

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Yes, that's what I though was amazing. It was during the CA energy crisis. A guy was using locomotives to generate electricity. They had a tanker truck of fuel and he warned them to keep an eye on the fuel level. They called a few days later and said it was running but had quit generating electricity. Come to find out they were out of fuel yet running at full RPM

EDIT - Actually he was from Otis Orchards, WA. Right in your neck of the woods

Platootod said:

Does anybody has experience about control (synchronize)2 generater
by plc?
Thanks a lot

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AB make (or used to) a module for synchronising a generator. It is (or was) a 1771-style module.

A trainee paralleled almost 180 out - kind of exciting.

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I'll bet it was! Explosion? Machine left its foundation?

I have synched alternators 100's of times

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Do you stand on one foot when throwing the switch?

Platootod,

The simple answer to your question is yes, PLCs can do most anything, however, just because it is possible, that does NOT necessarily make it a good idea. Here are a few issues that you should ponder before trying to do this:
1) You want to close the connection when their outputs are in or very near sync. Everything from lightbulbs to oscilloscopes can show the voltage difference. It would take some effort to create a way for the PLC to sense this, but it is possible.

After connected, they will follow each other, but you should carefully consider the unintended consequences.
2) If one is trying to go faster, it won't but it will take more of the load.
3) You must be certain that there are no phase problems (as in 3 phase)
4) What happens if you loose a phase somewhere (circuit breaker trip)
5) How do you address fuel issues
6) How do you handle mechanical problems such as low oil or over temp, etc.
7) In order to do do a controlled connection, one generator needs to go very slightly different speed than the other. So it is desirable to sense the speed of one and control the speed of the other.

I'm sure there other issues but here is a place to start. I have made the assumption that you want to do this is a fully automated fashion. If not some of these issues go away, but then what is the point when it can be done manually, if the proper provisions are present to do so?

Best Regards,

Bob A.

Oh dear!!! Have seen this done several times and they could only be described as an absolute disaster!!! Several here in Sydney that I have pulled out and replaced with a reliable system. The biggest problem is controlling reactive and active load sharing, after the generators are synchronised together. Generally there are a number of PIDs to set up - starting, idle speed, synchronising and load sharing and another if paralleled with the mains. Not an insignificant task!!!

I would suggest that you at least use a couple of cheap Deep Sea controllers if sinking 2 generators together and load sharing. Even Crompton Instruments have some inexpensive generator controllers.

If going up against the mains talk to Woodward about their GCP31 controllers for the generators and their LS4 ACB controllers for the soft transfer/co-generation. Use the PLC to monitor the engines (low oil pressure etc), and if you wish the Woodward controllers via a modbus RTU interface, and to tell the GCP31 controllers and LS4 ACB controllers what to do. Also get Woodward out to tune the controllers up - they are quite expensive but will do a much better job than you and in half the time. About the least expensive, reliable system I can think of quite frankly.

Generators are a big part of my business and as far as I am concerned you can stick PLC synchronising control where the sun don't shine. Companies like Woodward exist because they have huge resources to 'get it right'. I do not have those resources and I would guess neither do you. Why re-invent the wheel.

I normally never believe anyone but check myself. Some years ago I was commissioning 2 generators in a telephone exchange. My boss was with me. Before closing the 2 'synchronised' generators together we always checked the phases 'red to red', 'white to white', 'blue to blue' with a multimeter. If the generator controllers said the sets were synchronised the phase to phase check confirmed it just in case someone had made a mess of connecting the voltage sensing to the generator controllers. Voltage should be close to zero or within 5-10% of normal. I went to check and my boss blew up. 'I have been doing this for years and if I say I have checked it then it is right. Close the b****y breaker'. I did close the breaker and bounced 1 generator of it's mounts. Not a pretty sight I can tell you. The boss vanished and left me with the mess.

Witnessed another company testing a HV system (11kV) up against the mains. The guy was too lousy to pay for a HV guy to come in and stick a voltage measurement device 'up the tubes' of the HV breakers before closing 'alledged' synchronised generators to the mains to check synchronisation as described above phase to phase. The wiring of the HV/LV PTs was in fact incorrect. A very large bang and 2 destroyed HV alternators and HV breakers, 1 broken engine main shaft etc etc. Very expensive excercise to save a few dollars.

I'll bet it was! Explosion? Machine left its foundation?
Nothing got damaged, lights went out for a second, just tripped shorepower (800 amp), and half the shipyard, Hawaii had a couple generators drop off line. There was a loud buzz, the turbine and alternator mount rocked scared the bejeezus out of the guys in the engineroom. Trainee then had to put the whole mess back together - whole bunch of paralleling then. I am sure I was more nervous than he. He got it right that time and forever more.

Do you stand on one foot when throwing the switch?[/QUOTE]
Nah this was all done at a remote panel. If the boat was rolling you had to stand on both feet well apart to keep from falling over.

Dan Bentler

Thanks a lot for all answer

Some company in Vietnam use Siemens logo to syncronize 2 gen set .
Do you have some example for this control? Anymore idea?

I had my say.

Stop mucking about and buy a generator controller.

http://www.selco.com/Products/Products/T4500%20Auto%20Synchronizer%20for%20Conventional%20Governors.aspx

Or Make the breaker when the synchroscope is at 5 to 12.