Monday, February 13, 2012

Connecting your generator to the grid

Power companies require that you disconnect your generator from the grid whenever grid power is lost or goes out of spec. (This is different from the function of a generator 'transfer' switch.)
The Beckwith M-3410 Intertie/Generator Protection Relay is 'approved' to perform this function.

This is basically a computer in a box that monitors voltage, frequency & currents and opens or closes contacts when anything goes outside of programmable limits. You will need an additional contactor (relay) to carry the main current between your generator and the grid. The 3410 will control the 'coil' of this relay.

The M-3410 can also display and track voltages, currents, kWhrs and much more information on a connected computer.

You will also need a little more circuitry for a system with added features, like possible off grid operation or high voltage transmission (480V) for longer distances to the power house.


9 comments:

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Anonymous said...

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chuck said...

Hi All;
I just got on this sight and thought it is great what you are doing here. I have two streams on my property but I don't think there is enough flow to get much power out of them. One thing I am working on is wood gasifiers I have a 160 hp chevy motor I plan on using to turn a 50 hp induction moter/generator. What realy caught my eye was how that is what you are using to put power back in the grid. I have seen the ways you have wired them but there is 3 drawnings used but each is a little different could someone help me figure out what caps I will need and how to wire them together to use a 3 phase 50 hp 460 volt motor to sigle house hold system back to the grid. Thanks
Chuck

pengukuran kadar air said...

How to connect M-3410 to computer? using cables or some kind of wireless technology?

Rob said...

The M-3410 connects to the computer via an
RS-232 port/cable.
It can also communicate via a COM2 port and RS485.
The Beckwith software, IPScom, running on the computer
allows you to read/display all the information like voltages, currents, kWatt Hours etc.

Jon said...

First of all thanks for this site!
You offer here to the world a huge wealth of information condensing what must be thousands of hrs of research into the content that fills these pages, It's very much appreciated by all!
I had a quick question, Can a 3 phase generator be used to push power into a single phase grid? I have a 3 phase generator but the grid around here is only single phase, I know it can be done with a c-2c bridge but they want it to de-energies when the grid goes down...

hope to hear from you soon!
Jon

Scott said...

I have a 75hp (55kw) 3 phase induction motor, How many kw's do you think I can pull off of it If I use a C-2C bridge for single phase operation? Dosn't the C-2C bridge make grid interfacing allot more complex? Syncing? self exciting?
What about using just a single leg of the generator?

I really appreciate any help you can offer me.

Rob said...

Jon,
To connect to the grid in most places, the power company will want some form of intertie protection device that will disconnect your power if the grid power goes out of spec or fails in some way. The Beckwith M-3410 is one such device.

Scott,
The size of your induction generator does not tell you how much power output you will actually be able to 'pull off' as you put it. It is the (water) power input that will tell you that. So tell me head and flow and I can give you a ball park maximum power available.

Once three phase is converted with a C-2C to single phase there is no difference with any other single phase as far as syncing or grid interfacing.