Author Topic: ST alternator connected to grid  (Read 17083 times)

cold comfort farm

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ST alternator connected to grid
« on: May 23, 2008, 11:08:34 PM »
Hi, I am looking at using a 240v 50hz alternator connected to the grid via an islanding / phase relay.  The relay will isolate the generator if the mains goes down making it safe for people to work on here in the UK. This part works OK
I am now looking to connect my lister up to a suitable AC generator and wondered what the ST 2 Alternators are like.  I am confused about the comments on reliability and dirty output.

Any comments are welcome. ???

Stephen

rcavictim

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Re: ST alternator connected to grid
« Reply #1 on: May 24, 2008, 12:30:03 AM »
Why is it so many folks here want to go to great expense and trouble to give the power they make which is quite expensive after all is said and done, for next to nothing to the local utility?   ??? ??? ???      Then there is the liability, your liability and insurance needed, even more cost to you!

Wanna slow down your meter from the utility?  Put your own loads on your own generator and pull less power through the utility's meter!

IF you absolutely insist on giving the utility almost free electricity use an induction motor as a generator, this will prevent an expensive (again your expense) fireworks display and smoke show.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
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mobile_bob

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Re: ST alternator connected to grid
« Reply #2 on: May 24, 2008, 02:43:30 AM »
amen RCA!!!

i have never understood why anyone wants to feed the grid except for maybe the solar panel folks
even then i would be apt to just close the shutters on the panels rather than give the power away (or nearly so)

it just seems counter to what any self respecting power producing diy'er would want to do, at least to me.

far better to fly under the radar and forget feeding the system in my opinion.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

mobile_bob

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Re: ST alternator connected to grid
« Reply #3 on: May 24, 2008, 05:27:39 AM »
Jens:

don't get me wrong, i understand the rationale behind using the grid as a big battery or flywheel so to speak

but somehow it just don't seem right!

:)

know what i mean?

not having the grid to fall back on is like finally being able to remove the training wheels from the bicycle when  you were a kid.
do you remember the huge feeling of freedom that gave you?  i do!

being able to unplug or never plug in, (in the first place) is a feeling that every self respecting diy power producer has to have in the back of
his mind somewhere,,, even if plugging in makes more sense economically.

for instance
if i could buy my power for 20 cents a kwatt hr, and it cost me 30 cents per kwatt hour to produce it myself
that 10 cents per kwatt hr in cost has a value to me far beyond the dime it represents.

sort of like

cost of electicity from the power company?  20 cents

cost to produce it myself?  30 cents

feeling of freedom and having some control over my own production?  priceless!

i fully realize that may not be a rational thought, but

i can think of a few thousand other things that one can and does spend money on that make even less sense,
and i bet you can too.

like 4 dollar latte's,  3 dollar cigars :), 8 buck cans of chew, 60k 1 ton diesel 4x4 duelly p/u trucks as a grocery getter that never leaves the pavement,
etc.

in the scheme of things i guess that even if it cost a buck a kw/hr to produce ones own power, it still ain't bad.

(might not be long before the power companies want a buck a kw/hr anyway)

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

mike90045

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Re: ST alternator connected to grid
« Reply #4 on: May 24, 2008, 04:39:44 PM »
i have never understood why anyone wants to feed the grid except for maybe the solar panel folks
even then i would be apt to just close the shutters on the panels rather than give the power away (or nearly so)

Because I use the grid as my big fat battery bank I never have to worry about adding water to !

I "charge" it for 6 hours in the day, and by the time it runs down, it's a new day.  I only "bought" a couple hundred KW from them last year.  http://www.mike-burgess.org/PVinfo_1.html

But you CANT just connect to the grid, you have to have approved gear (grid interactive inverter) and a billing agreement with them, before they read the meter going backwards, and cut you off.

cold comfort farm

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Re: ST alternator connected to grid
« Reply #5 on: May 24, 2008, 06:41:36 PM »
Jens, List.
I live on a farm with 2 houses on one meter (yep legal) this in turn gives a base load of around 400watts tick over in summer and slightly more in the winter.
I have a 3hp Lister and am wanting to run it in the evening when the loads goes above 500watts (ish) to keep the Lister loaded.
I could isolate some of the lower current circuits but I find it easier to feed what I can make into my grid then let the power company top up the rest.  I don’t anticipate giving the power companies any power if I can help it.  I would like to find a way to shut the Lister down if I am feeding the grid but that’s a bit complicated. I also don’t anticipate providing enough power to warrant an export meter.

I have wired the circuit similar to how you connect 2 or more generators together through an intelligent relay, this is acceptable on building sites and is standard practice. I can only assume the relay is similar to what’s in an inverter.  In short it checks the frequency of the grid with the genset frequency.  If it’s within tolerance it stays closed.  If the tolerance drifts for any reason then the relay breaks the connection between the grid and my Lister.  The Lister then goes into shut down as there is a solonoid on the fuel line, which is powered from the grid side.

The Lister can be Isolated from the grid with a lockable isolator so if the grid did go down for maintenance then it can be isolated by the appointed person on the line and no one can start the Lister.  This all conforms to G83 regulations. You do not need to have an inverter providing this is all signed off by the leccy board.

So my question again is would an ST be Ok for this application.

Hope that helps explain my setup.


mike90045

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Re: ST alternator connected to grid
« Reply #6 on: May 24, 2008, 07:08:54 PM »
  In short it checks the frequency of the grid with the genset frequency.  If it’s within tolerance it stays closed.  If the tolerance drifts for any reason then the relay breaks the connection between the grid and my Lister.  The Lister then goes into shut down as there is a solonoid on the fuel line, which is powered from the grid side.

The Lister can be Isolated from the grid with a lockable isolator so if the grid did go down for maintenance then it can be isolated by the appointed person on the line and no one can start the Lister.  This all conforms to G83 regulations. You do not need to have an inverter providing this is all signed off by the leccy board.

So my question again is would an ST be Ok for this application.


I don't think that an ST head "can" feed a power grid.  It does NOT produce a clean sine wave. It may do odd things when it sees "voltage" that it has not generated. 

There is no way a lister/ST can "sync" with a grid, you have a 1/30 chance of throwing a switch and getting it right.

A lister is not frequency stable enough to feed a grid, it does drift (the grid freq, is remarkably stable !)

The sync/sense electronics in a inter-tie inverter have such strict anti-island requirements, I doubt a relay acts fast enough to meet them. It's something like "Disconnect if 2 cycles are missed, and monitor for 5 clean grid minutes before reconnect. There are also min & max grid voltage thresholds it checks too.

Grid tie systems don't need 2 meters, they can just spin the old fashioned meters backwards, and then when not running, the meter spins fwd as normal.  Photo attached.

Your best bet is with an induction motor/generator, and as you "try" to overdrive it, it will generate, and stay freq locked to the grid.
 
Otherwise, we'll just look for the smoke.


cold comfort farm

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Re: ST alternator connected to grid
« Reply #7 on: May 24, 2008, 10:18:07 PM »
Mike, Jens.
Thanks for the comments.
There is a few little lights that all light up in a row when the generator is in sync with the grid then I can lock them together.  It works a treat.  After the relay has Islanded it cannot come back in automatically, that’s  where the inverter wins over our installation.  We have an electronic meter that cant run backwards so 2 meters have to be fitted which can be quite a cost, so I am told.

I have thought about running a squirrel cage motor but not sure how the relay would work with it.

Please don’t forget that if the Leccy Co don’t give me my certificate then I  will have to split the circuits out. Thanks for the info on the dirty sine wave, I think I will give it a miss.

carlb23

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Re: ST alternator connected to grid
« Reply #8 on: May 24, 2008, 10:24:14 PM »
Well i guess i will put my 2 cents in here.  While i do not have my lister grid tied, if i could generate electricity for less than i pay for it from the grid and could utilize the excess heat to help heat my home in the winter i would do it in a second.  First off I would use an induction motor and overspeed it and have it feed right back into the grid.  You could also setup an induction motor to generate without the grid by using a few caps but thats another story and you could would not want to have the caps attached when tied to the grid. If you size the motor correctly you can have the lister run under a constant load anywhere from 75 to 85% and be very efficient at producing power and heat. You need only run it for as long a day as you need to backfeed the grid so that when you turn off the lister the meter goes forward and you have a basic net metering situation.

We have 10kw of solar panels and a 1.8kw wind turbine both grid connected.  We generate over 15,000kWH of energy each year.  We only true up with the utility once a year on April 1.  We turn our meter backwards all spring, summer and fall and when winter comes we use the electricity to heat our home using an air source heat pump and two solar air heaters. We have a 96% efficient gas furnace for backup but it never comes on.

When April comes around we usually have very little energy to sell back to the electric co.  Usually about 30 dollars worth just enough the offset the $2.50 monthly customer charge that we have to pay.  Other than the 2.50 per month we do not pay for electricity, we have clean flicker free 60hz all the time and if the grid goes down i still have my lister for backup.

We just sold our 15 Renewable energy credits ( we sell the right to others to say they made the renewable energy not the energy itself) to broker who will sell them to a utility so they can avoid paying a penalty for not making enough renewable energy we got $260 each for them that a net profit of  3900 dollars plus  approximately 2325 dollars in avoided cost since we do not buy power from the utility.

Starting next month the fine per energy credit goes from 300 dollars to 711 dollars so next year we will probably get 625 to 650 dollars for each of our 15 renewable energy credits.

You can help the planet and make money at the same time. 


Grid connected and making money


carl

cold comfort farm

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Re: ST alternator connected to grid
« Reply #9 on: May 25, 2008, 10:48:51 AM »
carlb23, List

I have part plumbed the Lister into the heating circuit, The heat it produces will provide about 1kw worth of hot water in the summer and contribute in the winter.  As my Lister is only a 3HP so will create about 2kw after losses etc.  It also will help on cold days when the Lister is to be started because I can circulate warm water around the jacket.

Does anyone actually know how to run an induction motor because some say use 3 phase and use some caps on the other phases, some say single and don’t use caps????? which is it.  Unless I totally understand 110% its not worth the risk of experimenting.

If I do understand then I will give it a go.

Interesting comment about the ROCs going up in price.
Unfortunately we are about to re roof the house and do a bit of renovation so the Lister project will have to go on hold for a short while, unless I can sneak off every now and then. lol


Stephen

LowGear

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Re: ST alternator connected to grid
« Reply #10 on: May 26, 2008, 06:52:58 PM »
carlb23,

Your system sounds like the stuff dreams are made of - for some.  Your email is with comcast so I'll jump to the conclusion that you're in the states.  I sure wish you'd expand on hooking up to the grid.  Condiserations like expenses and extra expenses for the tie-in.  Pounds of paperwork?  Expertise load?

And selling Renewable energy credits - REC - now that sounds interesting.  Where/how did you get hooked up with your REC purchaser?  Pounds of paperwork?  Expertise load?

I'm on page 3 of 6 the thread AC/DC and nothing yet.  Would you do a short and "simple" thread on these two related topics.

Casey

NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245

cold comfort farm

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Re: ST alternator connected to grid
« Reply #11 on: May 26, 2008, 07:38:30 PM »
Well I have just bought a Lister 1.5kw genset on Fleebay, so short / medium term I can just run my new lister straight off.  It also has electric start as a bonus.  Its not a Startomatic more a Petter engine (I think).  I got it at the right price so as long as the Alternator is OK I am now sorted.
I got the wiring set up more permanent today. I have upgraded the line to 35mm2 cable so its now above the leccy recommendations of 25mm2.  Its bloody heavy cable though and not easy to form into neat runs, more pipe bending territory

Thanks for the advice guys / Girls.



carlb23

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Re: ST alternator connected to grid
« Reply #12 on: May 27, 2008, 12:34:08 AM »
carlb23,

Your system sounds like the stuff dreams are made of - for some.  Your email is with comcast so I'll jump to the conclusion that you're in the states.  I sure wish you'd expand on hooking up to the grid.  Condiserations like expenses and extra expenses for the tie-in.  Pounds of paperwork?  Expertise load?

And selling Renewable energy credits - REC - now that sounds interesting.  Where/how did you get hooked up with your REC purchaser?  Pounds of paperwork?  Expertise load?

I'm on page 3 of 6 the thread AC/DC and nothing yet.  Would you do a short and "simple" thread on these two related topics.

Casey



Casey,

I will try to sum it up as easily as i can.  Yes i do live in the States  New Jersey to be exact.   When we installed our 10kw of solar the state of New Jersey was paying over 70% of the total installed cost.  My out of pocket was less then 8K total.  As far as the interconnect there was no charge from the utility company and they installed a new meter to make sure it would run backwards correctly.  We did not have to jump through any hoops everything was pretty easy and only a few forms needed to be filled out.  if you go to this site you will get an idea of how far the state is willing to go the get people into renewable energy. Since we installed our solar back in late 2004 they have reduced the subsidy by quite a bit and it will probably be going away completely soon.

http://www.njcleanenergy.com/renewable-energy/programs/programs

The state maintains a bulletin board as a clearing house for the sale of REC's and they even track you estimated production based on you system size roof angle and orientation to due south.  They credit your account every month automatically.  All you need to do is log onto your account and post that you want to sell a particular number of REC's and brokers/aggregations will contact you. It is all very simple, My PV's as well as  my wind turbine are connected to my main panel box through their respective inverts to standard breakers. Each inverter is hooked to a 220vac 25 amp breaker. check out the links below of my lister, solar and wind projects.

http://www.youtube.com/watch?v=pp9w12H6HX8
http://www.youtube.com/watch?v=LL2zUvQIIuY
http://www.youtube.com/watch?v=UfGjlHNX-68

carl

Carl

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Re: ST alternator connected to grid
« Reply #13 on: May 27, 2008, 02:32:07 AM »
Metric wire?  Where do you live?  Just what the world needs, more confusion about things that absolutely need to be standardized and clearly understood.

I saw some once on a molded power cord.  All I needed was a calculator to figure out what the frig it was.  That's soooo convenient. Turned out it was AWG #14.  Would have been a lot easier if they had simply printed THAT.  Never go anywhere without your bullshit to reality conversion tables.
« Last Edit: June 22, 2008, 04:14:53 PM by rcavictim »
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

LowGear

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Re: ST alternator connected to grid
« Reply #14 on: May 27, 2008, 03:59:56 AM »
Hi Carl,

Thanks, that was great.  I'm afraid Hawaii isn't so generous.  The power companies and the oil companies seem to have quite a bit of pull.  90+% of all electricity is produced with diesel.  And the environmental clubs are fighting biodiesel because it would come from nasty countries for the first five or six years until local farmers got on-board. 

The National Resource Conservation Service - NRCS -has a 25% grant program for farms and some small businesses for alternative energy but I'm waiting for this next government to provide opportunities like you took advantage of in 2004.  An NO! I'm not moving to frost bite falls, mainland to get a super grant on my AE dreams.  NRCS is giving me a 75% grant for farm irrigation and once you taste that more than 50% grant stuff it’s hard to go back to Kansas.  And yes all my US taxpaying brothers and sisters I do appreciate your sacrifices. 

Thanks again.

Casey
NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245