Author Topic: AC Coupling Control Issues  (Read 3090 times)

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Eraser3000

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AC Coupling Control Issues
« on: October 01, 2016, 06:45:20 PM »
Rant,

Anybody attempt to AC couple fairly large systems off grid?

Wow what a pain.  Who new you had to turn into a control engineer just to make everything play.

Does anybody know any rules of thumb for inverter/coupling ratios?

Just trying to get the conversation going with anyone who has experience.

Thanks

« Last Edit: October 01, 2016, 11:30:23 PM by Eraser3000 »

SparWeb

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Re: AC Coupling Control Issues
« Reply #1 on: October 04, 2016, 09:31:35 PM »
Last year, a member of Fieldlines reported difficulties with SMA inverters that were AC coupled through the "Sunny Island" product.
They posted inverter logs that showed strange behaviours - failure to synchronize IIRC.
That member's system is smaller and less complex than yours but not by much.
I don't think his problem was ever completely understood, but troubleshooting did identify the offending machine, and replacing it with a higher-capacity unit solved the problem.

Is yours a system that's evolved over time to reach this configuration?  It looks like there are two buildings being served, which are far apart, but coupled by the 240 VAC line, plus a 480 VAC system charged solely by the big WT and distributed back to the building with a 480 VAC line.  More detail will help us understand, but the whole system schematic above sure is a great start.

And welcome to Fieldlines, too!
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

SparWeb

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Re: AC Coupling Control Issues
« Reply #2 on: October 08, 2016, 02:28:33 PM »
Since the other member I mentioned hasn't checked in recently, I thought I'd post links for you Eraser.

http://www.fieldlines.com/index.php/topic,148654.msg1032948.html#msg1032948

http://www.fieldlines.com/index.php/topic,148681.msg1035778.html#msg1035778

Hope it helps.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

Eraser3000

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Re: AC Coupling Control Issues
« Reply #3 on: October 08, 2016, 09:00:55 PM »
Thanks for the reply.
I have basically decided to scale up in order to defeat the problem.

Yes my system evolved several times.  The "other building" is my power building.  Basically just batteries those charge controllers the small wind etc.

That is what I started with and allowed me to build my house and get moved in, and then I started on the quest to heat and cool everything off renewables.

I've been a member for quite awhile and posted awhile back on some Outback protocol stuff I was working on. But I finally decided to share a few projects.

Start of new inverter install.
10007-0

Three hung.
10008-1

250 AMP breaker. Batteries are getting a box once I'm done and will have a small blower to get rid of Hydrogen etc.

10009-2

Installed Dissconnect.


« Last Edit: October 08, 2016, 10:16:19 PM by Eraser3000 »

Eraser3000

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Re: AC Coupling Control Issues
« Reply #4 on: October 08, 2016, 09:06:28 PM »
For the bus bars I used some .25 Inch X 2.5" pieces of aluminum left over from connecting batteries years ago.


I ended up having to mill out some of the bar because it was blocking the AC out knockouts.


Installed.


And underneath.
10014-3

Eraser3000

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Re: AC Coupling Control Issues
« Reply #5 on: October 08, 2016, 10:14:26 PM »
Thanks for the links, I think that user abandoned those inverters and went with the Ozinverter?

Thanks

Since the other member I mentioned hasn't checked in recently, I thought I'd post links for you Eraser.

http://www.fieldlines.com/index.php/topic,148654.msg1032948.html#msg1032948

http://www.fieldlines.com/index.php/topic,148681.msg1035778.html#msg1035778

Hope it helps.

clockmanFRA

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Re: AC Coupling Control Issues
« Reply #6 on: October 09, 2016, 02:38:40 AM »
Yes,........

Manufactures want to lock you in to their particular products with expensive control equipment, its a shame they don't say this in their product literature.

With help from 'Oztules' I went the simple, robust, and very importantly cost effective 'OzInverter'.

AC coupling is important for us here, as its a cheap way of powering our 230vac Mini Grid, so we are using lots of smallish 3kW GTI's with PV. The Mini Grid powers our needs for our small community of houses/buildings.

Therefore a 6kW 'OzInverter', or my 10kW 'OzInverter' can supply and run the Mini Grid, any bigger Inverter just hammers the batteries, or you need a very big, expensive, battery bank.

Very soon I will have another 4off 3kW GTI's, (toroid type cheap as chips Old stock) powering in to the 'OzInverter' created Mini Grid.

'Oztules' reckons that the 6kW 'OzInverter' can handle 8kW of Back charging from the GTI's, I have only so far managed/tested 5kW with out any problems.
The 'OzInverter' back charges, its the H bridge.  As the batteries fill there is a push back from the batteries and the 'OzInverter' AC output voltage rises slightly and the GTI's quickly drop out/shut down. (the manufactures set the drop out voltage according to the agreed Nations format).
 I can fine tune my GTI's for a sequential shut down and a quicker start up procedure.

No way would we use the HZ frequency raising to control stuff, washing machine, micro wave, cooker timer etc don't like a rise of 10HZ.

Note, I also have a fail safe GTI switch off system, (never operated so far), that is activated by ancillary relay on my Midnite classic 200 DC controller. I have 5kW of PV and 3off 3.7m  wind turbines that are direct connected and charging my 1300ah 48vdc batteries. At present I use the DC controllers to finish the batteries charging regime.

So the 'OzInverter', running from my precious batteries, is bridging the gap while the GTI's AC output starts up again.

Keep it simple, Robust and Cost is important, so I am always trying to keep things simple but safe.

 Control equipment..... so my 2off DC controllers, and 4off diversion controllers, are the biggest buy in expense so far, and Yes, I have the biggest circuit breakers MidNite sell, but otherwise that's it.

Eraser, I see you have a 30kW wind turbine? I am not sure what or who's it is but its output control is going to be interesting if you are not using up that excess.

I have 8kW of heavy duty dumpload heaters operating from diversion controllers for my 3 wind turbines, and on those stormy windy winter nights its nice to get extra heat.

Note, the Dump load heaters diversion controllers are also useful for keeping the batteries spot on charge, after all they are just directly connected to the batteries and just dumping excess.
 Please ensure that the Dump load heaters are not fastened to anything combustible or even near anything combustible .   Yes, I have had some hair raising moments, after 8 years of experience mine now stand on movable metal cradle in the middle of a room. 

DC PV Solar Controllers, ..... I think 'Oztules' is looking at them now.    So that should bring the cost even further down in regards creating your own Mini Grid.  And best of all, we are not beholden to any particular Manufacture.

Personally if I was to do all this again, I would just stick with PV and more PV, its now a very good cost and easy to control.

Edit..... Brilliant Bruce, ....... I can now edit my above post sometime after originally posting, I noticed a mistake in my description on the dump loads so all sorted.

« Last Edit: October 09, 2016, 11:03:15 AM by clockmanFRA »
Everything is possible, just give me time.

Eraser3000

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Re: AC Coupling Control Issues
« Reply #7 on: October 09, 2016, 08:03:42 AM »
I had a typo in my first diagram.  The three Inverters I was using for the 480 were FVX3524s.
New diagram shows my overall control system for the Wind Turbine and Load System.
I am also implementing an up to 90 degree storm/high wind YAW offset.
 
10015-0

Eraser3000

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Re: AC Coupling Control Issues
« Reply #8 on: October 09, 2016, 08:09:40 AM »
Yes,........

Manufactures want to lock you in to their particular products with expensive control equipment, its a shame they don't say this in their product literature.

Yes its true. I am glad there is some of this technology available though, "off the shelf".

With help from 'Oztules' I went the simple, robust, and very importantly cost effective 'OzInverter'.

AC coupling is important for us here, as its a cheap way of powering our 230vac Mini Grid, so we are using lots of smallish 3kW GTI's with PV. The Mini Grid powers our needs for our small community of houses/buildings.

Awesome.

Therefore a 6kW 'OzInverter', or my 10kW 'OzInverter' can supply and run the Mini Grid, any bigger Inverter just hammers the batteries, or you need a very big, expensive, battery bank.

Very soon I will have another 4off 3kW GTI's, (toroid type cheap as chips Old stock) powering in to the 'OzInverter' created Mini Grid.

'Oztules' reckons that the 6kW 'OzInverter' can handle 8kW of Back charging from the GTI's, I have only so far managed/tested 5kW with out any problems.
The 'OzInverter' back charges, its the H bridge.  As the batteries fill there is a push back from the batteries and the 'OzInverter' AC output voltage rises slightly and the GTI's quickly drop out/shut down. (the manufactures set the drop out voltage according to the agreed Nations format).
 I can fine tune my GTI's for a sequential shut down and a quicker start up procedure.

No way would we use the HZ frequency raising to control stuff, washing machine, micro wave, cooker timer etc don't like a rise of 10HZ.

Note, I also have a fail safe GTI switch off system, (never operated so far), that is activated by ancillary relay on my Midnite classic 200 DC controller. I have 5kW of PV and 3off 3.7m  wind turbines that are direct connected and charging my 1300ah 48vdc batteries. At present I use the DC controllers to finish the batteries charging regime.

So the 'OzInverter', running from my precious batteries, is bridging the gap while the GTI's AC output starts up again.

Keep it simple, Robust and Cost is important, so I am always trying to keep things simple but safe.

 Control equipment..... so my 2off DC controllers, and 4off diversion controllers, are the biggest buy in expense so far, and Yes, I have the biggest circuit breakers MidNite sell, but otherwise that's it.

Eraser, I see you have a 30kW wind turbine? I am not sure what or who's it is but its output control is going to be interesting if you are not using up that excess.

I attached new control diagram.

I have 8kW of heavy duty dumpload heaters operating from diversion controllers for my 3 wind turbines, and on those stormy windy winter nights its nice to get extra heat.

In addition there are 40Kw dump load oustide by the tower.

Note, the Dump load heaters are also useful for keeping the batteries spot on charge, after all they are just directly connected to the batteries and just dumping excess.
 Please ensure that the Dump load heaters are not fastened to anything combustible or even near anything combustible .   Yes, I have had some hair raising moments, after 8 years of experience mine now stand on movable metal cradle in the middle of a room. 

DC PV Solar Controllers, ..... I think 'Oztules' is looking at them now.    So that should bring the cost even further down in regards creating your own Mini Grid.  And best of all, we are not beholden to any particular Manufacture.

Personally if I was to do all this again, I would just stick with PV and more PV, its now a very good cost and easy to control.

I will certain look into Ozinverters for future use.

Bruce S

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Re: AC Coupling Control Issues
« Reply #9 on: October 10, 2016, 08:53:13 AM »
clockmanFRA;
Don't thank me it was all DamonHD and JW's doing.
Cheers
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clockmanFRA

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Re: AC Coupling Control Issues
« Reply #10 on: October 11, 2016, 11:56:56 PM »
whoops!, thanks Bruce.

Big thanks then,  ......  to DamonHD and JW.
Everything is possible, just give me time.

camillitech

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Re: AC Coupling Control Issues
« Reply #11 on: October 31, 2016, 01:06:06 AM »
Rant,

Anybody attempt to AC couple fairly large systems off grid?

Wow what a pain.  Who new you had to turn into a control engineer just to make everything play.

Does anybody know any rules of thumb for inverter/coupling ratios?

Just trying to get the conversation going with anyone who has experience.

Thanks

Hi,

my system isn't anywhere near the size of yours, but it does run a 120m square house, power heating hot water etc all year round with a combination of AC and DC coupling https://lifeattheendoftheroad.wordpress.com/2016/10/22/ The basic schematic is on there, it's a little chaotic and that post is more for my reference than anything else.
It works really well using Hugh's 'phase control' circuit http://scoraigwind.co.uk/tristar-follower-to-control-ac-heaters/ to divert excess heat into a large thermal store.

One thing for sure, it's not been an easy ride and the first thing I did was ditch the frequency shifting function on my SMA SI6.0H as soon as I installed it. I know others who successfully use it with total 'AC coupled' systems but mine has several 'DC coupled' inputs too and I require the flexibility to add more.

It's about to get a whole lot more complicated shortly as I've now installed an Outback GVFX 3048 and extra 950Ah battery bank which I intend to integrate into the system  somehow. Just to complicate matters even further I'm installing another 6kW 'AC coupled' wind turbine as I plan to run an EV too.

My main issues have been with GTI's 'dropping out' and some of the SI's annoying idiosyncrasy and German logic, but then it is primarily for use on full AC coupled systems. If I were to do it again I'd go with multiple Outbacks, I do like their simplicity.

From my experience so far I'd say that GTI's inverters with transformers work far better than ones without in AC coupled systems. Having said that I've been doing inverter trials for Hugh at Scoraig and Powerspout in NZ and the Ginlong series of Solis inverters seem to outperform the SMA GTI's for a fraction of the cost when using hydro at least. Never tried one on a wind turbine, which is the real test of an AC coupled system.

Cheers, Paul 

OperaHouse

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Re: AC Coupling Control Issues
« Reply #12 on: November 01, 2016, 11:38:23 AM »
Thanks for that post, it just gave me an idea for a new project.  I'm developing a proportional controller based on a $3 NANO that will do phase control based on the voltage of the battery to operate heaters from an AC inverter.  $10 sounds a lot better than that $109 device.

Eraser3000

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Re: AC Coupling Control Issues
« Reply #13 on: February 04, 2017, 09:27:32 PM »
Thanks for sharing Paul, and for the link.

Did you ever get the Outback added in to your system?

I have worked out the issues, at least 96 % of them.   Finally making some power 2305 KWhs last month, and it didn't run the whole month. 

I have had good luck with the Ginlongs, and I really love my SMA's.

Cheers

Rant,

Anybody attempt to AC couple fairly large systems off grid?

Wow what a pain.  Who new you had to turn into a control engineer just to make everything play.

Does anybody know any rules of thumb for inverter/coupling ratios?

Just trying to get the conversation going with anyone who has experience.

Thanks

Hi,

my system isn't anywhere near the size of yours, but it does run a 120m square house, power heating hot water etc all year round with a combination of AC and DC coupling https://lifeattheendoftheroad.wordpress.com/2016/10/22/ The basic schematic is on there, it's a little chaotic and that post is more for my reference than anything else.
It works really well using Hugh's 'phase control' circuit http://scoraigwind.co.uk/tristar-follower-to-control-ac-heaters/ to divert excess heat into a large thermal store.

One thing for sure, it's not been an easy ride and the first thing I did was ditch the frequency shifting function on my SMA SI6.0H as soon as I installed it. I know others who successfully use it with total 'AC coupled' systems but mine has several 'DC coupled' inputs too and I require the flexibility to add more.

It's about to get a whole lot more complicated shortly as I've now installed an Outback GVFX 3048 and extra 950Ah battery bank which I intend to integrate into the system  somehow. Just to complicate matters even further I'm installing another 6kW 'AC coupled' wind turbine as I plan to run an EV too.

My main issues have been with GTI's 'dropping out' and some of the SI's annoying idiosyncrasy and German logic, but then it is primarily for use on full AC coupled systems. If I were to do it again I'd go with multiple Outbacks, I do like their simplicity.

From my experience so far I'd say that GTI's inverters with transformers work far better than ones without in AC coupled systems. Having said that I've been doing inverter trials for Hugh at Scoraig and Powerspout in NZ and the Ginlong series of Solis inverters seem to outperform the SMA GTI's for a fraction of the cost when using hydro at least. Never tried one on a wind turbine, which is the real test of an AC coupled system.

Cheers, Paul

Eraser3000

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Re: AC Coupling Control Issues
« Reply #14 on: February 04, 2017, 09:30:19 PM »
Yeah, I am doing this very thing an my 240AC system, works great.. Did you ever play around with the NANO and get something going?


Thanks for that post, it just gave me an idea for a new project.  I'm developing a proportional controller based on a $3 NANO that will do phase control based on the voltage of the battery to operate heaters from an AC inverter.  $10 sounds a lot better than that $109 device.

Eraser3000

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Re: AC Coupling Control Issues
« Reply #15 on: February 04, 2017, 09:32:21 PM »
In case anyone is interesting in the final control system diagram. Here it is.

10224-0

10225-1


camillitech

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Re: AC Coupling Control Issues
« Reply #16 on: February 05, 2017, 12:47:03 AM »
Hi Eraser,

first let me say that is an amazing system you have there and I wish I had a fraction of your 'grip' on the subject. Me, I'm just a 'grease monkey' with a minor qualification in marine electronics (six week course  :-[ ) so most of it is way above my head.

Anyway I'm working on a rather crazy scheme at the moment to intergrate the Outback GVFX 3048 but it's in the experimental stage until I get my 6kW wind turbine up. I'm pouring the 15 cubic meter base as we speak.



The final 7 cubic meters is arriving by truck on Monday.

It is a KW6 grid tied turbine https://www.kingspanenviro.com/wind/kw6 and I plan to 'AC Couple' it via the 3kW Outback, which on the face of it is totally irrational and stupid. However the turbine was cheap and the SMA SI6.0H grid that feeds the house is maxed out with other AC and DC coupled turbines and panels.

So, here is the crazy plan. The KW6 feeds a WB6000 into a small grid dedicated to heating 2 x 3kW immersion elements in my 1500lt thermal store. This grid is created by the Outback and a 950Ah battery bank both of which I 'acquired' for very little money. Now I know this is a recipe for 'magic smoke' if the unused power on the grid ever exceeds the Outback's rating. What I'm doing to mitigate this is using two of these https://www.immersun.co.uk/wp-content/uploads/2014/08/Instruction-Manual-v1.1.pdf with the CT on the Outback's 'AC out' and set to say 200W or even less. This (I hope) will keep the batteries topped up (they'll have a TriStar in 'diversion mode to prevent over charging) and after that the Immersun devices will divert all power to the heating elements (up to 3 for each unit but only 3kW at a time). If the store gets too hot the water is then circulated by a relay in the Immersun and if that doesn't 'do the trick' an air heater is switched on, if that fails then a third one takes over. The problem is that if they all go 'tits up' or something else goes wrong then the Outback will probably fry or at least shut down cos it cannae handle 6kW or more of 'reverse power' so to speak. So what I'm working on now is a fuse or MCB that will trip or blow if power to the Outback's 'AC out' exceeds 1kW. In that event the fuse/MCB will blow/trip, the mini grid will fail, the GTI will shut down and the KW6 will 'freewheel'. Unlike most wind turbines the Kingspan/Proven downwind turbines are quite happy to do this.

OK, I know it's fraught with problems and crazy but I'm trying to utilize stuff that I already have. If it doesn't work I'll just buy another SI6.0H and increase my 'AC coupling' potential on the main grid or buy two more Outback 3048's and use those to supply my main grid and keep the SI as 'back up'.

The house is totally 'off grid' and all electric so we don't even have to cut wood but I'd like to run an EV too.

Cheers, Paul
« Last Edit: February 05, 2017, 12:58:31 AM by camillitech »

Eraser3000

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Re: AC Coupling Control Issues
« Reply #17 on: February 05, 2017, 04:20:30 PM »
Hey Camillitech,

Looks like you have a nice sized project there.
I dont think your plan is a crazy one. That is precisely what I ended up doing with my build. Minus the Immersun and a few details.

One thing, did you get the Inverter model wrong? The Outback GVFX 3048 is a grid tie unit, it requires a grid to put out AC.

"I plan to 'AC Couple' it via the 3kW Outback",
"which on the face of it is totally irrational and stupid"

I think its a great idea, I was told by some big company experts that it was impossible to do the same thing with my 30KW unit.

In Hindsight it was more difficult than I thought it would be. If those Immersun units work as advertised that should take most of the hard part out of the project.
I say that but pouring 15 cubic meters of concrete and running cable and building up the system from the ground up is a substantial project for one guy.

My concrete pour in the end was 50 cubic yards of concrete, and 1400 feet of electrical cable. Lots of labor for one person.

How did you build your 1500 liter tank? And how did you insulate? Do you have any pictures?

Another thing, Outback will tell you that you will burn their Inverter's up by oversizing the GTI's on the system, and I'm sure you can eventually, but if you have Intelligent loads that can keep the system in check the inverters don't end up feeling it. Also the Outback will trip out on you if certain conditions are met, and the GTI's will drop off. Another thing is they will over heat pretty fast, so you can use their built in Digital output as an emergency cut off of some kind.

My thermal stores are sitting at 206F and 199.8F at the moment, If you over temp can you shut the wind turbine off?

Kudos to you for taking on a big project! Most people don't want to tackle anything that seems too big to handle.

Here is a link to  the big tower build: http://www.anotherpower.com/board/index.php/topic,1212.0.html

Ungrounded Lightning Rod

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Re: AC Coupling Control Issues
« Reply #18 on: February 05, 2017, 07:49:43 PM »
For the bus bars I used some .25 Inch X 2.5" pieces of aluminum left over from connecting batteries years ago.

Electrical connections between aluminum and other conductors (copper, steel) can degrade dangerously with time and lead to both failures and fires.

The aluminum has a different coefficient of expansion, so connections work lose.  It forms a very tough, non-conductive, oxidation layer that reduces contact area and increases resistance.  This increases heating with variable loads, leading to acceleration of the problem.

Use of aluminum wiring caused a lot of house fires (generally years after instalation) before specialized connectors were developed that could handle keeping the transition connected.  Even with this improvement it has been largely abandoned for home wiring, except for the drop from the utility to the (sealed) metering box.  (You'll notice there are some (pricier) breakers, switches, etc. with special aluminum-rated terminals, and special crimp-on lugs, for use with legacy or service drop aluminum wiring.)

Cutting a busbar out of aluminum and bolting it into place, with no special attention to the transition, may be asking for trouble a few years down the road.  I'd either replace it with copper when finances or opportunity warrant, or at least look into the issues of making the connections safe and long-lasting.

Burning down the house, or even the electrical shed, negates the utiity of an R.E. system.  B-)

camillitech

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Re: AC Coupling Control Issues
« Reply #19 on: February 06, 2017, 06:46:38 AM »
Wow http://www.anotherpower.com/board/index.php/topic,1212.0.html that puts my baby to shame Eraser.

One thing, did you get the Inverter model wrong? The Outback GVFX 3048 is a grid tie unit, it requires a grid to put out AC.

I know, it was a bit of a gamble buying it, but it was less than half price, brand new and delivered to my door. Methinks Outback's literature puts a lot of people off. Mine works just fine without any grid and has no problem whatsover synchronizing to the SI 6.0H grid or my 15kVa 1500rpm generator.

I think its a great idea, I was told by some big company experts that it was impossible to do


Yes I was told by Trace 5 years ago that is was not possible to 'AC couple' their SW4548e my 'AC coupled' hydro turbine and SMA WB1200 disagreed  ;)

How did you build your 1500 liter tank? And how did you insulate? Do you have any pictures?


I cheated  :)





it's an Akvaterm http://www.akvaterm.fi/eng/Accumulators/Akva.38.html

My thermal stores are sitting at 206F and 199.8F at the moment, If you over temp can you shut the wind turbine off?



The Proven/Kingspan range are quite happy to run off load, indeed they are designed to do so in the event of battery voltage (on the DC coupled versions) exceeding 60V.

Cheers, Paul

OperaHouse

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Re: AC Coupling Control Issues
« Reply #20 on: February 06, 2017, 10:04:09 AM »
That is one impressive tank with convenience outlets for personal use.

camillitech

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Re: AC Coupling Control Issues
« Reply #21 on: February 06, 2017, 10:50:44 AM »
That is one impressive tank with convenience outlets for personal use.

I tried to 'future proof' it with as many tappings as possible but one more immersion element would have been useful for the next madcap scheme. I have one spare at the moment and the bottom 6kW one is tapped directly into the 15kVa generator so it's always running at least 50% loaded to prevent bore glazing. Trouble is I'm gonna have to utilize this one for my wind turbine diversion plan. Gonna have a peak inside it and see if I can configure it as 2 x 3kW, though that may complicate things with the internal thermostat.

The generator rarely 'auto starts' but it's nice to flash it up on those cold windless winter dark days to put some heat into the store.

Cheers, Paul

Eraser3000

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Re: AC Coupling Control Issues
« Reply #22 on: February 06, 2017, 09:08:44 PM »
I used a dry and a wet antioxidant made for aluminum and copper, but i do see your point.


Good information.


For the bus bars I used some .25 Inch X 2.5" pieces of aluminum left over from connecting batteries years ago.

Electrical connections between aluminum and other conductors (copper, steel) can degrade dangerously with time and lead to both failures and fires.

The aluminum has a different coefficient of expansion, so connections work lose.  It forms a very tough, non-conductive, oxidation layer that reduces contact area and increases resistance.  This increases heating with variable loads, leading to acceleration of the problem.

Use of aluminum wiring caused a lot of house fires (generally years after instalation) before specialized connectors were developed that could handle keeping the transition connected.  Even with this improvement it has been largely abandoned for home wiring, except for the drop from the utility to the (sealed) metering box.  (You'll notice there are some (pricier) breakers, switches, etc. with special aluminum-rated terminals, and special crimp-on lugs, for use with legacy or service drop aluminum wiring.)

Cutting a busbar out of aluminum and bolting it into place, with no special attention to the transition, may be asking for trouble a few years down the road.  I'd either replace it with copper when finances or opportunity warrant, or at least look into the issues of making the connections safe and long-lasting.

Burning down the house, or even the electrical shed, negates the utiity of an R.E. system.  B-)

Eraser3000

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Re: AC Coupling Control Issues
« Reply #23 on: February 06, 2017, 09:13:42 PM »

I know, it was a bit of a gamble buying it, but it was less than half price, brand new and delivered to my door. Methinks Outback's literature puts a lot of people off. Mine works just fine without any grid and has no problem whatsover synchronizing to the SI 6.0H grid or my 15kVa 1500rpm generator.


Ok i misunderstood, that Sunny Island should work great.

How did you build your 1500 liter tank? And how did you insulate?

Looks great!