Frequency Problems

[russ_fae_fyvie]

Just when we thought we'd cracked it, we are now finding really massive fluctuatinos in the Frequency in the system. I have asked the people who installed it, but I've got a feeling they don't know (no answers from them yet) !

So I am looking for advice from maybe someone with Sunny Boy experience because this may, or may not have something to do with that.

As you may know, we now have the Future Energy 1kW Turbine up and running, over the last few days thats been producing a good steady amount (over 20kWh over the last 10 days or so) which is wired into the batteries with a Morningstar 60A Controller. We have also had a good input from the 1.44kW PV System, (about 3 to 5 kWh per day) and the Sunny Boy 1700 puts the AC into the MCB in the house, any excess goes back to the Sunny Island/Batteries.

Over the last 3 or 4 days however the frequency in the system generally rises as the day goes on and by the time we get to around 3.30pm (this was yesterday) the frequency has gone up to 55Hz which then means the Sunny Boy shuts down as it has a max setting of 54.89Hz.

This is obviously not good for all the electronic items in the house and to be honest, I havent got a clue whats happening.

In my very basic understanding, if the Turbine is feeding DC directly into the Batteries, how would that affect the AC side ?

On the other hand, if the Turbine is working too well and the batteries are fully charged (which I can't see would happen as the wind wasn't particularly strong but was just a steady 150 - 250w over the day) would the Sunny Boy be effected ?

Unfortunately its difficult to get anyone locally to come and look at the overall system and tell me whats going on. I seem to remember the installer told me when the batteries were fully charged, the Sunny Boy increased its frequence (for some reason) but going to 55 seems, to me, to be wrong ?

Help !

[camillitech]

Jeez Russ, you are having some bad luck mate, can't really help other than offer my sympathy and guess that the problem is the inverter.

I recently fitted a frequency meter to my system for no reason other than it was on a now redundant panel that used to monitor my Navitron AC hydro turbine. All I can say is that no matter what's running, weather it be inductive loads, resistive loads, or what's charging, wind, hydro or genny, weather the batteries are at 47.9 or 58.9 it never varies more than .5Hz. It makes no difference if I'm pulling 4Kw out or putting 4Kw in. Surely it must be the inverter

Cheers, Paul

[Iain]

Hi
Off another forum:-

If your Sunny Boy is going to function properly with the Sunny Island, it must be programed for "Off-Grid" mode. This can be done with an SMA Service Cable or a WebBox. Please call us if you plan on doing this.

When setting your Sunny Boy to Off Grid, it allows the Sunny Island to control its output via Frequency Shift. If there is more power that is produced, and cannot be used, the Sunny Island raises its frequency, to supply the adequate amount of current from the Sunny Boy to the loads panel. If it needs more, or less, the Sunny Island controls that with its frequency.

Please let me know if this answers your question.

Any use??
Iain

[russ_fae_fyvie]

Hi Iain,

Thats interesting, sounds like whats happening to our system because it was only recently set fo 'Off Gird' mode, looks like the bettereis are getting plenty from the Wind and the Sunny Boy see's they are full and thats when the Sunny Island shifts the frequency. I just can't see how going up to 55Hz is a good thing and we must look at other options if that is the way they have to work.

Thanks very much for that, it does seem to confirm whats happening.

Going to have to lok at a better way of doing this, the way its sets up at the moment, it looks like the Wind has priority in charging the batteries and so the Sunny Boy has to do all that to compensate. If the PV ad the priority, then if the batteries are fully charged by the PV, then the Turbine Charge Controller would kick in the Dump Loads instead ?

Or we jsut get rid of the Sunny Boy and feed the PV into the Batteries directly through another Controller (this has been mentioned in another Thread so I won't repeat it all again!)

[Iain]

Hi
Another bit

The frequency at most, will be increased to 62Hz, that is when the system does not need any more power, and the Sunny Island must throttle the Sunny Boy completely to 0watts. Usually, if the grid is down, it will operate within 60-62Hz. There is the best explanation in section 17.5 of the manual, labeled "Frequency Shift Power Control." Please take a look at this explanation in the manual.

- I have not seen a problem with computers in the past when running at this frequency. However, I do recommend contacting the manufacturer of that specific equipment to see if that would make an impact on your electronics.

- Many clocks use frequency to keep time. If, the Sunny Island has had to change the frequency during the day to control the Sunny Boys, it will then correct itself at night in order to keep your clocks correct. For Example, if the frequency had to rise to 61Hz for one hour during the day, it will correct that by changing the frequency to 59Hz for one hour during the night to manage the time.

Iain

[russ_fae_fyvie]

Hi again, that looks like the American version which is 60Hz basic, so going by that the max overspeed would be 2Hz (to 62, of 52 in our case) thats why I'm surprised ours went up to 55 !

[Iain]

Hi
I put the last one in as it had the page number for the description in the manual. The manual should also give the frequency "limits"

Looking at the data sheets the control for the uk one is from 45-55 hz, so sounds like yours is about right.
Good luck
Iain

[russ_fae_fyvie]

Cheers !

[billi]

If the PV ad the priority, then if the batteries are fully charged by the PV, then the Turbine Charge Controller would kick in the Dump Loads instead ?

Or we jsut get rid of the Sunny Boy and feed the PV into the Batteries directly through another Controller (this has been mentioned in another Thread so I won't repeat it all again!)

Russ it takes normally  a few hours after bulk charge  in absorption charge to get the battery really full
In these few hours the incoming watts  from PV  and Wind will have to be reduced by the controllers morningstar and the Sunny Island trying to tell the Sunny boy to reduce its performance

So wind is still pumping in the battery and Sunny Island   perhaps thinks it comes from the PV and tries to reduce the sunny boy s input  

But i could be wrong as well cause do not know much about Sunny Island and sunny boy

That is what i meant on your other thread  , you have to be careful and make sure  that the wind controller  is dumping loads after the Sunny Island is regulating the PV down , because other way round  the 60 A Morningstar is too small to cope with the PV and the wind

Billi

Perhaps some additional controller for the Sunny Island  would help to use the extra power when Frequency rises
i think SMA has a (pricey )product called "Smart Load"  or an alternative is called "Distributed Intelligent Load  Controller"  sold in some uk renewable energy shops

[russ_fae_fyvie]

Cheers Billi, I think I need someone local (if they exist!) to look at the complete system and come up with a solution.

It is frustrating to get really good input from the PV and the Wind only to find the problems we are getting.

Thanks for everyones input.

[rogeriko]

Please get rid of the sunny boy I think this is the third time I have told you this. I have installed at least 20 off grid homes, no-one has a sunny boy everyone is happy. For a start you are loosing half your power and it is messing with your frequency which normally dosnt matter but in your case it is a problem so you know what you have to do. When  the Sunny Island realises there are no sunny boys connected the frequency will not budge from exactly 50.0hz no matter how much power you draw or dont draw.

[russ_fae_fyvie]

Thanks, I think I know what to do now, sorry I didn't ignore your other comments, I'm just trying to get my head around it all !!

Its just a matter of finding someone locally who knows how to take it out and get an alternative Controller wired into the house.

Unfortunately finding someone around here who knows what they are doing with an Off Gird house are like trying to find hens teeth !

I have emailed the people responsible for the original installation with exactly your recommendations but I have a feeling they don't really know what they are are doing, hence the mess we ended up in !

I will get rid of the Sunny Boy, once I can make sure whoever does the work knows more than the others !!

ta
 

[billi]

I have my problems to understand the frequency problem ! And why the AC coupling  is not making sense !

Sure i personally go for charge-controller .....

But what is wrong  with the sunny boy to a Sunny Island ?

I mean all grid connected PV s  must have the problem  of frequency  unbalance

What can  do that frequency unbalance to  ones consumers ?

And in relation to Russ setup  i think we have to come up with an idea of how to cope nicely with the dumping of max 3 kw  (PV and wind )

I personally  think (if that frequency unbalance is ok)  i just would ad  a few more panels to the sunny boy 1700   , instead of ripping all apart/rewiring  and sell the sunyboy and buy a charge controller

But i just wrote that to find out, what  the options are

Billi

[camillitech]

This messing about with the frequency does seem to be a peculiarity of the Sunny boy and only seems to cause problems on the wood boiler. I can't remember what make it is http://www.navitron.org.uk/forum/index.php/topic,13593.0.html but personally I'd be thinking about swapping it for a Perge. It would solve the problem of burning out fan motors and reduce the load on Russ's system.

Perhaps something for DaveB275 to consider also.

Cheers, Paul

[billi]

...would not all grid tie installs  as well face the problem of frequency  changes ?
I  suppose not as much as a Off grid  setup with a Grid-tie inverter