RFI From Inverter

[Pwablo]

What about this??

View attachment 16707

Hi John

This I know all about, unfortunately this fundamental requirement is apparently ignored by everyone even the regulator when it comes to Solar. Ofcom don't feel it falls under their remit currently unless it causes harm to essential services like military, aviation, emergency services, critical infrastructure etc etc. licensed amateurs who they actually class as a service can be freely fobbed off along with most of the general population.

Then dig a bit deeper and we find that most manufacturers wrongly think that if they gain CE or UKCA approval (Which is mostly a paperwork exercise) that they are in the clear.
People need to appreciate that the CE or UKCA marking only means that the manufacturer has handed in paperwork stating they have tested the products EMC and said it passed. Nobody witnesses the testing and nobody checks the product. I would suggest that nobody seems to be checking if the correct standards have even been used either?

https://www.gov.uk/guidance/ukca-ma...nd-documentation#conformity-assessment-routes

If one looks into the standards used for Inverter EMC compliance, the UK seems to accept the generic standard of EN61000-6-3 is as all that is needed, and gloss over the fact that there is a product specific standard EN55011 which should take presidence over the generic standard (Even the generic standard states that it should not be used if a product specific standard exists !). This is of course in stark contrast to many EU countries who rightly require both standards to gain approval and CE marking. (See previously posted RDI report in this thread!)

Looking at what is tested in each standard, it becomes evident that the generic one is no longer fit for purpose for today's generation of Solar Inverters, especially the Hybrid ones, as EN61000-6-3 only tests the Radiated (enclosure) and AC emissions. The Product specific standard EN55011 tests Radiated, AC Port and Panel DC port emissions, and is used by most European countries along with the generic standard, to confer compliance for CE marking. But alas not here in good old blightly,

Now a huge amount of Hybrid Inverters are being installed with batteries, and there is no requirement to test emissions on the DC battery ports !! And this test is not in any standard either!! You could'nt make it up. My experience has just shown how much RFI can be conducted via this DC Battery port..... Then the poor old sparkies that are installing this stuff, have no clue about EMC, as was mentioned earlier in this thread.....or their obligation either under the law to ensure that the entire system is compliant to the Essential Requirements, even if individual components are CE / UKCA marked.
Yet the entire industry has little to no knowledge of any of this, or of any mitigation methods, or any means to test for emissions when an install is completed.

Its a huge cluster F*** !

Broken Britain

Away to watch the Rugby. Good Luck Lads ! May the worst team loose

Have a good weekend

Paul

 

[binky]

Playing devils advocate, could b) not apply to the telecoms equipment?

Oh yes! We used to have a Navy radio operator living next door to us as a child. He was also a very keen radio ham, the first to manage to contact someone in Japan, from his garden shed. What a pain on the neck, his signal was strong enough to interfere with the TV, and even come over the stereo spaeakers, when truned off. He did fit filters for us and other neighbours, but people further away were still complaining about his radio gear.

 

[johnb2713]

Oh yes! We used to have a Navy radio operator living next door to us as a child. He was also a very keen radio ham, the first to manage to contact someone in Japan, from his garden shed. What a pain on the neck, his signal was strong enough to interfere with the TV, and even come over the stereo spaeakers, when truned off. He did fit filters for us and other neighbours, but people further away were still complaining about his radio gear.

Aye, one of our neighbours was G3HFD, he had a 600' wire antenna and all homebrew stuff, the valve heaters alone were 4 kW in his shed. He could transmit and then listen and you hear his transmission come back having been around the world in the right conditions. He also used to make filters for everyone, usually soldered up in a Old Holborn tobacco tin. RF always seems like black magic to me, it's the work of satan LOL.

 

[Pwablo]

Aye, one of our neighbours was G3HFD, he had a 600' wire antenna and all homebrew stuff, the valve heaters alone were 4 kW in his shed. He could transmit and then listen and you hear his transmission come back having been around the world in the right conditions. He also used to make filters for everyone, usually soldered up in a Old Holborn tobacco tin. RF always seems like black magic to me, it's the work of satan LOL.

It happens a lot when they brew their own antennas (especially wire ones in built up areas) and use more power than is required. On that note, Ofcom just raised the Full license limit to 1kW (up from 400w), so I would expect that there will be a lot more complaints about RFI flooding the help desk in the short term. IMO there is simply no need to use a lot of power, if propagation is there, then you can contact much of the world with less than 100w and the right antenna/location.

 

[Radiotowers]

It happens a lot when they brew their own antennas (especially wire ones in built up areas) and use more power than is required. On that note, Ofcom just raised the Full license limit to 1kW (up from 400w), so I would expect that there will be a lot more complaints about RFI flooding the help desk in the short term. IMO there is simply no need to use a lot of power, if propagation is there, then you can contact much of the world with less than 100w and the right antenna/location.

I work contests with just 5 watts and manage to work Australia (VK) and New Zealand (ZL) most years, even in low sunspot years.
I wonder if Ofcom ( or the BBC) will actually deal with RFI.
I reckon the higher powers are Ofcoms mitigation of the higher noise levels we experience, they cant reduce the noise but they can allow higher power to get above the noise. And with the higher power comes the responsibility of ensuring the EMF levels are within limits.

 

[kitweuk]

Hi

I am hoping this is the right place to seek some knowledgeable advice. I am an amateur radio operator and have recently had a new build property developed next door to mine in a very rural setting. Unfortunately the developers have installed a very noisy Sunsynk ECCO Hybrid 3.6Kw inverter and the amount of interference it is generating has rendered my radio equipment inoperable for some 2 months now. Ofcom identified the source of the noise initially, but seem unable to act, but fortunately the installer seems willing to help install some mitigation if I determine the solution and bare the costs. So far we have identified that the RFI drops significantly but not completely when the DC side to the panels are isolated, and also I noticed a drop in noise levels when cheap clip on ferrites were installed on the cables to the strings, however some RFI is still escaping when the inverter is in production mode, so we believe that the AC cable is also being used as an antenna. We dont believe that ferrites are sufficient to address any differential mode currents, so it is clear that a more robust and professional solution will be called for.

I am after some advice if anyone can help? I have limited experience with solar systems, but have found that there a few manufacturers who produce EMC filters for both AC and DC applications specifically for solar inverters, to help systems meet the mandatory EMC requirements as per the Essential Requirements directive. To name a few, TE Connectivity, Shaffner and TDK Lambda. Have any of the installers here fitted such filters before? What type could be recommended in this instance? The panels are 335W Clearline Fusions PV 16's 14 off in 2 arrays of 7 panels each. The string voltage is 252V and the current 10.3 Amps. The max AC current for the Inverter is 17W @ 250VAC.

I have data sheets for the Inverter and the Panel, which I can provide if anyone is up to the challenge?

My initial thoughts are 2 off Shaffner FN2200B-25-33 DC EMC filters for the Solar panels and 1 off Shaffner FN2090LL-30-08 AC EMC Filter on the AC cable to the consumer unit. Am i on the right track here?

Any help would be greatly appreciated with this issue, as I have not asked for any of this hassle, it has pretty much been dumped on me and I really dont want to have to give up my hobby and enjoyment of my home as a result.

Thanks in advance.

Paul

I stumbled across this thread searching for EMC/RFI solutions.
I too am a radio amateur and have a small cottage in rural SW Scotland that I have been renovating which is now complete and my thoughts have now turned to building a radio shack. I am also thinking of having solar as I have some land that would accommodate the panels. The inverter I have been looking at is the Sunsynk ECCO 3.6Kw but am aware that this could spell disaster for my radio activities so have been looking at possible solutions to mitigate the RFI. I am aware that the majority of the RFI is emitted from the DC cables from the Solar panels acting as aerials. My plan would be to utilise Shaffner filters as noted above but to also run the DC cables as a twisted pair to help cancel out emissions https://emianalyst.wordpress.com/2016/08/31/how-cable-twisting-improves-emi/
but to also run these cables through a flexible steel conduit such that it acts as a Faraday cage https://www.cef.co.uk/catalogue/pro...763984&utm_content=Smart: Industrial Controls

Talking of a Faraday cage I have also thought of mounting the whole inverter system in a Faraday cage by making an enclosure lined with a conductive material such as this https://www.ebay.co.uk/itm/36467072...7779&msclkid=d99393c665f211087f13f6248f0b9604
and then glanding in the steel conduit into this enclosure.

 

[Pwablo]

I stumbled across this thread searching for EMC/RFI solutions.
I too am a radio amateur and have a small cottage in rural SW Scotland that I have been renovating which is now complete and my thoughts have now turned to building a radio shack. I am also thinking of having solar as I have some land that would accommodate the panels. The inverter I have been looking at is the Sunsynk ECCO 3.6Kw but am aware that this could spell disaster for my radio activities so have been looking at possible solutions to mitigate the RFI. I am aware that the majority of the RFI is emitted from the DC cables from the Solar panels acting as aerials. My plan would be to utilise Shaffner filters as noted above but to also run the DC cables as a twisted pair to help cancel out emissions https://emianalyst.wordpress.com/2016/08/31/how-cable-twisting-improves-emi/
but to also run these cables through a flexible steel conduit such that it acts as a Faraday cage https://www.cef.co.uk/catalogue/products/5134895-25mm-galvanised-steel-flexible-conduit-pack-10m-reel-and-10-glands?gclid=fcedc8a226941b166e83ad40c61512f9&gclsrc=3p.ds&msclkid=fcedc8a226941b166e83ad40c61512f9&utm_source=bing&utm_medium=cpc&utm_campaign=Smart Shopping: Industrial Controls&utm_term=4587437396763984&utm_content=Smart: Industrial Controls

Talking of a Faraday cage I have also thought of mounting the whole inverter system in a Faraday cage by making an enclosure lined with a conductive material such as this https://www.ebay.co.uk/itm/36467072...7779&msclkid=d99393c665f211087f13f6248f0b9604
and then glanding in the steel conduit into this enclosure.

Hi
Since installing the Inline AC and DC filters we found that these only slightly reduced the RFI. The majority of the RFI on these inverters is actually coming from the Battery DC Cable. Sunsynk have been aware of this for a while as they introduced ferrites to be installed on the Battery DC Cable and BMS Cable and added these plus instructions to their new inverter kits, however even with these ferrite rings fitted the RFI is still significant. In my opinion, if you want an RFI free installation then choose a different manufacturer, and ensure that you choose one that claims compliance with EN61000-6-3, EN55011 and FCC 15 Part B. I would also ensure that I have it in writing from any manufacturer, that they have adhered to the Electromagnetic Compatibility Directive 2016 and that the device fully complies to the letter of the Essential Requirements. If your heart is still set on the ECCO 3.6kw Inverter, you will without a doubt need the ferrite rings fitted with more than 2 wraps thru the core (you should be able to get 3 wraps thru with 35mm square DC Cable with a 13mm dia), and perhaps also need the DC Battery Cables shrouded in metal braided sleeve tied to ground, however there would still be no guarantee, that even with these measures, that it would sufficient to mitigate the RFI.

Hope this helps

 

[binky]

I suspect a European inverter might be far more compliant with EMI legislation. If you use a steel frame for the ground array, that might also help, alternatively build a wooden frame and earth the panels to a ground rod. My own array is on my garage, when I replaced the roof with metal box profile sheeting, I had to earth it as the induced voltages in the roof was quite disconcerting - proper tingle!

 

[apprentice87]

Hi
Since installing the Inline AC and DC filters we found that these only slightly reduced the RFI. The majority of the RFI on these inverters is actually coming from the Battery DC Cable. Sunsynk have been aware of this for a while as they introduced ferrites to be installed on the Battery DC Cable and BMS Cable and added these plus instructions to their new inverter kits, however even with these ferrite rings fitted the RFI is still significant. In my opinion, if you want an RFI free installation then choose a different manufacturer, and ensure that you choose one that claims compliance with EN61000-6-3, EN55011 and FCC 15 Part B. I would also ensure that I have it in writing from any manufacturer, that they have adhered to the Electromagnetic Compatibility Directive 2016 and that the device fully complies to the letter of the Essential Requirements. If your heart is still set on the ECCO 3.6kw Inverter, you will without a doubt need the ferrite rings fitted with more than 2 wraps thru the core (you should be able to get 3 wraps thru with 35mm square DC Cable with a 13mm dia), and perhaps also need the DC Battery Cables shrouded in metal braided sleeve tied to ground, however there would still be no guarantee, that even with these measures, that it would sufficient to mitigate the RFI.

Hope this helps

How are they able to import and sell the chinese crap if it does not comply with whatever "anti EMF" regs there are?? Does not "CE" marking indicate [or be supposed to indicate] that the stuff does comply with whatever regs??

john..

 

[Mike P]

Are you able to shield the battery cables?

 

[Pwablo]

How are they able to import and sell the chinese crap if it does not comply with whatever "anti EMF" regs there are?? Does not "CE" marking indicate [or be supposed to indicate] that the stuff does comply with whatever regs??

john..

Hi John

You are correct, the CE and UKCA marking should indicate that the manufacturer has complied with the required testing to the generic and/or harmonized EMC standards, but when neither of these standards require testing of the DC Battery Port, the manufacturer can still claim compliance and apply the mark, as they have conducted all the tests that were asked of them. In my opinion they should also consider the Electromagnetic Compatibility Directive 2016 which legislates the Essential Requirements, however they appear to overlook this. The RDI report conclusion summed it up as follow.

Essential requirements and harmonized standards
In addition, the findings and discussions with manufacturers show that too little account is
taken of practical situations
conformity assessment by manufacturers. This is due to the lack of risk analyzes in the
technical documentation, and the fact that manufacturers take the harmonized standard
instead of the essential requirements as a starting point.

i.e - They only care about taking the product to market and look no further till they have too....

 

[binky]

How are they able to import and sell the chinese crap if it does not comply with whatever "anti EMF" regs there are?? Does not "CE" marking indicate [or be supposed to indicate] that the stuff does comply with whatever regs??

john..

no one to enforce anything, goes with 'light touch regulation' and 'self certification'.

 

[apprentice87]

Hi John

You are correct, the CE and UKCA marking should indicate that the manufacturer has complied with the required testing to the generic and/or harmonized EMC standards, but when neither of these standards require testing of the DC Battery Port, the manufacturer can still claim compliance and apply the mark, as they have conducted all the tests that were asked of them. In my opinion they should also consider the Electromagnetic Compatibility Directive 2016 which legislates the Essential Requirements, however they appear to overlook this. The RDI report conclusion summed it up as follow.

Essential requirements and harmonized standards
In addition, the findings and discussions with manufacturers show that too little account is
taken of practical situations
conformity assessment by manufacturers. This is due to the lack of risk analyzes in the
technical documentation, and the fact that manufacturers take the harmonized standard
instead of the essential requirements as a starting point.

i.e - They only care about taking the product to market and look no further till they have too....

Could you not take all your findings to the british standards people and explain that the requirements need to be changed??

What about trading standards?? Mind you, they seem to only be interested in the little man, childish things like people selling fake cd's at car boot sales. In my own personal experience, they will not go anywhere near people that they think might have the financial muscle to fight back.

john..

 

[apprentice87]

no one to enforce anything, goes with 'light touch regulation' and 'self certification'.

Years ago, the GPO would have put a dead stop to it..

john..

 

[binky]

Years ago, the GPO would have put a dead stop to it..

john..

GPO were pretty hot on such things.

 

[UNG]

It would be interesting to check whether there are any excessive harmonics on the mains supply

 

[Pwablo]

Final Update.

After the unsuccessful attempt to mitigate the RFI with the Sunsynk supplied ferrite ring, and the purchased In Line filters, I advised Ofcom of the situation. Their engineer advised that they were working with this manufacturer on another case, and that they had supplied and installed a new model of this inverter which had resolved a lot of the RFI, and they would try and do the same for my case. A date was set for the end of March, when the original installer and a engineer would visit and swap out the inverter. The day came, the RFI went away, came back, went away again then came back off the scale. Nobody contacted me during this works, and I had to contact Ofcom to find out why the RFI was still present and as bad as it had ever been. Turned out that they had sent up the incorrect inverter ! ....after much frustration, emails and calls and another month of waiting, the device was finally changed at the end of April.

Initial tests were promising but it became obvious that there was still RFI present, mostly between 12Mhz and 15Mhz, peaking on 14Mhz (20m band),. It is also detectable on 7Mhz (40m band) but not as unworkable as 14Mhz. All the other bands are pretty clear now so the new inverter design which they introduced circa Aug 2023 is definitely an improvement over the old design, with and without the ferrite rings.

So Ofcom turned out to be really awesome. The engineer was excellent from start to finish and a credit to his department. That said, Sunsynk and the original installer do deserve some credit as they have responded and did the right thing , all be it slowly. They appear to have been working on this problem for a while, and have made some progress. So kudos to them for addressing issues caused by their products. Not so much for the problem to begin with.

I am not going to pursue any further mitigation now, as Ive simply had enough cost, hassle and stress from this issue, and will just learn live with a bit of interference.

Few photos of the Scope with the new inverter.

Happier days again.

73

 

[BenCos18]

glad you got it sorted