Advice about solar PV panels

Discussion in 'EMC Matters' started by MM5AHO, Dec 14, 2014.

  1. Ken G3SDW

    Ken G3SDW Moderator

    Well yes but not solve it but prove that it is the SMPS causing the problem, as i said they are the biggest cause of problems such as this today, they should if designed correctly not be a problem but sadly filter components are left out in production to save pennies, these are mainly mad in the PRC.

    Give it a go as you have nothing to lose.
  2. M0JAV

    M0JAV Moderator

    Good advice in this article
    https://rsgb.org/main/technical/emc/solar-pv-panels/
  3. gdb

    gdb New Member

    I start the journey of researching a solar panel grid-connect installation on a yet-to-be-built bungalow. I wish to have a list of questions to ask the snake-oil salesmen. The forum advice is summarised below (thank you all). Mistakes are mine.

    Questions
    1) G3VNH says ...I provided him with all the information from the Society at that time about the problems of Solar installations..... However I sent him away with copies of all the EMC column inches re solar installation from RADCOM.... Is this RSGB information collated and available somewhere?

    2) The inverter noise is described as "hash on all bands" ie broadband (G3PGA). The advice below suggests that the optimiser inverters, main inverter, grid-connect inverter (?) and miscellaneous SMPS creates the problem. The solution is installing ferrite filters on each end of DC and AC wiring, metal conduit for both, and consider inverter plus separate transformer (G3PGA). Various filters are mentioned (clip-on, TDK Noise-Filter snap-on, RSGB Fairite Type 43) with various turns for DC and AC wires (one turn, 5 bifilar). There is quite a difference between K1KP (QST20Solar20April2020165b25d.pdf)'s filter choices and contributors here.

    Is there a base set of ferrites and turns for DC and AC wiring which is a starting point? How sensitive is the choice of turns and cores?

    3) Any contributions to my list of questions for the salesmen would be welcome. Which anti-RFI standard should they be working to?

    Advice summary
    a) 4 large clip-ons [on the DC side of the inverter ?] - G3PGA

    b) line filter and common chokes on the ac connections, and at the entry to the conduit on the roof, and between the solar panels and the optimisers, metal conduit for the dc run from the roof to the inverter, and configuring the dc output loop on the roof into a transmission line with a minimal loop area. - K1KP (QST20Solar20April2020165b25d.pdf)

    c) DC wiring outside, no optimizers,...industrial-size filters on DC input and AC output - GM3SEK

    d) fit TDK Noise Filter snap-fix ferrite clamps at each end of the DC cabling... the DC leads had a single turn around the ferrite. Twin and earth cable from the AC output to the house distribution board had an RSGB EMC Committee approved Fair-Rite 43 material ferrite ring placed on each end of this 15 metre run - G3VNH

    e) I can see nothing obvious added behind the panels and when I mentioned "conditioner" [optimiser?] to the installers that resulted in blank looks. G3SDW

    f) a good impedance match between the panels and the inverter is important for the efficiency of the system and minimising any risk of RF radiation...run all the DC and AC cables in metal conduit - colinsanter

    Units installed by forum with reasonable success

    i) "New" StecaGrid 2000 inverter system - G3PGA
    ii) Fronius industrial inverter - GM3EK
    iii) 11 BenQ 330W panels and the ABB AURORA 3000 Inverter - G3VNH
    iv) 6 + 10 PV panels and an Aurora inverter system - G3SDW
    v) LG Electronics panels and an SMA Sunny Boy SB3600TL inverter - MM5AHO
    vi) SMA Sunny Boy inverter, and 16 X 250 Watt Mitsubishi solar PV panel - colinsanter
    vii) SMA Sunny Boy + Sharp panels - GM3TAL

    Thank you 73 Giles G0AJC

  4. Ken G3SDW

    Ken G3SDW Moderator

    Good morning Giles.

    There is a simple rule of thumb when venturing down the road of having Solar PV installed.

    Make sure the equipment being offered is made in Europe, mainly Germany, as equipment made in the PRC is often CE marked but that does not mean that it complies to EU regulations.

    Make sure that who ever installs the installation does it to the correct standards with RFI in mind, this means all cables dressed correctly with clamp on ferrites on all input and output cables of the type that GM3SEK recommends, nothing less than that..

    If all this is done, and it has been proved that Solar PV and HF radio can live side by side without any noise issues.

    Asking these questions to whoever the salesman is will no doubt give you a very blank look so you will need to talk to someone more technical at the supply company who will be doing the supply and installation work.

    Get all of this in writing and for them to agree regarding any RFI issues, that if there are any problems then they will have to rectify them, as it will be there responsibility to get it sorted.

    Good luck and as long as you and they follow these simple rules then you will not have a problem.

    73 Ken G3SDW
  5. gdb

    gdb New Member

    Hello Ken and thank you for the sensible tips,

    ".......There is a simple rule of thumb when venturing down the road of having Solar PV installed. Make sure the equipment being offered is made in Europe, mainly Germany, as equipment made in the PRC is often CE marked but that does not mean that it complies to EU regulations....."

    Yes...As Ruskin said a while back : There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper and people who consider price alone are this man's legitimate prey.

    "Make sure that who ever installs the installation does it to the correct standards with RFI in mind, this means all cables dressed correctly with clamp on ferrites on all input and output cables of the type that GM3SEK recommends, nothing less than that."

    Well, after your comment, I prowled and arrived at palomar-engineers.com's Solar System RFI page. I assume the clamp-on ferrites are "in-line" with no turns. It would seem that ring ferrites with multiple turns produce a better result :

    "The F240 rings with 1.4″ inside diameter can accommodate multiple turns (remember the RFI choking effectiveness is a function of the square of the number of turns – e.g. 2 ring turns = 4 snap on ferrites, 3 ring turns = 9 snap on ferrites). For single turn snap on or slip ferrite beads, you will need 6-12 inches of ferrite for each cable entering and exiting the inverter or one F240 of F400 (3″ hole) ring ferrite with 3-4 turns on the AC lines." (Incidentally, nice to see L = μ x N2 x A / l in a practical setting).

    Most of your contributors are using unspecified snap-ons, probably because persuading installers to use ferrite rings would be hard work. I conclude that the type of snap-on is not critical for European inverters. Just so long as one is there.


    "If all this is done, and it has been proved that Solar PV and HF radio can live side by side without any noise issues."

    Well...you're right. It does not seem that difficult. The amateur is an educated audience, used to licence conditions which preclude producing interference from amateur gear. The problem, as a friend found out, was a lay-person's solar panel installation across the street which, presumably, was a chinese cheapie. Noise levels through the roof...." for the sake of a snap-on, the spectrum was lost...". It's about education but extremely difficult to get the message across.
    Anyway, all the best and many thanks for the advice
    73 Giles G0AJC
  6. Ken G3SDW

    Ken G3SDW Moderator

    Clamp on ferrites of the type mentioned by GM3SEK are the type used for larger cables so putting turns which is better would not be an issue.

    The most important thing to remember, which many do not appreciate is to use the correct grade of ferrite, so not any old type will do.

    The first thing to do is to talk with one of there technical guys, i think you will know if he is technical though as his replies will give the game away, there is technical and there is technical, think you get my drift.

    Let us know how you get on as it is nice to pass on your findings to others.

    73 Ken G3SDW

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