Fronius inverter clipping production

Problems Investigating
#1

O.P.

Hi everyone. I have an issue with my solar system and i hope that i can get an idea of what is happening. Fronius inverter 6.0.3M connected to two strings of 3.7kw and 3.3kw (total 7kw). Mppt1 string production is clipped at peak hours (flat line) with total production maxing out at 5.5kw on a sunny day. Mppt 2 is showing a normal curve. Dynamic power limit is set to “off”. What could be the issue?

Another thing to add is that i have expanded the system by adding 2 additional panels to the first string and 1 additional panel to the second string of the same make and wattage to the existing. While production has increased for the first string, second string’s production remains the same. I have checked whether the additional panel is actually connected by shading it purposedly and production drops normally when shaded.

Below is a link to dropbox with several printscreens from solar.web

Thank you

#2

Hi, Does / is the MPPT1 string of panels exceeding the DC input limits of the inverter / string?

#3

Hi, i don’t think so since the limit is 16A.

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#4

Is it possible that the inverter splits the string limits equally i.e. 3kw per string?

#5

I facing the same problem but with Sungrow. Do you have the solution ?

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#7

No, unfortunately

#8

Just an update. Problem fixed by changing power reactive mode to c.cosφ and setting c.cosφ to +1.000. Thank you everyone for your input

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#9

Hi there, An old thread but I am having a similar situation with 8.8kW DC of panels (split evenly on two MPPT) which are being clipped to ~7.9kW output (with a Fronius Primo 10kW inverter - would not expect clipping) on a bright sunny day. How did you change the power reactive mode as described? Thanks!

#10

Hi @dnarna before looking for a possible technical problem can I ask if your inverter has been export / grid limited by your network operator?

#11

Hi, thanks for the response, @grannos! I do not believe it has been limited. I was generating more instantaneous kW for short periods earlier (often exceeding 8.8kW DC of system - closer to 9.5kW). I believe, and there could be other factors, I am dealing with straight up reduction of output due to panel heating, as these are the first consistently bright sunny days (>30C) since installed. Following days the system got up to 7.6kW or so, but didn’t “clip” or flatline at the top like it did before. While I was anticipating some reduction I am surprised how MUCH it is reduced by the heat (expected 8-10%, not around 14%). Guess I will keep an eye on it moving forward, but any thoughts are welcome. Thanks!

#12

Although this post is aged, I’m hoping I can get some advice on my current challenge. My Fronius CL 55 inverter is clipping production right about mid-morning each day and goes flat until late afternoon. error message indicates overheating could this be related to a fan failure. Happy to learn from your combined experiences

#13

Hi @al_energykn. I don’t know anything about the Fronius CL 55 series however it’s not unreasonable to think that the inverter’s output would be throttled if ( i ) a fan failed or ( ii ) the inverter started to overheat.

If you look at an earlier thread that I posted about the Fronius API Fronius Inverter FAN RPM you will see that the Fronius API should give you access to fan information on the CL inverter. You could try querying the API of your inverter to see what it says about the fan(s) and their status.

I would have thought that the Solar.Web portal would log some sort of error message too if a fan had failed.

Good luck

Grannos.