ERROR - Vmp exceeds the Vdcmax

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YK
ERROR - Vmp exceeds the Vdcmax

Hello,

I got that error message:
Module array voltage Vmp exceeds the Vdcmax (500.00V) of inverter 4326 times.
The maximum Vmp value is 1042.77V at hour 8456.
It is recommended that you reduce the number of modules per string.

The system:
32 x Canadian CS6K-260P
1 x SE-7600A 204 (cec2013)
Modules per string: 32
Strings in parallel: 1

Can you please provide an explanation on the error and how can I overcome it?

Thanks
Yoav

Paul Gilman

Dear Yoav,

That message means that SAM determined the array operating voltage exceeds the inverter's maximum rated voltage for 4,326 hours of the 8,760 hours in a year, and that the array's maximum voltage over the year was 1,042 Volts.

When the array voltage is greater than the inverter maximum voltage, SAM "clips" the voltage to the rated value, which limits the power to the inverter. Too much of this kind of clipping might suggest that the array is not properly configured for the inverter you chose.

To fix the problem, you can either change the number of strings, or choose an inverter with a higher maximum voltage rating. For example, you could try changing the number of modules per string to 16 and the number of strings in parallel to 2. That would halve the array operating voltage so that the maximum array voltage is 521 V, which still exceeds the inverter maximum voltage, but not by very much.

You can read more about inverter clipping online. Here's a link to one article on the subject:

https://www.solarpowerworldonline.com/2016/07/solar-inverters-clipping-d...

Best regards,
Paul.

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