Huawei optimizers - PNom ratio error

[WDC]

Hello,

I noticed a error when using Huawei 30/40/50KTL-M3 with MERC-1100W-P optimizers.

According to the MERC-1100W-P manual, the maximum power of an optimizer string is 20kWc.

In my configuration I have a Huawei 30KTL-M3 with 2 strings of 36 450Wc panels (18kWc per string), which should be accepted by PVSyst but I got this error.

How can I overstep this PNom ratio limit ?

Thank you in advance,

Best regards

[Robin Vincent]

Compatibility rules between optimizers and inverters are implemented in PVsyst directly based on Huawei's requests.

In this case, Huawei requested the maximum connected power to be limited to a certain DC/AC ratio.

This is what is displayed in the message box: with only two MPPT input used, the maximum allowed DC/AC ratio is 1.

Because you have a total connected STC power of 30.6kW, this configuration is not considered valid for Huawei.

Huawei asked us to strictly enforce their rules, so there is no possibility to overstep this one. The only solution is to change your system somehow (configuring more strings, or slightly altering your inverter AC power or modules power so keep the DC/AC ratio below 1).

 

Nb: Mixed orientation are only applied to different strings, not on different modules within a string. 

Since you can individually assign strings to each MPPT inputs with Huawei, the concept of mixed orientation is redundant and often misleading.

In future releases, the mixed orientation option may not be possible anymore with Huawei, and you will have to separate your subarray into two, each with its own orientation.