What is the difference between Grid lim. Pnom Ratio and Pnom Ratio

[Detroit Solar]

Hello all,

As the title states: What is the difference between Grid lim. Pnom Ratio and Pnom Ratio? 

 

My assumption is the What is the difference between Grid lim. Pnom Ratio is the DC (Modules) ratio to the AC limit of the inverter. 

The Pnom is the AC overbuild of the inverter. To simplify, if your POI limit is 500 and you have 550AC of inverters. 

 

Thanks

[dtarin]

That is correct.

[Detroit Solar]

thank you for the response. I did not finish my thought regarding that question. That will teach me to be on a conference call and attempt to write something. 

 

Then the Grid lim. Pnom Ratio is the DC overbuild at the inverter: If your inverter is 500kw and you have 650kw of modules then your Grid lim. Pnom Ratio would be: 1.3. 

 

Thank you again for your help

 

[Detroit Solar]

On 3/8/2023 at 4:01 PM, dtarin said:

That is correct.

Thank you.

 

thank you for the response. I did not finish my thought regarding that question. That will teach me to be on a conference call and attempt to write something. 

 

Then the Grid lim. Pnom Ratio is the DC overbuild at the inverter: If your inverter is 500kw and you have 650kw of modules then your Grid lim. Pnom Ratio would be: 1.3. 

 

Thank you again for your help

[dtarin]

Example: 700kWdc, 650kW inverter nameplate @ Pnom, 600kW grid limit

Pnom ratio = DC capacity/Inverter Pnom: 700/650
Grid limit Pnom ratio = DC capacity/Grid limit: 700/600

Generally, the grid limit is less than the inverter nameplate, so the DC/AC ratio is higher here. In the PVsyst report, the Grid lim. Pnom ratio is found under System Summary, and the Pnom ratio is found under PV Array Characteristics.