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Dear support,

I have checked rated active power of whole solar inverters such as type 36, 40, 50, 60, 100KTL. This power has been used for coefficient of overloading which suggests the software during design. But sometimes is used nominal power and sometimes is used maximal apparent power when power factor = 1. Those final active powers are different. Please unify the right calculation of overloading ratio.

For example: nominal power 50kW and 60kWp of panels does overloading ratio 120% to DC site. But apparent power 55kVA (power factor 1) makes active power 55kW than overloading ratio is 109%. I am afraid to overload it correctly. Design of cables, circuit breakers is following.

In fact nominal power occurs anytime but maximal power when power factor=1 occurs sometimes. Which parameter is correct technically to use?

Thank you.

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Hello Miroslav S,

On 7/1/2022 at 10:24 AM, Miroslav S said:

But sometimes is used nominal power and sometimes is used maximal apparent power when power factor = 1.

Could you explain in more detail how you mean that? Sometimes there is used apparent power and sometimes is used nominal power?

Thank you in advance for the clarification and kind regards,
Frederik

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Hello,

I will try to explain that in example. Inverter SUN 50KTL has an apparent power 55kVA and nominal active power 50kW. When power factor = 1 then active power equals 55kW. Which power is suitable for coeficient of overloading - 50kW or 55kW? PVSOL gives me some combination of  inverters versus panels automatically with supposed overloading as you know. 50kW or 55kW is correct? I have two different overloading after that (60kWp/50kW versus 60kWp/55kW). This should be unified for every inverters SUN KTL. Please doublecheck the right power for every inverters SUN.

Thank you.

BR.

Miroslav

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• 2 months later...

Dear support,

I haven't got some response from you.

BR,

M. Sebek

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Hello Miroslav S,

sorry for coming back to you so late. I accidentally missed your question.

If the displacement factor equals 1, we take the value for active power to calculate the sizing factor.
If the displacement factor does not equal 1, we take the apparent power and displacement factor for calculating the sizing factor.

For the inverter you mentioned using a cos phi of 1 yields

while a cos phi of 0.9 yields

I hope this clears your issues?

Kind regards,
Frederik

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