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AC circuit inverter to injection


azein
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Dear,

In the new module you added to PVsyst lately, there is the possibility to account for AC losses, and PVsyst automatically detects the correct cable size.

From my understanding, the cable sizes given are for Aluminium not copper, am I right?

Also, can you explain how these wiring losses are calculated:

fixed resistance value or temperature dependent?

maximum current injection all the time or real current values used?

cosPhi=1 or less?

Best

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The losses are computed using a fixed resistivity, corresponding to a temperature of 50°C (see the help "Glossary > Metal resistivity").

By default, it is supposed to be copper (i.e. 22 mOhm·mm²/m).

For the array, this value may be modified in "Detailed Losses" / "Ohmic losses" / "Detailed computation" / "Wires".

For the AC losses, the resîstivity is taken for copper, as specified in the Hidden parameters, topic "System design parameters", item "Copper resistivity".

The losses displayed in the dialog are computed for STC conditions. But the loss is accumulated at each simulation hour according to the real current of course.

The current is taken according to the real power as managed during the simulation, it doesn't change with a different CosPhi.

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Thank you Andre for the quick response.

In this case, it means you are using the PVC insulation values from table B.52-1 of IEC 60364-5-52 and not XLPE, is that right?

I understand this AC cabling tool is not meant to be used as a cable sizing tool, so probably that's why you do not offer to choose insulation type, ambiant temperature coefficient, cable grouping coefficient, but as a suggestion I think it may be helpful to add these 3 options in a drop list for a quick cable size estimation.

About the voltage drop value, is it calculated from standard voltage drop tables (which are usually given for resistivity at 90 degreesC), or for resistivity at 50 degreesC ?

Best wishes and thanks for the hard work,

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