PV स्ट्रिंग कैलकुलेटर

How this is calculated#

The tool sizes a PV string. It finds how many modules fit in a string, the string current, the fuses and the d.c. isolator. It reads AS/NZS 5033:2021. It reads the inverter limits from the plate you enter.

1. Cold voltage. The tool corrects the module Voc for the coldest cell (Cl 4.2.1.2). The factor is 1 + coefficient × (Tmin − 25 °C). Tmin is the record low.
2. Most modules. It divides the voltage limit by the corrected Voc. The limit is the lower of the inverter maximum and the domestic limit in Cl 3.1 (Cl 4.2.1.3.1).
3. Fewest modules. It finds the hot cell as the record high plus the cell rise you enter. It then finds the fewest modules that keep Vmp above the MPPT minimum.
4. String current. It works 1.25 × KI × Isc (Cl 3.3.3.1). It adds the fault current from the other strings (Cl 3.3.3.2).
5. Fuses. A fuse window sits above 1.2 times the string current and at most the module rating (Table 3.1).
6. Cable and isolator. It gives the cable currents (Table 4.2), the isolator ratings (Table 4.3) and the smallest conductor (Cl 4.4.2.3).

Worked example#

• 10 modules of 49.5 V Voc, 2 strings, 600 V inverter. The tool gives 5 to 11 modules per string. The string maximum voltage is 535.1 V. The string current is 17.38 A and the array current is 34.75 A. No string fuses are called for.

Limits#

• The tool derives the AS/NZS 5033 figures from the text until the Standard is checked. It says so in a warning.
• AS/NZS 5033 sets no cell rise. The tool uses the rise you enter.
• The inverter limits are the ones on its plate. Read them from the data sheet.
• The tool does not size the cable. Use the DC cable size calculator at these currents and at the hot cable temperature.
• Above 120 V, hold the voltage drop from the furthest module to the inverter to 5 % of Vmp.

See also: PV string voltage and temperature, Solar string sizing for a 600 V inverter and PV and inverter basics.