PV string calculator
Modules per string, string current at isolator para sa PV.
Reads AS/NZS 5033:2021 and AS/NZS 4777.2:2020. Tables checked 2 Oct 2026.
Subukan ang isang job 8
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- Size solar strings for a 600 V inverterThe modules per string for 49.5 V modules on a 600 V inverter at −5 °C.
- Check string fuses on three parallel stringsWhether three parallel strings of 13.9 A modules call for string fuses, and their rating.
- Size strings for a 1000 V inverterThe modules per string for a commercial inverter.
- Size strings for a cold inland siteThe modules per string at a record low of −8 °C, on a 600 V inverter.
- Check a string on a hot roofWhether the hot voltage stays above the tracker's minimum.
- Check two strings need no fuseWhether two strings in parallel need string fuses.
- Check the array current at the inverterThe array's short-circuit current against the inverter input.
- Size strings for a house trackerThe modules per string for a 450 V window.
Mga input
Worked example gamit ang mga default na input.
- Module Voc
- 49.5 V
- Module Vmp
- 41.5 V
- Module Isc
- 13.9 A
- Voc temperature coefficient
- −0.27 %/K
- Vmp temperature coefficient
- −0.35 %/K
- Pinakamataas na series fuse ng module
- 25 A
- Pagwawasto ng cold voltage
- Coefficient ng gumawa, Cl 4.2.1.2(a)
- Pinakamababang naitalang temperatura
- −5 °C
- Pinakamataas na naitalang temperatura
- 35 °C
- Pagtaas ng cell sa ibabaw ng ambient
- 35 K
- Installation
- Pang-tahanan, limit na 1000 V
- Mga module kada string
- 10
- Mga string na nakaparalelo
- 2
- KI, bifacial factor
- 1
- Backfeed current mula sa inverter
- 0 A
- Rating ng string fuse
- 0 A
- Pinakamataas na d.c. voltage ng inverter
- 600 V
- MPPT minimum voltage
- 150 V
- Pinakamataas na boltahe ng MPPT
- 550 V
- Inverter Isc PV
- 0 A
Mga module kada string
5 hanggang 11
- Pinakamataas na boltahe ng string
- 535.1V
- String Vmp sa pinakamainit na cell
- 349.6V
- Maximum string current
- 17.38A
- Array current papunta sa inverter
- 34.75A
- d.c. isolator, pinakamababa
- 34.75 A sa 535.1 V
- String fuse
- Not called for
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- Voc correction, 1 + coefficient × (Tmin − 25 °C)×1.08
AS/NZS 5033:2021 Cl 4.2.1.2
- Pinakamataas na boltahe ng module sa pinakamalamig na cell53.51V
AS/NZS 5033:2021 Cl 4.2.1.2
- Limit para sa domestic installation1,000V
AS/NZS 5033:2021 Cl 3.1
- Pinakamaraming module kada string11
AS/NZS 5033:2021 Cl 4.2.1.3.1
- Pinakamainit na cell, pinakamataas na naitala kasama ang pagtaas70°C
- Module Vmp sa pinakamainit na cell34.96V
- Pinakakaunting module kada string para sa MPPT minimum5
- Pinakamataas na boltahe ng string535.1V
AS/NZS 5033:2021 Cl 4.2.1.3.1
- String Vmp sa pinakamainit na cell349.6V
- String Vmp sa pinakamalamig na cell458.6V
- Pinakamataas na string current, 1.25 × KI × Isc17.38A
AS/NZS 5033:2021 Cl 3.3.3.1
- Fault current mula sa ibang string, (SA − 1) × ISTRING MAX17.38A
AS/NZS 5033:2021 Cl 3.3.3.2
- Saklaw ng string fuse: higit sa 1.2 × ISTRING MAX at hindi lalampas sa rating ng module20.85 hanggang 25A
AS/NZS 5033:2021 Table 3.1
- Current ng string cable17.38A
AS/NZS 5033:2021 Table 4.2
- Array cable current papunta sa inverter34.75A
AS/NZS 5033:2021 Table 4.2
- Pinakamababang current rating ng d.c. isolator34.75A
AS/NZS 5033:2021 Table 4.3
- Pinakamababang voltage rating ng d.c. isolator535.1V
AS/NZS 5033:2021 Table 4.3
- Pinakamaliit na conductor4mm²
AS/NZS 5033:2021 Cl 4.4.2.3
- Temperatura ng cable malapit sa mga module, record high plus 40 K75°C
AS/NZS 5033:2021 Cl 4.4.2.2
Tungkol sa calculator na ito
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.
- 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.
- 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).
- 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.
- 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).
- Fuses. A fuse window sits above 1.2 times the string current and at most the module rating (Table 3.1).
- 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).
| Step | Table or clause | What it decides |
|---|---|---|
| Cold voltage | Cl 4.2.1.2 | The module voltage at the coldest cell |
| String length | Cl 4.2.1.3.1 | The most modules in a string |
| String current | Cl 3.3.3.1 and Cl 3.3.3.2 | The current for cable and fuse |
| Fuse window | Table 3.1 | The fuse range |
| Isolator | Table 4.3 | The current and voltage ratings |
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.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Paano hinahanap ng tool ang pinakamaraming module kada string?
Itinatama nito ang module Voc sa record low temperature, gamit ang coefficient ng maker o ang AS/NZS 5033 Table 4.1. Hinahati nito ang mas mababa sa inverter maximum at sa 1000 V o 1500 V na limit sa voltage na iyon, at nira-round down.
Paano hinahanap ng tool ang pinakakaunting module kada string?
Kinakalkula nito ang module Vmp sa pinakamainit na cell: ang record high kasama ang cell rise na iniinput mo. Hinahati nito ang MPPT minimum sa voltage na iyon at nira-round up. Walang itinatakdang cell rise ang AS/NZS 5033, kaya ang 35 K default ay assumption ng AmpSize.
Kailan ginagamitan ng fuse ang string?
Kapag nakaparallel ang mga string, maaaring magpakain ng fault sa isang string ang iba. Idinadagdag ng tool ang current na iyon sa backfeed at ikinukumpara ito sa maximum series fuse ng module. Kapag mas mataas ito, ang fuse ay nasa itaas ng 1.2 beses ng maximum string current at nasa o mas mababa sa module rating.
Na-verify ba ang mga figure ng AS/NZS 5033?
Oo. Binasa ang Table 4.1 at ang mga limit ng voltage, current at cable laban sa nakalimbag na pahina ng AS/NZS 5033:2021. Tingnan ang bawat figure laban sa kasalukuyang standard bago mo ito pagkatiwalaan.
Mga worked example
- DC isolator rating for a 10 kW solar arrayRate the d.c. isolator and size the frame earth for a four-string domestic array. Check one data sheet that passes and one that fails per pole.
- Solar string sizing for a 600 V inverterHow many 49.5 V modules fit a string on a 600 V inverter at −5 °C? Work cold Voc, hot Vmp, the string current, fuses and the d.c. isolator by AS/NZS 5033.
Background
- PV array isolators and earthingHow parallel strings feed a fault, what Ithe, Ie and make and break mean for a d.c. isolator, and how AS/NZS 5033 earths and alarms a PV array.
- PV string voltage and temperatureWhy a PV string's voltage rises in the cold and falls in the heat, how AS/NZS 5033 limits it, and how the string current, fuses and isolator follow.
Mga clause at table na binabasa ng tool na ito
- AS/NZS 5033:2021 Cl 3.1Maximum voltage of PV d.c. circuits
- AS/NZS 5033:2021 Cl 3.3.3.1Maximum string current
- AS/NZS 5033:2021 Cl 3.3.3.2Fault current from parallel strings
- AS/NZS 5033:2021 Cl 3.3.4.1When strings take overcurrent protection
- AS/NZS 5033:2021 Cl 4.2.1.2PV module maximum voltage
- AS/NZS 5033:2021 Cl 4.2.1.3.1String voltage limit
- AS/NZS 5033:2021 Cl 4.4.2.2PV cable temperature
- AS/NZS 5033:2021 Cl 4.4.2.3Smallest PV conductor
Bawat clause at table, kasama kung paano ito na-verify
Huling na-check ang mga table noong 2 Oct 2026.
Mga kaugnay na tool
- DC cable size calculatorSize a d.c. cable up to 1500 V for current and voltage drop.AS/NZS 3008.1.1
- PV isolator and earthing calculatorRate the PV array cables, d.c. isolator and earthing.AS/NZS 5033AS/NZS 3000
- Power factor correction calculatorFind the capacitor kvar to lift a power factor.AS/NZS 3000
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