Size of Cable

That depends on what you wish to survive when 2000A of current flows and how long this current will be sustained.

https://www.answers.com/Q/What_wire_size_should_you_use_for_2000_amps

Hi Mr. Robin,

Thank you for you comment.

My concern is regarding the grouping correction factor when I'm sizing the cable of 2000A do I need to consider that each inverter is one circuit (since each inverter will not generate the same current at the same time) ?

I would size anything based on the cable rating and submit my project, but I want to understand more about this issue.

You should include a note that when using parallel conductor runs it is critical that all conductors be the same length to ensure equal resistance - otherwise the shortest, lowest resistance conductor will carry the bulk of the load, will heat up, increasing its resistance, then the current will shift to another conductor, then it will heat up, and so on - the current oscillating from one conductor to another until catastrophic failure. An electrical inspector here said that a sign that the conductors were not the same length was if the installation was neat - if the conductors go to their respective lugs in a tidy and orderly fashion it usually means that they have been cut to different lengths to mate cleanly with both close and distant lugs - looks good, but is strong evidence that the installation is wrong.

Here is an Australian manufacturers handbook which can be down loaded from the link.

If you refer to page 35 you will get relevant information to assist you but it would appear you will need a minimum two 630 Sqmm cables in parallel to handle the current depending on the configuration of the cables.

https://www.olex.com.au/eservice/Australia-en_AU/fileLibrary/Download_540225217/Australia/files/OLC15984%20Handbook%20July%202016%20FA%20V3%20LR.pdf

British Standard 7671. Again.

If in doubt, consult a qualified Electrical Engineer.

Two things to consider:

1. Will the circuit protective device open if a short circuit is placed on the cable, before the cable melts?
2. Will there be an acceptable voltage at the far end of the cable at the circuit protective device's full load current given the volt drop on the cable?

The current rating of any cable/busbar system is determined by how much heat the load generates, which must be less than how much heat the system can dissipate. There will be a maximum running temperature that is permitted which will be found in the contract specification directly or indirectly if the spec refers to tables in an approved standard. How many watts of heat are generated per meter is just the square of the current multiplied by the resistance of the cable per meter. How much heat is dissipated per meter depends on the cable insulation, the ambient temperature of the soil, the maximum temperature of the soil, the size of the duct, the material the duct is made of, if the duct ends are sealed, if there are any other cables in the same duct, if the route slopes, how deep the duct is buried, what the surrounding material is made of. There are tables which average out most of these factors and tell you how much to de-rate any cable run in an underground duct. There is a second table that tells you how much more to de-rate the cable for every degree that your site ambient is higher than the ambient used to formulate the tables.

Cables only get made in standard sizes so using the manufacturer's data, choose a cable that is rated just above 2000amps, multiply the stated cable rating by the various de-rating factors and if the result is still above 2000amps use that cable. If the result is below 2000amps choose the next higher rated cable and repeat the de-rating calculations until you get a result above 2000amps.

<...4: ...need neutral cable for the system...>

A glance at the intended schematic drawing would say, and it can't be seen from here.

You will have only 4 parallel circuits, the 22 circuits are combined at your solar distribution panel. Those 4 circuits are the ones that need to be derated if they operate close to one another.

The cable is sized to carry the maximum output of all 22 inverters together.

The need for group conductor derating depends on your exact and specific method to interconnect the inverter switchboard to the main distribution bus.

The cables between the inverter board and the switchgear must run in 3 phase groups, but it is not really practical to stuff 6 current carrying conductors of that size in a single conduit, so now you just need to consider duct bank derating, i.e. 4 conduits, where you specify the spacing between conduits, the conduit material, and what they are buried in.

Here is a sample duct configuration similar to your needs, showing the information you need.

https://www.calcware.com/?page_id=73

Dear Mr. Rwilliams,

thank you for your valuable information.

I have attached my Single line diagram for your reference.

now I understand more about the system.

I would put anything in my degree project but I'm very interested to learn new things.

the busbars will be connected to the MCCB 4p

so now i need to consider 4 circuits depending on the gap between each other am i right?

https://cr4.globalspec.com/search/sitesearch?do=show&srchobjs=t%2Cbe%2Cc&order=asc&query=Cable+Sizing&sort=textmatchrank&ts=7