Adding an inverter with 4 MPPT

[Damian]

Hi,

I have a problem and I hope someone would help me. I want to create 1MW power plant in PV Syst. I am using Huawei SUN 2000 36 KTL inverters which have 4 MPPT and modules with power of 330W. There are 17 modules in one string. Two strings of 17 modules are connected in parallel and those two strings are connected to first MPPT. Another two strings are connected to second MPPT and so on. How to implement this in PVsyst?

[dtarin]

Create a system with 8 strings per inverter.

[Damian]

Thanks for reply, but I know that I have to make 8 strings. The problem shows up when the strings in one inverter have different sizes. For example let's consider one inverter - Huawei sun 2000 36 KTL:

Two strings (connected in parallel) consist of 14 modules each and those strings are connected to first MPPT

Two strings (connected in parallel) consist of 16 modules each and those strings are connected to second MPPT

Two strings (connected in parallel) consist of 19 modules each and those strings are connected to third MPPT

Two strings (connected in parallel) consist of 21 modules each and those strings are connected to fourth MPPT

How to implement this in PVsyst?

[dtarin]

Will the inputs to the inverter be connected together, or operated independently? if independent, you may have higher clipping losses. Some string inverters have jumpers which connect the inputs together, and typically will lower your clipping losses in these unbalanced scenarios. Photo 1 shows the configuration to use to model your scenario, however a string size of 21 seems too high for a 1000V inverter, but your location is not known, so I cant say for certain.

[Damian]

Thanks again for reply. I did not know about this power sharing function, so I have to play with this to see the reults. I do not know what you mean by saying 'inputs connected together/jumpered or operated independently'. Can you explain that in more details? So what would you do, which option would give results closer to real environment?

[Damian]

And I agree that 21 modules in one string is too much but it was just for example

[dtarin]

Err on the side of caution and model as shown.

[shahaf]

Hello.

In continues for the topic of Demian i have a TWO question too...

1. If im using a same inverter with several of sub arrays could i go to the option of OPEN option and go to the ADDITIONAL PARAMETERS tab and choose my multi mppt options and choose some mppts

and in this case i could do power sharing according to the several mppts that i choosed?

2. in this case - each mppt could be different sub array/orientation?

THX ALOT

[dtarin]

1. Yes

2. Yes, they will need to add in total to the number of mppts for all inverters in design. If you are encountering high overcurrent losses in the waterfall, allocate more mppt inputs to the subarrays with higher DC/AC ratio. If it is even, allocate them evenly.

[Zark]

Hi,

One question about this. In the Power Sharing option, What do it mean "Inverter Confg."?

[Zark]

Hi, Regarding Power Sharing capability. What does Inverter Conf mean?

[dtarin]

It means you have the MPPT enabled for multiple subarrays (4). Config 1 or 2 means you can have two different configurations if you wanted subarrays 1 and 2 to be together (input into same inverter), and 3&4 into another (or some other combination).

To utilize the mppt share, check the square boxes you wish to have operate as such, and assign to a configuration, then balance Pnom ratios if that is the correct approach for your system.