Simulate use of Y-plug (extra parallel strings) in pvsyst

[Mrodriguez]

Hello

Im trying to design a solar pv plant using a Y-connector, when using this type of connector two strings can be connected in parallel and combined, towards one string input in an inverter.

see picture:

Y-plug and Y-socket

 

We got approval from manufacturer to use this component. However im not sure what is the best way to configure the extra strings in the simulation.

I am thinking of two different methods:

Method 1:

Within system configuration. Disable the option of "use multi-mmpt feature". This would allow me to place as much strings as desired in one inverter.

Method 2:

Modify inverter file, to add more string inputs, while keeping the same number of mppt's.

Are any of these two methods valid for simulating extra strings using Y-connectors?

Or do you perhaps know a different way?

Thanks in advance for the support and time invested.

[André Mermoud]

The use of Y-connectors is not involved in PVsyst in any way.

With some inverter, the number of input connectors is specified. But this is not used by PVsyst.

The only relevant information is the number of strings effectively connected to the input of each MPPT input. PVsyst doesn't check if this matches the number of connectors.

For the use of the option "Use multi-MPPT feature", please read the Help "Project design > Grid-connected system definition > Multi-MPPT inverters: power sharing"

[Shibin Paulose]

Hello,

Even I am facing this same dilemma. I am using a 100kW inverter with 9 MPPTs (Sungrow SG110CX) and 355Wp modules. My string configurations are as follows: MPPT 1: 19*3 (two strings are connected using Y-connector), MPPT 2: 18*3 (two strings are connected using Y-connector), MPPT 3, 4 & 5: 20*2 each, MPPT 6: 20*1, MPPT 7: 19*2, MPPT 8: 19*1, MPPT 9: 20*1.

When I try to assign 3 strings into one MPPT input (for MPPT 1 & 2), PVsyst shows an error saying the inverter is strongly undersized since the Pnom ratio becomes 1.72.

I am attaching a screenshot for reference. Please suggest a way to circumvent this problem to simulate the system parameters.

Thanks in advance!