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Hi there!
I'm new in the forum. This time I bring a question about inverters.
I was hired to oversee the Electrical Installation of a public building in East-Timor (South East Asia). As you can imagine, this location is wonderful for a PV installation, with 340 sunny days a year. I have a University degree in Electronics Engineering and I have 14+ years' experience in low voltage Electrical Installations. I have also taken two courses of PV Engineering and I'm on may way of getting an Masters' degree in PV Engineering.
In the project I'm working for, the PV system has already been designed. It was designed to use three inverters of 50 kWp in parallel, each one with eight strings of 23 PV panels, making it a total of 552 PV panels. The Designer has requested the panels to be of the brand Canadian Solar and the inverters AE Solar Energy. The inverters proposed by the Designer consist on four DC inputs and one MPPT, so to allocate the 8 strings, they are parallelled in the inverter's DC box.
Now the Contactor has presented me with a complete solution from the brand CHINT, which I appreciate, since the PV panels and the inverter would be of the same brand.
The problem with the proposed solution is that these CHINT inverters have only three DC inputs, with three MPPTs. These inverters allow for the installation of 9 DC strings, by parallelling three strings on each DC input. Actually, the inverters come with 9 DC terminals for connections of the strings. and I would imagine that inside the inverter's DC box there is some sort of parallel connection of the strings. The Contractor insists they can allocate the 8 strings of PV panels in the 9 DC terminals, by "lust leaving one of them unused". This would be three strings for two of the MPPTs and two strings for the third one.
As far as I understand, one of the MPPTs would be operating at 2/3 the current at DC side with respect of the others.
My question is, is this a viable solution? Can I just leave one of the DC terminals unused? Would this imbalance between the three MPPTs make the whole system work at 2/3 the power? I really don't know what happens inside the inverters beyond each MPPT to figure out what happens if the one of the three MPPTs operates at 2/3 the power.
Another question is, what kind of a downgrade is to change from Canadian Solar for CHINT for the PV panels? I know Canadian Solar is a Tier 1 brand of PV panels, and I don't know CHINT yet.
Any help will be much appreciated.
Have a nice day guys!
I'm new in the forum. This time I bring a question about inverters.
I was hired to oversee the Electrical Installation of a public building in East-Timor (South East Asia). As you can imagine, this location is wonderful for a PV installation, with 340 sunny days a year. I have a University degree in Electronics Engineering and I have 14+ years' experience in low voltage Electrical Installations. I have also taken two courses of PV Engineering and I'm on may way of getting an Masters' degree in PV Engineering.
In the project I'm working for, the PV system has already been designed. It was designed to use three inverters of 50 kWp in parallel, each one with eight strings of 23 PV panels, making it a total of 552 PV panels. The Designer has requested the panels to be of the brand Canadian Solar and the inverters AE Solar Energy. The inverters proposed by the Designer consist on four DC inputs and one MPPT, so to allocate the 8 strings, they are parallelled in the inverter's DC box.
Now the Contactor has presented me with a complete solution from the brand CHINT, which I appreciate, since the PV panels and the inverter would be of the same brand.
The problem with the proposed solution is that these CHINT inverters have only three DC inputs, with three MPPTs. These inverters allow for the installation of 9 DC strings, by parallelling three strings on each DC input. Actually, the inverters come with 9 DC terminals for connections of the strings. and I would imagine that inside the inverter's DC box there is some sort of parallel connection of the strings. The Contractor insists they can allocate the 8 strings of PV panels in the 9 DC terminals, by "lust leaving one of them unused". This would be three strings for two of the MPPTs and two strings for the third one.
As far as I understand, one of the MPPTs would be operating at 2/3 the current at DC side with respect of the others.
My question is, is this a viable solution? Can I just leave one of the DC terminals unused? Would this imbalance between the three MPPTs make the whole system work at 2/3 the power? I really don't know what happens inside the inverters beyond each MPPT to figure out what happens if the one of the three MPPTs operates at 2/3 the power.
Another question is, what kind of a downgrade is to change from Canadian Solar for CHINT for the PV panels? I know Canadian Solar is a Tier 1 brand of PV panels, and I don't know CHINT yet.
Any help will be much appreciated.
Have a nice day guys!
