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Where we left off from last time
As discussed, in our previous presentation, a lot of trial and error is involved when trying to design large commercial solar systems that involve multiple inverters, sometimes with different capacities, same brands though, and in some cases more than one kind of solar panel.
With smaller systems this trial and error process is just acceptable but does not “cut it” with larger systems.
So previously we took a spreadsheet approach that allowed a certain level of automation to occur and through the process, relevant information could be displayed.
We looked at the generation of string voltages, signage, warnings if certain parameters were exceeded, DC/AC ratios.
In this presentation we look at the generation of more data that can be used.
In the case above we have:
- 2 x inverters sizes, a 100 and a 30 kW
- Both Huawei's
- Different number of MPPT
- Same Isc
In regards to the solar panels:
- We have a 445 and a 450 watt option
- Different Vocmax ratings
- Same amx series fuse ratings
Panel and inverter: with the lot
All the info is there but. . . .
All the info is there in detail for Inverter no. 1 with panel option selected but we need a summary that acts as its own report.
We could do this manually but, hey, we are using a spreadsheet so let’s use some of the tools available!
Inverter 1 panel inverter summary
So, we have:
- Inverter details
- Total amount of solar
- DC/AC ratio
- Total current, signage
- Panel brand
- No. of panels
- Number of strings
Obviously all the above info is needed as part of the project going forward but how to extract?
Inverter 1 , brand model and capacity
With Inverter no. and Inverter option no. this can be achieved by extracting from the larger section
But with Inverter Brand, Model and Capacity we look again to one of the lookup functions, in this case being XLOOKUP
We use Xlookup which first looks at the value in D48
This searches for his info in B21:K21
Then finds the corresponding reference in B22:K23.
Now this formula also returns the model number as well as there is a spill
I could have included capacity in the same formula but did it separately
In this case the xlookup referenced the summarized information @ W58
Again, the formula searches in range B21:K21 and returns the capacity value from range B32:K32
Inverter 1 , amount of solar and DC/AC ratio
Amount of solar in kW derived from here.The DC/AC ratio is obtained from the solar divided by the capacity of the inverter.
String with highest VocMax use the Max function in Excel which searches all the strings
In this case they are all the same!
Inverter 1 , Total current
The total current is derived from the number of panels row.
For example if the number is zero then the SUMIF function does not count the Isc of the panel.
In this case all are counted.
Inverter 1 , Panel brand
With panel brand we use Xlookup which references the Solar panel option first
Then looks at the range B2:K2 which
Extracts the value from B3:K3.
This calculation assumes that different panels will not be used within the one inverter!
Inverter 1 , Wattage, no. of panels and strings
Wattage uses the total then divides by total number of panels
The no. of panels just sums the column heading Wattage of the number of strings uses the countif function and looks at the Number of panels row so if number is not zero it is included ( see below)
One inverter. . . .
If the project only involved one inverter the information shown would enough for:
- Solar signage, total current being 139.2 amps
- Solar signage, highest VocMax being 1284.51 Volts
- Brand, model and number of both inverters and panels, BOM list
- DC isolators based on number of strings, BOM list
But our particular project involves more than one inverter and more than one panel.
In our next presentation we put it all together based on the 2 x different inverter models, 3 x inverters and 2 x different panels used.
The aim is to design the system, extract all relevant information and the end result can be used in a variety of ways.
Note: the inverters used have a VocMax of 1500 V and a rated input voltage of 1080 V. Triggers can be used with conditional formatting to show cell colour change if certain parameters are exceeded.
We have barely touched what can be done and in further presentations we will look at yet more advanced techniques which can help the designer installer put together these large scale systems more easily using a spreadsheet approach.
Look at part 1 if you have missed it: https://www.greenwoodsolutions.com.au/news-posts/large-scale-inverter-panel-configurations
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