Smart Module and Smart Retrofit technology compensates for voltage and power mismatch which results from uneven strings in parallel. It enables a variance in string length of up to 25%
Requires single or dual add-on optimizers, 1st gen smart modules, or TS4-O/TS4-L.
Here are some important guidelines to follow when designing strings of different lengths:
- Strictly follow the inverter minimum and maximum MPP voltage windows.
- Design the strings to be as long as possible within the voltage window to reduce homerun losses and improve efficiency.
- Design shade on the longer strings or evenly across strings as much as possible.
- Have the number of longer strings as low as possible (i.e. prefer 2 shorter strings and 1 long than only 1 shorter string and 2 long strings).
- .Please note that the TS4 DUO products (TS4-R-O-Duo for example) must be used on strings of equal length only.
How to Calculate Maximum String Mismatch
To calculate maximum amount of string-to-string mismatch use the following equation:
1-(short string/long string)= % mismatch; must be less than or equal to 25%
Short string voltage must be above the inverter MPP minimum and the longest string must be below the inverter MPP maximum voltage. Remember to adjust the voltage of the shorter string for the historical high temp for your area.
Comments
2 comments
Hello, I was wonder about the calculation at the end of this article: it says one minus the ratio of short-string to long-string. But it neither the equation nor the text surrounding (esp. preceding) it say what unit those two quantities are. Voltage? number of modules? I presume voltage but it would be nice to say so explicitly.
Have a nice day.
Answer to Bob's question:
The unit is [number of modules].
As long all modules are of the same type - the result would be the same with [voltage].
(the voltage can be written as factor in front of numerator & denominator, which cancels out)
The whole answer could be written as:
The string mismatch [%] is the complement to the string ratio to 1 - which must be less or equal 25%.
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