Introduction to field mismatch
No two solar panels are identical. Even after going through same manufacturing process, panels made for a specific ratings does not have same specific outputs. There is generally tolerance range of 5%. For example a two panel made for 100W specification can have have two separate ratings of 95W and 105W.
Series mismatch degrades solar cell performance.
Generally while installing a plant this factor is ignored and panels having extreme ends of specification might get connected in series which further leads to degradation. Plant which intended to give a desired output does not perform on its full potential.
Steps for Revival
- Take initial readings(STC) for the plant.
- Take Readings(STC) for individual Solar panels from solar analyzers.
- Extract the data from analyzers and sort the solar panels on the basis of there short circuit current.
- According to available infrastructure Re-rack solar panels on the basis of their efficiency within previously sorted panels on the basis of similar short circuit currents.
- Now make Series parallel connections and convert it Total cross tied connection or any suitable configuration.
- Take new readings(STC) of the plant. Mark the improvements.
Refer for different configurations Changing photovoltaic array interconnections to reduce mismatch losses: a case study