Analytical Monitoring of Bypass Diode Short Circuit Signatures in PV SCADA Data in Ground-Mounted Solar Farms

In Sunalytic’s string-level analytical monitoring of a ~10-20 MWp ground-mounted fixed-tilt crystalline silicon solar photovoltaics (PV) power plants in Southeast Asia, PV string losses due to bypass diode short circuit (BDSC) in PV modules were recorded on a regular basis, and verified by drone thermal images. Two types of SCADA data signatures that appear to precede BDSC failures are presented: both (1) rapid generation fluctuations, and (2) relatively stable generation. These observations are taken from single-BDSC-affected PV strings, a PV string affected by >1 BDSC, and also BDSC-affected PV strings located in the same section. Bypass diodes more robust to operational cyclic and heat stresses may be needed to mitigate this problem in solar farms. It is also clearly shown that effective analytics can detect such losses well ahead of scheduled drone thermal scans, helping asset owners to avoid unnecessary downtime and fetch higher financial returns.