A power optimizer failure is a malfunction of the module-level DC optimizer in a string, so that the unit no longer works properly. In monitoring it usually appears as one or two optimizers that stop reporting and produce nothing while the others in the string keep producing. It can also show up as a string voltage higher than the number of optimizers, or as a whole string going down, although wiring and junction boxes are the more common causes of a dead string. To confirm it, disconnect the wires between the optimizers and measure each optimizer's output to find the one that does not give the safety voltage. On site, lift the panel, check the connections, and measure the DC voltage of both the optimizer and the module. Check the faulty unit's connections, polarity, module and voltage, then contact the manufacturer and replace the optimizer. If it cannot be fixed, bypass it with a shorter string. Bring a spare optimizer to site and record the new serial number so the monitoring layout can be updated.
affectsc1 drafted · lead DC power optimizer
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dtbl=18 h=be3988d02f18tbl=12.r1 h=3de003f378a5presents_asc2 drafted · lead Power optimizer not reporting
The monitoring platform raises alerts such as no communication with power optimizer; one or two non-contiguous optimizers show no production while the others produce.
sec=h9 h=340119fa6bbdsec=h15 h=bdb6f66b1bbasec=h12 h=f22f27581a43c3 drafted · lead String voltage above expected proposed
String voltage higher than the number of optimizers in the string can point to a malfunctioning optimizer, once extra optimizers or directly connected modules are ruled out.
tbl=18 h=be3988d02f18tbl=12.r1 h=3de003f378a5tbl=12 h=4914ccee6efec4 drafted · lead String not producing proposed
A string that goes down may be caused by an optimizer, but wiring is the more likely cause.
detected_byc5 drafted · lead MLPE string safety voltage check
Disconnect the wires between the optimizers in the string and measure each optimizer's output. The faulty unit is the one that does not output the 1V safety voltage.
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dtbl=18 h=be3988d02f18tbl=12.r1 h=3de003f378a5c6 drafted · lead DC voltage measurement
Measure the DC voltage of both the optimizer and the module on site.
sec=h9 h=340119fa6bbdsec=h12 h=f22f27581a43sec=h17 h=5ed399c8170fc7 drafted · lead Performance monitoring
Monitoring platform alerts and the time of the last measurement help find non-reporting optimizers.
sec=h9 h=340119fa6bbdsec=h15 h=bdb6f66b1bbasec=h12 h=f22f27581a43review note: support check: partial - Monitoring alerts and last-measurement time are mentioned, but the passages do not call this performance monitoring; the claim is a reasonable paraphrase though.
mitigated_byc8 drafted · lead Power optimizer replacement proposed
Bring a spare optimizer to site. Record the new serial number so the monitoring layout can be updated.
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dsec=h12 h=f22f27581a43sec=h17 h=5ed399c8170fc9 drafted · lead Wiring and terminal check
Check the optimizer's connections, polarity, module and voltage.
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dsec=h9 h=340119fa6bbdc10 drafted · lead Contact manufacturer service
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dc11 drafted · lead String configuration correction
If the malfunction cannot be resolved, leave out the faulty optimizer and connect a shorter string.
tbl=12.r6 h=bcad92bf266atbl=18.r3 h=d2b40070159dc12 drafted · lead Power optimizer re-pairing
Remote pairing may restore production, but keep monitoring the string. If wiring changes the resistance, the string will likely go down again.
distinguished_fromc13 drafted · lead Cable Defect — told apart by DC voltage measurement
A string that is down is more often a wiring issue. Check the string DC voltage at ground level and inspect the junction boxes first. Only on-site checks of optimizer and module voltage confirm the optimizer as the cause.