One of four 10.0-3 inverters showed a blinking green and Code 550, and was producing about 25% less than the others. These are fed by 4 strings of 11 Renesola 300's with an Isc of 8.69, and there are 15A fuses in all four strings. All inverters have Delta lightning arrestors.
I shut down the inverter, removed all fuses, and switched the jumper to smoff (the jumper was correctly in smon initially), the fuse in string 2 was blown, and string 2 was showing zero voltage at the input terminals (with wires from the array connected)...all other strings were showing voltage correct for the conditions. The fuses are mounted on a circuit board.
While checking the array for mechanical/connection issues, I noticed over 300 ohms on string 2. Returning to the inverters, I disconnected string 2 from the inverter terminals, and got similar ohms checking from string 2 + to - DC terminals.
I reconnected string 2 at the array, and now got voltage that corresponded with the other strings at the inverter with the string 2 wires disconnected from the DC inverter terminals.
I don't want to use these terminals again, and will move string 2 to an unused input with a new fuse. Any suggestions / feedback would be appreciated.
Sound like lightning damage? We've had some storms since I was last at the site.
I shut down the inverter, removed all fuses, and switched the jumper to smoff (the jumper was correctly in smon initially), the fuse in string 2 was blown, and string 2 was showing zero voltage at the input terminals (with wires from the array connected)...all other strings were showing voltage correct for the conditions. The fuses are mounted on a circuit board.
While checking the array for mechanical/connection issues, I noticed over 300 ohms on string 2. Returning to the inverters, I disconnected string 2 from the inverter terminals, and got similar ohms checking from string 2 + to - DC terminals.
I reconnected string 2 at the array, and now got voltage that corresponded with the other strings at the inverter with the string 2 wires disconnected from the DC inverter terminals.
I don't want to use these terminals again, and will move string 2 to an unused input with a new fuse. Any suggestions / feedback would be appreciated.
Sound like lightning damage? We've had some storms since I was last at the site.