We just installed one 8.7KW solar PV system. We used SMA 11000TL inverter as the customer wants to expand the size in the future. The inverters works well. But the output is only about 10Kwh per day. According to the simulation, it should have at least 800Kwh per day. We checked all the wiring, but would not find out the problem.
The system is to use 30 pieces of canadian solar 290W, 10 pieces in one string, total there are three strings. Before we energized the system, the technician made a mistake by connecting the "-" to the "-", and then he grouped the wrong "+" and ''-" by mistakes as he got confused by the wires. But he finally was able to find out and correct it. After these have been corrected, the inverters was able to work.
However, after one months of observation, the output is total under performance. We just would not figure out the problem. We measured the voltage of the system which is 390V, and current is only 2amps which is very low.
We hope someone would give us advise where it goes wrong. If the wires is wrong, the inverter should be be working at all.
Submitted
11 years ago
Comments
Since you had a problem in the beginning with the array wiring I would go back and verify that all the wiring is correct. If you don't have the array wired correctly the inverter might still operate but it won't be getting the full power from the array,
Next compare the output of each of the three strings independently. If they are not all equal look at the one that is the lowest and find out what is wrong with it. Start eliminating modules in the string until you find the bad one.
My bet would be that you have some modules wired incorrectly, maybe in all three strings.