A relatively simple fault that occurs regularly with solar installations is a lack of power on one of the module strings. Although the cause is usually a simple one, locating the faulty module or open circuit can often be more difficult than you expect. pvTector can help.
It does exactly what its name suggests: pvTector detects open-circuit faults in cables. It works much like a conventional cable detector. A small transmitter superimposes two different signals onto each of the DC lines of the PV module string – one signal for the positive and a slightly different signal for the negative line. Moving the receiver along the module array converts the signals into audible tones. The warning tone sounds whenever the receiver is close to a module or one of the module string’s DC power lines. If you are near the negative line, you hear the negative warning tone; if you are near the positive line, you hear the positive warning tone. To find out where the break has occurred, move from one module to the next until the positive tone suddenly changes to negative (or vice versa).
Now that you have discovered where the fault is, you can proceed to pinpoint it precisely. If the system lacks maintenance access points and you are unable to gain direct access to the modules, you have the option of attaching the receiver to a telescopic pole or to an unmanned aerial vehicle. It has never been easier to pinpoint the location of an open circuit.