Fault detection in solar arrays based on an efficiency threshold

Large photovoltaic installations present faults that can reduce significantly their power yield. For instance, a protection fuse can compromise the performance of the array making that several solar modules stop generating. This work presents a fault detection system based on efficiency measurements of a solar array and its comparison to an expected theoretical efficiency which serves as a threshold that was modeled as a plane using parameters that can be obtained from the manufacturer's data-sheet or by software simulation. A set of experiments were executed in order to validate the proposed fault detection algorithm under short-circuit, open-circuit and partial shadowing faults. The results show that this method could detect short circuits in bypass diodes, open circuits in protection fuses and shadows in the array in small solar systems.