A Circuit Analysis-Based Fault Finding Algorithm for Photovoltaic Array Under L-L/L-G Faults

At the level of photovoltaic (PV) array inclusive of blocking diodes, line-to-line (L-L) faults and line-to-ground (L-G) faults are difficult to diagnose. These faults may appear at any string of PV array, and if not cleared in time can create irreversible damages to PV modules. In this paper, this complex problem is resolved in two steps: 1) a comprehensive study is presented with the dc circuit analysis of PV array under different faults. The critical observations are summarized in five statements, where each statement is related to a specific fault and 2) a fault-finding algorithm (FFA) based on these statements is proposed. The FFA not only identifies the exact faulty strings but also holds the ability to classify the faults. In the end, the proposed FFA and its five statements are verified through extensive MATLAB/Simulink simulations and numerous experimental tests. Compared to previous studies, the circuit analysis and its five statements are original. Besides that the proposed FFA is simple, fast, requires no training, and scalable to any array size.