SUMMARY
Automatic diagnosis through individual PV panel is especially required for hard to reach locations such as solar rooftop or exterior building. Therefore, a novel solution for diagnosing photovoltaic (PV) panels through their PV string is proposed. Our solution not only measures IV curve of PV panels, but it can also determine disconnected or loose location of power cable. Large pulse communication technique is used to implement this solution to achieve low cost and zero power shut down. Comparison with other existing solutions is also discussed. The proposed technique is implemented on a five-panel PV string. Its satisfactorily testing results are presented under strong and weak sunlight conditions. For further understanding in PV panel, an amorphous silicon PV panel is characterized and also modeled to be a simple equivalent circuit.