Online modular level fault detection algorithm for grid-tied and off-grid PV systems

This paper presents a new fault detection and diagnosis technique for solar photovoltaic (PV) systems operating under grid-tied and off-grid modes. The proposed technique is capable to identify the type and location (module level) of a fault. This technique relies on the local measurements, and model prediction outputs for fault detection and diagnosis. Multiple low cost sensors were used to acquire/monitor solar irradiance, PV module temperature, voltage and current at module level in a PV system. A low cost PV monitoring system based on power line communication (PLC) to monitor the status of each PV module is also described in this work. A new algorithm is developed to detect different types of faults, and to display other essential system information (with a watch window size of 10 min). Additionally, a user friendly web application is developed for easy access of monitored data via Internet. The proposed technique is shown to have lower computational requirements; therefore, the same microcontroller is used for data communication and fault detection without any external hardware or additional simulation software. This technique has been experimentally validated using the PV system developed at the Solar Laboratory, Alternate Hydro Energy Centre (AHEC), IIT Roorkee, India. Experimental results have demonstrated the effectiveness of proposed technique in detecting the various fault occurrences in both grid-tied and off-grid PV system.