Current indicator based fault detection algorithm for identification of faulty string in solar PV system

The maximum power generation in the solar photovoltaic (PV) array is reduced due to the abnormal conditions such as module mismatch, string faults and damage of the PV modules, which reduces the efficiency and reliability of the system. Conventional protection devices fail to detect the faults, which leads to protection issues and fire threats in the PV plants. This paper proposes a new fault detection algorithm to identify the faults in the PV array and the PV string. A simple analysis is developed for fault detection under different fault conditions, such as line–line (L‐L) fault, line–ground (L‐G) fault and short‐circuit fault with multiple strings, and the values of their current indicator and threshold are predetermined. Based on these values, the proposed fault detection algorithm identifies the fault in the PV array and the PV string, with a reduced number of current sensing devices. The effectiveness of the proposed algorithm is tested and verified through MATLAB simulation and experimentation under various operating conditions of the solar PV plant.