A Matlab/Simulink-based simulation study of the PV string/array is conducted that focuses on the current parameters. The paper illustrates the variation of current parameters of the PV string and PV array according to two environmental conditions: solar radiation and temperature. The photocurrent of the PV string and current output of the PV array is highly sensitive to the amount of solar radiation while both saturation and reverse saturation currents escalate with the temperature. The percentage of current output reduction is categorized into three groups which correspond to the amount of solar radiation absorbed by the PV array. The simulation results are used as the performance indicator in developing a simple fault detection algorithm. © Institute of Technology PETRONAS Sdn Bhd (Universiti Teknologi PETRONAS) 2024.