Analysis of Intra-String Line-Line Fault in Photovoltaic System

Line-to-line fault (LLF) is one of the most important fault occurring in photovoltaic (PV) systems. necessitating comprehensive investigation and analysis to develop optimal fault detection methodologies. This study focuses on analyzing a specific LLF variant known as intrastring line-to-line fault (ISLLF), wherein one or more modules within individual strings are short-circuited. The power-voltage (P-V) and current-voltage (I-V) curves of PV systems contain extensive data valuable for fault detection. Thus, exact analysis of these curves to extract various features is essential. The extremum points of P-V curve indicate the severity of occurred faults in PV system. In this paper, different states of triple and quadruple ISLLF are simulated and according to the obtained result, mathematical equations are presented for extremum values. Additionally, the performance of the maximum power point tracking (MPPT) controller is evaluated, and the requisite constraints for optimal power selection using MPPT across different states of the P-V curves are presented. The derived equations suggest insights into accurately determining the severity and location of LLF occurrences.