A Nonlinear Fault Detection Scheme for PV Applications

While major faults in grid-connected PV systems are easily detectable using currently available methods, there are some instances where fault conditions can escape normal detection means. This paper proposes a nonlinear observer to detect these smaller faults using a model-based approach. This observer is validated through a Lyapunov stability analysis and verified by simulation results. The proposed observer is simple to calculate and can be utilized by a system expert to detect the presence of a fault condition.