16. Short Circuit Fault Detection in Photovoltaic Inverter Using FRA Analysis and FFT Method

The inverter is an extremely important element in photovoltaic systems, so its surveillance is necessary for the continuity and stability of PV systems. The main aim of this paper is to improve the availability of inverters used in photovoltaic installations by developing fast, efficient and reliable fault diagnosis methods adapted to the installation to make sure the good functioning of the system with good performance, with or without the presence of short-circuit fault. To diagnose a short-circuit fault in the inverter, we used two methods; the first method is the frequency response analysis (FRA), in this case, the inverter is represented by RLC network identified by transfer functions which depend on the frequency, therefore the slightest change in the configuration of the RLC network generates a variation in the impedance of the latter and thus a shift in the transfer function. The FRA approach allows the detection of changes in the transfer function due to defects that may occur during the manufacture or operation of the inverter; the second method is Fast Fourier Analysis Transform (FFT), this method is used to visualize the spectrum of the signals at the output of the inverter at high frequencies.