Characterizing DC Arcs for Photovoltaic Arc Fault Detection

Arc faults, one of the leading causes of electrical fires in photovoltaic energy systems, can be due to equipment failure or improper installation. Therefore, an arc fault detector is essential to protect people’s lives and properties and is now required by many safety codes. Since an arc is a chaotic phenomenon, it is important to study the electrical characteristics in order to develop a robust arc fault detector. An automated mechatronics testbed was developed to allow highly repeatable testing needed to create a library of arc voltage and current waveforms. Electrode material and geometry, electrical voltage and current, and electrode gap separation profile were set as experimental parameters. These factors are hypothesized to affect the electrical characteristics and signature of the arc. In this paper, examples of data from the arc generation system are presented to showcase how the results of the parameter values can be compared. For each parameter value combination, or "recipe," the paper will show how the testbed is used to capture and plot the arc voltage and current time-domain waveforms, the gap profile (separation distance vs. time), and the Short-Time Fourier Transform (STFT) of the measured electrical signals. The results of the analysis presented in this paper can be used in the development of a reliable and effective arc fault detector.