A low-cost arc fault detector for aerospace applications

The protection of the electrical plant, equipment and components in aerospace applications represents a topic of advanced researches. In the last years, in particular, great efforts have been focused on the problem of the arc-fault detection. The impressive advancement of the electronic devices has been exploited. As well known, in many cases the arcs are not detected by the conventional overcurrent breakers, despite their effects can be as serious as those produced by a short-circuit, since they may cause fires on board the aircrafts. Arc-fault detection requires recognizing the arc signature contained in the current waveform. For this reason, an inescapable choice to face this problem is to adopt proper digital signal processing techniques. The detection reliability strongly depends on the criteria adopted in order to discriminate the arcing condition from other possible artefacts, due for example to normal electrical transients. In a previous work, the authors have proposed a technique based on the estimation of the energy which may be related to the arcing activity. It has been proven that it allows to establish a solid decision-making process for the parallel arc detection. In this paper the aspects related to the practical implementation of the proposed method are faced, with particular care to the impact of the unavoidable measurements uncertainties on the reliability of the method. This analysis has led to the development of an advanced prototype of a low-cost single-chip parallel arc fault detector, which can be employed to develop a very attractive AFCB (Arc Fault Circuit Breaker). A deep experimental activity has been hence carried out in laboratory. The well-recognized guillotine test has been used in order to assess the actual behaviour of the developed device.