Assessment of detection method using mechanical waves generated by serial arc for airborne application

This paper presents a study of the propagation of mechanical waves, generated by a serial arc in DC, along an electrical wiring system. It is shown that the serial arc generates a wideband mechanical disturbance, which propagates along a material medium. The propagation conditions and frequencies for a relevant detection are analyzed and discussed. Then, in order to quantify the detection method performances under representative airborne conditions, a mock-up is built with cables bundles, terminal blocks and clamps. Firstly, the system response to a mechanical shock is studied. The propagation key characteristics are quantified: transverse and longitudinal propagation modes are investigated, in order to establish whether one is prominent. Attenuation phenomena linked to propagation along the conductor's strands, to the presence of terminal blocks and to the cables insulation, are quantified. The coupling between adjacent electrical poles is studied. Then, a DC serial arc is generated and accelerations are measured on various points of the mock-up. An evaluation is made of the maximum distance for which a serial arc can be detected, as a function of the arc power. Finally, the opportunity to use this technique, in order to detect a serial arc on an aircraft, is summarized.