Two winding resonating arc fault sensor which boosts arc fault signals while rejecting arc mimicking noise

Abstract

An arc fault detector for detecting electric power lines includes a current transformer preferably in the shape of a toroid, with a neutral conductor and at least one line conductor passing through the aperture of the toroid. The sensor has two multi-turn windings each formed around a portion of the toroidal core, with one winding adjacent to each of the hot and neutral wires respectively, with both windings connected in series in a way which re-enforces arc fault noise generated by arc faults involving the line and neutral, but which causes signal reduction for noise signals from the line and neutral, or either, to ground. The windings and core are also selected to self resonate at a frequency or over a band of frequencies that excludes power line carrier frequencies but which includes arc fault frequencies. The core may also have a third winding, acting as a grounded neutral transmitter, or ground fault detector, or instead of a third winding, one of the arc fault sensing windings can act as dual function sensor for both.

Dependencies are inferred from the claim text.