Parallel arc fault diagnostic for aircraft wiring

A system for detecting and locating parallel arcing faults in a set of wires, the voltage at which a parallel arcing fault occurs being below a predetermined test voltage level, each parallel arcing fault producing two or more electromagnetic waveforms and ultrasonic emissions, each electromagnetic waveform having a leading edge, the system comprising:

• a first device coupled to the set of wires for applying a current to a wire under test while grounding the remaining wires of the set of wires so as to charge a capacitance defined between the wire under test and the remaining wires up to the predetermined testing voltage, the first device being adapted to locate the distance to the parallel arcing fault using one or more leading edges of one or more electromagnetic waveforms being conducted on the wire under test;
• a second device for locating and calculating the distance to the parallel arcing fault, the second device being comprised of a controller and two or more receivers, each receiver being electrically coupled to the controller for receiving one or more leading edges of one or more electromagnetic waveforms being radiated by the parallel arcing fault;
• and
• a third device for locating and calculating the distance to the parallel arcing fault, the third device being adapted to sense one or more leading edges of one or more electromagnetic waveforms as well as the ultrasonic emissions emitted from the parallel arcing fault.

A device for detecting and locating parallel arcing faults in a set of wires, the voltage at which a parallel arcing fault occurs being below a predetermined test voltage level, each parallel arcing fault producing an incident waveform and a reflected waveform, each waveform having a pulse width, the device comprising:

• a controller for receiving information and for processing the information to produce a number of control signals;
• a current source having a first terminal coupled to the controller and a second terminal coupled to a first node, the current source being receptive to a first control signal from the controller at the first terminal to produce direct current at a level as indicated by the first control signal so as to charge a capacitance up to the predetermined testing voltage, the capacitance being defined between a wire under test and the remaining wires of the set of wires;
• and
• a timing circuit having a first terminal coupled to the first node and a second terminal coupled to the controller, the timing circuit being receptive to the incident waveform and the reflected waveform at the first terminal so as to measure the pulse width of the incident waveform and the reflected waveform and produce at the second terminal a locating signal being proportional to the distance from the device to the parallel arcing fault.

A method for detecting parallel arcing faults in a set of wires, each parallel arcing fault producing two or more electromagnetic waveforms, each electromagnetic waveform having a leading edge, the method comprising:

• selecting a wire of the set of wires to define the wire as a wire under test while coupling the remaining wires in the set of wires to ground;
• charging a capacitance defined between the wire under test and the remaining wires using a current source;
• and
• finding one of the remaining wires that causes a parallel arcing fault to occur between the wire under test and the one of the remaining wires by using a sequencer to selectively uncouple each wire of the set of wires or couple each wire of the set of wires to the current source or ground.

A method for detecting and locating parallel arcing faults in a set of wires, each parallel arcing fault radiating electromagnetic waveforms, each electromagnetic waveform having a leading edge, the method comprising:

• converting into multiple digital pulses from multiple impulses that are caused by multiple leading edges of multiple electromagnetic waveforms, the multiple impulses being received by multiple antennas of multiple receivers;
• receiving by a controller a first digital pulse from a first receiver at a first point in time and a second digital pulse from a second receiver at a second point in time;
• and
• calculating a distance to the parallel arcing fault by determining the difference between the first point and the second point in time, the sign of the difference being indicative of the direction of the parallel arcing fault.

A device for detecting and locating parallel arcing faults in a set of wires, each parallel arcing fault radiating electromagnetic waveforms as well as ultrasonic emissions, the device comprising:

• an ultrasonic receiver having an electrostatic transducer for receiving a sonic pulse from the ultrasonic emissions at a first point in time;
• an antenna for receiving a leading edge of an electromagnetic pulse from the electromagnetic waveforms at a second point in time;
• and
• a controller electrically coupled to the ultrasonic receiver and the antenna, the controller calculating a distance to the parallel arcing fault by determining the delay between the sonic pulse at the first point in time and the leading edge of an electromagnetic pulse at the second point in time.

A method for detecting parallel arcing faults in a set of wires, the voltage at which a parallel arcing fault occurs being below a predetermined test voltage level, the method comprising:

• selecting a first wire of the set of wires and defining the first wire as a wire under test while grounding the remaining wires in the set of wires to define these remaining wires as ground wires;
• charging a capacitance defined between the wire under test and the ground wires using a current source until the voltage on the wire under test ramps up to the predetermined test voltage level;
• providing an arc sensing means responsive to the occurrence of an arc discharge;
• and
• determining that a parallel fault exists if said arc sensing means indicates the occurrence of at least one arc discharge.