Method for diagnosing degradation in aircraft wiring

• US 20030105598A1
• Filed: 07/29/2002
• Published: 06/05/2003
• Est. Priority Date: 12/08/1999
• Status: Active Grant

• Current Assignee: Harry E. Orton
• Original Assignee: Harry E. Orton
• Inventors: Orton, Harry E.
• Granted Patent: US 6,909,977 B2
• Time in Patent Office: Days
• US Class Current: 702/38
• CPC Class Codes: G01R 31/008 on air- or spacecraft, railway rolling stock or sea-going vessels
• CPC Class Codes: G01R 31/088 Aspects of digital computing
• CPC Class Codes: G01R 31/1218 using optical methods; using charged particle, e.g. electron, beams or X-rays
• CPC Class Codes: G01R 31/1272 of cable, line or wire insulation, e.g. using partial discharge measurements locating faults in cables G01R31/083
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72
• CPC Class Codes: H02H 1/0023 sensing non electrical parameters, e.g. by optical, pneumatic, thermal or sonic sensors

Abstract

Wiring in new and older aircraft use bundled insulated conductors that are subject to deterioration over time that can result in on-board fires, loss of in-flight control and eventual crashes of the aircraft. The present invention provides a diagnostic method which permits the on-line and non-destructive diagnosis of the insulation degradation in a portion of the wiring comprising: a) measuring the current flow at locations of the aircraft wiring utilizing an optical current sensor with a bandwidth of dc to 50 kHz; b) determining the current flow within a high frequency bandwidth; and c) analysing the results of the current flow differential determination and initiate the following: i) detect and locate the point of cable failure; ii) initiate an alarm annunciation; and iii) initiate an on-board sectionalized fire suppression system.

Claims

1. A method of on-line diagnosis of insulation degradation in a portion of an aircraft wiring cable comprising the steps of:

i) measuring the current flow at two locations on said cable utilizing an optical current sensor with a bandwidth of dc to 50 kHz;

ii) determining the current flow difference between said two locations at one or more frequencies in the range 10 kHz to 50 kHz;

iii) analyzing the results of the current flow difference to locate a potential cable wiring fault.

2. The method of claim 1 wherein said current flow measurement is carried out at multiple sectionalized locations in the aircraft.

3. The method of claim 1 further comprising the steps of annunciating an alarm in a central processing unit if a potential cable wiring fault is located.

4. The method of claim 1 further comprising the steps of initiating an on-board fire suppression system if a potential cable wiring fault is located.

5. The method of claim 1 wherein said analysis is carried out by a central processor.

6. The method of claim 5 wherein said potential cable wiring fault is located by said central processor carrying out a time domain reflectometry technique.

7. The method of claim 1 further comprising the step of determining the harmonic component of the 400 Hz insulation leakage current to establish the degree of insulation deterioration that has occurred.

8. In an aircraft or other vehicle having an insulated electrical cable, the improvement comprising providing optical current sensors with a bandwidth of dc to 50 kHz mounted at two spaced locations on said cable for measuring the current flow at said two spaced locations on said cable, and central processing means connected to said optical current sensors for determining the current flow difference at one or more frequencies in the range 10 kHz to 50 kHz and analysing the results of the current flow difference to locate a potential cable wiring fault.