High voltage cable testing method

• US 7,764,067 B2
• Filed: 12/27/2007
• Issued: 07/27/2010
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Lindsey, Robert W.
• Primary Examiner(s): Dole; Timothy J
• Assistant Examiner(s): ZHU, JOHN X
• Application Number:
  US12/005,311
• Publication Number:
  US 20090167315A1
• Time in Patent Office: 943 Days
• Field of Search: 324/519, 324/541, 324/539, 324/543, 324/544, 324/509
• US Class Current: 324/519
• CPC Class Codes: G01R 31/088 Aspects of digital computing
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72
• CPC Class Codes: H02H 3/50 responsive to the appearance of abnormal wave forms, e.g. ac in dc installations

Abstract

A method of testing a cabling system is disclosed. The method may include discharging an input filter capacitor associated with an accessory component, charging an accessory bus capacitor to a desired voltage level, and connecting the accessory bus capacitor to the input filter capacitor. The method may also include continuously monitoring a voltage waveform associated with the accessory bus capacitor. The method may further include determining a difference between the voltage waveform and a nominal voltage profile, and detecting a fault if the difference is greater than a threshold value.

Claims

1. A method of testing a cabling system, comprising:

discharging an input filter capacitor associated with an accessory component;

charging an accessory bus capacitor to a desired voltage level;

connecting the accessory bus capacitor to the input filter capacitor in parallel using a switch;

continuously monitoring a voltage waveform associated with the accessory bus capacitor;

determining a difference between the voltage waveform and a nominal voltage profile; and

determining a fault if the difference is greater than a threshold value.

2. The method of claim 1, further including discharging the accessory bus capacitor before charging it to the desired voltage level.

3. The method of claim 1, further including determining the nominal voltage profile based on at least the desired voltage level and capacitances of the input filter capacitor and the accessory bus capacitor.

4. The method of claim 1, further including updating a stored nominal voltage profile with characteristic parameters associated with the measured voltage waveform.

5. The method of claim 1, further including:

continuously monitoring a current waveform associated with the accessory bus capacitor;

determining a difference between the current waveform and a nominal current profile; and

detecting a fault if the difference is greater than a threshold-value.

6. The method of claim 5, further including determining the nominal current profile based on at least the desired voltage level and capacitances of the input filter capacitor and the accessory bus capacitor.

7. The method of claim 5, further including updating the nominal current profile with characteristic parameters associated with the measured current waveform.

8. The method of claim 1, further including:

providing a warning signal;

displaying a test report on a display device; and

listing possibilities for repairs.

9. The method of claim 1, wherein charging the accessory bus capacitor includes:

connecting the accessory bus capacitor to a power source;

charging the accessory bus capacitor with the power source until the accessory bus capacitor reaches the desired voltage level; and

disconnecting the accessory bus from the power source.

10. The method of claim 1, wherein the desired voltage level is lower than 50 volts.

11. The method of claim 1, wherein the nominal voltage profile consists of voltage intensities associated with the accessory bus capacitor before and after connecting the accessory bus capacitor to the input filter capacitor.

12. The method of claim 5, wherein the nominal current profile consists of a peak current intensity and a current pulse transition time associated with the accessory bus capacitor.

13. A high voltage cable testing system, comprising:

an accessory bus capacitor;

an input filter capacitor associated with an accessory component,;

an accessory switch connecting the input filter capacitor to the accessory bus capacitor, in parallel, and configured to connect and disconnect the input filter capacitor from the accessory bus capacitor;

a power source connected to the accessory bus capacitor and configured to charge the accessory bus capacitor to a desired voltage level; and

a controller connected to the high voltage cable testing system and configured to perform a high voltage cable test using the accessory bus capacitor, the input filter capacitor, and the accessory switch.

14. The high voltage cable testing system of claim 13, further includes a voltage sensor coupled to the accessory bus capacitor, configured to:

measure a voltage waveform; and

send the voltage waveform to the controller.

15. The high voltage cable testing system of claim 13, further includes a current sensor coupled to the accessory bus capacitor, configured to:

measure a current waveform; and

send the current waveform to the controller.

16. The high voltage cable testing system of claim 13, further includes a display device configured to indicate a fault if the fault is detected.

17. The high voltage cable testing system of claim 13, wherein the controller includes:

a storage unit configured to store a nominal voltage profile and a nominal current profile;

a communication unit, configured to close the accessory switch to discharge the input filter capacitor, control the power source to charge the accessory bus capacitor to a desired voltage level, connect the accessory bus capacitor to the input filter capacitor, and monitor a voltage waveform and a current waveform associated with the accessory bus capacitor; and

a processing unit, configured to compare and determine a difference between the voltage waveform and a nominal voltage profile, and determine a fault if the difference is greater than a threshold.

18. The high voltage cable testing system of claim 13, further includes a high voltage bus capacitor and a high voltage bus switch.

19. A method of testing a cabling system, comprising:

discharging an input filter capacitor associated with an accessory component;

discharging an accessory bus capacitor;

charging the accessory bus capacitor to a desired voltage level;

connecting the accessory bus capacitor to the input filter capacitor in parallel using a switch;

continuously monitoring a voltage intensity associated with the accessory bus capacitor;

determining an open fault if the voltage intensity is not below a threshold value, after steady-state is reached;

comparing the voltage intensity, after steady-state is reached, with a nominal voltage value; and

determining a fault if the voltage intensity is not equal to the nominal voltage value.

20. The method of claim 19, further including:

providing a warning signal;

displaying a test report on a display device; and

listing possibilities for repairs.