Method for identifying risks as a result of stray currents

• US 20040104723A1
• Filed: 08/12/2003
• Published: 06/03/2004
• Est. Priority Date: 08/12/2002
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Braun, Wolfgang, Halfmann, Ulrich, Schneider, Egid, Altmann, Martin
• Granted Patent: US 6,924,648 B2
• Time in Patent Office: Days
• US Class Current: 324/217
• CPC Class Codes: B60M 5/00 Arrangements along running rails or at joints thereof for current conduction or insulation, e.g. safety devices for reducing earth currents insulating rail joints E01B11/54; conductive connections between rails in general H01R3/00, H01R4/00, H01R4/70
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

A method is for identifying risks as a result of stray currents which flow to ground from a rail which returns a traction current in a track with a DC power supply. In accordance with a first embodiment, in which the voltage between the rail and ground is measured and an increased risk as a result of stray currents is indicated if there is a discrepancy from a voltage reference value, provision is made for the voltage to be measured at a plurality of measurement points along the track and for the measurements to be evaluated in an evaluation center. In accordance with a second embodiment, provision is made for activating a short-circuiter to connect a parallel path to the rail for returning the traction current. The current level in the parallel path is then measured and an increased risk as a result of stray currents is indicated if there is a discrepancy from a current-level reference value. Further, the method includes joint evaluation of a plurality of measurements which have been ascertained along the track.

Claims

1. A method for identifying risks as a result of stray currents which flow to ground from a rail which returns traction current in a track with a DC power supply, comprising:

measuring a voltage between the rail and the ground;

indicating a relatively increased risk as a result of stray currents upon the measured voltage indicating a discrepancy from a voltage reference value, wherein the voltage is measured at a plurality of measurement points along the track; and

transmitting the measurements to an evaluation center where they are evaluated centrally.

4. The method as claimed in claim 1, wherein the measurements from adjacent measurement points are evaluated together.

5. The method as claimed in claim 1, wherein the reference value is ascertained for an as-new track and over a period with a known train sequence and wherein the subsequent measurements are taken over a period of largely the same length with largely the same train sequence.

6. The method as claimed in claim 1, wherein a relatively increased risk is indicated for the section of track between adjacent measurement points having a relatively greatest discrepancy from the reference value.

7. The method as claimed in claim 1, wherein the location with the relatively greatest risk is indicated as being at least close to the measurement point which delivers the relatively lowest measurement for the voltage.

8. The method as claimed in claim 1, wherein the measurements are transmitted to an evaluation center using a communications system.

12. The method as claimed in claim 4, wherein the reference value is ascertained for an as-new track and over a period with a known train sequence and wherein the subsequent measurements are taken over a period of largely the same length with largely the same train sequence.

25. The method of claim 8, wherein the measurements are transmitted in one second intervals.

2. A method for identifying risks as a result of stray currents which flow to ground from a rail which returns the traction current in a track with a DC power supply, comprising:

activating a short-circuiter to connect a parallel path to the rail for returning the traction current;

measuring a current level in the parallel path; and

indicating a relatively increased risk as a result of stray currents upon the measured current level indicating a discrepancy from a current-level reference value.

3. The method as claimed in claim 2, wherein the current level is measured at a plurality of measurement points along the track and wherein the measurements are evaluated centrally.

9. The method as claimed in claim 3, wherein the measurements from adjacent measurement points are evaluated together.

10. The method as claimed in claim 2, wherein the reference value is ascertained for an as-new track and over a period with a known train sequence and wherein the subsequent measurements are taken over a period of largely the same length with largely the same train sequence.

11. The method as claimed in claim 3, wherein the reference value is ascertained for an as-new track and over a period with a known train sequence and wherein the subsequent measurements are taken over a period of largely the same length with largely the same train sequence.

13. The method as claimed in claim 2, wherein the reference value is ascertained for an as-new track and over a period with a known train sequence and wherein the subsequent measurements are taken over a period of largely the same length with largely the same train sequence.

14. The method as claimed in claim 2, wherein a relatively increased risk is indicated for the section of track between adjacent measurement points having a relatively greatest discrepancy from the reference value.

15. The method as claimed in claim 2, wherein the location with the relatively greatest risk is indicated as being at least close to the measurement point which delivers the relatively highest measurement for the current level.

16. The method as claimed in claim 2, wherein the measurements are transmitted to an evaluation center using a communications system.

17. A method, comprising:

measuring a voltage between a rail and the ground at a plurality of points;

transmitting the measurements; and

determining a risk of stray currents from the rail, upon the transmitted measurements indicating a measured voltage differing from a voltage reference value at least one of over a period of time and by a determined amount.

18. The method of claim 17, wherein the method is for determining a risk as a result of stray currents which flow to the ground from a rail which returns traction current in a track with a DC power supply.

23. The method of claim 17, wherein the measurements from the plurality of points along the track are transmitted to an evaluation center using a communications system.

24. The method of claim 23, wherein the measurements are transmitted in one second intervals.

26. The method of claim 17, wherein a risk of stray currents is determined upon the measured voltage differing from the voltage reference value by at least 50%.

27. The method of claim 17, wherein a risk of stray currents is determined upon the measured voltage differing from the voltage reference value by at least 50% over a period of a plurality of days in succession.

28. The method of claim 17, wherein a risk of stray currents is determined upon the measured voltage differing from the voltage reference value over a period of a plurality of days in succession.

32. The method of claim 17, wherein a risk of stray currents is determined upon the measured voltage differing from the voltage reference value by at least between 10% and 50%.

33. The method of claim 17, wherein a risk of stray currents is determined upon the measured voltage differing from the voltage reference value by at least between 10% and 50% over a period of a plurality of days in succession.

36. The method of claim 17, wherein the measurements are transmitted to a relatively centrally located evaluation center for evaluation

19. A method, comprising:

connecting a parallel path to a rail for returning traction current;

measuring a current level in the parallel path; and

determining a risk of stray currents from the rail upon the measured current level differing from a current-level reference value at least one of over a period of time and by a determined amount.

20. The method of claim 19, wherein the method is for determining a risk as a result of stray currents which flow to the ground from a rail which returns traction current in a track with a DC power supply.

21. The method of claim 19, wherein a short-circuiter is activated to connect the parallel path to the rail.

22. The method of claim 20, wherein a short-circuiter is activated to connect the parallel path to the rail.

29. The method of claim 19, wherein a risk of stray currents is determined upon the measured current level differing from a current-level reference value by at least 50%.

30. The method of claim 19, wherein a risk of stray currents is determined upon the measured current level differing from a current-level reference value by at least 50% over a period of a plurality of days in succession.

31. The method of claim 19, wherein a risk of stray currents is determined upon the measured current level differing from a current-level reference value over a period of a plurality of days in succession.

34. The method of claim 19, wherein a risk of stray currents is determined upon the measured current level differing from a current-level reference value by at least between 10% and 50%.

35. The method of claim 19, wherein a risk of stray currents is determined upon the measured current level differing from a current-level reference value by at least between 10% and 50% over a period of a plurality of days in succession.

37. The method of claim 19, wherein measurements from a plurality of points along the track are transmitted to an evaluation center using a communications system.

38. The method of claim 37, wherein the measurements are transmitted in one second intervals.