Cathodic protection remote monitoring method and apparatus

• US 20030074162A1
• Filed: 10/11/2002
• Published: 04/17/2003
• Est. Priority Date: 10/12/2001
• Status: Active Grant

• Current Assignee: American Innovations, Ltd.
• Original Assignee: Enviro-Sense, LLC
• Inventors: Oosthuysen, Johan, Fourie, Julius W.
• Granted Patent: US 7,027,957 B2
• Time in Patent Office: Days
• US Class Current: 702/188
• CPC Class Codes: C23F 2213/32 Pipes
• CPC Class Codes: G01R 31/12 Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing G01R31/08, G01R31/327 and G01R31/72 take precedence; measuring in plasmas G01R19/0061; measuring dielectric constants G01R27/2617; ESD, EMC or EMP testing of circuits G01R31/002
• CPC Class Codes: G01R 31/3275 Fault detection or status indication

Abstract

A method for determining the influence of one of a plurality of cathodic protection circuits along a pipeline includes switching one of a plurality of cathodic protection circuits off, while the remainder of the plurality of cathodic protection circuits are left on, with a portable pipe-to-soil potential measurement unit measuring the pipe-to-soil potential along the pipeline. From these measurements, a calibration curve is generated and an apparatus for monitoring the cathodic protection circuits is strategically positioned on the pipeline. The apparatus includes a remote monitoring unit having a pipe-to-soil potential measurement unit for measuring the potential between the ground bed and pipeline. The remote monitoring unit is off except while making measurements. The remote monitoring unit may optionally include a pipeline current measurement unit connected at a second connection point on the pipeline for measuring the current passing through the pipeline between the first and second connection points.

Claims

1. A method for monitoring the cathodic protection status of a rectifier on a conductive structure comprising:

a) placing the rectifier having a first predetermined output at a first location on the structure;

b) changing the output of the rectifier to a second predetermined output;

c) measuring the difference between the first and second outputs of the rectifier at a plurality of locations on the structure, wherein the locations are remote from the rectifier at the first location;

d) recording the influence that the difference of the outputs has on the structure-to-soil potential at each location;

e) selecting at least one location on the structure remote from the rectifier where the influence from the rectifier on the structure-to-soil potential is discernable;

f) placing a remote monitoring unit at the selected remote location;

g) measuring the structure-to-soil potential with the remote monitoring unit; and

h) comparing the structure-to-soil potential measured by the remote monitoring unit with the results from step d).

2. The method according to claim 1 wherein the remote monitoring unit is capable of measuring the structure-to-soil potential value continuously, periodically, or on demand.

3. The method according to claim 1 wherein the remote monitoring unit is capable of relaying the measurements to a central location via a relay means.

4. The method according to claim 3 wherein the relay means is selected from the group consisting of a satellite, a mobile phone, a land line, and a radio.

5. The method according to claim 1 wherein the results of measurements carried out by the remote monitoring unit is transmitted to a server.

6. The method according to claim 4 wherein the results of measurements are accessible through the internet.

7. The method according to claim 1 wherein the status of multiple rectifiers are monitored at a single location remote from the rectifiers.

8. The method according to claim 7 wherein the total number rectifiers being monitored is greater than the total number of remote locations where measurements are carried out.

9. The method according to claim 8 wherein a correlation is made between the results of measurements at multiple remote locations and the known effect that a particular rectifier has at these remote locations.

10. The method according to claim 1 wherein the structure is a pipeline.

11. The method according to claim 10 further comprising measuring the return current in the pipeline at a predetermined point on the pipeline.

12. The method according to claim 11 wherein both pipe-to-soil potential and return current at a predetermined point on the pipeline are measured and compared to predetermined threshold values.

13. The method according to claim 10 wherein the remote monitoring unit further monitors leak detection devices.

14. The method according to claim 10 wherein the remote monitoring unit further monitors the output of sacrificial anodes.

15. The method according to claim 10 wherein the remote monitoring unit is used as an above ground reference for smart pigging operations.

16. The method according to claim 15 wherein the remote monitoring unit detects a pig'"'"'s passage.

17. The method according to claim 10 wherein the remote monitoring unit further measures case-to-soil potential.

18. The method according to claim 10 wherein the remote monitoring unit further monitors hydrocarbon leaks in a casing vent.

19. A method for monitoring the amount of current obtained by a section of pipe comprising:

measuring the return current at one end of the pipe;

measuring the return current at the other end of the pipe;

calculating the difference in return current measured between the two ends of the pipe; and

transmitting the results to a central location.

20. The method according to claim 19 wherein the amount of current obtained by a section of pipe is compared to a predetermined baseline value.

21. An electrical disconnect device comprising:

a stationary portion having at least one conductive contact point positioned thereon;

a movable portion having at least one conductive contact point positioned thereon;

an actuator for moving the movable portion between the stationary and movable portions whereby when the movable portion is in a closed position, the contact points are in physical contact with each other, and when the movable portion is in an open position, the contact points are separated by a predetermined distance.

22. The device according to claim 21 wherein the movable and stationary portions are connected to an electrical circuit and the movable portion is in the open position when the electrical circuit is not active.

23. The device according to claim 22 wherein the movable portion is in the open position at least 50% of the time.

24. The device according to claim 22 wherein the movable portion is in the open position at least 80% of the time.

25. The device according to claim 22 wherein the electrical circuit includes a remote monitoring unit.

26. The device according to claim 25 wherein the remote monitoring unit monitors cathodic protection parameters on a pipeline.

27. The device according to claim 25 wherein the remote monitoring unit monitors the output of sensors on a pipeline.

28. The device according to claim 25 wherein the remote monitoring unit monitors the status of a cathodic protection rectifier on a pipeline.

29. The device according to claim 25 wherein the predetermined distance between the contact points are a predetermined distance apart in the open position to avoid arcing across the contact points.

30. The device according to claim 22 wherein said electrical circuit includes a battery.

31. The device according to claim 30 wherein the voltage of said battery is sensed while said device is in the open position and the movable portion of said device is moved into the closed position when said voltage drops below a predetermined level.

32. The device according to claim 30 wherein said battery is charged by a solar panel.

33. The device according to claim 21 further comprising a microprocessor and on-board clock for opening and closing the movable portions at predetermined times.

34. An electrical circuit comprising a disconnect device, wherein said disconnect device in is in an open position a majority of the time, such that the electrical circuit is not active said majority of the time.

35. The electrical circuit according to claim 34 wherein said electrical circuit includes a battery.

36. The electrical circuit according to claim 35 wherein the voltage of said battery is sensed while said device is in the open position and the movable portion of said device is moved into the closed position when said voltage drops below a predetermined level.

37. The electrical circuit according to claim 35 wherein said battery is charged by a solar panel.

38. A current interruption assembly comprising:

a plurality of interrupters, each interrupter having an internal clock,

wherein the internal clocks are capable of being synchronized with each other and wherein the interrupters are programmed to repetitively switch multiple current sources on and off in a consecutive manner such that only one current source is switched off at any given time.

39. The assembly according to claim 38 wherein the interrupters are capable of switching multiple current sources on and off in unison at least once during each repetition of switching current sources off consecutively.

40. The assembly according to claim 39 wherein the interrupters are programmable whereby the times that each current source will be on or off during the cycle of switching on and off consecutively is predetermined.

41. The assembly according to claim 39 wherein the interrupters are programmable whereby the times that each current source will be on or off during the cycle of switching on and off in unison is predetermined.

42. The assembly according to claim 39 wherein the interrupters are programmable whereby a time delay between one interrupter switching back on and the next interrupter in the consecutive switching cycle switching off is predetermined.

43. The assembly according to claim 39 wherein the interrupters are programmable whereby the current sources are switched off in unison any number of times during one cycle of switching the current sources on and off consecutively.

44. The assembly according to claim 38 further comprising a logger with an internal clock synchronized with the interrupters.

45. The assembly according to claim 44 wherein the logger is programmable to read, display and store values automatically during predetermined time periods.

46. The assembly according to claim 38 further comprising a remote monitoring and control unit.

47. The assembly according to claim 46 wherein the remote monitoring and control unit is capable of activating and deactivating the interrupter remotely.