Method and device for installing and removing a current transformer on and from a current-carrying power line

• US 6,756,776 B2
• Filed: 11/12/2002
• Issued: 06/29/2004
• Est. Priority Date: 05/28/2002
• Status: Expired due to Fees

• Current Assignee: Amperion Incorporated
• Original Assignee: Amperion Incorporated
• Inventors: Perkinson, Joseph C., Brown, Scott D.
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US10/293,729
• Publication Number:
  US 20030222747A1
• Time in Patent Office: 595 Days
• Field of Search: 324/76.11, 324/126, 324/127, 336/229, 336/212, 336/178
• US Class Current: 324/127
• CPC Class Codes: H01F 17/062 Toroidal core with turns of coil around it
• CPC Class Codes: H01F 38/30 Constructions

Abstract

A current transformer to be installed around a current-carrying conductor. The transformer has a split core with two parts, which can be opened to allow the transformer to be installed around or removed from the current-carrying conductor. A winding wound on the core is operatively connected to a switch so that the winding can be shorted prior to opening the split core when the transformer is removed from the current-carrying conductor in order to reduce the magnetic force holding the split core parts together. The winding is shorted by the switch prior to closing the split core parts when the transformer is installed around the conductor in order to minimize the damage to the core due to the induced magnetic force thereon. A mechanical tool is used to open or close the split-core parts. The switch can be linked to the tool for shorting and opening the winding.

Claims

1. A method of reducing magnetic forces exerted on a current transformer (90) positioned about a current-carrying conductor (5), wherein the current transformer (90) comprises a magnetically permeable core (100) having at least two split core parts (110, 120) separable by a gap (130), and wherein

the gap can be closed so as to allow the split core parts to form a substantially closed-loop around the current-carrying conductor in a closed configuration, and

the gap can be widened so as to allow the current transformer to be removed from the current-carrying conductor, and wherein the current transformer further comprises a winding (140) having a plurality of turns of an electrical conductor wound around the magnetically permeable core, said method comprising the steps of:

shorting the winding prior to closing the gap between the split core parts for achieving the closed configuration; and

shorting the winding prior to separating the split core parts from each other if the split core parts are in the closed configuration.

2. The method of claim 1, further comprising the step of

opening the winding after the split core parts are in the closed configuration.

3. The method of claim 2, further comprising the step of

opening the winding after the split core parts are separated from each other.

4. The method of claim 1, further comprising the step of

opening the winding after the split core parts are separated from each other.

5. A device for reducing magnetic forces exerted on a current transformer (90) positioned about a current-carrying conductor (5), wherein the current transformer comprises a magnetically permeable core (100) having at least two split core parts (110, 120) separable by a gap (130), and wherein

the gap can be closed so as to allow the split core parts to form a substantially closed-loop around the current-carrying conductor in a closed configuration, and

the gap can be widened so as to allow the current transformer to be removed from the current-carrying conductor, and wherein the current transformer further comprises a winding having a plurality of turns of an electrical conductor wound around the magnetically permeable core, said device comprising:

a shorting device (192) in operative engagement with the winding (140) so as to be able to short the winding; and

a mechanism (194), positioned relative to the split core parts so as to be able to close the gap between the split core parts or to separate the split core parts from each other.

6. The device of claim 5, wherein the mechanism is operatively connected to the shorting device so as to cause the shorting device to short the winding prior to closing the gap, and to short the winding prior to separating the split core parts from each other if the split core parts are in the closed configuration.

7. The device of claim 6, wherein the mechanism (194) is adapted to cause the shorting device to open the winding after the gap is closed.

8. The device of claim 7, wherein the mechanism (194) is adapted to cause the shorting device to open the winding after the split core parts are separated from each other.

9. The device of claim 6, wherein the mechanism (194) is adapted to cause the shorting device to open the winding after the split core parts are separated from each other.

10. A current transformer (90) to be positioned about a current-carrying conductor (5), comprising:

a magnetically permeable core (100) having at least two split core parts (110, 120) separable by a gap (130), wherein the gap can be closed so as to allow the split core parts to form a substantially closed-loop around the current-carrying conductor in a closed configuration, and the gap can be widened for separating the split core parts from each other so as to allow the current transformer to be removed from around the current-carrying conductor;

a winding (140) having a plurality of turns of an electrical conductor wound around the magnetically permeable core; and

a shorting device (192) positioned relative to the winding so as to be able to;

short the winding prior to closing the gap, and to be able to

short the winding prior to separating the split core parts if the split core parts are in the closed configuration.

11. The current transformer of claim 10, further comprising

a mechanism (194), positioned relative to the split core parts so as to be able to close the gap between the split core parts or to separate the split core parts from each other.

12. The current transformer of claim 11, wherein the mechanism is operatively connected to the shorting device so as to cause the shorting device to short the winding.

13. The current transformer of claim 12, wherein the mechanism is adapted to cause the shorting device to open the winding after the gap is closed.

14. The current transformer of claim 12, wherein the mechanism is adapted to cause the shorting device to opening the winding after the split core parts are separated from each other.

15. The current transformer of claim 10, wherein the shorting device is able to open the winding after the gap is closed.

16. The current transformer of claim 10, wherein the shorting device is able to open the winding after the split core parts are separated from each other.

17. The current transformer of claim 10, further comprising another winding (150) wound around the magnetic permeable core for obtaining an induced current when the split core parts are in the closed configuration.