Gas-insulated switchgear device with optical current sensor
View Patent ↗An exemplary gas-insulated switchgear device is disclosed which includes a current sensor and a voltage sensor located at a partition insulator. The current sensor can include a magneto-optical fiber on a flexible carrier strip and can be manufactured separately for being easily mounted to an assembled switchgear device. The current sensor can include an electro-optical fiber extending radially into the partition insulator and whose ends are embedded in recesses in the bus bar as well as in the metal embracing of the partition insulator for accurately integrating the voltage.
1. A gas-insulated switchgear device, comprising:
an enclosure;
a chamber arranged in said enclosure, and filled by an insulating gas or vacuum;
at least one bus bar arranged in said chamber for carrying an electrical current; and
at least one fiber loop of a magneto-optical fiber wound around said at least one bus bar at a distance from said at least one bus bar for measuring electrical current through said bus bar;
a loop-shaped, flexible carrier strip carrying said fiber; and
a shield wall separate from said carrier strip and arranged between said carrier strip and said chamber.
2. The device of claim 1 , wherein said enclosure comprises:
plural tube sections extending along an axial direction, wherein said shield wall is arranged axially between two of the tube sections.
3. The device of claim 2 wherein said tube sections and said shield wall are metallic, said device comprising:
a non-conductive seal arranged between at least one of said tube sections and said shield wall.
4. The device of claim 3 , comprising:
a conductive part between said two tube sections for carrying a current between said tube sections, wherein said part is arranged radially outside of said fiber loop.
5. The device of claim 1 , wherein said carrier strip is arranged in a recess formed at a radially outward facing side of said shield wall, said device comprising:
a lid closing said recess, is the lid being arranged radially outside said carrier strip.
6. The device of claim 1 , comprising:
at least one partition insulator for dividing said chamber into partitions, wherein said partition insulator forms an electrically insulating partition wall axially separating two partitions and extending from said enclosure to said bus bar, said shield wall being arranged radially outside said partition wall.
7. The device of claim 6 wherein said shield wall is connected to said partition wall.
8. The device of claim 1 , comprising:
a voltage sensor arranged at said shield wall.
9. The device of claim 8 wherein said voltage sensor is an electro-optical voltage sensor.
10. The device of claim 8 , wherein said voltage sensor comprises:
a light guiding element or rod extending radially inwards from said shield wall.
11. The device of claim 10 wherein said light guiding element or rod is formed of a material whose refractive indices or birefringence change linearly under an applied electric field.
12. The device of claim 8 , wherein said voltage sensor includes a light guiding element which extends at least from said shield wall to at least said bus bar, and wherein a radially outer end of said light guiding element extends into a recess in a radially inward facing surface of said shield wall and/or a radially inner end of said light guiding element extends into a recess in a radially outward facing surface of said bus bar.
13. The device of claim 11 , wherein a radially outer and/or radially inner end of said light guiding element or rod carries a metal shielding electrically connected to the shield wall and/or to the bus bar.
14. The device of claim 10 , wherein said light guiding element or rod extends through a radial bore in an insulating partition wall of said device, wherein said partition wall extends from said enclosure to said bus bar.
15. The device of claim 14
wherein said light guiding element or rod is embedded in resin or in oil in said radial bore, or
wherein said radial bore is in gas-exchange with said chamber, through a filter blocking at least part of SF 6 decomposition products.
16. The device of claim 8 , wherein said voltage sensor comprises:
a light guiding element arranged at a radially inner side of said shield wall, and being looped at least once around said bus bar.
17. The device of claim 16 wherein said light guiding element is a transversally poled electro-optical fiber.
18. The device of claim 16 , wherein said light guiding element is mounted on a mount comprising carbon fiber.
19. The device of claim 8 , comprising:
an electro-optical sensing element having electrodes, wherein one of said electrodes is connected to an electrode ring arranged radially inside said shield wall and extending at least partially around said bus bar at a distance from said bus bar.
20. The device of claim 19 wherein said sensing element is arranged radially outside said shield wall and/or wherein a second of said electrodes is electrically connected to said enclosure.