Inline disconnect for multiphase electric utility line applications
A group-operated switching system for multi-phase electrical transmission lines including a number of inline axial switches for opening and closing circuits to control electrical flow through the transmission lines. The switches include axially mounted load break vacuum interrupters and are mechanically and electrically isolated from each other and from a control box. The control box communicates with the inline switches via RF communications. Power for the switch electronics and operations can be provided from line power, a battery, or a capacitive source.
1. A switching system for controlling current through a transmission line, comprising:
an inline switch disposed within the transmission line, the inline switch comprising a disconnect blade and an interrupter having a non-rotating blade driven axially by a motorized cabinet and mounted axially inline with the disconnect blade; and
a control box connected to the motorized cabinet for remotely controlling operation of the inline switch, the inline switch mechanically and electrically isolated from the control box;
wherein the inline switch has an open configuration and a closed configuration;
wherein current does not flow to the interrupter when the inline switch is in the closed configuration; and
wherein the disconnect blade provides an open air gap and operates as a visual indicator when the inline switch is in the open configuration.
2. The switching system as in claim 1 , wherein the inline switch further comprises switch electronics for communicating with the control box and for controlling the motorized cabinet.
3. The switching system as in claim 2 , wherein the control box remotely controls operation of the inline switch via radio frequency transmission.
4. The switching system as in claim 1 , wherein the interrupter is a load break vacuum interrupter.
5. The switching system as in claim 4 , wherein the load break vacuum interrupter is arranged in series with other load break vacuum interrupters to allow switching to a desired voltage rating.
6. The switching system as in claim 4 , wherein the load break vacuum interrupter is arranged in parallel with other load break vacuum interrupters to allow switching to a desired voltage rating.
7. The switching system as in claim 4 , wherein the load break vacuum interrupter is a 38 kV loadbreak vacuum bottle having a current rating up to 3000 A.
8. The switching system as in claim 7 , wherein the load break vacuum interrupter is arranged in series with other load break vacuum bottles to allow switching up to 230 kV.
9. The switching system as in claim 1 , wherein the inline switch further comprises a gear drive mechanism housed in the motorized cabinet for driving the non-rotating blade of the interrupter.
10. The switching system as in claim 1 , wherein the motorized cabinet and inline axial switch electronic component are powered from line power using a current transformer.
11. The switching system as in claim 1 , wherein the motorized cabinet and inline axial switch electronic component are powered using a battery.
12. The switching system as in claim 1 , wherein the motorized cabinet and inline axial switch electronic component are powered using a capacitive source.
13. The switching system as in claim 1 , wherein the inline axial switch is powered from line power.
14. The switching system as in claim 1 , wherein the interrupter is operable in high-voltage, high-current load conditions.
15. The switching system as in claim 1 , wherein the inline switch further comprises a vacuum interrupter column configured to move inline with the interrupter, whereby the inline switch is in series with a strain insulator, and whereby the inline switch is insulated to ground.
16. A method of actuating a switching system for controlling current through a transmission line, the method comprising:
providing an inline switch disposed within the transmission line and a control box, the inline switch comprising a disconnect blade, an interrupter having a non-rotating blade and mounted axially inline with the disconnect blade, and a motorized cabinet, wherein the control box is connect to the motorized cabinet, and wherein the inline switch is mechanically and electrically isolated from the control box; and
remotely controlling, via the control box, operation of the inline switch by operating the motorized cabinet to axially drive the non-rotating blade of the interrupter to open or close the inline switch.
17. The method of claim 16 , wherein remotely controlling operation of the inline switch is through radio frequency transmission.
18. The method of claim 16 , wherein the interrupter is a load break vacuum interrupter, the method further comprising arranging the load break vacuum interrupter in parallel with other load break vacuum interrupters to allow switching to a desired voltage rating.
19. The method of claim 16 , wherein the interrupter is a load break vacuum interrupter, the method further comprising arranging the load break vacuum interrupter in series with other load break vacuum interrupters to allow switching to a desired voltage rating.
20. The method of claim 19 , wherein the load break vacuum interrupter is a 38 kV loadbreak vacuum bottle having a current rating up to 3000 A, and wherein the load break vacuum interrupters arranged in series allow switching up to 230 kV.