Series vacuum interrupters with grading capacitors integrated in a molded switch housing

Patent metadata

Field	Value
Publication number	US-10818455-B2
Application number	US-201916667403-A
Country	US
Kind code	B2
Filing date	Oct 29, 2019
Priority date	Nov 19, 2018
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A switching module for use in a high voltage switch includes: a vacuum interrupter (VI), an elastomeric insulating sleeve disposed around the VI; an insulating housing molded around the VI and the sleeve; and a pair of grading capacitors. Each grading capacitor includes an inner and an outer electrode while insulation between the electrodes is solid insulation of the housing molded at the time when the housing is molded. One of the electrodes is galvanically connected to the fixed contact through a first terminal in the switching module and the other electrode is galvanically connected to the moving contact through a second terminal in the switching module. The capacitance of the first grading capacitor is substantially equal to the capacitance of the second grading capacitor.

First claim

What is claimed is:

1. A switching module for use in a high voltage switching device, the switching module comprising:
a vacuum interrupter (VI) having a fixed contact and a moving contact;
an insulating sleeve disposed around the VI;
an insulating housing of insulating material molded around the VI and the sleeve; and
a pair of grading capacitors molded in the insulating housing and comprising a first grading capacitor and a second grading capacitor, each grading capacitor comprising an inner and an outer electrode that are concentric and an insulating member formed from the insulating material of the insulating housing disposed between the inner electrode and the outer electrode, wherein a capacitance of the first grading capacitor is substantially equal to a capacitance of the second grading capacitor.

2. The switching module of claim 1 , wherein the inner electrode and outer electrode of both grading capacitors are molded out of conductive plastics.

3. The switching module of claim 2 , wherein each of the inner electrode and the outer electrode of both grading capacitors extends in an arc around the VI in a plane normal to a VI axis extending longitudinally through a central region of the VI and the arc section extends in the VI axis direction for a specified length.

4. The switching module of claim 3 , further comprising an arc angle of the arc for each of the inner electrodes and the outer electrodes that is less than 180° wherein a gap exists between arc ends of the inner and outer electrodes in each grading capacitor.

5. The switching module of claim 4 , wherein the inner electrode and outer electrode of each grading capacitor share an axis with the VI but are offset axially.

6. The switching module of claim 5 , wherein the inner electrode of both grading capacitors also includes a shield section attached to the arc section, wherein the shield section of the inner electrode extends 360° around the VI and provides shielding of an external triple point of the VI.

7. The switching module of claim 6 , wherein the shield section of the inner electrode of the first grading capacitor is placed between the inner electrode of the second grading capacitor and the moving contact of the VI and wherein the shield section of the inner electrode of the second grading capacitor is placed between the inner electrode of the first grading capacitor and the fixed contact of the VI.

8. The switching module of claim 7 , wherein the VI further comprises a fixed contact stem attached to the fixed contact, a moving contact stem attached to the moving contact, the inner electrode of the first capacitor and the outer electrode of the second capacitor are galvanically connected to the VI moving stem, while the inner electrode of the second capacitor and the outer electrode of the first capacitor are galvanically connected to the VI fixed stem, whereby the first and second grading capacitors are connected in parallel with the VI contacts.

9. The switching module of claim 8 , wherein the arc angle of the arc section for each of the inner electrode and the outer electrode is approximately 150°.

10. The switching module of claim 9 , wherein the inner electrode and outer electrode of both grading capacitors are offset axially by at least 1.5 inches.

11. The switching module of claim 7 , wherein:
the VI further comprises a fixed contact stem attached to the fixed contact, and a moving contact stem attached to the moving contact;
the inner electrode of the first capacitor and the outer electrode of the second capacitor are galvanically connected to one terminal of a low voltage switch, while the other terminal of the low voltage switch is galvanically connected to the VI moving stem;
the inner electrode of the second capacitor and the outer electrode of the first capacitor are galvanically connected to the VI fixed stem; and
the low voltage switch is either a mechanical or a semiconductor switch or relay and is configured to conduct current in both directions when closed;
whereby both the first and second grading capacitors are connected in parallel with the VI contacts, when the low voltage switch is closed.

12. The switching module of claim 11 , wherein:
a full bridge rectifier is connected in parallel across the low voltage switch and a storage capacitor is coupled to the full bridge rectifier and configured to be charged by the full bridge rectifier; and
when both the switch and VI in the switching module are open, the grading capacitors are configured to charge the storage capacitor whereby energy is harvested from a power line to which the HV switching device is connected.

13. A high voltage (HV) switching device, comprising:
two or more switching modules connected in series, each switching module comprising:
a vacuum interrupter (VI) having a fixed contact and a moving contact;
an insulating sleeve disposed around the VI;
an insulating housing of insulating material molded around the VI and the sleeve; and
a pair of grading capacitors molded in the insulating housing and comprising a first grading capacitor and a second grading capacitor, each grading capacitor comprising an inner and an outer electrode that are concentric and an insulating member of insulating material disposed between the inner electrode and the outer electrode, wherein a capacitance of the first grading capacitor is substantially equal to a capacitance of the second grading capacitor,
wherein the inner electrode and outer electrode of both grading capacitors are molded out of conductive plastics,
wherein each of the inner electrode and the outer electrode of both grading capacitors extends in an arc around the VI in a plane normal to a VI axis extending longitudinally through a central region of the VI and the arc section extends in the VI axis direction for a specified length,
wherein an arc angle of the arc for each of the inner electrodes and the outer electrodes is less than 180° wherein a gap exists between arc ends of the inner and outer electrodes in each grading capacitor,
wherein the inner electrode and outer electrode of each grading capacitor share an axis with the VI but are offset axially,
wherein the inner electrode of both grading capacitors also includes a shield section attached to the arc,
wherein the shield section of the inner electrode extends 360° around the VI and provides shielding of an external triple point of the VI,
wherein the shield section of the inner electrode of the first grading capacitor is placed between the inner electrode of the second grading capacitor and the moving contact of the VI and wherein the shield section of the inner electrode of the second grading capacitor is placed between the inner electrode of the first grading capacitor and the fixed contact of the VI, and
wherein the VI further comprises a fixed contact stem attached to the fixed contact, a moving contact stem attached to the moving contact, the inner electrode of the first capacitor and the outer electrode of the second capacitor are galvanically connected to the VI moving stem, while the inner electrode of the second capacitor and the outer electrode of the first capacitor are galvanically connected to the VI fixed stem, whereby the first and second grading capacitors are connected in parallel with the VI contacts;
wherein each switching module has a first and a second terminal and wherein each pair of adjacent switching modules are connected in series with the second terminal of one of the pair of switching modules connected to the first terminal of an other of the pair of switching modules, each switching module has a same total capacitance of the pair of grading capacitors acr

Assignees

• S & C Electric Co

Inventors

• Djogo Goran

Classifications

• H01H33/59

  Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the AC cycle · CPC title

• H01H2033/6623

  Details relating to the encasing or the outside layers of the vacuum switch housings · CPC title

• H01H33/66 Primary

  Vacuum switches · CPC title

• H01H2033/6668

  with a plurality of interruptible circuit paths in single vacuum chamber · CPC title

• H01H33/66207 Primary

  Specific housing details, e.g. sealing, soldering or brazing · CPC title