Switching system for breaking a current and method of performing a current breaking operation

Patent metadata

Field	Value
Publication number	US-10002722-B2
Application number	US-201615551807-A
Country	US
Kind code	B2
Filing date	Feb 19, 2016
Priority date	Feb 20, 2015
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A switching system for breaking a current, including a contact arrangement having a first and second terminals, a resonance circuit connectable across the contact arrangement, In the closed state the first switch enables current to flow through the resonance circuit in a first flow direction and into the contact arrangement in a direction opposite to a contact arrangement arc current flow direction. A second switch connected to the resonance circuit and to the second terminal. In the closed state the second switch enables current to flow through the resonance circuit in a second flow direction opposite to the first flow direction. A control system arranged to alternatingly set the first and second switches in the closed state and then in the open state upon a current breaking operation, until a current pulse, emanating from energy supplied by a contact arrangement arc current, flowing through the resonance circuit and into the contact arrangement reaches an amplitude which is equal to or greater than a magnitude of a contact arrangement arc current.

First claim

The invention claimed is:

1. A switching system for breaking a current, comprising:
a contact arrangement having a first terminal and a second terminal,
a resonance circuit connectable across the contact arrangement,
a first switch connected to the resonance circuit and to the first terminal, wherein the first switch is switchable between an open state and a closed state, wherein in the closed state the first switch is arranged to enable current to flow through the resonance circuit in a first flow direction and into the contact arrangement in a direction opposite to a contact arrangement arc current flow direction,
a second switch connected to the resonance circuit and to the second terminal of the contact arrangement, wherein the second switch is switchable between an open state and a closed state, wherein in the closed state the second switch is arranged to enable current to flow through the resonance circuit in a second flow direction opposite to the first flow direction, and
a control system,
wherein the control system is arranged to alternatingly first set the first switch, and then the second switch, first in the closed state and then in the open state upon a current breaking operation, until a current pulse, emanating from energy supplied by a contact arrangement arc current, flowing through the resonance circuit and into the contact arrangement reaches an amplitude which is equal to or greater than a magnitude of the contact arrangement arc current.

2. The switching system as claimed in claim 1 , wherein in each iteration of alternatingly first setting the first switch, and then the second switch, first in the closed state and then in the open state, the control system is arranged to:
set the first switch in the closed position, enabling a first current pulse to flow through the resonance circuit in the first flow direction,
set first the first switch in the open state and then the second switch in the closed state when the first current pulse has become zero to enable a second current pulse to flow through the resonance circuit in the second flow direction, and
to set the second switch in the open state when the second current pulse first has become zero.

3. The switching system as claimed in claim 1 , comprising an arc extinguisher arranged to extinguish an arc across the contact arrangement.

4. The switching system as claimed in claim 1 , wherein the resonance circuit comprises a capacitor and an inductor.

5. The switching system as claimed in claim 1 , wherein the second switch is connected across the resonance circuit.

6. The switching system as claimed in claim 1 , comprising a third switch switchable between an open state and a closed state, wherein the third switch is connected to the second terminal of the contact arrangement and to the resonance circuit, and wherein the control system is arranged to set the third switch in the closed state simultaneously with setting the first switch in the dosed state and to set the third switch in the open state simultaneously with setting the first switch in the open state.

7. The switching system as claimed in claim 6 , comprising a fourth switch switchable between an open state and a closed state, wherein the fourth switch is connected to the resonance circuit and to the first terminal of the contact arrangement, and wherein the control system is arranged to set the fourth switch in the closed state simultaneously with setting the second switch in the closed state and to set the fourth switch in the open state simultaneously with setting the second switch in the open state.

8. The switching system as claimed in claim 1 , wherein the first switch and the second switch are semiconductor switches.

9. The switching system as claimed in claim 7 , wherein the third switch and the fourth switch are semiconductor switches.

10. The switching system as claimed in claim 1 , wherein the control system is configured to alternatingly switch first the first switch and then the second switch, first in the closed state and then in the open state, with a first frequency for a first time interval and subsequently with a second frequency slower than the first frequency for a second time interval.

11. A method of performing a current breaking operation by means of a switching system comprising a contact arrangement having a first terminal and a second terminal, a resonance circuit connectable across the contact arrangement, a first switch connected to the resonance circuit and to the first terminal, wherein the first switch is switchable between an open state and a closed state, wherein in the closed state the first switch is arranged to enable current to flow through the resonance circuit in a first flow direction and into the contact arrangement in a direction opposite to a contact arrangement arc current flow direction, a second switch connected to the resonance circuit and to the second terminal, wherein the second switch is switchable between an open state and a closed state, wherein in the closed state the second switch is arranged to enable current to flow through the resonance circuit in a second flow direction opposite to the first flow direction, and a control system , wherein the method comprises:
alternatingly first setting the first switch, and then the second switch, first in the closed state and then in the open state by means of the control system, upon a current breaking operation, until a current pulse, emanating from energy supplied by a contact arrangement arc current, flowing through the resonance circuit reaches an amplitude which is equal to or greater than a magnitude of the contact arrangement arc current.

12. The method as claimed in claim 11 , wherein each iteration of the step of alternatingly first setting the first switch, and then the second switch, first in the closed state and then in the open state comprises:
a) setting the first switch in the closed state, enabling a first current pulse to flow through the resonance circuit in the first flow direction,
b) setting first the first switch in the open state and then the second switch in the closed state when the first current pulse has become zero to enable a second current pulse to flow through the resonance circuit in the second flow direction, and
c) setting the second switch in the open state when the second current pulse first has become zero.

13. The method as claimed in claim 12 , wherein the switching system comprises a third switch switchable between an open state and a closed state, wherein the third switch is connected to the second terminal of the contact arrangement and to the resonance circuit, wherein the step of alternatingly first setting the first switch, and then the second switch, first in the closed state and then in the open state comprises:
setting the third switch in the closed state simultaneously with setting the first switch in the closed state, and
setting the third switch in the open state simultaneously with setting the first switch in the open state.

14. The method as claimed in claim 13 , wherein the switching system comprises a fourth switch switchable between an open state and a closed state, wherein the fourth switch is connected to the resonance circuit and to the first terminal of the contact arrangement, wherein the step of alternatingly first setting the first switch, and then the second switch, first in the closed state and then in the open state comprises:
setting the fourth switch in the closed state simultaneously with setting the second switch in the closed state, and
setting the fourth switch in the open state simultaneously with setting the second switch in the open s

Assignees

• Abb Schweiz Ag

Inventors

• Backman Magnus
• Valdemarsson Stefan

Classifications

• H02H3/02

  Details · CPC title

• H02H3/087

  for DC applications · CPC title

• H01H2009/543

  third parallel branch comprising an energy absorber, e.g. MOV, PTC, Zener · CPC title

• H01H33/04

  Means for extinguishing or preventing arc between current-carrying parts · CPC title

• H02H3/081

  and depending on the direction · CPC title