DISTRIBUTED ENERGY SYSTEM DISCONNECT SWITCH WITH MECHANICAL ISOLATION

• US 20130099567A1
• Filed: 05/24/2012
• Published: 04/25/2013
• Est. Priority Date: 10/19/2011
• Status: Active Grant

• Current Assignee: ABB Installation Products International, LLC (ABB Limited)
• Original Assignee: Thomas & Betts International Incorporated (ABB Limited)
• Inventors: Pfitzer, Hans-Erik
• Granted Patent: US 9,190,871 B2
• Time in Patent Office: Days
• US Class Current: 307/29
• CPC Class Codes: H01H 21/24 biased to return to normal position upon removal of operating force
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy wind motors F03D
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/388 Islanding, i.e. disconnection of local power supply from the network
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects

Abstract

A switching assembly includes a first terminal and a second terminal, and a contactor connected to the first terminal, where the contactor includes a relay switch and a coil. The switching assembly further includes a first switch connected to the second terminal, and a a rectifier bridge connected in series between the contactor and the first switch. The switching assembly also includes a control unit configured to selectively apply a control signal to the coil to cause the relay switch to open or close based on a voltage measured at the first terminal or based on a voltage drop measured across the rectifier bridge.

Claims

1. A switching assembly, comprising:

a first terminal and a second terminal;

a contactor connected to the first terminal, wherein the contactor includes a relay switch and a coil;

a first switch connected to the second terminal;

a rectifier bridge connected in series between the relay switch and the first switch; and

a control unit configured to selectively apply a control signal to the coil to cause the relay switch to open or close based on a voltage measured at the first terminal or based on a voltage measured across the rectifier bridge.

2. The switching assembly of claim 1, wherein, when selectively applying a control signal to the coil to cause the relay switch to open or close, the control unit is further configured to:

determine if the voltage measured at the first terminal is less than a threshold voltage, and

cause the relay switch to open if the voltage measured at the first terminal is less than a threshold voltage.

3. The switching assembly of claim 1, wherein, when selectively applying a control signal to the coil to cause the relay switch to open or close, the control unit is further configured to:

determine if the voltage measured across the rectifier bridge indicates a failure in a rectifier of the bridge, and

cause the relay switch to open if the voltage measured across the rectifier bridge indicates a failure in a rectifier of the bridge.

4. The switching assembly of claim 1, wherein, when the control unit applies a control signal to the coil to cause the relay switch to open, the second terminal is mechanically isolated from the first terminal.

5. The switching assembly of claim 1, wherein the rectifier bridge comprises a first silicon controlled rectifier (SCR) connected in parallel with a second SCR.

6. The switching assembly of claim 5, wherein a cathode of the first SCR is connected to the first switch and an anode of the first SCR is connected to the relay switch, and wherein a cathode of the second SCR is connected to the relay switch and an anode of the second SCR is connected to the first switch.

7. The switching assembly of claim 5, wherein the first terminal is connected to a first power source and the second terminal is connected to a second power source.

8. The switching assembly of claim 7, further comprising:

a second switch connected between the first terminal and the second terminal, wherein the second switch is connected in parallel with the relay switch, the rectifier bridge and the first switch.

9. The switching assembly of claim 8, wherein the control unit is further configured to:

cause the relay switch of the contactor to close, the first switch to close, the second switch to open, and the first and second SCRs to turn on based on power being delivered into the first terminal from the first power source,

cause the relay switch of the contactor to open based on a failure of delivery of power into the first terminal from the first power source or based on a failure of either of the first and second SCRs, and

cause the second switch to close, the relay switch of the contactor to open, and the first switch to open based on power being delivered into the first terminal from the first power source and based on a failure of delivery of power into the second terminal from the second power source.

10. The switching assembly of claim 9, wherein a non-critical load is coupled to the first terminal and a critical load is coupled to the second terminal.

11. The switching assembly of claim 10, wherein, when the relay switch of the contactor is closed, the first switch is closed, the second switch is open, and the first and second SCRs are turned on, power is delivered from the first power source to the non-critical load, power is delivered from the second power source to the critical load, and power is delivered from the second power source through the relay switch of the contactor, the first switch and the first and second SCRs to the non-critical load.

12. The switching assembly of claim 11, wherein, when the relay switch of the contactor is open, power is delivered from the second power source to the critical load, and no power is delivered from the second power source through the relay switch of the contactor, the first switch, and the first and second SCRs to the non-critical load.

13. The switching assembly of claim 12, wherein, when the relay switch of the contactor is open, the first switch is open and the second switch is closed, power is delivered from the first power source to the non-critical load and through the second switch to the critical load.

14. The switching assembly of claim 7, wherein the first power source comprises a public utility power source.

15. The switching assembly of claim 14, wherein the second power source comprises a distributed energy source.

16. A switching assembly, comprising:

a first rectifier bridge coupled to a first phase of a first voltage source;

a first contactor coupled in series with the first rectifier bridge, wherein the first contactor includes a first relay switch and a coil;

a second rectifier bridge coupled to a second phase of the first voltage source;

a second contactor coupled in series with the second rectifier bridge, wherein the second contactor includes a second relay switch and the coil;

a third rectifier bridge coupled to a third phase of the first voltage source;

a third contactor coupled in series with the third rectifier bridge, wherein the third contactor includes a third relay switch and the coil; and

a control unit configured to selectively apply a control signal to the coil to cause the first relay switch, the second relay switch and the third relay switch to open or close based on voltage measurements of the first phase, the second phase and the third phase of the first voltage source or based on voltages measured across the first, second or third rectifier bridges.

17. The switching assembly of claim 16, wherein, when selectively applying a control signal to the coil to cause the first relay switch, the second relay switch and the third relay switch to open or close, the control unit is further configured to:

determine if any of the voltage measurements of the first phase, the second phase, or the third phase of the first voltage source are less than a threshold voltage, and

cause the first relay switch, the second relay switch and the third relay switch to open if any of the voltage measurements of the first phase, the second phase, or the third phase of the first voltage source are less than a threshold voltage.

18. The switching assembly of claim 16, wherein, when selectively applying a control signal to the coil to cause the first relay switch, the second relay switch and the third relay switch to open or close, the control unit is further configured to:

determine if any of the voltages measured across the first, second or third rectifier bridges indicates a failure in a rectifier of the first, second or third rectifier bridges, and

cause the first relay switch, the second relay switch and the third relay switch to open if any of the voltages measured across the first, second, or third rectifier bridges indicates a failure in a rectifier of the first, second or third rectifier bridges.

19. The switching assembly of claim 16, wherein each of the first, second and third rectifier bridges comprises a first silicon controlled rectifier (SCR) connected in parallel with a second SCR.

20. The switching assembly of claim 16, wherein the first voltage source comprises a utility power source and wherein the switching assembly is coupled between the utility power source and a distributed energy power source.