Hybrid high direct current circuit interrupter

• US 5,793,586 A
• Filed: 10/25/1996
• Issued: 08/11/1998
• Est. Priority Date: 10/25/1996
• Status: Expired due to Fees

• Current Assignee: United States Department of Energy
• Original Assignee: United States Department of Energy
• Inventors: Rockot, Joseph H., Jha, Kamal N., Mikesell, Harvey E.
• Primary Examiner(s): Gaffin, Jeffrey A.
• Assistant Examiner(s): Medley, Sally C.
• Application Number:
  US08/736,752
• Time in Patent Office: 655 Days
• Field of Search: 361/93, 361/13, 361/8, 361/2, 361/3
• US Class Current: 361/8
• CPC Class Codes: H01H 33/596 for interrupting dc
• CPC Class Codes: H01H 9/541 Contacts shunted by semiconductor devices

Abstract

A device and a method for interrupting very high direct currents (greater than 100,000 amperes) and simultaneously blocking high voltages (greater than 600 volts). The device utilizes a mechanical switch to carry very high currents continuously with low loss and a silicon controlled rectifier (SCR) to bypass the current around the mechanical switch while its contacts are separating. A commutation circuit, connected in parallel with the SCR, turns off the SCR by utilizing a resonant circuit to divert the SCR current after the switch opens.

Claims

1. An electrical current interrupter for interrupting a high current in a conductor, comprising:

a mechanical switch, connectable in series with the conductor;

a first thyristor connected in parallel with said mechanical switch, said first thyristor for bypassing the high current while said mechanical switch opens; and

a commutation circuit connected in parallel with said first thyristor in order to minimize the voltage across contacts of said switch when said current transfers to said first thyristor and said commutation circuit, said commutation circuit for turning off said first thyristor;

wherein said commutation circuit includes a resonant circuit connected in parallel with said first thyristor and a diode connected in parallel with said first thyristor; and

wherein said resonant circuit includes a capacitor, an inductor, and a second thyristor connected in series with each other.

2. The current interrupter of claim 1 wherein said commutation circuit further includes a power supply connectable to said capacitor for charging said capacitor.

3. The current interrupter of claim 2 wherein said first thyristor comprises a plurality of thyristors connected in parallel.

4. The current interrupter of claim 2 further including a standby circuit for supplying current to said first thyristor while said mechanical switch is closed, wherein said standby circuit includes a rectifier, said rectifier connected in series with the parallel combination of said first thyristor and said commutation circuit, and a current source and a diode connected in a series string, said series string connected in parallel with said first thyristor.

5. The current interrupter of claim 1 further including a standby circuit for supplying current to said first thyristor while said mechanical switch is closed, wherein said standby circuit includes a rectifier, said rectifier connected in series with the parallel combination of said first thyristor and said commutation circuit, and a current source and a diode connected in a series string, said series string connected in parallel with said first thyristor.

6. The current interrupter of claim 5 wherein said first thyristor comprises a plurality of thyristors connected in parallel.

7. The current interrupter of claim 1 wherein said first thyristor comprises a plurality of thyristors connected in parallel.

8. The current interrupter of claim 1 further comprising a snubber circuit connected in parallel with said first thyristor for limiting the rate of change of voltage (dv/dt) across said first thyristor.

9. The current interrupter of claim 1 wherein said mechanical switch comprises a first switch and a second switch connected in series.

10. The current interrupter of claim 1 wherein said mechanical switch has liquid metal wetted contacts.

11. The current interrupter of claim 1 wherein said mechanical switch is a vacuum switch.

12. An electrical current interrupter for interrupting a high current in a conductor, comprising:

a mechanical switch, connectable in series with the conductor;

a first thyristor connected in parallel with said mechanical switch, said first thyristor for bypassing the high current while said mechanical switch opens;

a commutation circuit connected in parallel with said first thyristor in order to minimize the voltage across contacts of said switch when said current transfers to said first thyristor and said commutation circuit, said commutation circuit for turning off said first thyristor, comprising;

a resonant circuit and a diode, each connected in parallel with said first thyristor,

wherein said resonant circuit includes a capacitor, an inductor, and a second thyristor connected in series, and

wherein said resonant circuit further includes a power source connectable to said capacitor for charging said capacitor;

a standby circuit for supplying current to said first thyristor when said mechanical switch is closed, said standby circuit comprising;

a rectifier, said rectifier connected in series with the parallel combination of said first thyristor and said commutation circuit, and

a current source and a diode connected in a series string, said series string connected in parallel with said first thyristor; and

a snubber circuit, connected in parallel with said first thyristor, for limiting the rate of change of voltage (dv/dt) across said first thyristor.

13. The current interrupter of claim 12 wherein said first thyristor comprises a plurality of thyristors connected in parallel.