Superconducting energy storage apparatus

• US 5,532,638 A
• Filed: 09/20/1993
• Issued: 07/02/1996
• Est. Priority Date: 09/21/1992
• Status: Expired due to Term

• Current Assignee: Chubu Electric Power Company Incorporated, Hitachi, Ltd.
• Original Assignee: Chubu Electric Power Company Incorporated, Hitachi, Ltd.
• Inventors: Misawa, Hirokazu, Kubo, Morihiro, Itoh, Takeshi, Ishigaki, Yukio
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): LE, DINH THANH
• Application Number:
  US08/123,477
• Time in Patent Office: 1,016 Days
• Field of Search: 307/245, 307/246, 307/632, 307/633, 307/284, 361/91, 361/100, 361/19, 361/54, 361/55, 327/365, 327/366, 327/419, 327/438, 327/442, 327/443, 327/447, 327/368, 327/376, 327/377, 257/38, 363/37, 363/14
• US Class Current: 327/368
• CPC Class Codes: H01H 9/542 Contacts shunted by static switch means
• CPC Class Codes: H02H 7/001 for superconducting apparatus, e.g. coils, lines, machines
• CPC Class Codes: Y02E 40/60 Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment

Abstract

In a superconducting energy storage apparatus including an AC-DC converter unit, a superconducting coil, a quench protection unit and a mechanical type persistent current switch, a self-firing type thyristor switch is connected in parallel to the mechanical type persistent current switch to be first operated in the event of an occurrence of trouble in an associated electric power system, and a control unit generates an ON instruction signal for turning on the persistent current switch so as to immediately establish a persistent current mode.

Claims

1. A superconducting energy storage apparatus improved in generating a persistent current mode operation in response to a possible fault generated in an electric power system, said apparatus comprising:

an AC-DC converter having a power receiving side connected to an electric power system;

a quench protection unit connected in parallel with said AC-DC converter;

a superconductive coil connected in parallel with said quench protection unit;

a mechanical type persistent current switch connected in parallel with said AC-DC converter;

a self-firing type thyristor switch Connected to be in parallel with said mechanical type persistent current switch and to self-fire in response to a voltage applied thereto due to said fault and which is higher than a predetermined voltage; and

control means for closing said mechanical type persistent current switch in response to the self-firing of said self-firing type thyristor switch, such that a closed circuit is formed consisting essentially of said coil and the mechanical type persistent current switch to enable a persistent current mode operation in the closed loop.

2. An apparatus according to claim 1, further comprising a DC detector for detecting that current flows through the self-firing type thyristor switch, and for providing a detector output signal to the control means as an indication that said detected current is flowing.

3. An apparatus according to claim 1, wherein the control means includes detection means for detecting a self-fired ON state of the self-firing type thyristor switch, and a control unit for turning on the mechanical type persistent current switch in response to an output signal from the detection means indicating the self-fired ON state.

4. A superconducting energy storage apparatus improved in generating a persistent current mode operation in response to a possible fault generated in an electric power system, said apparatus comprising:

an AC-DC converter having a power receiving side connected to an electric power system;

a quench protection unit connected in parallel with said AC-DC converter;

a superconductive coil connected in parallel with said quench protection unit;

a mechanical type persistent current switch connected in parallel with said AC-DC converter;

a self-firing type thyristor switch connected to be in parallel with said mechanical type persistent current switch, and to self-fire in response to a voltage applied thereto due to said fault and which is higher than a predetermined voltage; and

control means for turning on said mechanical type persistent current switch in response to the self-firing of said self-firing type thyristor switch;

wherein the self-firing type thyristor switch and the superconductive coil form a first closed loop when the self-firing type thyristor switch is in the self-fired ON state; and

wherein said control means turns on said mechanical type persistent current switch in response to detection of a current flowing through said self-firing type thyristor switch, thereby forming a second closed loop consisting essentially of the superconductive coil and the mechanical type persistent current switch to enable a persistent current mode operation in the second closed loop.