US-12626841-B2 - Superconducting power supply system

Abstract

The present disclosure relates to a superconducting power supply system which may comprise: a superconducting cable connected between terminals; a recovery pipe forming a closed loop with the superconducting cable to recover a liquid coolant of the superconducting cable; a pump for providing a circulating pressure of the liquid coolant through the recovery pipe; a refrigerator for maintaining a temperature by cooling the liquid coolant; and a superconducting fault current limiter for maintaining the temperature of a superconducting element immersed in a supercooled liquid coolant by introducing the liquid coolant recovered through the recovery pipe.

Inventors

• Ki Nam RYU
• Min Jee KIM

Assignees

• LS ELECTRIC CO., LTD.

Dates

Publication Date

20260512

Application Date

20220214

Priority Date

20210319

Claims (6)

1. 1 . A superconducting power supply system, comprising: a recovery pipe forming a closed loop with a superconducting cable to recover liquid coolant from the superconducting cable, the superconducting cable being connected between terminals; a pump providing circulating pressure of the liquid coolant being circulated through the recovery pipe; a refrigerator that cools the liquid coolant to maintain its temperature; a superconducting fault current limiter; an inlet pipe configured to connect the superconducting fault current limiter with the recovery pipe at a first part of the superconducting fault current limiter, at least a portion of the liquid coolant being introduced to the superconducting fault current limiter through the inlet pipe; and an outlet pipe configured to connect the superconducting fault current limiter with the recovery pipe at a second part of the superconducting fault current limiter, the liquid coolant introduced to the superconducting fault current limiter being discharged to the recovery pipe, wherein the superconducting fault current limiter comprises: a first container containing a subcooled liquid coolant in which a superconducting element is immersed; and a second container configured to accommodate the introduced liquid coolant and surround the first container such that the introduced liquid coolant is in contact with the subcooled liquid coolant through an outer wall of the first container, wherein at least a portion of the liquid coolant is introduced to an outer wall of the first container and exchanges heat with the subcooled liquid coolant through the outer wall of the first container, wherein a liquid level of the liquid coolant in the second container is higher than that of the subcooled liquid coolant in the first container, and wherein a side area of the first container corresponding to a difference between the liquid level of the liquid coolant and a liquid level of the subcooled liquid coolant is a condensation surface that maintains an internal pressure of the first container by condensing the subcooled liquid coolant when it is vaporized.
2. 2 . The superconducting power supply system of claim 1 , wherein the refrigerator exchanges heat with a part of the recovery pipe at a front end of the superconducting fault current limiter.
3. 3 . The superconducting power supply system of claim 1 , wherein the superconducting cable and the superconducting element are sequentially cooled by the liquid coolant cooled by the refrigerator, the liquid coolant being commonly used for both the superconducting cable and the superconducting element.
4. 4 . The superconducting power supply system of claim 1 , wherein the second container is configured to accommodate the introduced liquid coolant and surround the first container such that the introduced liquid coolant is in contact with an entirety of the subcooled liquid coolant, except for an upper surface, through the outer wall of the first container.
5. 5 . The superconducting power supply system of claim 1 , wherein the second container is configured to accommodate the introduced liquid coolant and surround the first container such that the introduced liquid coolant is in contact with a part of an upper side of the subcooled liquid coolant through the outer wall of the first container.
6. 6 . The superconducting power supply system of claim 1 , wherein a height of the condensation surface is 5 to 30 centimeters (cm).

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a National Stage of International Application No. PCT/KR2022/002151, filed on Feb. 14, 2022, which claims priority to and the benefit of Korean Patent Application No. 10-2021-0035773, filed on Mar. 19, 2021, the disclosure of which is incorporated herein by reference in its entirety. FIELD The present disclosure relates to a high-temperature superconducting power supply system, and more particularly, to a high-temperature superconducting power supply system using a superconducting cable and a fault current limiter. BACKGROUND In general, a superconductor is a material that exhibits zero resistance at a specific temperature and below a specific current, and among them, a material exhibiting superconductivity at 77K or higher, which is the vaporization point of liquid nitrogen used as a coolant, is called a high temperature superconductor (HTS). The advantage of a superconducting power supply system using a superconducting cable is that it can transmit more than 5 times or more current while using a cable that is ⅓ the thickness of a general power cable. Therefore, it is possible to provide a power grid that can meet the increase in power demand. In Korean Laid-Open Patent Publication No. 10-2018-0112593 (SUPERCONDUCTING POWER SYSTEM AND REFRIGERANT WITHDRAWING PIPE, published on Oct. 12, 2018) discloses a configuration in which power is supplied using a superconducting cable, but the superconductivity of the superconducting cable is maintained by circulating a liquid refrigerant. In the above published patent, in order to maintain the temperature of the refrigerant, a recovery pipe in which a multi-layered polymer coating layer having low thermal conductivity is formed on a metal film having high reflectivity is used. In addition, sensors for detecting the temperature, pressure, and vacuum of the refrigerant using monitoring are added, but there is no special countermeasure against the occurrence of fault current, so supplementation is necessary. In particular, when an unexpected accident occurs in the power system and a fault current flows in, there is a disadvantage in that it is impossible to respond with the provided monitoring system. As a different technology, a superconducting fault current limiter has been proposed to respond to fault current in a superconducting power supply system. As an example of a superconducting fault current limiter, there is Korean Laid-Open Patent Publication No. 10-2008-0102157 (MULTI-BATH APPARATUS AND METHOD FOR COOLING SUPERCONDUCTORS, published on Nov. 24, 2008). The above superconducting fault current limiter includes a cooling bath for cooling the superconductor and a shield bath surrounding the cooling bath, and controls the pressure so that the cooling bath is maintained in a subcooled state and the shield bath is maintained in a saturated state. A refrigerator is located on the inner upper part of the shield bath. The refrigerator does not come into contact with the liquid nitrogen in the shield bath, and serves to liquefy the saturated liquid nitrogen again in a phase-changed state to gas. In addition, a cryogenic storage tank is provided separately, and a configuration for supplying liquid nitrogen to the shield bath to compensate for the liquid level of the shield bath is included. The combination of the above published patents may use the same cryogenic storage tank and consider a configuration in which a fault current limiter is applied, but it is not easy to maintain the temperature of the superconducting cable and the temperature of the superconducting fault current limiter through each path in the same cryogenic storage tank. In addition, since the refrigerator should be used for each of the superconducting fault current limiter bodywork and the cryogenic storage tank, problems such as an increase in installation cost and power consumption can be predicted. SUMMARY In consideration of the above problems, the present disclosure is directed to providing a superconducting power supply system that adds a superconducting fault current limiter to a superconducting power supply system using a superconducting cable, minimizes installation and operating costs, and is easy to maintain. More specifically, the present disclosure is directed to providing a superconducting power supply system capable of improving reliability and economy by operating a superconducting fault current limiter without using a refrigerator of the superconducting fault current limiter itself. The present disclosure is also directed to providing a superconducting power supply system capable of maintaining the pressure of a superconducting fault current limiter. A superconducting power supply system according to an aspect of the present disclosure for solving the above technical problems may include a superconducting cable connected between terminals; a recovery pipe forming a closed loop with the superconducting cable to recover liquid c