Quenching recovery cooling system for superconducting current limiter

Abstract

The utility model relates to a resistance type superconducting current limiter, in particular to a quench recovery cooling system for a superconducting current limiter. The service life of power equipment can be effectively prolonged, and the maintenance cost is reduced. In the current limiting process of the resistance type superconducting current limiter, the problem that the service life is shortened or even damaged due to the fact that power equipment in a system is impacted by fault current is solved. Comprising a superconductive current limiter and a supercooled liquid nitrogen circulating system, and the superconducting current limiter is arranged in the low-temperature container. The supercooled liquid nitrogen circulating system comprises a first Dewar tank and a second Dewar tank; wherein the first Dewar tank is provided with a pressurizing device for pressurizing liquid nitrogen in the first Dewar tank and a refrigerating machine for refrigerating in the first Dewar tank. The first Dewar tank is connected with the second Dewar tank through a second liquid nitrogen communicating pipe, and a second control valve is arranged on the second liquid nitrogen communicating pipe.

Description

Technical Field

[0001] The utility model relates to a resistance-type superconducting current limiter, in particular to a quench recovery cooling system for a superconducting current limiter. Background Art

[0002] A superconducting current limiter is an electrical device with excellent current limiting characteristics. It can play a role in current limiting in a circuit, thereby protecting the circuit and equipment from the impact of overload and short-circuit current. The working principle of the superconducting current limiter is based on the characteristics of superconductors, that is, in a superconducting state, current can flow unimpeded through the superconductor, while in a non-superconducting state, the resistance of the superconductor will increase sharply, limiting the flow of current. When a fault current appears in the circuit, the superconducting current limiter can respond quickly and limit the current to a lower level. However, after the resistance-type superconducting current limiter quenches, the surface temperature of the superconducting tape is too high, so that the time it takes to restore the superconducting state is a few seconds, or even longer, which cannot meet the system reclosing requirements. The utility model proposes a superconducting tape quenching rapid recovery and a control system thereof, which can realize the rapid recovery of the superconducting tape to a superconducting state through heat conduction and heat convection, so as to meet the system reclosing requirements and promote the development of the resistance-type superconducting current limiter. Summary of the invention

[0003] The utility model aims at the defects in the prior art and provides a superconducting current limiter quench recovery cooling system.

[0004] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme, including a superconducting current limiter and a supercooled liquid nitrogen circulation system; the superconducting current limiter is placed in a low-temperature container.

[0005] The supercooled liquid nitrogen circulation system comprises a first dewar tank and a second dewar tank; wherein the first dewar tank is provided with a pressurizing device for pressurizing the liquid nitrogen in the tank and a refrigerator for refrigerating the tank.

[0006] The first Dewar tank is connected to the second Dewar tank through a second liquid nitrogen conducting pipe, and a second control valve is arranged on the second liquid nitrogen conducting pipe.

[0007] The second Dewar tank is connected to the low-temperature container through a third liquid nitrogen conducting pipe, and a third control valve is arranged on the second Dewar tank.

[0008] Furthermore, the first Dewar tank is connected to the supercooled liquid nitrogen spraying device through a first liquid nitrogen conducting pipe, and a first control valve is provided on the first liquid nitrogen conducting pipe.

[0009] Furthermore, the superconducting current limiter quench recovery cooling system also includes a control system, which includes a controller and a voltage probe, and the controller is communicatively connected with the voltage probe, the first control valve, the second control valve, and the third control valve respectively.

[0010] Furthermore, the supercooled liquid nitrogen spray device adopts an annular structure, at least 20 holes are provided at the bottom of the annular structure, and the annular structure is made of G10 material. The annular structure is located above the superconducting current limiter; the holes are located above the superconducting current limiter.

[0011] Specifically, the cold liquid nitrogen spray device is connected to the first dewar tank, and the first dewar tank is made to have a higher internal air pressure than the cold liquid nitrogen spray device through a pressurizing device. The hole of the cold liquid nitrogen spray device is directly opposite to the superconducting current limiter. When the superconducting current limiter loses superconductivity, the first control valve is opened, so that the liquid nitrogen in the first dewar tank is sprayed onto the surface of the superconducting current limiter through the cold liquid nitrogen spray device under the action of high air pressure, thereby removing bubbles on the surface of the superconducting current limiter and cooling the superconducting current limiter at the same time. According to Bernoulli's principle, in a fluid, the flow rate is inversely proportional to the pressure, that is, the greater the flow rate, the smaller the pressure; the smaller the flow rate, the greater the pressure. Therefore, after the supercooled liquid nitrogen spray device is set, the speed of the liquid nitrogen flow will increase when it passes through.

[0012] Furthermore, voltage probes are installed at the left and right ends of the superconducting current limiter to detect the voltage at both ends of the superconducting current limiter to monitor whether the superconducting current limiter is quenched.

[0013] Furthermore, the superconducting current limiter is connected to the load through a circuit breaker.

[0014] Compared with the prior art, the utility model has beneficial effects.

[0015] The utility model can effectively increase the service life of power equipment and reduce maintenance costs. In the current limiting process, the resistance-type superconducting current limiter avoids the problem that the power equipment in the system is impacted by the fault current and thus suffers a reduction in service life or even damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the utility model is not limited to the following descriptions.

[0017] Figure 1 Schematic diagram of the superconducting current limiter quench recovery cooling system.

[0018] Figure 2 This is a top view of the supercooled liquid nitrogen spray device. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and beneficial effects of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments.

[0020] like Figure 1-2As shown, the specific embodiment includes a superconducting current limiter 05 and a supercooled liquid nitrogen circulation system; the superconducting current limiter 05 is placed in a low temperature container 06. The supercooled liquid nitrogen circulation system includes a first dewar tank 22 and a second dewar tank 09; wherein the first dewar tank 22 is equipped with a pressurizing device 21 for pressurizing the liquid nitrogen in the tank and a refrigerator 08 for refrigerating the tank. And the first dewar tank 22 is filled with liquid nitrogen.

[0021] Specifically, the refrigerator 08 refrigerates the liquid nitrogen in the first dewar tank 22 ; the pressurizing device 21 pressurizes the liquid nitrogen in the first dewar tank 22 , so that the pressure in the first dewar tank 22 is higher than the pressure in the cryogenic container 06 .

[0022] The first Dewar tank 22 is connected to the second Dewar tank 09 through a second liquid nitrogen conducting pipe 19 , and a second control valve 23 is provided on the second liquid nitrogen conducting pipe 19 .

[0023] The second Dewar tank 09 is connected to the cryogenic container 06 via a third liquid nitrogen conduit 24 , and a third control valve 07 is provided on the second Dewar tank 09 .

[0024] Preferably, the first Dewar tank 22 is connected to the supercooled liquid nitrogen spraying device 20 through a first liquid nitrogen conducting pipe 13 , and a first control valve 04 is provided on the first liquid nitrogen conducting pipe 13 .

[0025] Preferably, the superconducting current limiter quench recovery cooling system also includes a control system, which includes a controller 01 and a voltage probe 02, and the controller 01 is communicatively connected with the voltage probe 02, the first control valve 04, the second control valve 23, and the third control valve 07 respectively.

[0026] Specifically, the control system can automatically adjust the state of the control valve according to the signal of the voltage probe 02 to control the flow and pressure of the liquid nitrogen and achieve rapid recovery of the superconducting tape after quenching.

[0027] Preferably, the supercooled liquid nitrogen spraying device 20 adopts an annular structure, at least 20 holes are provided at the bottom of the annular structure, and the annular structure is made of G10 material. The annular structure is located above the superconducting current limiter 05; the holes are located above the superconducting current limiter 05.

[0028] Preferably, the voltage probes 02 are installed at the left and right ends of the superconducting current limiter 05 to detect the voltage at both ends of the superconducting current limiter 05 so as to monitor whether the superconducting current limiter 05 is quenched.

[0029] Preferably, the superconducting current limiter 05 is connected to the load 18 via the circuit breaker 03 .

[0030] Embodiment 1: A superconducting current limiter quench recovery cooling system includes a superconducting current limiter, a supercooled liquid nitrogen circulation system and a control system thereof. The superconducting current limiter is composed of a cryogenic container 06 and a superconducting current limiter 05. The supercooled liquid nitrogen circulation system is composed of a first dewar tank 22 and a second dewar tank 09. The first dewar tank 22 is provided with a pressurizing device 21 and a refrigerator 08. The first dewar tank 22 is connected in series with a first liquid nitrogen conducting pipe 13 and a supercooled liquid nitrogen spraying device 20. The first liquid nitrogen conducting pipe 13 is provided with a first control valve 04, the first dewar tank 22 and the second dewar tank 09 are connected through the second liquid nitrogen conducting pipe 19, the second liquid nitrogen conducting pipe 19 is provided with a second control valve 23, the second dewar tank 09 is equipped with a pressurizing pump 25, the low temperature container 06 is connected with the second dewar tank 09 through the third liquid nitrogen conducting pipe 24, the third liquid nitrogen conducting pipe 24 is provided with a third control valve 07, and the control system is connected by the controller 01 with the voltage probe 02, the first control valve 04, the second control valve 23 and the third control valve 07 respectively. The cooling liquid nitrogen in the first dewar tank is pressurized into the superconducting current limiter so that the superconducting current limiter can quickly resume work.

[0031] Specifically, the power supply is connected to the superconducting current limiter 05 through the seventh connecting line 12, the supercooled liquid nitrogen circulation system is composed of a first dewar tank 22 and a second dewar tank 09, the pressurizing device 21 and the refrigerator 08 are connected to the first dewar tank 22 through a low-temperature liquid nitrogen vacuum pipeline, wherein the first dewar tank 22 is connected in series with the first liquid nitrogen conducting pipe 13 and the supercooled liquid nitrogen spraying device 20, the first liquid nitrogen conducting pipe 13 is equipped with a first control valve 04, and the first dewar tank 22 and the second dewar tank 09 are connected through a second liquid nitrogen conducting pipe 19 The second liquid nitrogen conducting pipe 19 is provided with a second control valve 23, the second Dewar tank 09 is equipped with a pressure pump 25, the low temperature container 06 is connected with the second Dewar tank 09 through a third liquid nitrogen conducting pipe 24, and the third liquid nitrogen conducting pipe 24 is provided with a third control valve 07. The control system is connected by the controller 01 with the voltage probe 02, the first control valve 04, the second control valve 23 and the third control valve 07 respectively, and the superconducting current limiter 05 is connected with the load 18 through the eighth connecting line 16, and the circuit breaker 03 is connected with the load 18.

[0032] The refrigerator 08 and the pressurizing device 21 always provide a high-pressure and low-temperature environment for the first dewar tank 22 .

[0033] When the system voltage is restored, the controller 01 controls the booster pump 25 through the sixth control signal line 11 to transfer the liquid nitrogen in the second Dewar tank 09 to the first Dewar tank 22 through the second liquid nitrogen conducting pipe 19 .

[0034] The controller 01 controls the first control valve 04 to allow the high-pressure, supercooled liquid nitrogen in the first dewar tank 22 to enter the low-temperature container 06 through the first liquid nitrogen conduit 13, and generates high-speed, high-pressure supercooled liquid nitrogen to the superconducting current limiter 05 through the liquid nitrogen supercooling liquid nitrogen spray device 20, so that the heat of the superconducting current limiter 05 is quickly dissipated through heat convection and heat conduction, and the superconducting current limiter 05 is quickly restored to a superconducting state.

[0035] When the voltage probe 02 detects that the voltage across the superconducting current limiter 05 changes, the controller 01 controls the high-pressure, supercooled liquid nitrogen in the first dewar tank 22 to enter the cryogenic container 06 through the first liquid nitrogen conducting pipe 13, and at the same time the third control valve 07 is opened to transfer the excess liquid nitrogen in the cryogenic container 06 to the second dewar tank 09 through the third liquid nitrogen conducting pipe 24.

[0036] When the system voltage is restored, the controller 01 controls the booster pump 25 through the sixth control signal line 11 to transfer the liquid nitrogen in the second Dewar tank to the first Dewar tank 22 through the second liquid nitrogen conducting pipe 19 .

[0037] Cryogenic container 06 superconducting current limiter 05 first dewar tank 22 pressurizing device 21 refrigerator 08 first liquid nitrogen conducting pipe 13 first control valve 04 second dewar tank 09 second liquid nitrogen conducting pipe 19 second control valve 23 pressurizing pump 25 third liquid nitrogen conduit 24 third control valve 07 controller 01 pressure detection device 02 supercooled liquid nitrogen spraying device 20 first connecting line 14, second connecting line 15 third connecting line 26 fourth connecting line 10, fifth connecting line 17 sixth control signal line 11 circuit breaker 03 seventh connecting line 12 eighth connecting line 16 load 18.

[0038] The working principle is as follows: when a short circuit fault occurs in the system, the superconducting current limiter 05 quickly quenches and switches to a resistance state, and the fault current is limited to a low level, and then the circuit breaker 03 cuts off the fault current. The voltage probe 02 monitors the change in the voltage at both ends of the superconducting current limiter 05, and sends an action command to the controller 01 through the first connecting line 14 and the second connecting line 15. The controller 01 controls the first control valve 04 and the third control valve 07 to open. The high-pressure, supercooled liquid nitrogen in the first dewar tank 22 enters the low-temperature container 06 through the first liquid nitrogen conducting pipe 13, and the liquid nitrogen supercooled liquid nitrogen spray device 20 generates high-speed, high-pressure supercooled liquid nitrogen to the superconducting current limiter 05. Through heat convection and heat conduction, the heat of the superconducting current limiter 05 is quickly dissipated and quickly restored to a superconducting state. The high-speed, high-pressure supercooled liquid nitrogen generated by the supercooled liquid nitrogen spray device 20 can also reduce the bubbles generated by the superconducting current limiter 05 due to quenching, and improve the insulation capacity of the superconducting current limiter 05. At the same time, the excess liquid nitrogen in the superconducting current limiter 05 is transferred to the second dewar tank 09 through the third liquid nitrogen conducting pipe 24. When the system fault is removed and the superconducting current limiter 05 is restored to the superconducting state, the liquid nitrogen in the second dewar tank 09 is transferred to the first dewar tank 22 through the booster pump 25.

[0039] Embodiment 2: The supercooled liquid nitrogen spray device 20 is connected in series with the first liquid nitrogen conducting pipe 13 and is arranged above the superconducting current limiting element 05 to flush the bubbles on the surface of the superconducting current limiting element 05.

[0040] When a short circuit fault occurs in the system, the superconducting current limiter 05 quickly quenches and switches to a resistance state. After limiting the fault current to a lower level, the circuit breaker 03 cuts off the fault current. The voltage probe 02 monitors the change in the voltage across the superconducting current limiter 05, and sends an action command to the controller 01 through the first connecting line 14 and the second connecting line 15. After receiving the action command, the controller 01 opens through 07. The high-pressure, supercooled liquid nitrogen in the first dewar tank 22 enters the low-temperature container 06 through the first liquid nitrogen conducting pipe 13, and the liquid nitrogen supercooled liquid nitrogen spray device 20 generates high-speed, high-pressure supercooled liquid nitrogen to the superconducting current limiter 05. Through heat convection and heat conduction, the heat of the superconducting current limiter 05 is quickly dissipated and quickly restored to a superconducting state. The high-speed, high-pressure supercooled liquid nitrogen generated by the supercooled liquid nitrogen spray device 20 can also reduce the bubbles generated by the superconducting current limiter 05 due to quenching, and improve the insulation capacity of the superconducting current limiter 05. At the same time, the excess liquid nitrogen in the superconducting current limiter 05 is transferred to the second dewar tank 09 through the third liquid nitrogen conducting pipe 24. When the system fault is removed and the superconducting current limiter 05 is restored to the superconducting state, the liquid nitrogen in the second dewar tank 09 is transferred to the first dewar tank 22 through the booster pump 25, so as to realize the rapid recovery of the superconducting current limiter.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. Therefore, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope defined by the claims of the present invention.

Claims

1. A superconducting current limiter quench recovery cooling system, comprising a superconducting current limiter (05) and a supercooled liquid nitrogen circulation system; characterized in that: The superconducting current limiter (05) is placed in a low temperature container (06); The supercooled liquid nitrogen circulation system comprises a first dewar tank (22) and a second dewar tank (09); wherein the first dewar tank (22) is provided with a pressurizing device (21) for pressurizing the liquid nitrogen in the tank and a refrigerator (08) for refrigerating the tank; and the first dewar tank (22) is filled with liquid nitrogen; The first Dewar tank (22) is connected to the second Dewar tank (09) via a second liquid nitrogen conducting pipe (19), and a second control valve (23) is provided on the second liquid nitrogen conducting pipe (19); The second Dewar tank (09) is connected to the low-temperature container (06) via a third liquid nitrogen conducting pipe (24), and a third control valve (07) is provided on the second Dewar tank (09).

2. A superconducting current limiter quench recovery cooling system according to claim 1, characterized in that: The first Dewar tank (22) is connected to the supercooled liquid nitrogen spraying device (20) via a first liquid nitrogen conducting pipe (13), and a first control valve (04) is provided on the first liquid nitrogen conducting pipe (13).

3. A superconducting current limiter quench recovery cooling system according to claim 2, characterized in that: The superconducting current limiter quench recovery cooling system also includes a control system, which includes a controller (01) and a voltage probe (02). The controller (01) is respectively connected in communication with the voltage probe (02), the first control valve (04), the second control valve (23), and the third control valve (07).

4. A superconducting current limiter quench recovery cooling system according to claim 2, characterized in that: The supercooled liquid nitrogen spraying device (20) adopts an annular structure, at least 20 holes are arranged at the bottom of the annular structure, and the annular structure is made of G10 material. The annular structure is located above the superconducting current limiter (05); and the holes are located above the superconducting current limiter (05).

5. A superconducting current limiter quench recovery cooling system according to claim 3, characterized in that: The voltage probes (02) are installed at the left and right ends of the superconducting current limiter (05) and are used to detect the voltage at both ends of the superconducting current limiter (05) so as to monitor whether the superconducting current limiter (05) is quenched.

6. A superconducting current limiter quench recovery cooling system according to claim 1, characterized in that: The superconducting current limiter (05) is connected to the load (18) via the circuit breaker (03).

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