KR20230082751A - Superconducting current-limiting DC circuit breaker - Google Patents

Abstract

According to an embodiment of the present invention, a superconducting current-limiting DC circuit breaker comprises: a current-limiting unit connected to a power system; and a blocking unit connected to an end of the current-limiting unit. The current-limiting unit includes a superconductor element. When a fault current is applied to the power system, the superconductor element becomes in a normal conduction state to generate superconductor element resistance in the current-limiting unit.

Description

Superconducting current-limiting DC circuit breaker {Superconducting current-limiting DC circuit breaker}

The present invention relates to a DC circuit breaker, and more particularly, to a superconducting current limiting type DC circuit breaker that primarily limits an overcurrent input to the circuit breaker using a superconducting current limiting device.

A supergrid refers to a large-scale power grid connected between countries. It is a technology that mutually shares power resources produced in countries with abundant energy resources with other countries that lack energy resources through the supergrid.

Currently, research on high-voltage direct current transmission for Northeast Asian Super Grid connection is being actively conducted worldwide. Direct current technology is being developed and commercialized centering on high voltage direct current transmission, but recently, low voltage direct current transmission technology development is also being promoted worldwide. As such, as research and development on DC transmission is carried out, blocking technology that can block it in case of a system failure must also be secured.

However, unlike alternating current, direct current does not have a natural zero point due to frequency, so it is difficult to block it when a system failure occurs.

Registered Patent Publication No. 10-1884680 (2018.08.02)

In the prior art, when a system fault occurs due to a fault current such as overcurrent or short-circuit current, the DC circuit breaker cuts off the circuit.

DC circuit breakers do not have a natural zero point by frequency, so a high arc is generated, and if the accident current is not interrupted, secondary accidents such as fire and explosion may occur. In order to prevent this, it is necessary to secure the breaking capacity of the DC circuit breaker, but having a circuit breaker with a high breaking capacity is burdensome in terms of cost.

An object of the present invention is to propose a superconducting current limiting type DC blocking technology that limits fault current and cuts off the limited current.

A superconducting current limiting type DC circuit breaker according to an embodiment of the present invention includes a current limiting unit connected to a power system; and a blocking unit connected to an end of the current limiting unit, wherein the current limiting unit includes a superconducting element, and when a fault current is applied to the power system, the superconducting element is in a normal conduction state, and resistance of the superconducting element is generated in the current limiting unit. that can be characterized.

In addition, the superconducting current-limiting type DC circuit breaker according to an embodiment of the present invention may be characterized in that the superconductor element is coupled to a circular bobbin and configured in a spiral type.

In addition, the superconducting current limiting type DC circuit breaker according to an embodiment of the present invention may be characterized in that the magnitude of the resistance of the superconducting element is calculated by the time required for the superconductor to reach a normal conduction state.

The present invention has an effect of reducing the burden of blocking power of the DC breaker by primarily limiting the fault current input to the DC breaker by coupling the superconducting current limiter to the front end of the DC breaker.

1A is a superconductor element having a spiral type structure according to an embodiment of the present invention.
Figure 1b is a superconductor element of a helical type structure.
2 is a simulation result of magnetic flux density and magnetic field strength of a superconductor element having a spiral type structure according to an embodiment of the present invention.
3 is a simulation result of magnetic flux density and magnetic field strength of a superconductor element having a helical type structure.
4 is a circuit for testing the superconducting DC circuit breaker of the present invention.
5 shows simulation results of DC blocking experiments for each superconductor device structure and for each fault current size.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

While describing each figure, similar reference numerals have been described for similar components. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention.

The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being “connected” or “connected” to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be.

On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, it should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, a superconducting current limiting type DC circuit breaker according to a preferred embodiment of the present invention will be described. In order to clarify the gist of the present invention, descriptions of conventionally known matters are omitted or simplified.

The superconducting current limiting type DC circuit breaker may include a current limiting unit 100 connected to the power system and a blocking unit 200 connected to an end of the current limiting unit 100 .

The current limiting unit 100 includes a superconducting element, and when a fault current is applied to the power system, the superconducting element becomes in a normal conduction state, and resistance of the superconducting element may occur in the current limiting unit 100 .

As shown in FIG. 1A, the superconductor element is combined with a bobbin in the form of a circular frame and can be configured in a spiral type. It can be configured as a spiral type that grows. At this time, the superconducting element may be a material that exhibits superconductivity at an extremely low temperature close to 0K (-273.2 degrees), such as mercury, vanadium, lead, or the like.

The current limiting unit 100 is electrically connected to the front end of the blocking unit 200 to primarily limit the fault current before the fault current is applied to the blocking unit 200 .

Therefore, the interruption unit 200 reduces the fault current burden by reducing the fault current in the current limiting unit 100, thereby securing the stability of the system. In addition, since the fault current limited by the current limiting unit 100 is applied, it may be possible to block fault current higher than the blocking capacity of the blocking unit 200 .

In detail, when a normal current is applied to the circuit due to the characteristics of the superconductor element, current loss does not occur due to the characteristics of 0 resistance, whereas when a fault current is applied to the circuit due to a system failure, the size of the fault current is preset. When the threshold value is exceeded, the superconductor element transitions to a normal conduction state, and impedance is introduced into the power system circuit, resulting in superconducting element resistance in the current limiting unit 100, and the generated superconducting element resistance causes the current limiting unit 100 to have an accident. The size of the current is primarily limited, and the blocking operation speed of the blocking unit 200 may be determined by the size of the limited fault current. The predetermined threshold value may be the minimum value of the magnitude of the fault current that may affect the damage of power devices connected to the power system, and may be set by the user.

Resistance of the superconducting element generated when a fault current is applied to the current limiting unit 100 may be calculated using the following equation.

시간동안

의 전기장을 가해주면 쿠퍼쌍의 운동량

가 증가하는 것을 확인할 수 있다.Equation 1 below represents the characteristics of the superconductor device, using Equation 1

during time

Momentum of a Cooper pair when an electric field of

can be seen to increase.

는 쿠퍼쌍 전자)(here,

is a Cooper pair electron)

의 증가로 에너지

또한 비례하여 증가하는 것을 확인할 수 있다.Therefore, as shown in Equation 2 below, the momentum of the Cooper pair

as an increase in energy

It can also be seen that it increases proportionally.

은 페르미 준위,

은 쿠퍼쌍의 중량)(here,

is the Fermi level,

is the weight of a silver Cooper pair)

In addition, the temperature change due to the critical magnetic field and critical current density of the superconductor element can be confirmed in Equations 3 and 4 below, and through this, the critical magnetic field and current density of the superconductor element change in temperature due to the movement of Cooper pair electrons. influence can be seen.

은 초전도체 임계전류밀도,

은 온도,

은 초전도체 임계자장,

은 초전도체의 두께,

은 초전도체의 길이,

은 쿠퍼쌍의 밀도,

은 진공 투자율)(here,

is the superconductor critical current density,

silver temperature,

Silver superconductor critical magnetic field,

is the thickness of the superconductor,

is the length of the superconductor,

is the density of Cooper pairs,

silver vacuum permeability)

을 표현할 수 있으며, 이는 발열량

와 같이 동일한 단위로 변환되어 수학식 6으로 표현할 수 있다.Work required for magnetization as shown in Equation 5 below using the relationship between magnetic field and current density in Equations 3 and 4

can be expressed, which is the calorific value

It can be converted into the same unit as in Equation 6.

는 자계의 세기,

는 자속밀도,

는 전압,

는 전류,

는 시간)(here,

is the strength of the magnetic field,

is the magnetic flux density,

is the voltage,

is the current,

time)

Through Equations 1 to 6, it can be confirmed that the heat generated also increases as the magnetic flux density and the strength of the magnetic field increase.

는 수학식 7을 이용하여 산출할 수 있다. And the intensity of the average magnetic field generated by the superconducting device

Can be calculated using Equation 7.

Through Equations 1 to 7, the amount of heat generated can be confirmed according to the magnetic flux density and the strength of the magnetic field generated in the superconductor element.

A superconductor element may be converted to a normal conduction state by heat, and when heat generated in the superconductor element increases, the transition to the normal conduction state may occur rapidly. That is, as the strength of the magnetic field increases, the superconductor device quickly reaches a critical value.

In Equation 8 below, the resistance of the superconducting device can be calculated using the time required to reach the threshold value of the superconducting device. The critical value may be the temperature at which the normal conduction state of the superconductor is reached.

은 초전도체의 최대 초전도 소자 저항,

는 초전도체의 상전도 상태의 전이 시정수,

은 초전도체의 초전도 소자 저항,

은 초전도체의 상전도 상태 전이 시간)(here,

The maximum superconducting element resistance of the silver superconductor,

is the transition time constant of the normal conducting state of the superconductor,

Superconducting element resistance of silver superconductor,

is the phase transition time of the superconductor)

Through this, it can be seen that the resistance of the superconducting element increases as the transition time of the superconducting element to the normal conduction state becomes shorter. Fast blocking characteristics of the blocking unit 200 can be secured.

In addition, inductance is introduced into the power system circuit by the structure of the spiral-type superconductor element of the current limiting unit 100, and the blocking operation time of the blocking unit 200 may be determined by the input inductance.

The inductance applied to the power system circuit can be calculated by Equations 9 and 10.

은 인덕턴스,

은 초전도체 소자의 권선 횟수,

는 권선한 초전도체 소자의 면적,

은 초전도체 소자의 최내각 지름,

는 초전도체 소자의 각각의 두께,

는 초전도체 소자 사이 간격)(here,

is the inductance,

is the number of turns of the superconducting element,

is the area of the wound superconductor element,

is the diameter of the innermost angle of the superconducting element,

is the thickness of each of the superconducting elements,

is the spacing between the superconducting elements)

According to the present invention, it is possible to compare the blocking operation time of the blocking unit 200 by the current limiting unit 100 to which the helical-type superconductor element is applied corresponding to the structure of the superconductor element of the present invention.

The inductance applied to the power system circuit by the helical-type superconductor element of FIG. 1B can be calculated using Equation 11 below.

는 초전도체 소자의 지름,

는 권선한 초전도체 소자의 높이)(here,

is the diameter of the superconducting element,

is the height of the wound superconductor element)

Under similar conditions, the inductance input to the power system circuit by the superconductor element of the spiral type structure and the superconductor element of the helical type structure can be calculated as shown in Table 1.

superconductor type helical spiral length [mm] 3002.08 2963.68 number of turns [turn] 3.8 4 inductance yield 0.005 0.007 Measures 0.005 0.007 innermost diameter [mm] - 200 outer diameter [mm] 250 Spacing [mm] 8 thickness [mm] One width [mm] 10

At this time, it can be seen that the magnitude of the inductance introduced into the power system circuit by the superconductor element having the spiral type structure is greater than the magnitude of the inductance introduced into the power system circuit by the superconductor element having the helical type structure.

The magnitude of the magnetic field generated in the superconductor element according to the magnitude of the fault current applied to the current limiting unit 100 may be measured by applying Equations 1 to 11.

In order to analyze the characteristics of the electromagnetic field generated in the current limiting unit 100 by the superconductor element in the current limiting unit 100, the magnetic flux density and magnetic field generated by increasing the fault current to 460 A, 580 A, and 700 A by 120 A are A simulation was performed to measure the intensity.

[A/m]의 값이 측정되는 것을 확인할 수 있다. As shown in FIG. 2, in the current limiting unit 100, the average magnetic flux density generated by the superconductor element of the spiral type structure is 0.8517 T, and the average magnetic field strength is 67.7778

It can be seen that the value of [A/m] is measured.

[A/m]이 측정된 것을 확인할 수 있다.On the other hand, FIG. 3 shows the measured values of the magnetic flux density and magnetic field strength calculated by applying the helical-type superconductor element to the current limiting unit 100, with an average magnetic flux density of 0.8206 T and an average magnetic field strength of 65.3024

It can be confirmed that [A/m] is measured.

[A/m]만큼 큰 것을 확인 할 수 있다.Therefore, the magnetic flux density and magnetic field strength calculated by the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention and the magnetic flux density and magnetic field strength calculated by the current limiting unit 100 to which the superconductor element of the helical type structure is applied Comparing, the magnetic flux density calculated by the current limiting unit 100 including the superconductor element of the spiral type structure is about 0.0311 T and the magnetic field strength is about 2.4754

It can be confirmed that it is as large as [A/m].

That is, the amount of heat generated in the current limiting unit 100 including the superconductor element of the spiral type structure may be greater than the amount of heat generated in the current limiting unit 100 to which the intensity and the superconductor element of the helical type structure are applied.

Referring to the simulation results of FIGS. 2 and 3 , the phase conduction state transition phenomenon of the superconductor device partially occurs, and as the magnetic field passes, the intensity of the magnetic field at an arbitrary point may be high.

As the strength of the magnetic field increases, the superconductor device quickly reaches a critical value, whereby the phase transition of the superconductor device is quickly performed, and thus the resistance of the superconductor device can be rapidly increased. In addition, the current limiting unit 100 may limit the fault current applied to the power system circuit by inputting the superconducting element resistance to the power system circuit. At this time, the fault current limiting rate of the current limiting unit 100 can be measured using the circuit of FIG. 4 , and the blocking characteristics of the blocking unit 200 can also be measured using this. At this time, the blocking characteristic of the blocking unit 200 can be measured when the blocking operation of the blocking unit 200 is completed due to the phase conduction state transition characteristics of the superconductor element at the operating time of the blocking unit 200 .

In order to check the blocking characteristics of the blocking unit 200, the operating time of the circuit breaker of the blocking unit 200 and the completion time of the blocking operation can be measured using the conditions of Table 2.

Superconducting element length [m] Superconducting element type number of power Voltage level [V] fault current [A] steady current [A]

3
Spiral type and helical type 50 627 637 26.79 44 550 571 23.50 38 477 525 20.38 32 400 469 17.09

이 삽입될 수 있다.도 4의 DC 전원에 627 V, 550 V, 477 V, 400 V 전압을 인가하여 한류부(100)의 임피던스 증가량, 고장전류 제한률 및 차단부(200)의 차단기의 동작시점, 차단 완료시점을 측정할 수 있다.R1 in FIG. 4 is an arbitrary resistance value to which normal current can be applied, R2 is a resistance value to which fault current is applied, and has a minimum resistance of 1 to measure the fault current limiting rate for the fault current of the current limiting unit 100.

4 may be inserted. Voltages of 627 V, 550 V, 477 V, and 400 V are applied to the DC power supply of FIG. It is possible to measure the point of time and the point of completion of blocking.

이며, 고장전류 제한률은 9.64 %일 수 있다. 반면, 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)는 임피던스 증가량은 0.11

이며 고장전류 제한률은 9.19 %일 수 있다. 이를 통하여 본 발명의 스파이럴 타입 구조의 초전도체 소자를 포함한 한류부(100)는 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)에 비해 임피던스 증가량은 약 0.02

, 사고 전류 제한률은 0.43% 높은 것을 확인할 수 있다. As shown in FIG. 5A, when the fault current is 627 V, the impedance increase amount of the current limiting unit 100 is 0.13

, and the fault current limiting rate may be 9.64%. On the other hand, the current limiting unit 100 to which the superconductor element of the helical type structure is applied has an impedance increase of 0.11

and the fault current limiting rate may be 9.19%. Through this, the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention has an impedance increase of about 0.02 compared to the current limiting unit 100 to which the superconductor element of the helical type structure is applied.

, it can be confirmed that the fault current limiting rate is 0.43% higher.

In addition, according to the impedance increase amount and the fault current limiting rate of the current limiting unit 100 of the present invention, the operation time of the circuit breaker of the blocking unit 200 is the blocking unit connected to the end of the current limiting unit 100 to which the superconductor element of the helical type structure is applied. The operation was performed about 0.15 ms faster than the operating point of the circuit breaker in (200), and it can be confirmed that the blocking completion point was shortened by 0.53 ms.

이며, 고장전류 제한률은 7.55 %일 수 있다. 반면, 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)는 임피던스 증가량은 0.07

이며 고장전류 제한률은 6.83 %일 수 있다. 이를 통하여 본 발명의 스파이럴 타입 구조의 초전도체 소자를 포함한 한류부(100)는 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)에 비해 임피던스 증가량은 약 0.02

, 사고 전류 제한률은 약 0.72 % 높은 것을 확인할 수 있다. As shown in FIG. 5B, at 550 V, the current limiting unit 100 increases the impedance by 0.09

, and the fault current limiting rate may be 7.55%. On the other hand, the current limiting unit 100 to which the superconductor element of the helical type structure is applied has an impedance increase of 0.07

and the fault current limiting rate may be 6.83%. Through this, the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention has an impedance increase of about 0.02 compared to the current limiting unit 100 to which the superconductor element of the helical type structure is applied.

, it can be seen that the fault current limiting rate is about 0.72% higher.

In addition, according to the impedance increase amount and the fault current limiting rate of the current limiting unit 100 of the present invention, the operation time of the circuit breaker of the blocking unit 200 is the blocking unit connected to the end of the current limiting unit 100 to which the superconductor element of the helical type structure is applied. The operation was performed about 0.03 ms faster than the operating point of the circuit breaker in (200), and it can be confirmed that the blocking completion point was shortened by 0.14 ms.

이며, 고장전류 제한률은 4.37 %일 수 있다. 반면, 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)는 임피던스 증가량은 0.03

이며 고장전류 제한률은 5.22 %일 수 있다. 이를 통하여 본 발명의 스파이럴 타입 구조의 초전도체 소자를 포함한 한류부(100)는 헬리컬 타입 구조의 초전도체 소자를 적용한 한류부(100)에 비해 임피던스 증가량은 약 0.02

, 사고 전류 제한률은 약 0.85 % 높은 것을 확인할 수 있다. As shown in FIG. 5C, at 477 V, the current limiting unit 100 increases the impedance by 0.05

, and the fault current limiting rate may be 4.37%. On the other hand, the current limiting unit 100 to which the superconductor element of the helical type structure is applied has an impedance increase of 0.03

and the fault current limiting rate may be 5.22%. Through this, the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention has an impedance increase of about 0.02 compared to the current limiting unit 100 to which the superconductor element of the helical type structure is applied.

, it can be seen that the fault current limiting rate is about 0.85% higher.

In addition, according to the impedance increase amount and the fault current limiting rate of the current limiting unit 100 of the present invention, the operation time of the circuit breaker of the blocking unit 200 is the blocking unit connected to the end of the current limiting unit 100 to which the superconductor element of the helical type structure is applied. The operation was performed about 0.33 ms faster than the operation point of the circuit breaker of (200), and the blocking characteristics were confirmed 0.58 ms faster at the time of blocking completion.

, 사고 전류 제한률은 약 0.04 % 높은 것을 확인할 수 있다. As shown in FIG. 5D, at 400 V, the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention has an impedance increase of about 0.01 compared to the current limiting unit 100 to which the superconductor element of the helical type structure is applied.

, it can be seen that the fault current limiting rate is about 0.04% higher.

In addition, by the current limiting unit 100 of the present invention, the operation time of the circuit breaker of the blocking unit 200 is 10.82 ms and the blocking completion time is 13.13 ms. The operation was performed about 0.16 ms faster than the operating point of the circuit breaker of the connected blocking unit 200, and in the case of the blocking completion point, it can be confirmed that the blocking characteristic is 0.56 ms faster.

Tables 3 and 4 show the simulation results of FIGS. 5A to 5D as tables. Looking at Tables 3 and 4, the current limiting unit 100 of the present invention applies a superconductor element of a helical type structure to each voltage. As the impedance increase is higher than that of the unit 100 by an average of 0.02 Ω, it can be seen that the power of the superconductor material also bears 0.85 kW to 5.18 kW higher power than the current limiting unit 100 to which the superconductor element of the helical type structure is applied.

3[m] Spiral type Voltage [V] 627 550 477 400 maximum fault current [A] 624.91 571.70 516.05 454.43 Fault current limit [A] 564.63 528.50 493.45 442.04 Impedance of superconducting element [Ω] 0.13 0.09 0.05 0.03 Breaker operating time [ms] 8.40 9.05 9.78 10.82 Circuit breaker operation completion time [ms] 11.30 11.48 11.96 13.13 The amount of power burden of the peak power of the cut-off unit 200 [kW] 57.70 45.82 33.98 28.08 The amount of power burden of the peak power of the current limiting unit 100 [kW] 38.51 24.94 12.44 5.02

3[m] helical type Voltage [V] 627 550 477 400 maximum fault current [A] 615.23 563.29 488.89 449.68 Fault current limit [A] 558.68 524.77 471.67 437.59 Impedance of superconducting element [Ω] 0.11 0.07 0.03 0.02 Breaker operation time [ms] 8.55 9.08 10.11 10.98 Circuit breaker operation completion time [ms] 11.83 11.62 12.54 13.69 The amount of power burden of the peak power of the cut-off unit 200 [kW] 61.20 46.03 35.28 28.66 The amount of power burden of the peak power of the current limiting unit 100 [kW] 33.33 20.29 7.32 4.17

That is, since the current limiting unit 100 including the superconductor element of the spiral type structure of the present invention has a higher impedance increase than the current limiting unit 100 to which the superconductor element of the helical type structure is applied, the fault current limiting rate of the current limiting unit 100 is 0.02% ~ 0.85% high, and the operating point of the circuit breaker of the blocking unit 200 connected to the end of the current limiting unit 100 is the breaker of the blocking unit 200 connected to the end of the current limiting unit 100 to which the superconductor element of the helical type structure is applied. The blocking operation was performed 0.03 ms ~ 0.33 ms faster than the operating time.

In addition, in the case of the blocking operation completion characteristic of the circuit breaker of the circuit breaker 200 connected to the end of the current-limiting unit 100, it is blocked in 0.14 ms to 0.58 ms, and thus the blocking unit connected to the end of the current-limiting unit 100 to which the superconductor element of the helical type structure is applied It was confirmed that the fault current blocking time of (200) was shortened by 0.14 ms to 0.58 ms.

Accordingly, in the present invention, the blocking unit 200 can secure blocking characteristics of quickly blocking the fault current in response to the fault current.

Therefore, according to the present invention, by connecting the blocking unit 200 to the end of the current limiting unit 100 including the superconducting element having a spiral type structure, the normal conduction state transition speed of the superconducting element can be shortened, thereby reducing the blocking speed. Since the current limiting rate and the operation time of the circuit breaker can be increased, the blocking performance of the DC circuit breaker can be increased with the same length of the superconductor element.

100: Hallyu department
200: blocking part

Claims (3)

Current limiting unit connected to the power system; and
A blocking part connected to an end of the current limiting part,
The current limiting unit includes a superconducting element, and when a fault current is applied to the power system, the superconducting element is in a normal conduction state and superconducting element resistance is generated in the current limiting unit Superconducting current limiting type DC circuit breaker. According to claim 1,
The superconducting current limiting type DC circuit breaker, characterized in that the superconductor element is combined with a bobbin in the form of a circular frame and configured in a spiral type. According to claim 1,
The superconducting current limiting type DC circuit breaker, characterized in that the magnitude of the resistance of the superconducting element is calculated by the time required to reach the normal conduction state of the superconductor.

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