KR20110122368A - The bus-connection system using the cicc superconduction magnet for protecting power system from fault current when connecting bus of the substation - Google Patents

Abstract

PURPOSE: A bus-connection system using the cicc supper-conduction magnet for protecting power system from fault current when connecting bus of the substation are provided to secure a malfunction in advance by forming a test switch. CONSTITUTION: In a bus-connection system using the cicc supper-conduction magnet for protecting power system from fault current when connecting bus of the substation, double bus(Bus2,Bus4) are conned to the buses of generators. A circuit breaker is arranged between the double bus. An CICC has a supper-conduction wire surrounded by a square metal pipe to limit a fault current. A CICC supper-conduction coils is manufactured by the circuit breaker and the CICC(Cable In Conduit Conductor) Superconductive magnets forming CICC supper-conduction coils are connected to each other.

Description

The bus-connection system using the CICC superconduction magnet for protecting power system from fault current when connecting bus of the substation}

The present invention uses a cable-in conduit-conductor (CICC) superconducting magnet having almost no electrical resistance for a double bus of a substation, thereby suppressing fault currents generated during an accident such as a lightning strike, ground fault, or short circuit. It relates to a busbar connection system that protects the safety of the connected equipment or people.

In more detail, if a short circuit occurs when the double buses of the same substation connected to different power plants are connected to each other, a fault current may be generated within a few milliseconds through the inductance of the coil of the superconducting magnet before the protection circuit breaker of the substation is operated. By restricting, it is possible to prevent the increase of equipment and cost due to the replacement of a high-capacity circuit breaker, to reduce the line extension, and to relax the power equipment standard, thereby significantly improving the power system flexibility, stability, and reliability.

If a power line breaks down in the power system, a fault current, which is a very large current, is generated. Fault currents are dozens of times the normal current (approximately 1000-3000 amps on transmission lines). Failure to handle this fault current can result in power outages and sometimes damage to power generation equipment.

The fault current phenomenon in KEPCO's transmission and distribution system is not a problem today. In order to solve this problem, a circuit breaker replacement, a bus disconnection, and a back-to-back method of temporarily changing AC to DC are also considered. These are issues that involve enormous economic problems.

The power system of Korea has a problem that the fault current increases in case of short circuit due to the continuous expansion of facilities due to the increase of demand instead of the short transmission line. For this reason, KEPCO is installing breakers in preparation for the overcurrent generated in the event of an accident such as a short circuit.

Accordingly, it may be considered to increase the capacity of the existing circuit breaker or to replace it with a new product, but this has a problem in that the technical or economical burden is considerable.

As another alternative, the bus separation method is applied to the 154kV system, but even this causes side effects such as overload of neighboring system, deepening of voltage fluctuations, and deterioration of power system stability, and partial separation of the 345kV system. However, the situation is installing the air reactor.

More specifically, in Korea, the main power system of KEPCO is strongly networked as a 345kV line. Here, a 154kV transmission line is being installed to connect customers. This system has short lines and increased fault currents due to continuous facility expansion. In order to reduce fault currents, 154kV separates buses from multiple substations and adopts radial operation.

This is an option for suppressing fault currents, but at the expense of system flexibility and supply reliability.

In addition, recently, a technique of applying a superconducting fault current limiter to a power system has been proposed. However, since a superconducting magnet used in a general superconducting current limiter is wound through a superconducting cable directly to a structure and manufactured through an insulation process , a structural support side according to a large current is applied. In the case of very unstable, accordingly, the possibility of quenching , which is a phase conduction transition phenomenon of the superconducting magnet, is very high, and as a result, the performance of the superconducting magnet gradually decreases as the quenching increases .

Also, commonly used Vacuum epoxy Impregnation method  The structural support of the superconducting cable by means of limiting contact with the refrigerant During driving  There is a drawback that makes it difficult to remove heat efficiently.

In other words, superconducting magnets applied to power systems Normal Quenching  Sufficient stability should be ensured without occurrence, and when the current is input to the superconducting magnet, Line According to the current change in the recovery of accidents or accidents AC  Sufficient margin for heat generation due to losses must be secured, but the conventional superconducting current limiter proposed to satisfy both the suppression effect of the fault current and the securing of the operational flexibility of the system can be applied to the power system. To secure the design and operation technology of the magnet For flag Alcohol is not presented clearly.

In order to solve the above problems, the present invention connects buses between power plants to each other through the same substation while supplying power between the power plants to each other, and in the event of a fault current in a short circuit, by limiting the fault current to the power system The purpose of the present invention is to provide a busbar connection system through a superconducting magnet using CICC, which has excellent mechanical strength and is suitable for energizing a large current.

In addition, it is an object of the present invention to provide a bus connection system configured to limit the fault current through the inductance of the CICC superconducting magnet immediately before the breaker installed in the power plant when the fault occurs and the fault current occurs.

In addition, when a steady current is supplied, a high fault current can be essentially absent by limiting the fault current only when a fault occurs and a fault current is generated without affecting the power system. It is an object of the present invention to provide a busbar connection system for prolonging the life of various equipment and preventing safety accidents by suppressing current.

In addition, an object of the present invention is to provide a bus connection system in which protection means for removing a fault current remaining while the resistance of the superconducting magnet becomes zero while returning to a normal current is provided.

In order to achieve the above object, the present invention provides a bus connection system for protecting a power system from a fault current generated when a bus is connected, wherein a substation includes a double bus each connected to buses of power plants, and between the double buses. In order to limit the breaker and the fault current in the substation connecting the substation, characterized in that the superconducting wire (CICC) formed by using a CICC superconducting coil (CICC) surrounded by a rectangular metal tube is arranged while being connected to each other We present a bus connection system using CICC superconducting magnet to protect the power system from the generated fault current.

The superconducting coil may be formed by flowing supercritical liquid helium at a pressure of about 5 atm into the inner conductor conductor (CICC) and cooling it to a cryogenic temperature.

The CICC superconducting magnet may be configured to limit the fault current through a change in the inductance of the superconducting coil before the breaker is activated when a short circuit occurs.

The power system may include a transformer connected to the power system to flow a fault current transformed into the superconducting coil of the CICC superconducting magnet, and a bridge circuit unit rectifying the fault current transformed through the transformer to DC. have.

The power system may include a protection circuit unit for removing a fault current remaining in the superconducting coil while returning to the normal current by the CICC superconducting magnet.

The protection circuit unit may be connected in series with a diode and a resistor for removing a fault current remaining in the superconducting coil in series.

In addition, the power system may be configured with a test switch unit for configuring the power supply in a short circuit state.

The following effects can be obtained for a bus connection system using a CICC superconducting magnet for protecting a power system from a fault current generated when a bus connection of a substation of the present invention occurs.

First, the CICC superconducting magnets manufactured using CICC in the bus connection system of the substation according to the present invention, unlike other current-limiting current limiters, the superconducting coils are DC reactors and do not generate phase transitions. Because of the structure to limit the fault current by using the inductance of the can reduce the performance degradation of the superconductor due to the phase conduction transition has the advantage that sufficient stability to be applied to the power system .

Secondly, when a fault occurs in the bus connection system of the substation according to the present invention, the fault current is configured by limiting the fault current through the impedance change of the CICC superconducting magnet before the breaker installed in the substation operates. There is an effect that can prevent the damage caused by the current.

Third, the bus connection system of the substation according to the present invention does not affect the power system when the normal current is supplied, and the fault current is increased while the impedance of the CICC superconducting magnet increases only when a fault occurs and a fault current is generated. Because it is a limiting method, it is possible to avoid the existence of a high fault current inherently, and also has the effect of extending the life of the various devices and preventing safety accidents by suppressing the fault current.

Fourthly, the substation of the present invention Busbar connection system  Returning to normal current Superconducting coil  As the resistance neared zero On superconducting coils Remaining  In which the fault current is connected in series with the diode With protection circuit  By removing the connection, it has the effect of securing the stability of the superconducting magnet.

Fifth, the bus connection system of the substation according to the present invention is configured with a test switch unit for arbitrarily configuring the power supply of the power system in a short circuit state to check the malfunction of the CICC superconducting magnet in advance to operate the CICC superconducting magnet It will have the effect of confirming the reliability of the.

Sixth, when a failure occurs in the bus connection system of the substation, a superconducting magnet using the CICC of the present invention is manufactured in a structure that not only maintains electrical insulation but also maintains the mechanical strength of the coil. Like the conducting magnet, the superconducting cable is wound directly on the structure and manufactured through the insulation process, which can solve the problem of very unstable in terms of structural support due to the large current .

Seventh, the CICC superconducting magnet in the substation bus connection system can effectively remove the heat generated from the inside and outside by the refrigerant inside the CICC has the effect of securing sufficient thermal hydraulic stability.

Eighth, the superconducting magnet mounted in the bus connection system of the substation of the present invention can expect the efficiency of the system operation because it does not act as a load on the system in the normal state because the electrical resistance is zero, and also in case of an accident, the fault current by its own inductance It can effectively protect expensive power devices due to fault current, and reduce the additional cost incurred when improving the performance of existing circuit breakers due to the increase of power system capacity by limiting fault current. There is.

Nine times validly, superconducting magnets are mounted on the bus bar-connecting system of the substation according to the present invention can minimize the loss (AC loss) generated inside the conductor by performing chromium plating in the superconducting wire rod surface, the supercritical helium (He) By forcibly circulating through the in- pipe twisted pair conductor (CICC), the refrigerant contact surface of the superconducting wire rod during the operation of the superconducting magnet is secured in the operation process, thereby effectively cooling the heat generated during operation.

1 is a diagram illustrating a bus connection system using a CICC superconducting magnet for protecting a power system from a fault current generated when a bus is connected to a substation according to an embodiment of the present invention.
Figure 2 is a product process diagram showing the manufacturing process of the CICC superconducting magnet used in the bus bar connection system of the present invention.
3 is a mounting configuration of the CICC superconducting magnet mounted to the power system according to an embodiment of the present invention.
4 is an operating state diagram showing a current flow in the bridge circuit unit for supplying a DC current to the superconducting coil of the CICC superconducting magnet mounted on the power system according to an embodiment of the present invention.
FIG. 5 is an operation state diagram illustrating a limit state of a fault current according to a CICC superconducting magnet mounted to a power system when a fault current occurs according to an embodiment of the present invention.

Hereinafter, a bus connection system using a CICC superconducting magnet for protecting a power system from a fault current generated during bus connection of a substation according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a bus connection system using a CICC superconducting magnet for protecting a power system from a fault current generated when a bus is connected to a substation according to an embodiment of the present invention.

Referring to FIG. 5, in the power system of the networked substation S1, bus buses Bus 2 and Bus 4 connected to buses Bus 1 and Bus 5 of the power plants G1 and G2 are configured.

The buses Bus2 and Bus4 represent double buses of the same substation S1, and the bus separation operation is enabled by opening the circuit breaker breaker 7. As a bus bar breaker, a circuit breaker 7 is present between the bus bar Bus2 and the bus bus Bus4. A cable-in conduit-conductor (CICC) superconducting magnet 100 is disposed in series with the bus bar.

Therefore, when the resistance of the superconducting magnet is 0, it substantially means bus connection, and when it is infinity, it means bus split.

The CICC superconducting magnet 100 is manufactured using an inner tube twisted pair conductor (CICC) manufactured by enclosing a superconducting wire with a rectangular metal tube to limit the fault current. A detailed description thereof will be described later.

At this time, the failure capacity generally reaches 45 kA according to the decrease in the impedance of the bus when a three-phase short circuit occurs in the bus Bus1 when the double bus is connected.

More specifically, if the internal impedance of the bus is normally 154kV when the double bus of the substation S1 is connected, the fault current decreases from 0.1Ω to 0.03Ω while the fault current increases from 15kA to 45kA and reaches up to 53kV. can do.

Therefore, when a short circuit accident occurs during bus connection, if a fault current having such a fault capacity flows to various equipments as it is, the damage thereof is considerable, and safety of a human body may be a problem.

To this end, a breaker having a breaker capacity of 50 kA is usually installed in the power system. However, damage due to a dropping surge voltage of a fault current is inevitable for about 5 cycles until a breaker operates after a short circuit accident.

In addition, when the buses of the power plants Bus1, Bus5 are connected to the double bus through the substation S1, the breakers 5, 6, 10, 11, and 7 do not exceed 50kV of the breaker capacity in any accident. This is because the power passing through the breaker only covers the current from one of the power plants G1, G2. On the other hand, breakers 3, 4 and 8, 9 attached to the line facing the customer's direction can absorb the entire power currents of both power plants (G1 and G2) in case of the corresponding line accident, so that they are exposed to the maximum fault current and have a large breaking capacity. There is a problem that replacement of the breaker is also required.

In order to prevent this, in the present invention, the CICC superconducting magnet 100 is configured to prevent damage due to a fault current while being installed between the double busbars, and in the case of FIG. 1, four of the nine circuit breakers installed in the substation S1 are Escape from the risk of fault currents exceeding the fault capacity.

Figure 2 is a product process diagram showing the manufacturing process of the CICC superconducting magnet used in the bus bar connection system of the present invention.

Referring to FIG. 5, the process of manufacturing a CICC superconducting magnet starts with a CICC manufacturing process (S100), and the CICC manufacturing process is a process for manufacturing a pipe internal conductor (CICC) surrounding a superconducting wire with a rectangular metal tube. to be.

The CICC manufacturing process (S100) requires a superconducting wire manufacturing technology, chromium plating technology of the superconducting wire, and the like.

The superconducting wire is processed by drawing the rod into 0.78mm thickness with a length of 10km or more.The superconducting wire is subjected to heat treatment for 600 hours at the maximum temperature of 660 degrees to form the superconducting material.

In this process, the superconducting wires are prevented from sintering (the phenomenon of the wires sticking together at high temperatures) and the losses occurring inside the conductor ( AC In order to minimize the loss ), the surface of the superconducting wire is chrome plated . The chromium plating is not only required to have a surface uniformity of 0.1 micron or less, but also to continuously perform plating operations up to 15 km.

The production of CICC, the superconductor, consists of a tube forming technology for wrapping a superconducting wire with a metal tube, a welding technique for welding in the longitudinal direction of a wrapped metal tube, a technique for forming a wire welded in a metal tube to a predetermined dimension, and a circular shape. Technology to mold CICC superconductors into squares is included.

The metal tube, which is the jacket material of the CICC, is made of a special metal (Incoloy 908) similar in thermal properties to the superconducting wire.

Also, the CICC Inside the metal tube Such as helium (He)  Superconducting, configured to inject refrigerant Wire rod  Refrigerant Contact surface  It can be secured during operation to effectively remove heat generated during operation.

In other words, CICC is a magnet made of conductors of 360 or 486 strands enclosed by a rectangular metal tube for high current operation of 35kA. The refrigerant contact surface of superconducting wires during operation of superconducting magnets In order to cool the heat generated during operation to 4.5K, supercritical helium ( He) of about 5 atmospheres Forced circulation through end- pipe stranded conductor (CICC) .

 As a next step for manufacturing the CICC superconducting magnet, a continuous winding process (S200) is configured, wherein the continuous winding process (S200) is a step of forming a CICC, which is a superconductor manufactured above, into a desired magnet shape.

Accordingly, a grit blasting process for removing residual stress of the CICC conductor and a process of continuously transporting the conductor and forming the straight and curved lines are performed.

In other words, the grit blasting process is a process of removing foreign substances on the surface of the conductor by colliding fine particles on the surface of the conductor, and removing residual stress present in the CICC.

The process of conveying CICC during this winding process is made through a roller capable of precise control, and the shape of the superconducting magnet is continuously made up to 1,700m through a three-point bending roller.

In the next step, the joint installation step (S300) and the heat treatment step (S400) is composed, the joint installation step is a step of forming a superconducting coil by installing the joint in a continuous wound CICC, that is to supply current from the power supply device For this purpose, a joint is installed to maintain a connection resistance of several nΩ or less.

In the heat treatment process, a vacuum heat treatment for 30 days is performed to make the superconductor. Substances (Nb and Sn) in the superconducting wire react with each other to form a superconductor (Nb ₃ Sn). At this time, the required temperature uniformity is spatially within ± 1.5 ° C and temporally within ± 3 ° C.

Also, due to the nature of the jacketed metal tube (Incoloy 908), the internal vacuum should be kept below 0.08 ppm at high temperature of 660 ℃ based on the oxygen partial pressure. If the vacuum heat treatment reaction is performed under these conditions, there is a high possibility of stress acceleration caused by grain boundary oxide (SAGBO) in the jacket, resulting in structural defects in the material, resulting in stable superconducting magnets. You will not be able to drive. For this reason, the vacuum heat treatment process requires a large heat treatment device and operation technology that is operated for a long time in a state requiring stable operation of the device and precise and delicate control of temperature and oxygen amount.

In the next step, an insulating taping (S500) process and an epoxy vacuum impregnation process (S600) are composed, and the insulating taping process uses a special tape (Kapton and S-glass) to insulate the conductors during operation of the superconducting coil. Taping process. The reason why two special materials are used for the special tape is to compensate for the other side even if one side is insulated.

When the insulating tape process is completed, a process of winding a plurality of layers of tape around the superconducting coil is further performed. This not only maintains the electrical insulation of the superconducting coil when vacuum impregnation is performed, but also maintains the mechanical strength of the coil.

Vacuum Pressure Impregnation (VPI) is a process that maintains electrical insulation and structural strength at 4.5 K cryogenic conditions by infiltrating epoxy into insulating tape. The process is completed by molding mold assembly, vacuum exhaust, epoxy injection, and three days of curing. Only when this vacuum impregnation process is completed is the magnet production completed.

In more detail, the superconducting magnet 100 developed so far can obtain a magnetic field of up to 13 Tesla, which is 260,000 times the Earth's magnetic field, and this magnetic field is necessary to make and trap the plasma required in the fusion reaction.

Therefore, the core technology of the superconducting magnet is to manufacture a superconducting magnet by forming a superconducting coil through the CICC joint.

The superconducting coil of the CICC superconducting magnet 100 has no resistance when a normal current flows in the power system of the substation S1 so that the current flows freely, but when an overcurrent occurs in a transmission line due to a short circuit, the superconducting coil immediately. It is configured to protect the power system by preventing the overcurrent from flowing with the increased resistance because the internal resistance is greatly increased.

That is, the superconducting coil of the CICC superconducting magnet 100 generates an automatic impedance immediately after an accident such as a short circuit, and does not limit the fault current by using a phase transition, but uses a change in inductance of the superconducting coil. will be.

3 is a configuration diagram of a CICC superconducting magnet mounted to a power system according to an embodiment of the present invention, Figure 4 is a DC current supply to the superconducting coil of the CICC superconducting magnet mounted to a power system according to an embodiment of the present invention. FIG. 5 is an operational state diagram showing a current flow in the bridge circuit unit, and FIG. 5 is an operational state diagram showing a limited state of a fault current according to a CICC superconducting magnet mounted to a power system when a fault current occurs according to a short circuit according to an embodiment of the present invention.

3 shows a CICC superconducting magnet 100 installed in a three-phase power system.

When a short circuit occurs, the CICC superconducting magnet 100 limits the fault current by changing the inductance of the superconducting coil before the breaker installed in the power system is operated.

To this end, in the power system, a bridge circuit unit for rectifying the transformer 200 connected to the power system and the fault current transformed through the transformer to DC to flow a fault current transformed by the superconducting coil of the CICC superconducting magnet 100 to the DC ( 300). In addition, although not shown, a cryostat for maintaining a superconducting state of the in-pipe twisted pair conductor (CICC) is configured.

As such, when the CICC superconducting magnet 100 is installed in a transformer (S1) of a three-phase power system, the number of superconducting coils can be reduced to one, unlike a single phase, and the manufacturing cost can be greatly reduced, and the DC power supply is a superconducting coil. Compensating for the large ripple of the current flowing in the 3 phase type has the advantage of reducing the need for DC due to the small ripple.

The basic operation principle of the CICC superconducting magnet 100 is to rectify alternating current through the bridge circuit unit 200 so that a DC current flows in the superconducting coil. When a normal power is applied to the power system, a constant current flows in the superconducting coil. .

Referring to FIG. 4, the flow of current in the bridge circuit unit 200 is shown, and the magnitude and direction of the arrow are diagrams of the magnitude and direction of the current.

The currents entering the bridge circuit 200 have their own three-phase phase difference, but the current passing through the superconducting coil is always constant. In other words, since di / dt is 0, there is almost no voltage drop by the superconducting coil at steady state current.

Therefore, the power loss in the bridge circuit unit 200 is a loss due to the in-pipe twisted pair conductor (CICC), a loss due to a transformer, and a loss due to a diode. Since the double-conductor stranded conductor (CICC) uses superconducting wire, there is little loss and the size of the reactor is small.

If a short-circuit accident occurs in the power system connecting the double bus of the substation S1, di / dt, which had an impedance of 0 in normal state, generates a large impedance after the accident, and the resulting impedance di / dt eventually causes superconductivity. This causes a voltage drop by the coil.

At this time, the voltage applied to the diode of each bridge circuit unit 200 is increased several times compared to the normal state, the fault current flows through the superconducting coil. Here, the fault current passes through the superconducting coil, and the amount of fault current passing through the bridge circuit unit 200 gradually increases. However, due to the inductance of the superconducting coil, the fixed current does not increase rapidly but gradually increases.

Therefore, even if a short circuit accident occurs in a state in which the double bus is connected in the substation S1, the power system does not have a great influence on the initial stage, and as a result, the breaker operates to cut off the power without the fault current fully increasing. In this case, the power system will be completely protected.

As a result, the superconducting coil of the CICC superconducting magnet 100 of the present invention is meaningful to operate for 5 cycles, which is a period until the breaker operates after an accident.

Referring to FIG. 5, when a short circuit occurs in a power system rated at 6.6 kV / 200 A, an operating state of a CICC superconducting magnet connected to a double bus of the power system is illustrated.

As such, when a short circuit occurs, a 4 kA (two cycle) current rapidly increased at 200 A, but it is returned to the normal current after two cycles through the change in the inductance of the superconducting coil of the CICC superconducting magnet 100.

More specifically, the operation of the superconducting coil of the CICC superconducting magnet 100, unlike the characteristics of the general surge voltage, when the fault current is generated, the initial peak value is low and the peak value gradually rises and then completely removed after 2 cycles. Showing characteristics.

That is, the fact that the initial peak value can be minimized when a fault current with a large fault capacity is generated in a short circuit accident during bus connection may be an important feature of the superconducting coil of the CICC superconducting magnet 100.

In addition, as shown in FIG. 3, the power circuit of the present invention has a protection circuit unit 400 for removing a fault current remaining in the superconducting coil while returning to a normal current as the CICC superconducting magnet 100 operates. Can be configured.

When the fault current is increased in the superconducting coil and the fault condition is removed again, the normal current flows in the system, but the fault current still exists in the CICC superconducting magnet 100, and the superconducting coil is continuously 0 because the resistance of the superconducting coil is zero. There is a problem that the fault current charged in the flow.

In order to prevent this, the protection circuit unit 400 may be configured in the power system, and the protection circuit unit 400 may include a diode and a resistor connected in series to remove the fault current remaining in the superconducting coil.

In addition, the power system may be configured with a separate test switch unit 500 for configuring the power of the power system in a short circuit state.

That is, by configuring a test switch unit 500 for arbitrarily configuring the power of the power system in a short circuit state, it is possible to confirm in advance whether a malfunction of the CICC superconducting magnet 100, so that the reliability of the operation can be confirmed in advance. Will have

In the detailed description of the present invention, specific embodiments have been described. However, it will be apparent to those skilled in the art that various modifications can be made without departing from the scope of the present invention.

100: CICC superconducting magnet 101: Tokamak device
103: PF structure 105: connecting structure
107: TF structure 200: transformer
300: bridge circuit portion 400: protection circuit portion
500: test switch unit

Claims (7)

In the bus connection system for protecting the power system from the fault current generated when the bus connection,
The substation consists of double busbars, each of which is connected to the busbars of the power plants.
Substations between the double bus bar and connected to each other while arranging the superconducting magnets formed with a CICC superconducting coil made by using an inner tube conductor (CICC) surrounding the superconducting wire with a rectangular metal tube to limit the fault current Bus connection system using CICC superconducting magnet to protect the power system from the fault current generated when the bus is connected. The method of claim 1,
The superconducting coils are formed by flowing supercritical liquid helium at a pressure of about 5 atm into the inner conductor conductor (CICC) and cooling them to cryogenic temperatures. Bus connection system using CICC superconducting magnet. The method of claim 2,
The CICC superconducting magnet is configured to limit the fault current through a change in the inductance of the superconducting coil before the breaker is activated when a short circuit occurs, so as to protect the power system from the fault current generated during the bus connection of the substation. Bus connection system using CICC superconducting magnet. The method of claim 2,
The power system includes a transformer connected to the power system to flow a fault current transformed into the superconducting coil of the CICC superconducting magnet;
And a bridge circuit unit configured to rectify the fault current transformed by the transformer into direct current. A bus line connecting system using a CICC superconducting magnet for protecting a power system from fault current generated when a bus line is connected to a substation. The method of claim 4, wherein
The power system protects the power system from the fault current generated during the bus connection of the substation, wherein the protection circuit unit is configured to remove the fault current remaining in the superconducting coil while returning to the normal current by the CICC superconducting magnet. Bus connection system using CICC superconducting magnet to 6. The method of claim 5,
CICC superconductivity for protecting the power system from the fault current generated during the bus connection of the substation, characterized in that the protection circuit unit is connected to the superconducting coil by connecting a diode and a resistor in series connected to remove the fault current remaining in the superconducting coil. Bus connection system using magnet. The method of claim 4, wherein
The power system is connected to the bus system using a CICC superconducting magnet for protecting the power system from the fault current generated when the bus is connected to the substation, characterized in that the test switch for configuring the power in a short circuit state.

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