KR20170046300A - High speed switch using supercritical fluid and current interrupt appratus using it and current interrupt method - Google Patents

Abstract

The present invention relates to a high-speed switch for disconnecting a circuit to flow or shut off a current, and a current interruption device and a current interruption method using the same. The high-speed switch using a supercritical fluid comprises: a chamber in which a supercritical fluid is filled; a fixed contact point provided inside the chamber; a movable contact point provided to face the fixed contact point inside the chamber; and a movable contact point actuator for driving the movable contact point such that the movable contact point is spaced apart from or closer to the fixed contact point. As a result, the moving distance of the movable contact point is short due to excellent insulating performance, thereby shortening the operation time of the switch and reducing the size of the switch. In addition, the supercritical fluid has a lower global warming index than sulfur hexafluoride, which can reduce environmental destruction.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-speed switch using a supercritical fluid, a current interruption device using the same, and a current interruption method using the same. BACKGROUND ART < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed switch for separating a circuit to energize or shut off a current, a current interruption device using the same, and a current interruption method.

In the event of a fault in the power system or a high voltage current, a current interrupter is used to shut down the fault current and protect the power plant. The current interrupting device cuts off the current when a fault current which flows to the power system reaches 10 times or more of the normal current due to a failure or an accident in the power system.

As shown in FIG. 1, the conventional DC current interrupter includes a main switch 10 connected in series with first, second, and third switches 11, 12, 13, and a switch 13 connected in parallel with the third switch 13 A power semiconductor switch 2, a capacitor 15 connected in parallel with the second and third switches 12 and 13 and a surge arrester 17 connected in parallel with the capacitor 15.

When the power system is normal, the current flows to the main power supply unit 10.

The first, second and third switches 11, 12 and 13 of the main power supply unit 10 are opened and the power semiconductor switch 2 is closed in order to interrupt the fault current when a failure occurs in the power system . At this time, the current of the third switch 13 is energized to the power semiconductor switch 2 closed by the arc voltage. As a result, the current of the third switch 13 is caused to flow to the power semiconductor switch 2, and the arc between the electrodes is extinguished.

When the power semiconductor switch 2 is opened again to interrupt the current, the arc of the second switch 12 is extinguished.

When the second and third switches 12 and 13 are completely opened, the current of the main power supply unit 10 is cut off and the current is supplied to the capacitor 15 to charge the capacitor 15.

When the voltage charged in the capacitor 15 becomes larger than the discharge start voltage of the surge arrestor 17, the current flows to the surge arrestor 17, and the energy accumulated on the circuit is absorbed and the current is cut off. At the same time, the arc of the first switch 11 is extinguished, thereby completing the current interruption operation of the current interruption device.

The cutoff time of the current cutoff device as described above is determined according to the insulation performance of the second switch 12. [ That is, the longer the time for securing the insulation of the second switch 12 is, the longer the time from the generation of the fault current to the current interruption becomes. As the cut-off time becomes longer, the current to be cut is greatly increased, making it difficult to cut off, and the influence of the fault current on the circuit is increasing. Therefore, it is necessary to use a switch having good operating characteristics and insulation characteristics in order to reduce the breaking time of the current breaking device.

Currently, the current cut-off time of the current cut-off device is 5ms, but the worldwide shut-down time is 2ms or less.

Generally, a current cut-off device is a switch with a vacuum circuit breaker or a gas circuit breaker using sulfur hexafluoride (SF ₆ ). However, the vacuum circuit breaker or the sulfur hexafluoride gas circuit breaker has a low insulation performance, so that the distance between the fixed contact and the movable contact point can be large enough to insulate the contacts. Since the moving distance of the movable contact is at least 10 mm or more during the switching operation of the circuit breaker, even if the operating speed of the circuit breaker is increased, the shortening of the breaking time is limited.

On the other hand, sulfur hexafluoride used in gas circuit breakers is a kind of greenhouse gas, and has a problem that the global warming index is very high, which is about 23,900 times that of carbon dioxide (CO ₂ ), which is harmful to the environment.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a high-speed switch with high insulation performance.

It is another object of the present invention to provide a current interrupter having a short interruption time of a fault current and a current interruption method using the same.

It is another object of the present invention to provide a high-speed switch using an insulating material that substitutes sulfur hexafluoride, which has a high global warming index, as an insulating gas.

According to an aspect of the present invention, there is provided a high-speed switch using a supercritical fluid, comprising: a chamber filled with a supercritical fluid; A fixed contact provided inside the chamber; A movable contact disposed inside the chamber so as to face the fixed contact; And a movable contact manipulator for driving the movable contact so that the movable contact moves away from or closer to the fixed contact; .

Preferably, the supercritical fluid is carbon dioxide (CO ₂ ).

Preferably, the controller may further include a controller for maintaining the supercritical fluid in a supercritical state; .

Preferably, the controller includes: a temperature regulator for regulating the supercritical fluid to a critical temperature or higher; .

According to another aspect of the present invention, there is provided a current interruption device using a high-speed switch using a supercritical fluid, the current interruption device comprising: a main current pathway for passing current in a normal operating state; A main current supply unit including three or more switches connected in series to each other; A power semiconductor switch installed on a primary current circuit connected in parallel to one of the switches belonging to the main power supply; A capacitor installed on a secondary current circuit which is a circuit connected in parallel with two series-connected switches on the main energizing path; And a surge arrester installed on a tertiary current circuit, which is a circuit connected in parallel with a capacitor on a circuit connected in parallel with two serially connected switches on the main energizing path; Wherein at least one of the three switches provided in the main conductive part includes a chamber filled with a supercritical fluid therein, a chamber internal fixed contact provided inside the chamber, and a chamber internal fixed contact inside the chamber, Or moving within the chamber.

Preferably, the main power supply unit includes first, second, and third switches, the third switch is connected in parallel with the power semiconductor switch, and the second and third switches are connected to the capacitor and the surge arrestor Respectively.

Preferably, the second switch is a switch composed of the chamber, the fixed contact, and the movable contact.

According to another aspect of the present invention, there is provided a current interruption method using a current interruption device, the current interruption method comprising the steps of: using the current interruption device described above, Second, and third switches are opened when a trip signal is received in a normal operating state in which current flows, and then a line current that flows through the electrodes of the third switch, When the interval between the gaps of the second switch becomes larger than a predetermined value, the power semiconductor switch is opened to change the current of the main power supply path to the secondary current circuit to charge the capacitor, and the charging voltage of the capacitor When the voltage rises to the discharge start voltage, the surge arrester installed in the tertiary current circuit starts discharging, It flows through the raster so that current is cut off.

Preferably, the second switch is a switch composed of the chamber, the fixed contact, and the movable contact.

Preferably, the second switch is closed first and then the first switch is closed to apply the current breaking device.

In the high-speed switch using the supercritical fluid of the present invention, supercritical fluid is used, so that the insulation performance is excellent, and the moving distance of the movable contact can be shortened. As a result, the operation time of the switch can be shortened and the size of the switch can be reduced.

In addition, supercritical fluids have a lower global warming index than sulfur hexafluoride, which can reduce environmental degradation.

Also, the current interruption device and the current interruption method using the high-speed switch of the present invention can shorten the interruption time of the switch, shorten the current interruption time of the entire device, and can be easily installed in the existing interruption device.

1 is a circuit diagram showing a configuration of a conventional current interrupting device.
2 is a configuration diagram showing a high-speed switch of the present invention.
3 is a circuit diagram showing a current interruption device of the present invention.
4 is a flow chart illustrating a current interruption method of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Also, the terms used in the present invention are used to describe specific embodiments and are not intended to limit the present invention, and the singular expressions include plural expressions unless the context clearly indicates otherwise. In the description, the same parts as those of the conventional art are partially explained.

A high-speed switch using a supercritical fluid according to the present invention is for switching a current conduction or a cutoff state to a highway. The supercritical fluid having a high insulation performance is used to efficiently transfer the arc energy generated in the process of separating the movable contact from the stationary contact Since the insulation performance is exhibited even if the distance between the two contacts is short, the moving distance of the movable contact is short, thereby shortening the cutoff time of the switch. In addition, carbon dioxide (CO ₂ ), a commonly used supercritical fluid, has a low global warming index and can reduce environmental destruction.

The high-speed switch using the supercritical fluid according to the present invention comprises a chamber 100, a fixed contact 200, a movable contact 300, an actuator 400, and a controller 500, as shown in FIG.

The chamber 100 is filled with supercritical fluid, and the stationary contact 200 and the movable contact 300 are provided therein.

Supercritical fluids have a density similar to that of a liquid, with a flow resistance similar to that of a gas, above the critical temperature and pressure. Especially, in the field of electric power, attention is paid to utilization as an insulating medium. Among the supercritical fluids, carbon dioxide (CO ₂ ) is most commonly used because the critical temperature is 32 ° C and the critical pressure reaches a supercritical state at a relatively low temperature and pressure of 74 atm. Supercritical fluid is fast moving, has a high thermal conductivity, has a short insulation distance, has a large heat capacity, has a high insulation performance, can be miniaturized, can stably flow a fault current, and quickly transfers heat generated by an arc between contacts Which helps in the recovery of insulation, and is advantageous in the arc of arc because of high density.

On the other hand, replacing the sulfur hexafluoride used as the insulating medium of the conventional switch with a supercritical fluid can reduce the size of the switch and improve the insulation performance. In addition, since carbon dioxide has a significantly lower global warming index than sulfur hexafluoride, environmental destruction can be prevented.

The stationary contact 200 is provided inside the chamber 100 and the movable contact 300 is disposed inside the chamber 100 in opposition to the stationary contact 200 and is spaced apart or approach the stationary contact 200.

Specifically, the fixed contact 200 is exposed at one end to the outside of the chamber 100, and the other end is disposed inside the chamber 100. The other end of the movable contact 300 is exposed to the outside of the chamber 100 and is drawn out of the chamber 100 and connected to the manipulator 400.

Thus, the electric current drawn from the outside of the chamber 100 through the fixed contact 200 is drawn out through the movable contact 300. However, the current direction of the switch may be reversed so that the current drawn from the outside of the chamber 100 through the movable contact 200 is drawn out through the fixed contact 300.

The movable contact 300 is moved in a state where the fixed contact 200 is fixed in order to cut off the circuit in the energized state. At this time, since the fixed contact 200 is fixed to the chamber 100, the movable contact 300 is sealed by the sealing member 210 and the movable contact 300 moves relative to the chamber 100, ) To seal the supercritical fluid in the chamber 100.

The actuator 400 drives the movable contact 300 to move so as to switch the current to the energized or cutoff state. As a result, the movable contact 300 can be spaced apart or approach the fixed contact 200. At least the end of the movable contact 300 is brought into contact with the end of the fixed contact 200 and the end of the movable contact 300 is not drawn out of the chamber 100 when the movable contact 300 is separated.

The controller 500 maintains the supercritical fluid in the chamber 100 in a supercritical state. The control unit 500 includes a temperature control unit 510 for controlling the supercritical fluid to a critical temperature or higher, and a heater may be used as the temperature control unit. And may further include a pressure regulating device for regulating the supercritical fluid to a critical pressure or higher, if necessary.

When the high-speed switch is constructed as described above, the arc energy generated between the two contacts 200 and 300 is effectively extinguished when the current is cut off, and the insulation performance is exhibited even when the distance between the two contacts 200 and 300 is short. 300) is shortened, it is possible to shorten the cut-off time of the switch.

Table 1 below compares the insulation performance of supercritical fluids used as insulation media for high-speed switches and other insulation media used in conventional switches.

Breakdown voltage due to insulation material
Sulfur hexafluoride gas

air

vacuum
Supercritical fluid nitrogen carbon dioxide Pressure (bar) One 5 One 5 - 40 70 74 Contact spacing (mm) - - - - - 0.35 0.38 0.05 Breakdown voltage (kV) - - - - - ~ 25 ~ 25 ~ 15 Breakdown voltage (kV / mm) for unit interval 7.4 30 3 6 20 ~ 70 ~ 65 ~ 300

From Table 1, it can be seen that the supercritical fluid has higher dielectric breakdown voltage for the unit interval than the sulfur hexafluoride gas, air and vacuum, which indicates that the insulation performance is good.

Especially, in the supercritical state, since the gap between the insulative contacts is very short as 0.05 mm, the movement distance of the movable contact to the stationary contact is short, so the movement time of the movable contact can be shortened and the operation time of the switch can be shortened .

For example, when the moving speed of the movable contact is 2 m / s, since the moving distance of the movable contact is 10 mm or more in the conventional switch, the breaking time is at least 5 ms. On the other hand, the switch of the present invention using carbon dioxide in the supercritical state has a gap of 0.05 mm between the contact points, so that the shutdown operation is completed within about 0.025 ms. Therefore, the cut-off time of the switch using the supercritical fluid can be remarkably shortened.

The current interrupting device according to another aspect of the present invention is a current interrupting device for interrupting a fault current or a high voltage current of a DC power system by using the high-speed switch using the supercritical fluid, and FIGS. 2 and 3 Includes the main power supply unit 10, the capacitor 15, and the surge arrestor 17 as shown in Fig.

The main power supply unit 10 includes three or more switches connected in series on a main power supply path for energizing a current in a normal operating state, of which three switches are respectively connected to first, second and third switches 11 , 1, 13). The power semiconductor switch 2 is installed on the primary current circuit connected in parallel with one of the three switches and the switch connected in parallel with the power semiconductor switch 2 is the third switch 13. [

The first switch 11 is a mechanical switch for isolating and inputting a circuit.

The second switch 1 is a high-speed switch using a supercritical fluid as described above. The second switch 1 protects the power semiconductor switch 2 connected in parallel with the mechanical switch connected to the subsequent stage from the transient voltage generated in the current interruption. Quot; switch " The supercritical switch 1 includes a chamber 100 filled with a supercritical fluid, a stationary contact 200 provided in the chamber 100, a stationary contact 200 in the chamber 100, And a movable contact point manipulator 400 that drives the movable contact point 300 so that the movable contact point 300 and the movable contact point 300 are spaced apart from or approach the stationary contact point 200.

The third switch 13 causes a cutoff current to flow to the power semiconductor switch 2 when the current is cut off and the power semiconductor switch 2 is installed in the primary current circuit connected in parallel with the third switch 13.

At this time, the first switch 11 and the supercritical switch 1 are bistable switches in which the on and off states are stably present, and the third switch is a bistable switch in which the on / off state of the instantaneous And is a monostable switch in which the contact is turned off for a predetermined time and then automatically returned to the on state. Therefore, the off state of the third switch 13 must be restored to the on state after the cut-off current is completely conducted to the secondary current circuit provided with the capacitor 15, and the voltage applied to the cut- (1).

Thus, when the current is cut off, all the switches of the main power supply unit 10 are opened, and the power semiconductor switch 2 is closed, so that the current of the third switch 13 is supplied to the power semiconductor switch 2. When the power semiconductor switch 2 is opened again, the supercritical switch 1 is isolated while the arc between the contacts is extinguished.

Though not shown in the drawing, the first and third switches may be constituted by supercritical switches, and all three switches may be constituted by supercritical switches. That is, it is preferable that at least one switch among the various switches on the main energizing path is constituted by a supercritical switch.

Further, the power semiconductor switch provided on the primary circuit connected in parallel with the third switch to the main power supply unit can be constituted by a bidirectional conduction switch. Here, the bidirectional conduction switch is a structure in which two unidirectional conduction switches are connected in series in opposite directions. Thereby, the current interruption device can perform bidirectional current interruption operation.

The capacitor 15 is installed on a secondary current circuit which is a circuit connected in parallel with two series-connected switches on the main energization path, and the switch connected in parallel with the capacitor 15 is connected to the supercritical switch 1 and the third switch 13).

The capacitor 15 functions as a secondary current circuit when the current in the main energization path is cut off. That is, the currents of the supercritical switch 1 and the third switch 13 are supplied to the secondary current circuit provided with the capacitor 15, whereby the capacitor 15 is charged.

The surge arrestor 17 is installed on a tertiary current circuit, which is a circuit connected in parallel with a capacitor on a circuit connected in parallel with two serially connected switches on the main energizing path, and a switch connected in parallel with the surge arresters 17 Like the capacitor 15, are the supercritical switch 1 and the third switch 13.

When the charging voltage of the capacitor 15 is larger than the discharging voltage of the surge arrestor 17, the surge arrestor 17 causes the current of the capacitor 15 to flow to the surge arrestor 17, The energy is absorbed and the current interruption is made. As a result, the arc between the contacts of the first switch is canceled.

The current blocking device may further include a discharger 18.

The discharge unit 18 prevents an excessive discharge current generated by the voltage charged in the capacitor 15 when the current interruption device is turned on after the interruption operation of the current interruption device is terminated, And a resistor 21.

The discharging switch 20 of the discharging unit 18 closes when the first switch 11 is opened after the interruption of the current and before the supercritical switch 1 of the main power supply unit 10 is closed .

A current blocking method according to another aspect of the present invention is shown in FIG. 4 as a current blocking method using the current blocking device.

The normal operating state (S10) is a state in which a normal current is energized in the main energizing path.

In the occurrence of an accident (S20), an accident such as occurrence of a fault current or a high voltage current occurs (S20) and a trip signal is generated.

At the start of the cut-off operation (S30), when the first switch, the supercritical switch and the third switch on the main energization path start the open operation simultaneously with the occurrence of the trip signal and the constant arc voltage is generated after the third switch is opened, The connected power semiconductor switch is closed so that the current of the third switch flows to the power semiconductor switch and the arc between the electrodes is eliminated.

In the main energization shutoff (S40), the current in the main energization path is cut off as the power semiconductor switch is opened. That is, when the supercritical switch is opened and the interval between the contact points is spaced by a certain distance, the power semiconductor switch is opened immediately after the arc is generated, so that the main energization path is shut off.

At this time, the current is supplied to the capacitor installed on the secondary current circuit so that the capacitor is charged. When the charging voltage of the capacitor rises up to the discharge start voltage of the surge arrester, the current flows into the surge arrester The energy charged on the circuit is absorbed through the surge arrester. As a result, the interruption operation of the current interruption device is completed.

In the capacitor discharge S50, when the first switch is opened after the current interruption, the discharge switch provided in the discharge portion is closed and then opened again to discharge the voltage charged in the capacitor. This can prevent the risk of malfunction that causes excessive discharge current from the voltage charged in the capacitor when the current interrupter is turned on.

The introduction of the current interruption device (S60) closes the supercritical switch provided in the main energization path, then closes the first switch, and the normal operation state in which a steady current flows in the main energization path.

While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: Main unit
11, 12, 13: first, second and third switches
1: Supercritical switch
2: Power semiconductor switch
15: Capacitor
17: Surge Arrest
100: chamber
200: Fixed contact
300: movable contact
400: Actuator
500:
510: Temperature controller

Claims (10)

A high-speed switch using a supercritical fluid for energizing or breaking a current,
A chamber filled with supercritical fluid therein;
A fixed contact provided inside the chamber;
A movable contact disposed inside the chamber so as to face the fixed contact; And
A movable contact manipulator for driving the movable contact so that the movable contact moves away from or closer to the fixed contact; Wherein the supercritical fluid is used as a high-speed switch. The method according to claim 1,
Wherein the supercritical fluid is carbon dioxide (CO ₂ ). The method according to claim 1,
A controller for maintaining the supercritical fluid in a supercritical state; Further comprising a supercritical fluid. The method of claim 3,
The controller may include: a temperature controller that adjusts the supercritical fluid to a critical temperature or higher; Wherein the supercritical fluid is used as a high-speed switch. A current interrupting device for energizing or breaking a current,
A main current supply unit including three or more switches connected in series on a main current path for energizing a current in a normal operating state;
A power semiconductor switch installed on a primary current circuit connected in parallel to one of the switches belonging to the main power supply;
A capacitor installed on a secondary current circuit which is a circuit connected in parallel with two series-connected switches on the main energizing path; And
A surge arrester mounted on a tertiary current circuit which is a circuit connected in parallel with a capacitor on a circuit connected in parallel with two serially connected switches on the main energizing path; Lt; / RTI >
At least one of the three switches provided in the main conduction part is a switch including a chamber filled with a supercritical fluid therein, a fixed contact provided inside the chamber, and a movable contact which is spaced apart from or approaching the fixed contact within the chamber And the current blocking device. The method of claim 5,
Wherein the main power supply unit includes first, second, and third switches,
The third switch is connected in parallel with the power semiconductor switch,
And the second and third switches are connected in parallel with the capacitor and the surge arrestor. The method of claim 6,
And the second switch is a switch composed of the chamber, the fixed contact, and the movable contact. 1. A current interruption method for energizing or breaking a current,
A current interrupting device according to claim 6,
Second, and third switches are opened when a trip signal is received in a normal operation state in which a normal current flows through the main energization path, and then the first, second, and third switches are opened, When the interval between the gaps of the second switch becomes larger than a predetermined value, the power semiconductor switch is opened to change the current of the main power supply path to the secondary current circuit to charge the capacitor, When the voltage rises to the discharge start voltage of the surge arrestor, the surge arrester installed in the tertiary current circuit starts discharging, and the line current flows through the surge arrester, thereby interrupting the current. . The method of claim 8,
And the second switch is a switch composed of the chamber, the fixed contact, and the movable contact. The method of claim 8,
Closing the first switch and then closing the first switch to apply the current breaking device

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