JP3127678B2 - DC high-speed circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high-speed circuit breaker having a vacuum valve as a current switching element, and more particularly, to a high-speed opening drive of a movable main contact having a built-in main contact by an electromagnetic repulsion coil. Circuit breaker with a vacuum valve, and a commutation circuit that is connected in parallel to the vacuum valve and generates a commutation current that is superimposed on the current flowing from the power supply to the load through the vacuum valve and creates a zero point in the vacuum valve passing current The present invention relates to a DC high-speed circuit breaker configured using the above.

[0002]

2. Description of the Related Art Among DC high-speed circuit breakers for protecting a ground fault and a short circuit in a power supply line of an electric railway, a DC high-speed circuit breaker having such a configuration as shown in FIG. 5 is known. In this example, a DC high-speed circuit breaker (hereinafter simply referred to as a circuit breaker) is a vacuum valve 1 having a built-in main contact.
And an electromagnetic repulsion coil 2 for opening the movable main contact in the vacuum valve 1 at high speed, a repulsion capacitor 30 constituting a power source of a current for generating an electromagnetic repulsion force in the electromagnetic repulsion coil 2, A repulsion circuit 20 including a power supply 50 and a repulsion switch 60 for connecting the repulsion capacitor 30 to the electromagnetic repulsion coil 2; Commutation reactor 4, which is connected in series with a parallel circuit of commutation capacitor 3 and commutation capacitor 3 to generate commutation current having a resonance frequency with commutation capacitor 3, A commutation circuit 10 comprising a commutation switch 6 for parallelizing a circuit comprising a commutation capacitor 3, a DC power supply 5 and a commutation reactor to a vacuum valve 1.
And is configured using The interruption of the DC current by the DC high-speed circuit breaker thus configured is performed as follows.

[0003] Figure 6 shows the phenomenon of circuit breaker each part at the time of direct current cutoff, as shown in the figure the uppermost, short-circuit accident occurs at the time t ₁ on the load side line of the circuit breaker, the inductance of the line When response rate of rise in the line current is detected at time t ₂ has been reached a certain value increases as an overcurrent, interrupting command from the detection control circuit breakers at this point is output, the rebound switch 60 a commutation switch 6 is turned at the same time as the commutation current I _t and repulsion current I _c begins to flow at the same time.
Although not shown here, the electromagnetic repulsion coil 2 (FIG. 5)
Is formed in a flat ring shape, and is a repulsive current flowing through the electromagnetic repulsion coil in a short-circuited disk integrated with the movable main contact in the vacuum valve, which is located parallel to and close to the ring surface. induced by I _c, the short circuit current I _s in the opposite direction to the repulsion current I _c flows, repulsive forces between the repelling current I _c and the short-circuit current I _s is generated, as shown in stages of repulsion of Figure 6 An attempt is made to open the movable main contact through the short-circuited disk with a waveform. The movable main contact is pressed against the fixed main contact with the contact force for ensuring the carrying capacity, breaking the main contact starts from the time t ₃ when the repulsive force is a contact force or more. On the other hand, superimposed current I _v next to the vacuum valve passing current from time t ₂ the line current I and commutation current I _t, the current I _v is after the main contact opening, separable distance is obtained capable of interrupting and the magnitude and frequency of the commutation current to pass through the zero point determined for after passes through the zero point at time t ₄ in FIG, it is blocked at this point. After the interruption, the line current I tends to flow through the commutation circuit 10, but the DC power supply of the line is usually constituted by a rectifier circuit, while the charge between the DC power supply 5 and the commutation capacitor 3 is charged. Since a high resistance is inserted as the resistance, a transient current period due to the impedance of the line power supply, the inductance of the line and the ground capacitance, the residual voltage and the capacitance of the current capacitor 3, and the inductance of the commutation reactor 4. After a lapse of time, the current flowing through the commutation circuit 10 settles down to a minute current flowing through the charging resistor, and the minute current is easily cut off by opening the commutation switch 6, and finally the cutoff operation of the circuit breaker is completed.

[0004]

However, in the circuit breaker having such a configuration, the electromagnetic repulsion force disappears in a short time (about several ms) due to the attenuation of the repulsion current caused by the resistance in the repulsion circuit. A separate mechanism is required to hold the main contact at a position equal to or greater than the required minimum separation distance against the contact force.In the above-described conventional example, the clutch mechanism is configured so that the clutch is applied to the movable main contact that has been moved. The maximum separation distance position that has been provided and reached can be held. However, when such a clutch mechanism is provided, the movable main contact, which gives a required contact force to the movable main contact, is held in the attained separation position while the contact spring, which is usually formed as a coil compression spring, is further compressed. Therefore, the clutch mechanism has a strong structure, which makes it difficult to directly connect to a vacuum valve having glass or porcelain as a component, complicating the structure around the clutch, and reconnecting the circuit breaker It is necessary to add a mechanism to release the clutch to the closing operation mechanism when trying to restart the operation, and the closing operation mechanism only needs to hold the contact spring in a pressurized state at the end of the closing operation. There is a problem that a new function is added to the function and the mechanism becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC high-speed circuit breaker which achieves this purpose with a simple and reliable mechanism without using a special mechanism for maintaining a required minimum separation distance.

[0006]

In order to solve the above-mentioned problems, the present invention provides a vacuum system having a built-in main contact and a movable main contact having a vacuum valve whose opening is driven at high speed by an electromagnetic repulsion coil. A circuit breaker, and a commutation circuit that is connected in parallel with the vacuum valve and generates a commutation current that is superimposed on a current flowing from a power supply to a load through the vacuum valve to create a zero point in the vacuum valve passing current. In the DC high-speed circuit breaker, the vacuum circuit breaker includes a blocking spring in addition to the electromagnetic repulsion coil for driving the opening of the movable-side main contact. A command for opening drive by the electromagnetic repulsion coil and a command for opening drive by the cut-off spring are given in parallel and at the same time, and the opening spring is driven by the cut-off spring. By reducing the time constant of the trip coil that trips the engagement mechanism that holds the machine in the machine state, the starting point of the opening of the movable main contact by the cut-off spring is determined by the electromagnetic repulsion of the movable main contact. It is assumed that the opening distance is substantially the same as when the maximum opening distance is reached by the opening drive by the coil.

[0007]

[0008]

As described above, if the vacuum circuit breaker is provided with a blocking spring in addition to the electromagnetic repulsion coil for driving the opening of the movable main contact in the vacuum valve, the breaking spring always opens the movable main contact. Since the movable main contact is moved together with the contact spring or the scaffold (spring seat) of the contact spring in the blocking direction when the opening is driven by the breaking spring, the required minimum separation distance has passed. The movable main contact can be prevented from returning to the fixed main contact side, and the separation distance that has already been reached can be maintained. In addition, the application of the shut-off spring can be performed by diverting the operation mechanism of a normal AC circuit vacuum circuit breaker, so that the DC high-speed circuit breaker can be configured simply and with high reliability.

In this case, the opening drive by the cut-off spring must be started before the movable main contact reaches its maximum separation distance by the opening drive by the electromagnetic repulsion coil and then returns to the required minimum separation distance. No. However, if the opening drive command by the electromagnetic repulsion coil and the opening drive command by the cut-off spring are given in parallel and at the same time,
As will be described in detail in the section of the embodiment, the time required for the movable main contact to reach the maximum separation distance is 10 to 15 ms, and the repulsion force is attenuated and disappears after the movable main contact reaches the maximum distance after the separation movement starts. The time required to return from the position of the maximum separation distance to the re-contact position with the fixed main contact again is 20 to 30 ms. On the other hand, after the opening drive command is issued by the breaking spring, the breaking spring is held in the opening drive standby state. The time required for the movement by the cut-off spring to start due to the operation of the tripping coil that trips the engaging mechanism is about 20 ms. Therefore, the movable main contact driven by repulsion must be maintained at the required minimum separation distance or more. Can be. As described above, the two opening drive commands need only be issued at the same time, and there is no need for a device or circuit for providing a time difference between the two commands, so that there is an advantage that the DC high-speed circuit breaker does not need to be complicated. .

However, the earlier the operation of the trip coil, the easier and more reliable the required minimum separation distance can be maintained.
The trip coil is usually driven from a DC power supply with a constant output voltage.However, a method of accelerating the operation of the trip coil is to reduce the number of turns of the coil and make the coil conductor thicker to increase the current flowing through the coil. A method to increase the reachable tripping drive force by at least the reduction in the number of turns and to shorten the time required to reach the drive force required for tripping, the minimum required driving force to trip the final ultimate drive force of the coil A method of reducing the time constant of the coil while maintaining it near the driving force is conceivable. However, the effect is limited under the limited design conditions (the size of the trip coil, that is, the upper limit of the coil diameter and length, the maximum allowable coil current, etc.) only by changing the coil design specifications. It is not easy to greatly reduce the time (approximately 20 ms in the above-mentioned example) obtained by the design aiming for a small and inexpensive ordinary as the time from the issuance of the opening drive command to the start of the movement of the movable main contact by the cut-off spring. . However, if the power supply for the tripping coil is a capacitor that is charged with a DC voltage, the time constant of the entire tripping circuit will be significantly reduced, and the time required for the tripping coil to disengage will be significantly reduced. Can be. Also, since this capacitor is charged from a DC power supply through a high resistance,
The discharge current of the capacitor, i.e., the trip coil current, can be arbitrarily increased without affecting the DC power supply circuit, and the trip coil has a structure similar to the electromagnetic repulsion coil, so that the time until the engagement trip is further increased. It can also be shortened.

[0011]

FIG. 1 shows an embodiment of the configuration of a DC high-speed circuit breaker according to the present invention. The circuit breaker has a vacuum valve 1 as a current switching element, and has a vacuum provided with an electromagnetic repulsion coil (not shown) for opening and driving a movable side main contact among main contacts built in the vacuum valve 1 and a breaking spring. A commutation circuit that generates a commutation current that is superimposed on the line current flowing from the circuit breaker 11 and the line from the DC power supply 100 to the load through the main contact in the vacuum valve 1 to the load. 10, a DC current transformer 12 provided on the load side line of the vacuum valve 1 for detecting the line current, and when the line current detected by the DC current transformer 12 reaches a predetermined size due to a line short-circuit accident or the like. And a detection control circuit 13 for outputting a shutoff command for shutting off the vacuum circuit breaker 11 and a closing command for parallelizing the commutation circuit 10 to the vacuum valve 1 for creating a zero point in the current flowing through the vacuum valve. ,true Valve 1 is constituted by using the non-linear resistor 14 for suppressing an overvoltage at the time of multiple recurrent arc generated between both contacts when interrupting small currents.

FIG. 2 shows the structure of the vacuum circuit breaker 11 shown in FIG.
An example is shown. In this embodiment, the vacuum circuit breaker is fixed.
Vacuum valve 1 with built-in main contact 1A and movable main contact 1B
And that the current from the repulsion capacitor 30 flows.
An electromagnetic repulsion coil 2 for driving the movable main contact 1B to open a pole;
Integrated with open / close drive rod 22 extending upward from movable main contact 1B
Disk-shaped short which receives the repulsive force from the electromagnetic repulsion coil 2
Necessary for the entanglement plate 21 and the fixed main contact 1A for the movable main contact 1B
Opening / closing drive rod for applying force of pressurizing wipe spring 24 for applying contact force
Insulated connecting bar 2 for transmitting to movable main contact 1B via contact 22
3 and a spring seat 25 serving as a scaffold for the pressure wipe spring 24.
The spring force of the cut-off spring 31 is integrally provided at the end,
Connecting bar 26 for transmitting to opening / closing drive rod 22 via
Normally keeps the cut-off spring 31 in the opening drive standby state.
To provide an engaging portion at the tip and
The connection bar 26 is driven downward by the force of the blocking spring 31 as shown in the figure.
An engagement lever for transmitting the force of the blocking spring 31 to the movable main contact 1B.
The bar 27 engages with the engaging portion at the tip of the engaging lever 27.
Opening of movable main contact 1B by cut-off spring 31
It is tripped and driven by the trip coil 33 for driving.
A latch lever 32 from which the engaging portion at the tip is pulled off, and a vacuum
The breaking operation characteristic of only the breaking spring 31 of the breaker was examined.
A manual shut-off switch 34 for detecting the detection control circuit shown in FIG.
Opening drive by the electromagnetic repulsion coil output from the path 13
Command for the opening operation by the shut-off spring.
Thyristor T for inputting disconnection command to each gate
h₁, Th _TwoAre provided as main components. Less than
Below, referring to Fig.1 and Fig.2, DC high-speed
The operation of the breaker will be described.

When a fault occurs in the DC line and the fault current reaches a predetermined level, two cutoff commands and one cut-off command are output from a detection control circuit 13 to which a detection current is input from a DC current transformer 12 (FIG. 1). The injection command is output at the same time. Shutdown command 1
One enters the gate of thyristor Th ₁ (FIG. 2) and another
One enters the gate of the Th _2. The input command activates the commutation switch 6 (FIG. 1) to turn it on. This allows
A commutation current starts flowing through the commutation circuit 10 and the movable main contact 1B in the vacuum valve 1
Due to the repulsive force generated between the wiping spring 21 and the short-circuiting plate 21, the opening is driven while further compressing the pressurizing wipe spring 24, whereby the current passing through the vacuum valve is cut off as shown in FIG. The movement of the movable main contact 1B at this time changes as shown in FIG. That is, the movement of the movable main contact 1B is T
slightly begins delayed time t ₃ from the disconnection instruction time point of input t ₂ to h ₁ (FIG. 6), shut-off command input after 10-15
ms, the maximum travel distance is reached, and thereafter, the decay of the repulsive current,
With the disappearance, the repulsive force falls below the force of the pressure wipe spring 24, the movable main contact 1B starts to return toward the fixed main contact 1A, and if there is no opening drive by the shut-off spring 31 described below, the two main The contact is closed again 20 to 30 ms after the movable main contact 1B starts the opening movement.
However, the cut-off command entered simultaneously with thyristor Th ₁ to the thyristor Th _2, the latch lever 32 is tripped by operation tripping coil 33 (FIG. 2), the pressurizing wiping spring 24 by the motion of the connecting bar 26 downwardly The force of the cut-off spring 31 is transmitted to the movable main contact 1B about 20 ms after the cut-off command is input via the insulating connection bar 23 and the opening / closing drive rod 22 while being loosened, so that the movable main contact 1B is prevented from returning thereafter.

FIG. 3B shows the movement characteristics of the movable main contact when the opening is driven only by the cut-off spring without using the electromagnetic repulsion coil. FIG. 3C shows the DC high speed according to the reference example of the present invention. 4 shows the operating characteristics of a movable main contact in a circuit breaker. FIG.
As can be seen from (c), even after the electromagnetic repulsion has been eliminated, the movable main contact can be maintained at a separation distance equal to or larger than the required minimum separation distance by the cut-off spring.

Further, as the tripping coil 33, a coil having a fast current rise after the start of energization and a small time constant is used.
Alternatively, if the tripping coil is driven by, for example, the discharge current of a capacitor charged with a DC voltage, a current that rises faster flows through the tripping coil 33, and the time at which the latch lever 32 is disengaged is released, Since the opening timing of the opening of the movable main contact by the cut-off spring is advanced, the reached movement distance can be reliably maintained without returning to the fixed main contact direction from the distance moved by the electromagnetic repulsive force as shown in FIG. .

[0016]

As described above, according to the present invention, there is provided a vacuum circuit breaker having a built-in main contact and a movable main contact having a vacuum valve whose opening is driven by an electromagnetic repulsion coil at a high speed. A DC high-speed circuit breaker comprising a commutation circuit that is connected in parallel with the valve and that generates a commutation current that is superimposed on the current flowing from the power supply to the load through the vacuum valve and creates a zero point in the vacuum valve passing current. Since the vacuum circuit breaker is provided with a blocking spring in addition to the electromagnetic repulsion coil for driving the opening of the movable main contact in the vacuum valve, the movable main contact together with the contact spring during the separation stroke by the electromagnetic repulsion coil is Alternatively, by moving the contact spring together with the scaffold, it is possible to prevent the movable main contact that has passed the required minimum separation distance from returning to the fixed main contact side, and to maintain the separation distance that has already been reached. In addition, the application of the shut-off spring for this purpose can be performed by diverting the operation mechanism of the ordinary AC circuit vacuum circuit breaker, and the DC high-speed circuit breaker can be configured simply and with high reliability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a configuration of a DC high-speed circuit breaker according to the present invention.

FIG. 2 is a structural principle diagram showing an embodiment of a vacuum circuit breaker used in a DC high-speed circuit breaker according to the present invention;

FIG. 3 shows an example of a moving characteristic of a movable main contact in a DC high-speed circuit breaker according to a reference example of the present invention. FIG. 3 (a) shows that the movable main contact is opened and driven only by an electromagnetic repulsion coil. FIG. 4B is a moving characteristic diagram showing the relationship between the moving distance of the movable main contact and the time from the issuance of the shutoff command for opening drive when the movable main contact is opened. FIG. FIG. 3C shows the movement characteristics when the movable main contact is both an electromagnetic repulsion coil and a cut-off spring.
A movement characteristic diagram when the opening drive is performed with a time difference as shown in FIG.

FIG. 4 shows an example of a moving characteristic of a movable main contact in the DC high-speed circuit breaker according to the embodiment of the present invention. FIG. 4 (a) shows that the movable main contact is opened and driven only by the electromagnetic repulsion coil. FIG. 4B is a moving characteristic diagram showing the relationship between the moving distance of the movable main contact and the time from the issuance of the shutoff command for opening drive when the movable main contact is opened. FIG. 3 (b), and FIG. 3 (c) shows a moving characteristic when the movable main contact is both an electromagnetic repulsion coil and a cut-off spring. ),
A movement characteristic diagram when the opening drive is performed with a time difference as shown in FIG.

FIG. 5 is a circuit diagram showing an example of a conventional DC high-speed circuit breaker having a vacuum valve whose movable main contact is driven to open by an electromagnetic repulsion coil.

FIG. 6 is a waveform chart showing a phenomenon of each part of the circuit breaker when DC current is cut off by the DC high-speed circuit breaker of FIG. 5;

[Explanation of symbols]

1 vacuum valve 1B movable main contact (movable main contact) 2 electromagnetic repulsion coil 10 commutation circuit 11 the vacuum interrupter 13 detects the control circuit 31 the opening spring 33 releasing coil Th ₁ thyristor Th ₂ Thyristor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 33/66 H01H 33/59

Claims (1)

(57) [Claims] 1. A vacuum circuit breaker having a built-in main contact and a movable main contact having a vacuum valve whose opening is driven at high speed by an electromagnetic repulsion coil, and a vacuum circuit breaker connected in parallel with the vacuum valve and passing through the vacuum valve. A DC commutation circuit that generates a commutation current that is superimposed on the current flowing from the power supply to the load to create a zero point in the current flowing through the vacuum valve, wherein the vacuum circuit breaker is An opening spring is provided in addition to the electromagnetic repulsion coil for opening the contacts, and the opening drive operation of the vacuum circuit breaker is performed by a command for the opening drive by the electromagnetic repulsion coil and the interruption spring. And a time constant of a tripping coil that trips an engagement mechanism that holds the shut-off spring in the opening drive standby state. To Thus, the starting point of the opening drive of the movable main contact by the cut-off spring is substantially the same as the time when the movable main contact reaches its maximum separation distance by the opening drive by the electromagnetic repulsion coil. DC high-speed circuit breaker characterized in that: