JPH0324009B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a circuit breaker tripping command that is generated by a small output current limited by an electronic circuit when a circuit breaker tripping mechanism is activated. This invention relates to a tripping device for a circuit breaker that can be tripped.

[Conventional technology]

1 to 4 of the drawings show a conventional example as a background of the present invention, in which FIG. 1 is a configuration diagram of a tripping circuit of a circuit breaker, FIG. 2 is a side sectional view of a tripping actuator, FIG. 3 is a partially enlarged view of FIG. 2, and FIG. 4 is a diagram showing the relationship between the main circuit current, the secondary current of the current transformer, and the current flowing through the tripping coil of the actuator.

In FIG. 1 of the drawings, a circuit breaker 1 has a circuit breaker 1 in which a circuit breaker 2 is inserted into the circuit, and a current transformer 3 is provided to detect the current flowing through this circuit.
The secondary output current of this current transformer 3 is input to a static overcurrent relay 4, and the overcurrent relay 4 detects a tripping current value according to a predetermined calculation method, and when the current value exceeds that value, the overcurrent relay 4 detects a tripping current value according to a predetermined calculation method. Outputs trip signal current. The overcurrent relay 4 includes a capacitor 5 for storing energy, and a tripping current is applied to the tripping coil of the actuator 6.
is operated so as to release the opening/closing mechanism 7 of the circuit breaker 1 and open the circuit breaker 2.

Generally, the above-described tripping command for the overcurrent relay 4 is output using an electronic circuit. Because the output level of this electronic circuit is low, a flux-switched actuator is used to release the circuit breaker opening/closing mechanism. Such a conventional actuator is shown in a side sectional view in FIG. 2, and the actuator has a first magnetic pole surface 11' integrally provided with a fixed armature portion on one end side of a magnetic frame 11 made of a magnetic material, A fixed guide pin 12 made of a non-magnetic material and integrally implanted in the magnetic frame 11 is connected to the first magnetic pole surface 1.
It is provided so as to protrude from 1'. A fixed guide pin 12 is inserted into a guide hole 13a provided in the center of the movable core 13 so that one end of the movable core 13 corresponds to the first magnetic pole surface 11', and the first magnetic pole surface 11' and the movable core A tripping spring 14 is installed between the spring 13 and the spring 13 so as to be always biased in the direction of opening. The other end 13b of the movable core 13, whose outer cylinder diameter is reduced in a stepped manner, is arranged to pass through the through hole 15 of the magnetic frame 11, and has a head protrusion 13c of the actuating member at its tip. There is. Also,
A tripping coil 1 surrounds the first magnetic pole surface 11'.
A pair of permanent magnets 17, 17 are provided adjacent to the tripping coil 16 and facing each other on both sides of the body of the movable core 13.

A conventional actuator with such a configuration is movable by forming a magnetic circuit in which the magnetic flux from the permanent magnets 17, 17 returns to the permanent magnets 17, 17 through the movable core 13, the first magnetic pole face 11', and the magnetic frame 11. It has an acting force that holds the core 13 in the attracted position of the first magnetic pole face 11'.

Now, the tripping DC current from the above-mentioned overcurrent relay 4 is applied to the tripping coil 16 by the permanent magnets 17, 17.
When the magnetic flux produced by The actuating member 13c moves linearly away from the surface 11', actuating the tripping member of the circuit breaker 1, releasing the opening/closing mechanism 7, and opening the interrupting portion 2.

[Problem that the invention seeks to solve]

As described above, the overcurrent relay 4 of the circuit breaker 1 is tripped by controlling the secondary current of the current transformer 3 inserted into the main circuit. This operating range is very wide, from ground fault interruption of 5 to 10% of the rated current to short circuit current of several thousand percent. An energy storage capacitor 5 is used in the overcurrent relay 4 so that the secondary power of the current transformer 3 provides sufficient mechanical energy for tripping even with a small current, and the actuator directly receives the tripping force. In the normal state of the circuit breaker, the tripping spring 14 is charged and held by a permanent magnet 17, and even when the overcurrent relay 4 is operated, the capacitor 5 is not discharged. The current flows through the tripping coil 16 of the actuator, reverse excites the holding magnetic path formed by the permanent magnet 17, releases the restraint of the tripping spring 14, releases the energy of the spring, and activates the actuating member 13c to interrupt the circuit. Pull out the device.

In this type of permanent magnet holding actuator, in order to stably hold the tripping spring 14 by the permanent magnet 17 and perform stable tripping even when the primary current of the current transformer 3 is small, The tripping spring 14 has a minimum load required for tripping, the holding force of the permanent magnet 17 is a value sufficient to restrain the tripping spring 14, and is not excessive, and the capacitor 5
Even if the energy output from the is small, it can be sufficiently tripped.

That is, in this method, the circuit breaker is not tripped directly by the output of the capacitor, but by the stored spring, and the current transformer secondary current and the discharge current of the capacitor control the operation of the spring. It is something. An actuator constructed in this manner cannot be expected to operate sufficiently quickly upon tripping due to the inertia of the circuit breaker tripping mechanism and the movable parts of the actuator. Furthermore, although there is no need to shorten the breaking time in a small current region, it is necessary for the circuit breaker to operate at a sufficiently high speed and complete the breaking quickly in the case of an overcurrent of several thousand percent such as in a short circuit. However, circuit breakers using this type of actuator tend to have a slight delay in tripping compared to electromechanical instantaneous tripping devices in which the tripping mechanism is actuated directly by an electromagnet that is actuated directly by the current in the main circuit. be.

In conventional permanent magnet holding actuators, the secondary current of the current transformer that is generated in response to the current flowing in the main circuit causes surplus current to occur in the large current region of the main circuit at the operating current of the actuator, as shown in Figure 4. The disadvantage is that the electromagnetic energy of the short circuit current is not fully utilized to trip the circuit breaker. Further, since the energy source for tripping the circuit breaker is not the secondary current of the current transformer but the stored energy of the spring, such a system can be called a spring trip type circuit breaker.

Furthermore, in conventional permanent magnet holding actuators, the mutual relationship between the fixed magnetic frame, movable core, permanent magnet, and tripping coil is such that when normally attracted by the permanent magnet, the tripping coil is By reverse excitation, the attraction is eliminated and the circuit breaker is tripped, but if the operating current is excessive, the movable core, once released from the magnetic pole surface, will be re-attracted due to the excessive reverse magnetic flux that overcomes the magnetic flux of the permanent magnet. This has the disadvantage that it generates force, reduces the force of the tripping spring, and reduces the degree of separation of the movable core.

Incidentally, as shown in FIG. 3, the magnetic flux of reverse excitation that passes through the air gap gr between the through hole 15 of the magnetic frame 11 and the cylindrical reduced portion 13b of the movable core 13 inserted therethrough is a radiation magnetic flux. Therefore, the force is canceled against the movable core, so it does not become an attractive force. Also, a magnetic frame 1 serving as a stopper for the movable core 13 is provided.
Even if there is a longitudinal magnetic flux generated in the air between the peripheral wall of the through hole 15 of No. 1 and the stepped portion of the movable core 13, the tripping coil is placed in a position such that the magnetic flux in the air becomes an effective attractive force. The disadvantage is that it is not placed.

In this way, in a circuit breaker that interrupts large currents, excessive electromagnetic force is generated in the contact mechanism when a short circuit occurs.
This force is transmitted to the tripping mechanism of the circuit breaker via the opening/closing mechanism at a certain rate of decline. In such a case, unless the tripping force is sufficient to sufficiently overcome this force, high-speed disconnection is impossible, and the performance of the circuit breaker is likely to deteriorate.

Therefore, the circuit breaker tripping device according to the present invention improves the above-mentioned drawbacks of the actuator, and can perform high-speed tripping by effectively utilizing excessive energy due to large current while reliably performing tripping operation with small current. The purpose is to remove it.

[Means for solving problems]

According to this invention, the circuit breaker tripping device includes a current transformer inserted in the main circuit of the circuit breaker;
an overcurrent relay having an output means for inputting the secondary current of a current transformer and outputting a current according to a predetermined calculation method; and an overcurrent relay provided corresponding to a circuit breaker tripping mechanism, through which the output current flows. A tripping circuit is constituted by an actuator that sometimes trips a circuit breaker, and the actuator includes a magnetic frame, a permanent magnet,
A tripping coil through which an output current of the overcurrent relay is passed, a movable core, an actuating means extending from the movable core to a tripping mechanism of the circuit breaker, and a tripping spring that drives the movable core in a direction to trip the circuit breaker. the magnetic frame includes first and second magnetic plates having parallel and opposing first and second magnetic pole surfaces; and a yoke portion surrounding the tripping coil, the permanent magnet generates a magnetic flux that attracts the movable core to the first magnetic pole face, and the movable core is attached within the spacing between the first and second magnetic pole faces. It is swingable and has a length that has a travel distance slightly larger than the stroke required for the tripping mechanism of the circuit breaker, and is mounted with a guide means and can be moved on either side of the movable direction depending on the position of the movable core. A magnetic space generating longitudinal magnetic flux is formed between the first and second magnetic pole faces, and in response to the opening operation of the circuit breaker, the reset mechanism trips the movable core against the force of the spring means. is moved to the first magnetic pole side and held by a permanent magnet, and when the overcurrent relay is activated in the closed state of the circuit breaker, the tripping coil absorbs the magnetic flux on the first magnetic pole surface supplied by the permanent magnet. In a device in which the holding state is canceled by canceling the holding state and the tripping mechanism of the circuit breaker is activated by a tripping spring, the tripping coil is wound around the empty side of the second magnetic pole face. The magnetic flux of the second magnetic pole surface is increased to generate an attractive force.

〔Example〕

A recommended embodiment of the present invention will be described below with reference to the accompanying drawings.The circuit breaker tripping circuit configuration is as shown in FIG. The one shown in FIG. 6 is used. FIG. 5 is a side sectional view of the actuator in the suction state, and FIG. 6 is a side sectional view of the actuator in the released state. As shown in the figure, in the actuator of the present invention, a permanent magnet 102 formed in a disk shape at one end side of a magnetic frame 101 made of a magnetic material, and a fixed armature 103 also formed in a disk shape. They are installed one on top of the other. A cylindrical movable core 105 is provided so that one end surface of the fixed armature 103 becomes the first magnetic pole surface 104 . Further, the guide pin 106 made of a non-magnetic material is arranged in the axial direction from one end side of the magnetic frame 101 to the permanent magnet 102, the fixed armature 103, the movable core 105, and the second magnetic pole face 1.
The other end of the magnetic Azusa 101 forming 07 is inserted,
An actuating member 108 is attached to one end thereof. Movable core 105 and guide pin 106 are connected to set screw 1
09, and the movable core 105
A tripping spring 110 is installed as a biasing means between the fixed armature 103 and the constantly movable core 10.
5 in the direction of opening. Fixed armature 1
03 and the second magnetic pole surface 107 of the magnetic Azusa 101, a tripping coil 11 is arranged around the movable core 105.
1 is provided.

The tip of the actuating member 108 is provided in correspondence with a tripping link 112 of the tripping mechanism of the circuit breaker, and is a release device that collapses the closing/opening mechanism of the circuit breaker and opens the circuit by rotating the tripping link 112. It is designed to release. Further, a reset lever 113 is provided corresponding to the flange 108a formed on the operating member 108, and this reset lever 113
works in conjunction with the opening/closing mechanism of the circuit breaker, and when the circuit breaker is closed, presses the flange 108a of the operating member and moves the movable core 105 to a position where it is attracted to the first magnetic pole surface 104 of the fixed armature 103. It is designed to allow

The movable core 105 has a first magnetic pole face 104 and a second magnetic pole face 104.
having a length that is movable between the pole face 107 of the circuit breaker and has a travel distance slightly larger than the stroke required for the tripping mechanism of the circuit breaker;
A magnetic air gap G is installed together with the guide means and generates a longitudinal magnetic flux between the first magnetic pole surface 104 and the second magnetic pole surface 107 on either side in the axial direction depending on the position of the movable core 105. It is formed to occur.

It should be noted that the permanent magnet 102 may be in the shape of a disk or in the form of a plurality of rectangles divided into two parts and provided so as to correspond to the periphery of the guide pin 106, respectively.

Embodiments of the actuator according to the present invention will be described below with reference to FIGS. 7 to 9 regarding the relationship between magnetic flux and operation. FIG. This is an explanatory diagram showing the magnetic flux generated by the coil as a solid line, and FIGS. 8 and 9 are explanatory diagrams showing magnetic flux changes corresponding to the position of the movable core, and FIG. 8 shows normal operation.
FIG. 9 shows the case when an excessive current is applied to the tripping coil.

As shown in FIG. 7, permanent magnet 1
Φ _B11 and Φ _B12 of the magnetic flux generated by the tripping coil 111 when the overcurrent relay is activated are in opposite directions with respect to the magnetic flux (Φ _A1 + Φ _A2 ) generated in the first magnetic pole surface 104 by 03. As a result, the restraint of the tripping spring 110 is released, and the movable core 105
Tripping is performed by moving toward the air G on the second magnetic pole face 107 side, and the current flowing through the tripping coil 111 at the time of tripping is instantaneous due to the inductance of the tripping coil 111. After a slight time delay without reaching the maximum value, the magnetic flux (Φ _B11 + Φ _B12 ) acting on the first magnetic pole face 104 reduces the magnetic flux (Φ _A1 + Φ _A2 ) of the permanent magnet 103, and the action of the tripping spring 110 is reduced. The movement of the movable core 105 begins when the force overcomes the attraction force. In the initial state of movement of the movable core 105, the first magnetic pole face 10
As the gap between 4 and 4 increases, the tripping coil 11
The current flowing through the tripping coil 111 also increases, and the magnetic flux in the air between it and the first magnetic pole face 104 becomes completely zero, but the current in the tripping coil 111 continues to increase, and the magnetic flux due to this current increases the magnetic flux of the permanent magnet. It overcomes the magnetic flux and finally turns into re-attractive force. Therefore, in this state, movement of the movable core 105 is prevented. but,
At this point in the actuator of the present invention, as the movement of the movable core 105 progresses and the distance between the movable core 105 and the second magnetic pole surface 107 decreases, the tripping coil 11
Since the leakage magnetic flux Φ _B2 within the magnetic pole 1 increases, the attractive force toward the second magnetic pole surface 107 side increases, and the movable core 105 is accelerated toward the second magnetic pole surface 107 side.

This effect becomes more pronounced when an excessive current flows as shown in FIG. 9, as the magnetic flux increases compared to the normal case shown in FIG. 8. Further, since this type of actuator generally has a long dimension in the axial direction, the leakage magnetic flux Φ _B2 has a large proportion, so by effectively utilizing this as a drive, a strong accelerating force can be obtained.

When the actuator operates to trip the circuit breaker, the actuator actuating member 108 contacts or collides with the trip link 112 of the circuit breaker tripping mechanism; Since the inertia of is added, the speed decreases according to the law of conservation of momentum. In order to reduce this speed reduction, the actuator needs sufficient acceleration, but since the attractive force of the movable core 105 to the second magnetic pole surface 107 is added to the acceleration force of the tripping spring 110, the movable core 105 It is possible to prevent a decrease in speed and improve the tripping speed.

10 to 12 show other embodiments of the present invention, in which FIG. 10 is a side sectional view of the actuator, and FIGS. 11 and 12 show a connection method for the tripping coil in FIG. 10. Figure 11 is a wiring diagram in which two tripping coils are connected in series.
The figure is a wiring diagram showing a case where tripping coils are connected in parallel.

As shown in FIG. 10, in another embodiment of the actuator of the present invention, a magnetic frame 201 made of a magnetic material is movable between a first magnetic pole surface 202 and a second magnetic pole surface 203 at both ends. A cylindrical movable core 204 is provided, and is formed so that a magnetic air G is generated between the first magnetic pole surface 202 and the second magnetic pole surface 203. A guide pin 205 made of a non-magnetic material is inserted from the outside of one side of the magnetic frame 201 through the movable core 204 in the axial direction.
The other end of 1 is guided outward, and an actuating member 2 is attached to the tip thereof.
06 is installed. The movable core 204 and the guide pin 205 are tightened together by a set screw 207, and a tripping spring 208 is installed between the movable core 204 and the first magnetic pole surface 202, so that the movable core 204 is always connected to the first magnetic pole surface. 202 is biased in the direction of separation. A tripping coil 20 is provided at both ends of the magnetic frame 201 so as to surround the movable core 24.
9,209' are arranged. In addition, the magnetic frame 201
Both tripping coils 209, 20
A pair of permanent magnets 210 are provided between the magnets 9'. The pair of permanent magnets 210 have a rectangular shape and are provided so as to face each other with the movable core 204 in between.

In addition, two tripping coils 209, 209'
can be connected in series as shown in FIG. 11 to supply current in the same direction from the output element 211 of the overcurrent relay, and as shown in FIG. are provided in parallel to be controlled by the two output elements 211 and 211', and for normal currents only the tripping coil 209 near the first magnetic pole face 202 is energized, and for excessive currents both tripping coils 209 are energized. coil 209,
209' may also be energized.

〔Effect of the invention〕

As described above, according to the circuit breaker tripping device of the present invention, the actuator is connected to the magnetic cassette, the permanent magnet, the tripping coil through which the output current of the overcurrent relay is passed, the movable core, and the movable core. Comprised of an actuating means extending to the circuit breaker tripping mechanism, a tripping spring means for driving the movable core in the circuit breaker tripping direction, a movable core guide means, and a movable core reset means, By winding the tripping coil around the air around the second magnetic pole surface, the magnetic flux of the tripping coil of the actuator is generated so that the attractive force to the second magnetic pole surface of the movable core is increased. The opening speed of the movable core is accelerated, making it possible to perform high-speed tripping especially when excessive current flows through the circuit breaker, ensuring the intended purpose of tripping with a small current. However, it is possible to perform high-speed tripping by using excessive energy due to large current, and the circuit breaker tripping command is reliably pulled out with a small output current limited by the electronic circuit. It has the following effects:

[Brief explanation of drawings]

1 to 4 show conventional examples of circuit breaker tripping devices, in which FIG. 1 is a configuration diagram of a circuit breaker tripping circuit, FIG. 2 is a side sectional view of a tripping actuator, Figure 3 is a partially enlarged view of Figure 2;
The figure shows the relationship between the main circuit current, the secondary current of the current transformer, and the current flowing through the tripping coil of the actuator. Figures 5 and 6 show an embodiment of the actuator according to the present invention. FIG. 5 is a side sectional view of the actuator in the attracted state, FIG. 6 is a side sectional view of the actuator in the open state, and FIGS. 7 to 9 show the magnetic flux and Fig. 7 is an explanatory diagram showing the magnetic flux generated by the permanent magnet with a chain line, and the magnetic flux generated by the tripping coil with a solid line.
9 are explanatory diagrams showing magnetic flux changes corresponding to the position of the movable core, FIG. 8 shows normal operation, and FIG. 9 shows the case when excessive current is applied to the tripping coil. 10 to 12 show other embodiments of the actuator according to the present invention, FIG. 10 is a side sectional view of the actuator, and FIG.
Figure 12 shows how to connect the tripping coils in Figure 10, Figure 11 is a connection diagram where two tripping coils are connected in series, and Figure 12 is a wiring diagram where two tripping coils are connected in parallel. It is a wiring diagram showing a case. In the figure, 1: circuit breaker diagram, 2: interrupter, 3: current transformer, 4: overcurrent relay, 5: capacitor, 6:
Actuator, 7: Opening/closing mechanism, 11: Magnetic Azusa,
13: movable core, 14: tripping spring, 16: tripping coil, 17: permanent magnet, 101: magnetic frame,
102: Permanent magnet, 103: Fixed contact, 10
4,107: Magnetic pole surface, 105: Movable core, 10
8: Operating member, 110: Trip spring, 111: Trip coil, 112: Trip link, 113: Reset lever, 201: Magnetic frame, 202, 20
3: Magnetic pole surface, 204 movable core, 206: Operating member, 208: Trip spring, 209, 209': Trip coil, 210: Permanent magnet, 211, 21
1': Output element.

Claims (1)

[Claims] 1. A current transformer inserted into the main circuit of a circuit breaker;
an overcurrent relay having an output means that receives the secondary current of the current transformer and outputs a current according to a predetermined calculation method; and an overcurrent relay provided corresponding to the circuit breaker tripping mechanism, through which the output current flows. an actuator that trips the circuit breaker when
A tripping coil through which the output current of the overcurrent relay is passed, a movable core, an actuating means extending from the movable core to a tripping mechanism of the circuit breaker, and a trigger for driving the movable core in the direction of tripping the circuit breaker. The magnetic frame includes first and second magnetic plates having parallel and opposing first and second magnetic pole surfaces; a yoke portion that magnetically connects the magnetic plates and surrounds the tripping coil; the permanent magnet generates a magnetic flux that attracts the movable core to the first magnetic pole surface; and the movable core The movable core has a length that is swingable within the spacing between the first and second magnetic pole faces and has a travel distance slightly larger than the stroke required for the tripping mechanism of the circuit breaker, and is mounted with a guide means. A magnetic space that generates a longitudinal magnetic flux is formed between the first and second magnetic pole faces on either side of the movable direction depending on the position, and a reset mechanism is activated in response to the opening operation of the circuit breaker. tripping the movable core against the force of the spring means.
The tripping coil is moved to the magnetic pole side and attracted and held by a permanent magnet, and when the overcurrent relay is activated in the closed state of the circuit breaker, the tripping coil cancels the magnetic flux on the first magnetic pole surface supplied by the permanent magnet. The circuit breaker is released from the holding state by a tripping spring, and the tripping mechanism of the circuit breaker is actuated by a tripping spring, wherein the tripping coil is wound around the second magnetic pole surface and the second A circuit breaker tripping device characterized by increasing magnetic flux on a magnetic pole surface to generate an attractive force. 2. The circuit according to claim 1, wherein the permanent magnet is disposed outside the first magnetic pole surface, and a portion of the magnetic flux generates a force that attracts the movable core to the first magnetic pole surface. Circuit breaker tripping device. 3 The permanent magnets are arranged inside the magnetic frame between the first and second magnetic pole surfaces so that the same polarity faces each other via the movable core, and the tripping coil is divided into two, with one side facing the first magnetic pole side. side, the other side is the second
The tripping device for a circuit breaker according to claim 1, wherein the circuit breaker tripping device is connected in series in the same winding direction to the magnetic pole face side of the circuit breaker. 4 The permanent magnets are arranged inside the magnetic frame between the first and second magnetic pole surfaces so that the same polarity faces each other via the movable core, and the tripping coil is divided into two, with one side facing the first magnetic pole side. side, the other side is the second
The tripping coils are arranged in the same winding direction on the magnetic pole side of the magnetic poles, and in a normal overcurrent, only the tripping coil on the first magnetic pole side is energized, but if an excessive short-circuit current occurs, the tripping coils on the first magnetic pole side are energized.
2. The circuit breaker tripping device according to claim 1, wherein the tripping coils disposed on the second magnetic pole surface side are both excited.