JPH05298965A - Circuit breaker equipped with resistance contact - Google Patents

Abstract

PURPOSE:To provide a good circuit breaker equipped with a resistance contact with which a compact and simple structure can be realized, with which a dielectric breakdown voltage of a resistance contact can be restricted low, and with which coordination of insulation and a lead time of the resistance contact can be secured sufficiently. CONSTITUTION:A resistance contact having a serially connected resistance body 9 are connected in parallel with a breaking part contact to be composed in such a way that the resistance contact is charged prior to the breaking part contact at the time of charging action. The resistance contact is provided with a first and a second electrodes 6, 13 disposed facing each other. End parts of the first and the second electrodes 6, 13 facing each other have almost semi- spherical base parts, and as contact parts in a closed condition, a a protrusion 6a is provided in a shortest gap part of one of the semi-spherical base part, and a recess 13a is provided at the other, so they get in contact with each other as the protrusion is engaged in the recess.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance contact having a structure in which a resistance contact is turned on before a breaking point contact is turned on and a surge voltage suppressing resistor is connected to both ends of the breaking point contact. The present invention relates to a circuit breaker, and more particularly, to an improvement in the structure of a resistance contact.

[0002]

BACKGROUND OF THE INVENTION Power circuit breakers generally include a main contact and an arc contact as breaker contacts. The normal load current is passed through the main contact, and the excessive surge voltage that occurs when the current is interrupted and turned on and causes arcing to wear the electrodes is processed at the arc contact. , Is configured to prevent wear of the main contacts. Such a configuration is effective in a high voltage circuit breaker.

On the other hand, in the case of a circuit breaker having an ultrahigh voltage or higher, the surge voltage generated by the closing operation becomes extremely high, and in particular, in order to sufficiently suppress the excessive surge voltage generated at the time of closing. In many cases, the surge voltage is suppressed by turning on the resistance contact prior to the arc contact and once connecting the external circuit via the resistor. Such a circuit breaker with a resistance contact is generally unitized as shown in FIG.

That is, in the circuit breaker with resistance contact shown in FIG. 5, the circuit breaker unit 22 and the resistance contact unit 23 are arranged side by side in the tank 21. Between one end (fixed side electrode) of both units 22 and 23,
It is fixed in an electrically insulated state via a support insulator 24, and a resistor 25 is connected between them by a conductor 26. In addition, both units 22,
A link mechanism 27 is provided between the other ends (movable electrodes) of 23.
And is mechanically connected via an operating device 28 provided outside the tank 21. Although not shown, the link mechanism 27
In some cases, a dedicated operating device corresponding to each of the units 22 and 23 may be individually provided without providing the above.

[0005]

However, the conventional circuit breaker with resistance contacts as described above has the following drawbacks. That is, since the breaker unit 22 and the resistance contact unit 23 are separately provided, there is a drawback that the circuit breaker becomes large in size. Further, as shown in FIG. 5, in order to drive the resistance contact unit 23, a link mechanism 27 is provided between the resistance contact unit 23 and the breaking unit 22, so that the driving force can be obtained from the breaking unit 22 side. Or, if a dedicated operating device is provided individually,
The structure is complicated and there is a lot of room for improvement in both design and assembly.

On the other hand, the fixed side and the movable side of the resistance contact part are directly attached to the fixed side and the movable side of the breaker, respectively, without forming the breaking part and the resistance contact part as separate units.
A method of integrating the fixed side and the movable side of the breaking portion and the resistance contact portion with each other is conceivable. When the resistance contact part is directly incorporated in the breaking part in this way, the structure of the circuit breaker as a whole can be made smaller and simpler than when the breaking part and the resistance contact part are formed as separate units. is there.

On the other hand, when the resistance contact portion is directly incorporated in the breaking portion in this way, the important point in design is that
Before turning on the arc contact of the breaking unit during closing operation, the resistance contact should be closed before the insertion time of the resistor, and during the breaking operation, discharge should occur between the breaking unit and closing contact. It is to emphasize insulation so that it does not occur. Among these, as the latter insulation enhancement measure, it is possible to substantially improve by forming the outer shape of the opposing end portion of the electrode forming the resistance contact into a hemispherical shape having a certain degree of curvature and relaxing the electric field at that portion. However, if the resistance contact electrode is made into a completely hemispherical shape in this way, the insulation breakdown voltage of the resistance contact becomes as high as that of the arc contact of the breaking part, and the arc contact becomes higher than that of the arc contact during the closing operation. This causes a problem that the resistive contact cannot be closed in advance for a sufficient time.

The present invention has been proposed in order to solve the problems of the prior art as described above, and its object is to reduce the size and simplification of the structure by directly incorporating the resistance contact portion in the breaking portion. (EN) Provided is an excellent circuit breaker with a resistance contact, which can be realized and which can suppress the insulation breakdown voltage of the resistance contact to a low level and can sufficiently secure insulation emphasis and lead time of the resistance contact. ..

[0009]

DISCLOSURE OF THE INVENTION A circuit breaker with a resistance contact according to the present invention comprises a resistance contact having a resistor connected in series,
In a circuit breaker with a resistance contact, which is connected in parallel with a breaker contact and is configured to make a resistance contact prior to the breaker contact during a closing operation, the resistance contacts are arranged opposite to each other. The first and second electrodes are provided with electrodes, and opposite ends of the first and second electrodes are provided with a substantially hemispherical base portion, and the shortest gap portion in the hemispherical base portion serves as a contact portion in a closed state. Is provided with a protrusion and the other is provided with a recess, and the protrusion is fitted into the recess so as to be contactable. Further, it is desirable that the size of the protrusion and the recess provided at the end of the resistance contact electrode be sufficiently smaller than that of the hemispherical portion that is the base portion of the electrode end.

[0010]

The above-mentioned structure is proposed by paying attention to the drawbacks in the above-mentioned prior art caused by the shape of the electrodes forming the resistance contact. That is, in the above-mentioned prior art in which the resistance contact portion is directly incorporated in the breaking portion, the resistance end is inserted into the arc contact at the time of making operation by making the outer shape of the opposite end portion of the resistance contact electrode into a complete hemispherical shape. The only problem was that the time was insufficient and as a result the dielectric breakdown voltage of the resistance contact was reduced. The present invention pays particular attention to this point, and slightly changes the outer shape of the opposing end portion of the resistance contact electrode, thereby reducing the insulation breakdown voltage of the resistance contact without reducing the insulation breakdown voltage between the breaking portion and the resistance contact. This is an attempt to reduce the voltage.

By the way, in the case of changing the outer shape of the opposing end portion of the resistance contact electrode to reduce the dielectric breakdown voltage of the resistance contact as described above, the first conceivable change is the shortest gap portion of the hemispherical end portion of the electrode. , The protrusions are provided on both sides to increase the electric field in this portion. However, since the resistance contact is designed to collide with each other at a high speed of several m / sec, when the protrusions are provided on the electrode ends on both sides, the protrusion is easily crushed by several opening and closing operations. After all, it is difficult to obtain the input characteristics as designed.

On the other hand, in the present invention, as described above, the protrusion is provided at one electrode end of the resistance contact, and
By forming a recess in the other electrode end of the resistance contact and fitting the projection into the recess, the breakdown voltage can be reduced and the impact applied to the projection during the closing operation of the resistance contact can be made extremely small. .. In particular, by matching the surface shapes of the protrusions and depressions, these contact parts, that is, the parts that receive the impact force during the closing operation, are not concentric points, but concentric circles. The force can be received in a considerably dispersed manner, and the wear of the resistance contact can be suppressed as much as possible.

On the other hand, in consideration of insulation emphasis, in the present invention, the base portion of the electrode end portion of the resistance contact has a hemispherical shape. It is considered that there is almost no possibility of causing a dielectric breakdown with the cutoff portion because a sufficient diameter dimension is provided so that the interface has a margin.

If the size of the protrusions and the depressions is made sufficiently smaller than that of the hemispherical portion that is the base portion of the electrode end portion, the dielectric breakdown voltage of the resistance contact is in the open state and in the initial stage of the closing operation. The effect of the protrusions and depressions of the resistance contact on the reduction of is small, and is almost the same as in the case where the shape is completely hemispherical. On the other hand, in the latter half of the closing operation, the effects of the protrusions and depressions gradually increase, and dielectric breakdown occurs at a much lower voltage than in the case where the hemispherical shape is completely formed, and the resistance contact is electrically closed. .. Conversely, the resistance contact is electrically turned on with a relatively large gap, so that a relatively long resistance insertion time can be obtained.

FIG. 4 is a characteristic diagram showing the dielectric breakdown voltage at the time of such a closing operation. The resistance contact (the present invention) consisting of electrodes having protrusions and depressions and the resistance contact consisting of a completely hemispherical electrode. (Prior Art) and the breakdown voltage of the arc contact of the breaker are shown by a solid line, a broken line, and a dashed line, respectively. As can be seen from FIG. 4, the resistance contact of the present invention shows almost the same dielectric breakdown voltage as that of the hemispherical resistance contact at the initial stage of contact opening, but the breakdown voltage rapidly decreases from the middle of making. start. As shown in FIG. 4, when the voltage applied to the circuit breaker during the closing operation is Vb, the resistance insertion time is S for a completely hemispherical resistance contact.
The stroke time is from ₂ to S ₃ , but with the resistance contact of the present invention, the stroke time is from S ₁ to S ₃ , and the resistance insertion time can be considerably extended.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a circuit breaker with a resistance contact according to the present invention will be described below with reference to FIGS. In this case, FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to a puffer-type circuit breaker with a resistance contact, and FIGS.
2 is an enlarged cross-sectional view showing the resistance contact of FIG. 1, FIG. 2 being an open state, and FIG. 3 being a closed state.

In the circuit breaker with resistance contacts shown in FIG.
A fixed portion 2 and a movable portion 3 are arranged to face each other on both sides in the tank 1 in the axial direction. The fixed part 2 includes a cylindrical main contact fixed side electrode 4 which constitutes a breaking part, a rod-shaped arc contact fixed side electrode 5 arranged in the central part thereof, and a resistance contact fixed side arranged adjacent to these electrodes. And an electrode 6. The resistance contact fixed side electrode 6 is provided with a coil spring 7, and in the opened state (not shown), the coil spring 7 causes the movable portion 3 side to be closer than the main contact fixed side electrode 4 and the arc contact fixed side electrode 5. It is configured so as to largely project.

Further, the main contact fixed side electrode 4 and the arc contact fixed side electrode 5 and the resistance contact fixed side electrode 6 are mechanically fixed in a state of being electrically insulated by a support insulator 8. There is. A resistor 9 is electrically connected by a conductor 10 between the main contact fixed side electrode 4 and the arc contact fixed side electrode 5 and the resistance contact fixed side electrode 6. In other words, on the fixed portion 2 side, the breaker portion and the resistance contact are electrically connected via the resistor 9 and mechanically fixed via the support insulator 8.

On the other hand, the movable part 3 is provided with a cylindrical main contact movable side electrode 11 forming a breaker part, a similarly cylindrical arc contact movable side electrode 12 disposed in the central part thereof, and adjacent thereto. The resistance contact movable side electrode 13 is arranged. In this case, the main contact movable side electrode 11 and the arc contact movable side electrode 12 are arranged to face the main contact fixed side electrode 4 and the arc contact fixed side electrode 5 described above, and the resistance contact movable side electrode 13 is the resistance contact. It is arranged so as to face the fixed-side electrode 6. In addition, the resistance contact movable side electrode 13 is provided in an extended portion of the flange of the main contact movable side electrode 11,
Therefore, on the movable portion 3 side, the breaker portion and the resistance contact are electrically connected and mechanically fixed. The resistance contact movable side electrode 13 is connected to the damper 14
And is configured to absorb the impact force generated during the closing operation.

Although not shown, the stroke between the resistance contact fixed side electrode 6 and the resistance contact movable side electrode 13 is about 60% of the stroke of the breaking portion, and the remaining stroke is resistance. It is adapted to be absorbed by the above-mentioned coil spring 7 provided on the contact-fixing side electrode 6. Further, the resistance contact fixed side electrode 6 and the resistance contact movable side electrode 13 both have a substantially hemispherical base portion, and the shortest gap portion in this hemispherical base portion serves as a contact portion in a closed state. Resistance contact fixed side electrode 6
Is provided with a projection 6a and the resistance contact movable side electrode 13 is provided with a recess 13a. Then, these protrusions 6a and the depressions 1
The size and shape of 3a are adapted so that its contact surface is wide.

In the figure, reference numeral 15 is an operating device for driving the movable portion 3 collectively, 16 is an operating rod for transmitting the driving force of the operating device 15 to the movable portion 3, and 17 is a periphery of the operating rod 16. The puffer cylinder 18 fixed to the puffer cylinder 18 is a puffer piston that is inserted into the puffer cylinder 17 and forms a puffer chamber 19. In this case, the puffer piston 18 is fixed in the tank 1. As we all know,
The puffer chamber 19 is compressed by the movement of the puffer cylinder 17 accompanying the driving of the movable portion 3, and is configured to blow the compressed gas to the arc generated at the arc contacts [5, 12] to extinguish the arc. There is.

The operation of the circuit breaker with resistance contact according to the present embodiment having the above-mentioned structure is as follows. First, during the closing operation, the movable part 3 starts to move to the fixed part 2 side which is the closing direction by the operation device 15. That is, the main contact movable side electrode 11, the arc contact movable side electrode 12, and the resistance contact movable side electrode 13 all start moving to the fixed portion 2 side.

At the time of movement of about 50% of the entire stroke, the main contact [4, 11] of the breaking portion, the arc contact [5,
12], the dielectric breakdown voltage is considerably high, but the dielectric breakdown voltage of the resistance contact [6, 13] is considerably low.
This is due to the fact that the initial gap of the resistance contact [6, 13] is narrow and the effect of the projection 6a and the depression 13a provided on both electrodes 6 and 13 thereof. In this way, the voltage applied to the circuit breaker at the time when the breakdown voltage of the resistance contact [6, 13] becomes considerably low is the resistance contact [6, 1].
3] is higher than the dielectric breakdown voltage, the resistance contact [6, 1
3] is electrically closed, a current flows through the resistor 9 provided on the fixed portion 2 side, and the surge voltage can be suppressed.

Further, if the movable part 3 continues to move, the resistance contact [6, 13] mechanically contacts at the time when it moves by the initial gap of the resistance contact [6, 13], and thereafter, the movable part 3 moves. 3 is a coil spring 7 of the fixed contact side electrode 6
While pressing, keep moving to the final loading position. During this period, the arc contacts [5, 12] and the main contacts [4, 11] are sequentially closed on the breaker side. Resistance contact [6,1
Since the time from the closing of [3] to the closing of the arc contacts [5, 12] is the resistance insertion time, it is a necessary condition for surge suppression that this time becomes a certain value or more. In the configuration of the present embodiment, the initial gap size of the resistance contact [6, 13] and the size and shape of the protrusion 6a and the recess 13a of both electrodes 6 and 13 are appropriately adjusted to achieve the above-described sufficient value. The resistance insertion time can be obtained.

Next, at the time of shut-off operation, the operating device 15
As a result, the movable portion 3 rapidly moves toward the operating device 15 side, which is the shutoff direction, and the puffer chamber 19 is compressed as the puffer cylinder 17 moves. That is, the main contact movable side electrode 11 and the arc contact movable side electrode 12 are separated from the main contact fixed side electrode 4 and the arc contact fixed side electrode 5, and move in such a manner that the gap is rapidly extended. At the same time, the resistance contact movable side electrode 13 also separates from the resistance contact fixed side electrode 6 and moves so as to rapidly extend the gap. In this case, the resistance contact fixed side electrode 6 whose pressure is released from the resistance contact movable side electrode 13 starts to move to the movable portion 3 side by the restoration (expansion) of the coil spring 7 in the compressed state. 7 is set so that the moving speed of the resistance contact fixed side electrode 6 due to the restoration is much slower than the moving speed of the movable portion 3, so that the resistance contact movable side electrode 13 causes the resistance contact fixed side electrode 6 to move. When it is sufficiently separated from, the resistance contact fixed side electrode 6 can be stopped at substantially the same position as in the closed state.

Therefore, when the current is cut off at the arc contacts [5, 12] by blowing gas from the puffer chamber 19, the gap of the resistance contacts [6, 13] is as shown in FIG.
As shown in Fig. 3, the stroke is sufficiently opened to the extent equivalent to the stroke of the breaking portion, and the possibility of dielectric breakdown at the resistance contact [6, 13] is extremely low. In addition, since the substantially hemispherical base portions of both electrodes 6 and 13 of the resistance contact [6, 13] are generally provided with a diameter dimension sufficient to have a margin in the electric field surface, There is almost no possibility of dielectric breakdown with the resistive contact. And the interruption is complete,
When the insulation of all the parts is completely restored, the coil spring 7 of the fixed contact fixed side electrode 6 finally extends to return to the initial state (open state) of the resistance contact.

As described above, in the present embodiment, by providing the projections 6a and the depressions 13a on both electrodes 6 and 13 of the resistance contact, only the dielectric breakdown voltage of the resistance contact is reduced during the closing operation, and the resistance is reduced. Insertion time can be lengthened.
Since the base portions of both electrodes 6 and 13 of the resistance contact have a substantially hemispherical shape having a sufficient size in the electric field plane, there is no problem that adversely affects other insulating characteristics. Therefore, in the present embodiment, by directly incorporating the resistance contact portion in the breaking portion, it is possible to realize the size reduction and simplification of the structure, and at the same time, sufficiently secure the insulation emphasis and the lead time of the resistance contact.

Further, since the contact portion of the resistance contact is a combination of the projection 6a and the depression 13a and the surface shape is adapted, the impact force at the time of making operation is not a point but a point.
Since the concentric surfaces can receive the dispersed particles, it is possible to suppress the wear of the resistance contact as much as possible. Further, in the actual circuit breaker assembly, it is extremely important to arrange the resistance contacts exactly in a straight line, but in this embodiment, the electrodes 6 and 13 of the resistance contact are provided with the projections 6a and the depressions 13a. Therefore, there is also an advantage that the resistance contact can be relatively easily arranged in a straight line by fitting the protrusion 6a into the recess 13a.

The present invention is not limited to the above-described embodiment, and, for example, contrary to the above-mentioned embodiment, a structure is provided in which the resistance contact fixed side electrode 6 is provided with a depression and the resistance contact movable side electrode 7 is provided with a protrusion. Is possible as well. Further, the present invention can be similarly applied to a double motion type circuit breaker in which electrodes on both sides are relatively moved, and can be similarly applied to various circuit breakers other than the puffer type circuit breaker.

[0030]

As described above, according to the present invention, the resistance contact portion is directly incorporated in the breaking portion, and the projection is formed on one of the electrodes on both sides constituting the resistance contact and the depression is formed on the other electrode. It is possible to realize small size and simplification, and moreover,
It is possible to provide an excellent circuit breaker with a resistance contact, which can suppress the insulation breakdown voltage of the resistance contact to a low level and can sufficiently secure insulation emphasis and the lead time of the resistance contact.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment in which the present invention is applied to a puffer-type circuit breaker with a resistance contact.

FIG. 2 is an enlarged cross-sectional view showing an open state of the resistance contact of FIG.

FIG. 3 is an enlarged cross-sectional view showing a closed state of the resistance contact of FIG.

FIG. 4 is a characteristic diagram showing a dielectric breakdown voltage during a closing operation of a circuit breaker with a resistance contact according to the present invention.

FIG. 5 is a configuration diagram showing an example of a conventional circuit breaker with a resistance contact.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank 2 ... Fixed part 3 ... Movable part 4 ... Main contact fixed side electrode 5 ... Arc contact fixed side electrode 6 ... Resistance contact fixed side electrode 6a ... Protrusion 7 ... Coil spring 8 ... Support insulator 9 ... Resistor 10 ... Conductor 11 ... Main contact movable side electrode 12 ... Arc contact movable side electrode 13 ... Resistance contact movable side electrode 13a ... Indentation 14 ... Damper 15 ... Operator 16 ... Operation rod 17 ... Puffer cylinder 18 ... Puffer piston 19 ... Puffer chamber

Claims (1)

[Claims] 1. A circuit breaker with a resistance contact configured such that a resistance contact having a resistor connected in series is connected in parallel with a breaker contact and the resistance contact is closed prior to the breaker contact during closing operation. In, the resistance contact comprises first and second electrodes arranged opposite to each other, and opposite ends of the first and second electrodes include a substantially hemispherical base portion, and As a contact part in the closed state in the shortest gap part in the base part, a protrusion is provided on one side and a recess is provided on the other side, and it is configured to be contactable by fitting the protrusion in the recess Circuit breaker.