JP3861468B2 - DC circuit breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a DC circuit breaker having a discharge disconnector for discharging a built-in capacitor for safety when checking a contact, and more particularly to a DC circuit breaker having a discharge disconnector that is easy to assemble.
[0002]
[Prior art]
FIG. 6 is a circuit diagram showing a configuration of a conventional DC circuit breaker. The circuit breaker 4 of the DC circuit breaker 31 and the circuit breakers 9 and 9 are interposed in the DC circuit 18 including the DC power source 1, the load 2 and the circuit breaker 3. A circuit in the ranges 12A and 13A in the alternate long and short dash line is the DC breaker 31. In the DC circuit breaker 31, a discharge disconnecting switch 5 and a series circuit 19 of a capacitor 7 and a switch 6 are connected in parallel to the circuit breaker 4 via separate disconnecting switches 10 and 10, respectively. As will be described later, the range 12A is placed on a carriage, and the range 13A is arranged on a fixed cradle. The disconnectors 9, 9 and 10, 10 are closed by pushing the cart to the cradle side and opened by pulling the cart to the near side. The switch 6 is formed of a thyristor, and is brought into a closed state by injecting a signal from the outside. Further, the discharge disconnector 5 is opened and closed manually. During the operation of the DC circuit breaker 31, the disconnecting devices 9, 9 and 10, 10 are closed, the discharging disconnecting device 5 and the switch 6 are opened, and the capacitor 7 is connected to a charging device (not shown). Is always DC charged. On the other hand, the DC circuit 18 is energized by closing the disconnector 3 and the circuit breaker 4.
[0003]
Next, a mechanism for operating the DC circuit breaker 31 of FIG. 6 to interrupt the DC circuit 18 being energized will be described. The circuit breaker 4 is opened and the switch 6 is closed in response to a break command from the outside. Thereby, an arc is generated between the contacts of the circuit breaker 4 and a discharge current from the capacitor 7 flows. This discharge current oscillates due to the capacitor 7 and the inductance of the circuit (not shown), and forms a zero point in the current flowing between the contacts of the circuit breaker 4. At this zero point, the arc between the contacts of the circuit breaker 4 is extinguished, and the DC circuit 18 is cut off.
[0004]
On the other hand, in order to check the contact point of the circuit breaker 4, it is dangerous to discharge the electric charge charged in the capacitor 7, so it is necessary to discharge the capacitor 7 in advance. The discharge disconnector 5 is for discharging the electric charge charged in the capacitor 7.
The procedure for discharging the capacitor 7 will be described next. When the disconnector 3 of the DC circuit 18 is in the open state, the cart is pulled out to the front side to open the disconnectors 9, 9 and 10, 10. In this state, the switch 6 and the discharge disconnector 5 are closed, and the electric charge charged in the capacitor 7 is discharged through the discharge disconnector 5.
[0005]
FIG. 7 is a side view showing the configuration of the DC circuit breaker 31 of FIG. The movable contact of the disconnector 9 is fixed to the carriage 12 side, and the fixed contact of the disconnector 9 is fixed via an insulator 9A on the cradle 13 side. Moreover, the movable contact of the disconnector 10 is fixed to the carriage 12 side, and the fixed contact of the disconnector 10 is fixed to the cradle 13 side via an insulating bushing 10A. Both ends of the circuit breaker 4 in the carriage 12 are connected to movable contacts of the disconnectors 9 and 10, respectively. The fixed contact of the disconnector 10 is pulled out to the right side of the insulating bushing 11 and connected to the discharge disconnector 5. The discharge disconnector 5 includes a fixed contact 14 and a movable contact 15, and the movable contact 15 is connected to the operation shaft 8 via an insulating lever 16. The movable contact 15 of the discharge disconnector 5 comes into contact with the fixed contact 14 so as to sandwich the sword-shaped fixed contact 14 with two conductive plates. The operation shaft 8 extends through the lower part of the carriage 12 to the front side (left side), and a handle 8A is formed at the left end. When the handle 8A is rotated, the operation shaft 8 is rotated, whereby the insulating lever 16 is also rotated, so that the fixed contact 14 and the movable contact 15 of the discharge disconnector 5 are brought into contact with and separated from each other.
[0006]
FIG. 8 is a back view showing the configuration of the DC circuit breaker 31 of FIG. 6, and is also a view taken in the direction of arrow A in FIG. The two fixed contacts 14 and 14 are fixed to the respective insulating bushings 11, and the discharge disconnector 5 is closed so that the movable contacts 15 bridge the fixed contacts 14 and 14. The dashed-dotted line in FIG. 8 shows the state which the disconnecting switch 5 for discharge opened. That is, the operating shaft 8 rotates the insulating lever 16 counterclockwise, thereby closing the discharge disconnector 5. On the other hand, when the operating shaft 8 rotates the insulating lever 16 in the clockwise direction, the discharge disconnector 5 is opened.
[0007]
Returning to FIG. 7, when checking the circuit breaker 4, the carriage 12 is first pulled leftward. Thereby, the disconnectors 9 and 10 are opened. Next, the handle 8A is manually operated to close the discharging disconnector 5. Thereby, a capacitor (not shown) is discharged and there is no risk of electric shock, so that the circuit breaker 4 can be inspected.
[0008]
[Problems to be solved by the invention]
However, the conventional apparatus as described above has a problem that it is difficult to assemble a discharge disconnector.
That is, the conventional disconnecting switch for discharge is composed of a single movable contact, and if the movable contact and the stationary contact are not assembled with high accuracy, the movable contact and the movable contact are not closed when closed. It was found that the contact state worsened. If the parallelism between the movable contact and the fixed contact, the parallelism between the two fixed contacts, and the position of the two fixed contacts are not accurate, the movable contact and the fixed contact There may be a contact state, or in the worst case, the fixed contact and the movable contact on one side may not contact each other. Therefore, conventionally, it took a great deal of time to assemble the discharge disconnector, and the assembly work was carefully performed so that the contact state between the movable contact and the fixed contact became good. In addition, since the electric charge charged in the capacitor is directly passed to the discharge disconnector, the contact of the discharge disconnector is easily damaged, and the life of the discharge disconnector is short.
[0009]
An object of the present invention is to provide a DC circuit breaker provided with a discharge disconnector that is easy to assemble, and to make the contact of the discharge disconnector less susceptible to damage.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a DC circuit breaker in which a series circuit of a DC-charged capacitor and a switch and a discharge disconnector are respectively connected in parallel to the circuit breaker, the discharge The disconnector is composed of two independent contact points connected in series, and each of the contact points is provided with a fixed contact and a movable contact that come in contact with and away from each other, and the movable contacts are preferably interlocked with each other. Thereby, since the contact operation of the fixed contact and the movable contact of each contact is independent at each contact, the contacts do not affect each other. Therefore, it is only necessary to adjust the contacts of the respective contacts, and the assembly of the discharge disconnector is facilitated.
[0011]
In this configuration, a discharge resistor may be connected in series to the discharge disconnector. As a result, the current flowing through the discharge disconnector is limited by the discharge resistance, and the contacts of the discharge disconnector are unlikely to be damaged.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on examples. FIG. 1 is a circuit diagram showing a configuration of a DC circuit breaker 31 according to an embodiment of the present invention. The discharge disconnector 20 is composed of two independent contacts connected in series, and the movable contacts of these contacts are interlocked by a connecting rod 24. Furthermore, a discharge resistor 21 is connected in series to the discharge disconnector 20. Others are the same as those of the conventional configuration of FIG. 6, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.
[0013]
FIG. 2 is a main part rear view showing the configuration of the DC circuit breaker 31 of FIG. Two fixed contacts 26, 26 of the discharge disconnector 20 are fixed to the respective insulating bushings 11 via conductors 25, and movable contacts 27, 27 are in contact with the fixed contacts 26, 26, respectively. The left movable contact 27 is rotatably supported on the operating shaft 8 via the insulating lever 16, and the right movable contact 27 is also supported rotatably on the support shaft 17 via the insulating lever 16. The two insulating levers 16 and 16 are connected in the middle with the connecting rod 24 described above. The two insulating levers 16, 16 are rotated by the rotation of the operation shaft 8, whereby the movable contacts 27, 27 are also rotated so as to contact and separate from the fixed contacts 26, 26. FIG. 2 is a diagram when the discharging disconnector 20 is in a closed state.
[0014]
FIG. 3 is a side view of the main part showing the configuration of the DC circuit breaker 31 of FIG. A discharge resistor 21 disposed on the other side of the operation shaft 8 is connected to one movable contact 27 via a lead wire 28 and to the other fixed contact not shown. FIG. 3 shows a case in which the discharge disconnector is in a closed state. A cart (not shown) on the left side of the cradle 13 is moved to the left side of the figure, and the disconnector 10 is in an open state.
[0015]
4 is a cross-sectional view taken along line XX in FIG. The fixed contact 26 is composed of two conductor plates, and sandwiches the conductor 25 and the movable contact 27. The holding force of the fixed contact 26 is formed via the spring 23. The movable contact 27 is configured to slide in a direction perpendicular to the paper surface of FIG.
FIG. 5 is a main part back view showing a state in which the discharging disconnector 20 of FIG. 2 is opened. When the operation shaft 8 of the discharge disconnector 20 in the state of FIG. 2 is rotated clockwise, the two insulating levers 16 are also rotated clockwise, whereby the movable contact 27 is rotated and the fixed contact is rotated. 26 is separated.
[0016]
In FIG. 5, since the contact operation of the fixed contacts 26, 26 and the movable contacts 27, 27 for each contact is independent, the contacts do not affect each other. Therefore, the assembly of the discharge disconnector 20 may be performed so that the contact and separation of each contact point are good. In addition, when the movable contact 27 is fitted between the fixed contacts 26 as shown in FIG. 4, the movable contact 27 is clamped by the spring 23, so that the relative positions of the movable contact 27 and the fixed contact 26 are changed. Even if there is a slight deviation, the movable contact 27 fits between the fixed contacts 26, and the contact state is kept good. Therefore, the assembly time of the discharge disconnector 20 is shortened, and the manufacturing cost is reduced.
[0017]
In addition, since the discharge resistor 21 is connected in series with the discharge disconnector 20, the current flowing through the contact of the discharge disconnector 20 is limited, and the contact is hardly damaged, and the life of the discharge disconnector 20 is extended. I was able to.
[0018]
【The invention's effect】
As described above, the present invention comprises two independent contacts in which discharge disconnectors are connected in series, and each of the contacts includes a fixed contact and a movable contact that come in contact with each other. By interlocking, the assembly of the discharge disconnector became easy and the manufacturing cost was reduced.
[0019]
Further, in this configuration, the life of the discharge disconnector is increased by connecting the discharge resistor to the discharge disconnector in series.
[Brief description of the drawings]
1 is a circuit diagram showing the configuration of a DC circuit breaker according to an embodiment of the present invention; FIG. 2 is a main part rear view showing the configuration of the DC circuit breaker shown in FIG. 1; FIG. 4 is a cross-sectional view taken along line XX in FIG. 3. FIG. 5 is a rear view of the main part showing a state where the discharge disconnector in FIG. 2 is opened. FIG. 7 is a side view showing the configuration of the DC circuit breaker in FIG. 6. FIG. 8 is a back view showing the configuration of the DC circuit breaker in FIG.
4: circuit breaker, 6: switch, 7: capacitor, 19: series circuit, 20: disconnector for discharge, 21: discharge resistor, 31: DC circuit breaker

Claims (2)

In a DC circuit breaker in which a series circuit of a DC-charged capacitor and a switch and a discharge disconnector are connected in parallel to the circuit breaker, two independent contacts in which the discharge disconnector is connected in series The contact is provided with a fixed contact and a movable contact that are in contact with each other, and the movable contacts are linked to each other. 2. The DC circuit breaker according to claim 1, wherein a discharge resistor is connected in series to the discharge disconnector.

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