JP2007335401A - Switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching device capable of eliminating instability of electric insulation performance accompanying floating of the potential of a metal non-grounding vacuum container and improving its cutting-off performance. <P>SOLUTION: A switching device comprises a cutting-off part 2 with two movable electrodes 4 made capable of contacting with and separating from respective fixed electrode 3 and is equipped with a metal non-grounding vacuum container 1 containing the cutting-off part 2, circuit terminals 14, 15 respectively connected to the fixed electrodes 3, an insulation mold 21 to cover the periphery of the metal non-grounding vacuum container 1, a ground layer 22 to cover the outer periphery of the insulation mold 21, and capacitors 20 respectively connected to the circuit terminals with its intermediate part being connected to the metal non-grounding vacuum container 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a switchgear, and more particularly to a switchgear suitable for one having a plurality of blocking portions in a metal non-grounded vacuum vessel.

  As an example of a conventional switchgear, there is a two-point cut-off vacuum circuit breaker that simultaneously opens two pairs of breakers connected in series to cut off current. In this switchgear, two pairs of blocking portions are arranged in parallel in a metal vacuum vessel. The fixed electrode of the blocking part is supported by the vacuum vessel through an insulating cylinder, and the two pairs of movable electrodes are connected by a connection conductor in the vacuum vessel. The connecting conductor is connected to the operating rod through an insulator in the vacuum vessel. The operating rod and the vacuum vessel are sealed by a sealing means attached to the vacuum vessel via an insulating cylinder. On the fixed electrode side of the blocking portion, there are provided two circuit terminals for electrical connection with an external circuit, that is, a bus side terminal and a load side terminal. Further, the periphery of the metal non-grounded vacuum vessel is covered with an insulator mold. (For example, refer to Patent Document 1.)

JP 2005-108766 A

  In the conventional switchgear described above, a grounding layer for preventing charging is provided on the outer periphery of the insulating mold, but the distance between the grounding layer and the metal non-grounded vacuum vessel is short, and the insulating mold is interposed. Therefore, the capacitance between the metal non-grounded vacuum container and the ground layer is increased. As a result, the potential of the metal non-grounded vacuum vessel is attracted to a potential near the ground potential.

  On the other hand, in the open state of the electrode, considering the state where the voltage at the bus terminal is 100% and the voltage at the load terminal is 0%, the movable electrode and the connecting conductor which are electrically connected to each other, etc. Is determined by the share of the capacitance reactance between each fixed electrode and the capacitance reactance between the metal non-grounded vacuum vessel, but the latter is larger than the former. , It deviates from the 50% potential and is attracted to the potential of the metal non-grounded vacuum vessel, that is, the potential near the ground potential.

  As a result, the voltage sharing ratio between the bus-side blocking unit connected to the bus-side terminal and the load-side blocking unit connected to the load-side terminal deviates from 1: 1, and the bus-side blocking unit connected to the bus-side terminal The breaker will share most of the voltage.

  Therefore, in spite of the two-point cut-off part, the voltage sharing rate at each cut-off part is greatly biased, so that the voltage stress on one of the cut-off parts becomes large, and the metal non-grounded vacuum vessel There is instability in electrical insulation performance due to floating potential. As a result, there has been a problem that the blocking performance cannot be improved.

The present invention has been made on the basis of the above-mentioned matters, and it eliminates instability in electrical insulation performance due to the floating potential of a metal non-grounded vacuum vessel, and improves its shut-off performance. An object of the present invention is to provide an openable switchgear.

  In order to solve the above-described object, the switchgear according to the present invention is a switchgear having a blocking part in which at least two movable electrodes can be brought into contact with and separated from each fixed electrode. A non-grounded vacuum vessel made of metal, a connection conductor connecting the movable electrode, an operation rod connected to the connection conductor via an insulator and led out of the non-grounded vacuum vessel made of metal, and the operation Sealing means for sealing the lead-out portion of the metal non-grounded vacuum vessel in the rod; circuit terminals connected to the fixed electrodes and led out of the metal non-grounded vacuum vessel; An insulating mold that covers the periphery of the grounded vacuum vessel, a grounding layer that covers the outer periphery of the insulating mold, and the circuit terminal are connected to each other, and an intermediate portion thereof is connected to a metal non-grounded vacuum vessel, Money A potential control means for controlling the potential of the non-grounded vacuum vessel made of metal, or connected between the ground layer and the non-grounded vacuum vessel made of metal to control the potential of the non-grounded vacuum vessel made of metal And a potential control means.

  According to the present invention, by controlling the potential of the metal non-grounded vacuum vessel, instability in electrical insulation performance can be eliminated, so that the shut-off performance of the switchgear can be improved.

  Hereinafter, embodiments of the opening and closing device of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a first embodiment of a switchgear according to the present invention. In FIG. 1, two blocking sections 2 are arranged in a metal non-grounded vacuum vessel 1. . Each blocking unit 2 includes a fixed electrode 3 and a movable electrode 4. Each blocking portion 2 is located in an insulating cylinder 5 connected to the metal non-grounded vacuum vessel 1. An arc shield 6 is provided in each insulating cylinder 5 corresponding to each blocking portion 2. An end plate 7 is provided on the fixed electrode side of each insulating cylinder 5.

  The movable electrode 4 of the interruption | blocking part 2 is each supported by the movable holder 8 which is a conductor. The movable holder 8 is connected by a connection conductor 9. The connection conductor 9 is connected to an operation rod 11 led out of the vacuum vessel 1 through an insulator 10 located in the metal non-grounded vacuum vessel 1. The operation rod 11 is connected to the operation device 12. A penetration portion of the operation rod 11 in the metal non-grounded vacuum vessel 1 is sealed with a sealing means 13 such as a bellows.

  The fixed electrode 3 of the blocking part 2 is supported by fixed holders 14 and 15 which are conductors. The fixed holders 14 and 15 are respectively led out to the outside of the metal non-grounded vacuum vessel 1 through the end plate 7 and become main circuit terminals for electrically connecting to an external circuit, that is, bus-side terminals and load-side terminals. . In this example, an AC power source 16 and a system inductance 17 are connected to the fixed holder 14 (bus terminal) on one side. In addition, a load 18 and a neutral point 19 are connected to the other fixed holder 15 (load side terminal).

  Two capacitors 20 and 20 are connected between one side of the fixed holder 14 (bus side terminal) and the other side of the fixed holder 15 (load side terminal), and an intermediate portion of the capacitors 20 and 20 is made of metal. It is connected to a non-grounded vacuum vessel 1. By these capacitors 20, 20, an intermediate potential between the bus-side terminal 14 and the load-side terminal 15 can be applied to the metal non-grounded vacuum vessel 1.

  The outer periphery of the metal non-grounded vacuum vessel 1, the insulating cylinder 5, the end plate 7, the fixed holders 14 and 15, and the capacitors 20 and 20 is covered with an insulating mold portion 21. Further, the outer peripheral surface of the insulating mold portion 21 is covered with a ground layer 22 for preventing charging.

  An example of the mounting state of the capacitors 20 and 20 will be described with reference to FIG.

  FIG. 2 is a perspective view of the insulating cylinder 5 viewed from below with the insulating mold portion 21 and the grounding layer 22 omitted. In FIG. 2, the same reference numerals as those in FIG. is there.

  As shown in the figure, the capacitors 20 and 20 are arranged so as to be shifted from each other in the opposite direction and slightly outward from the middle part of the two insulating cylinders 5, and one end of each of the capacitors 20 and 20 is disposed in the metallic non-grounded vacuum vessel 1. The other end is connected to the end plate 7 by a lead conductor 23.

  With the configuration described above, the capacitors 20 and 20 can be mounted so as to be connected between the bus-side terminal and the load-side terminal and to the metal non-grounded vacuum vessel 1. Further, the capacitors 20 and 20 are arranged so as to be shifted from each other in the opposite direction or slightly outward from the middle part of the two insulating cylinders 5, whereby the integration rate can be increased.

  Next, the operation of the above-described first embodiment of the switchgear according to the present invention will be described with reference to FIGS.

  In the first embodiment, an AC power source 16 and a system inductance 17 are connected to the bus-side terminal 14, and a load 18 is connected to the load-side terminal 15. In the steady state, both blocking units 2 are turned on, and power is supplied from the AC power supply 16 to the load 18 via both the bus-side and load-side blocking units 2.

  At this time, since the potentials of the bus-side terminal 14 and the load-side terminal 15 are also 100% potential (power supply voltage), the potential of the metal non-grounded vacuum vessel 1 is also 100%.

  In this state, when a ground fault A occurs between the load-side terminal 15 and the load 18, an accident current flows from the AC power supply 16 toward the generation point of the ground fault A. As a result, the potentials of the bus-side terminal 14 and the load-side terminal 15 are reduced to approximately 0% potential (ground potential).

  Here, when the fault current is detected by the protection relay and both the breaking parts 2 are opened, the fault current is cut off at the current zero point, the potential of the bus terminal 14 jumps to 100%, and the potential of the load terminal 15 is It remains at almost 0%. At this time, the potential of the metal non-grounded vacuum vessel 1 becomes a 50% potential obtained by sharing the potential difference between the bus-side terminal 14 and the load-side terminal 15 by the capacitor 20.

  On the other hand, the electric potentials of the movable holder 8, the connection conductor 9, and the movable electrode 4 that are electrically connected to each other are the reactance of the electrostatic capacitance between the fixed electrode 3 and the metal non-grounded vacuum vessel 1. However, since the latter is larger than the former, the potential of the metal non-grounded vacuum vessel 1 is attracted to 50% potential, resulting in instability in electrical insulation performance. Eliminated.

  As a result, the voltage sharing ratio between the bus-side blocking unit 2 connected to the bus-side terminal 14 and the load-side blocking unit 2 connected to the load-side terminal 15 is approximately 1: 1, and is imposed on each blocking unit. Since the applied voltage stress is reduced, the blocking performance at the blocking unit 2 can be improved.

  According to the first embodiment of the present invention described above, since the potential can be controlled by connecting the capacitor 20 to the metal non-grounded vacuum vessel 1, instability in electrical insulation performance is eliminated. can do. As a result, the blocking performance of the blocking unit 2 can be improved.

  Moreover, since the voltage sharing rate of the some interruption | blocking part 2 is improved, the voltage stress imposed on each interruption | blocking part 2 reduces. As a result, since the gap between the contacts of the blocking portion 2 can be shortened, there is an advantage that the switchgear can be miniaturized. Furthermore, since the movable side blocking speed of the blocking unit 2 can be reduced, there is an advantage that the cost can be reduced.

  In addition, there is an advantage that instability in electrical insulation performance can be eliminated by controlling the potential of the metal non-grounded vacuum vessel 1.

  FIG. 3 is a longitudinal sectional view of a second embodiment of the switchgear according to the present invention. In FIG. 3, the same reference numerals as those in FIG. Is omitted.

  In this embodiment, a capacitor 20A and a resistor 20B are connected in parallel between circuit terminals, that is, between the bus-side terminal 14 and the load-side terminal 15.

  Also in this embodiment, the same effect as that of the first embodiment of the present invention described above can be obtained. Further, when the time constants of the capacitor 20A and the resistor 20B are appropriately set, the frequency region in which the potential of the metal non-grounded vacuum vessel 1 can be controlled can be expanded to the low frequency region.

FIG. 4 is a longitudinal sectional view of a third embodiment of the switchgear according to the present invention. In FIG. 4, the same reference numerals as those in FIG. Is omitted.

  In this embodiment, two non-linear resistors 20C and 20C are connected between circuit terminals, that is, between the bus-side terminal 14 and the load-side terminal 15, and an intermediate portion of the non-linear resistors 20C and 20C is It is connected to a metal non-grounded vacuum vessel 1.

  According to this embodiment, since the voltage stress applied to each interrupting part 2 does not exceed the operating voltage of the non-linear resistors 20C, 20C, the dielectric breakdown between the contacts of one interrupting part 2 continues. Thus, it is possible to prevent the dielectric breakdown of the other blocking portion 2 from being induced, and finally to progress to the dielectric breakdown between the in-phase circuit terminals, and the same effects as those of the above-described embodiment can be obtained.

  FIG. 5 is a longitudinal sectional view of a fourth embodiment of the switchgear according to the present invention. In FIG. 5, the same reference numerals as those in FIG. Is omitted.

  In this embodiment, a non-linear resistor 20 </ b> D is connected between the metal non-grounded vacuum container 1 and the ground layer 22.

  In this embodiment, even if the ground potential of the metallic non-grounded vacuum vessel 1 rises due to causes such as continuous application of a unipolar voltage, it does not become higher than the operating voltage of the non-linear resistor 20D. That is, the non-linear resistor 20D limits the potential of the metal non-grounded vacuum vessel 1 to a certain value or less. As a result, the withstand voltage performance is stabilized. Further, similarly to the above-described embodiment, there is an advantage that the switchgear can be reduced in size and cost.

  FIG. 6 shows a longitudinal sectional view of a fifth embodiment of the switchgear of the present invention. In FIG. 6, the same reference numerals as those in FIG. Is omitted.

  In this embodiment, a linear resistor 20E for gradually decreasing the potential of the metal non-grounded vacuum vessel 1 is connected between the metal non-grounded vacuum vessel 1 and the ground layer 22.

  According to this embodiment, even if the ground potential of the metallic non-grounded vacuum vessel 1 rises due to a continuous application of a unipolar voltage, the static potential between the metallic non-grounded vacuum vessel 1 and the ground layer 22 is increased. Since the metallic non-grounded vacuum vessel 1 recovers to the ground potential with a time constant determined from the electric capacity and the resistance value of the linear resistor 20E, the withstand voltage performance is stabilized. Further, similarly to the above-described embodiment, there is an advantage that the switchgear can be reduced in size and cost. Furthermore, as compared with the above-described fourth embodiment, the voltage of the metal non-grounded vacuum vessel 1 can be controlled at a low cost.

  FIG. 7 is a longitudinal sectional view of a sixth embodiment of the switchgear according to the present invention. In FIG. 7, the same reference numerals as those in FIG. Is omitted.

  In this embodiment, between the bus-side terminal 14 and the load-side terminal 15 which are the above-described circuit terminals, two capacitors whose intermediate portions are connected to the metal non-grounded vacuum vessel 1, a linear resistor, or One of the non-linear resistors 20F and 20F is connected, and the resistor 20G is connected between the metal non-grounded vacuum vessel 1 and the ground layer 22 described above.

  Also in this embodiment, the same effect as that of the above-described embodiment can be obtained.

  In the above-described embodiment, the capacitor, the linear resistor, or the non-linear resistors 20F and 20F and the resistor 20G are inserted into the insulating mold part 21, but these are externally connected from the insulating mold part 21. It is also possible to pull it out and arrange it in an external form.

It is a longitudinal section showing a 1st embodiment of a switchgear of the present invention. It is the perspective view which looked at the insulation cylinder from the state in the state which abbreviate | omitted the insulation mold part and grounding layer in 1st Embodiment of the switchgear of this invention shown in FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the switchgear of this invention. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the switchgear of this invention. It is a longitudinal cross-sectional view which shows 4th Embodiment of the switchgear of this invention. It is a longitudinal cross-sectional view which shows 5th Embodiment of the switchgear of this invention. It is a longitudinal cross-sectional view which shows 6th Embodiment of the switchgear of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal non-grounding vacuum vessel 2 Blocking part 3 Fixed electrode 4 Movable electrode 5 Insulating cylinder 6 Arc shield 7 End plate 8 Movable holder 9 Connection conductor 10 Insulator 11 Operating rod 12 Operating device 13 Bellows (sealing means)
14 Bus side terminal (fixed holder)
15 Load side terminal (fixed holder)
16 AC power supply 17 Inductance 18 Load 19 Neutral point 20, 20A Capacitor 20B, 20G Resistor 20C, 20D, 20F Non-linear resistor 21 Insulation mold part 22 Ground layer 23 Lead conductor

Claims (9)

  An opening / closing device having a blocking part in which at least two movable electrodes can be brought into contact with and separated from each fixed electrode, and a connection for connecting the movable electrode to a metal non-grounded vacuum container that houses the blocking part A conductor, an operation rod connected to the connection conductor via an insulator and led out to the outside of the metal non-grounded vacuum vessel, and a lead-out portion of the metal non-grounded vacuum vessel in the operation rod are sealed. A sealing means; circuit terminals connected to the fixed electrodes and led out of the metal non-grounded vacuum vessel; an insulator mold covering the periphery of the metal non-grounded vacuum vessel; and the insulator mold A grounding layer covering the outer periphery of the metal plate, and a potential control means for controlling the potential of the metal non-grounded vacuum vessel, wherein the grounding layer is connected between the circuit terminals, and an intermediate portion thereof is connected to the metal non-grounded vacuum vessel. Switchgear, characterized in that it comprises. The switchgear according to claim 1,
The opening / closing apparatus, wherein the potential control means is constituted by a capacitor for controlling the potential of the metal non-grounded vacuum vessel to the potential between the circuit terminals. The switchgear according to claim 1,
The potential control means is configured by a capacitor and a resistor connected in parallel. The switchgear according to claim 1,
The electric potential control means is constituted by a non-linear resistor.   An opening / closing device having a blocking part in which at least two movable electrodes can be brought into contact with and separated from each fixed electrode, and a connection for connecting the movable electrode to a metal non-grounded vacuum container that houses the blocking part A conductor, an operation rod connected to the connection conductor via an insulator and led out to the outside of the metal non-grounded vacuum vessel, and a lead-out portion of the metal non-grounded vacuum vessel in the operation rod are sealed. A sealing means; circuit terminals connected to the fixed electrodes and led out of the metal non-grounded vacuum vessel; an insulator mold covering the periphery of the metal non-grounded vacuum vessel; and the insulator mold A grounding layer that covers the outer periphery of the metal, and a potential control means that is connected between the grounding layer and the metal non-grounded vacuum vessel and controls the potential of the metal non-grounded vacuum vessel. Open Apparatus. The switchgear according to claim 5,
The opening / closing device, wherein the potential control means is composed of a non-linear resistor that limits the potential of the metal non-grounded vacuum vessel to a certain value or less. The switchgear according to claim 5,
The open / close device according to claim 1, wherein the potential control means comprises a linear resistor that gradually reduces the potential of the metal non-grounded vacuum vessel. The switchgear according to claim 5,
Each of the circuit terminals is connected to each other, and an intermediate portion thereof is connected to a metal non-grounded vacuum vessel, and further includes second potential control means for controlling the potential of the metal non-grounded vacuum vessel. Opening and closing device characterized. The switchgear according to claim 8, wherein
The second potential control means is constituted by any one of a capacitor, a linear resistor, and a non-linear resistor.

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