JP2020202635A - Gas insulated switchgear - Google Patents

Abstract

To provide a gas insulated switchgear provided with a grounding switch or a disconnector (including a grounding disconnector) having a movable element that does not have a slit for preventing rotation, and capable of performing an abnormality diagnosis, especially an abnormality diagnosis for the movable element.SOLUTION: A gas insulated switchgear 10 is provided with at least one of a grounding switch 11, grounding disconnector, and disconnector as a switchgear. The switchgear 11 is provided with: a movable element 4 being linearly movable; a rod-like member 5a connected to the movable element 4 and rotates to linearly move the movable element 4; a motor 6 for rotating the rod-like member 5a; a current measurement device 7 for measuring a load current of the motor 6; and a computer 8 for inputting the load current measured by the current measurement device 7. The computer 8 determines that the movable element 4 is abnormal when a load current is larger than a load current Ia when a normal movable element 4 moves stably for an arbitrarily predetermined time Δt or more in a range of time t in which the normal movable element 4 moves stably.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gas-insulated switchgear.

The gas-insulated switchgear is a device that plays an important role in the power system, such as system protection from a short-circuit failure during a lightning strike and switching control for system operation. One phase is composed of equipment such as a gas circuit breaker, a circuit breaker, a grounding switch, a high-speed grounding switch, a main bus, a current transformer for an instrument, a voltage transformer for an instrument, and a cable connection. Three phases are arranged in parallel to form one circuit, and 10 to 20 Bay gas-insulated switchgear is connected by a main bus in the depth direction at one site. The grounding tank of each device is filled with SF ₆ gas having excellent insulation performance, and a high-voltage conductor is supported or fixed by an insulating spacer, an insulating cylinder, or the like. The insulation performance of SF ₆ gas is about 3 times that of air at atmospheric pressure (0.1 MPa · abs). In the gas-insulated switchgear, the gas pressure is raised to 0.6 to 0.7 MPa · abs, so the insulation distance required for electrical insulation is less than 1/10 of the atmosphere, and the air-insulated switchgear. It is much more compact than the one. Further, since the gas-insulated switchgear has a sealed structure and is not affected by the external environment, it is widely applied as a highly reliable device.

An example of a grounding switchgear or a disconnector provided in a conventional gas-insulated switchgear is described in Patent Document 1. In the grounding switchgear described in Patent Document 1, a tubular mover having a slit-shaped opening on a side surface is linearly driven by a rotation shaft to contact and separate from a stator to perform an opening / closing operation.

Japanese Unexamined Patent Publication No. 8-237828

The grounding switchgear and disconnector provided in the gas-insulated switchgear perform opening / closing operations by rotating the rotating shaft with, for example, a DC motor (DC motor) and linearly moving the mover. In a grounding switchgear or disconnector provided in a conventional gas-insulated switchgear such as the grounding switchgear described in Patent Document 1, the mover has a slit on the side surface, and a protrusion member for preventing rotation is fitted into the slit. The rotation is prevented.

An electric field is concentrated in the slit of the mover. In order to improve the withstand voltage of the mover, it is necessary to eliminate the slit and relax the electric field. However, if the mover does not have a slit, the mover may rotate together with the rotation shaft, resulting in malfunction. Further, if the structure of the mover is devised so that the mover does not rotate even if it does not have a slit, it cannot be said that there is a possibility that the operation of the mover may become abnormal due to this device. Therefore, in the gas-insulated switchgear, it is necessary to diagnose the operating state of the mover.

An object of the present invention is to provide a gas-insulated switchgear that includes at least one of a ground switchgear, a ground disconnector, and a disconnector as a switchgear having a mover, and can diagnose an abnormality of the mover.

The gas-insulated switchgear according to the present invention includes at least one of a ground switchgear, a ground disconnector, and a disconnector as the switchgear. The opening / closing device is connected to a mover that can move linearly, a rod-shaped member that is connected to the mover and rotates to move the mover linearly, a motor that rotates the rod-shaped member, and a load current of the motor. A current measuring device for measuring and a computer for inputting the load current measured by the current measuring device are provided. The computer uses the load current when the normal mover stably moves within a time range in which the normal mover moves stably for a predetermined time or longer arbitrarily determined. If it is larger than, it is configured to determine that the mover is abnormal.

According to the present invention, it is possible to provide a gas-insulated switchgear that includes at least one of a ground switchgear, a ground disconnector, and a disconnector as a switchgear having a mover, and can diagnose an abnormality of the mover.

It is sectional drawing which shows the structure of the gas insulation switchgear according to the Example of this invention. It is sectional drawing which shows the structure of the grounding switchgear provided in the gas insulation switchgear according to the Example of this invention. FIG. 5 is a cross-sectional view of a cylindrical mover, a rotating portion (rod-shaped member), a conductor, and an annular sliding member, perpendicular to the length direction of the rod-shaped member. This is an example of the waveform of the load current of the DC motor when the mover is in the normal state and the rotating part is moving the mover. This is an example of the waveform of the load current of the DC motor when the mover is in the first abnormal state while the rotating portion is moving the mover. This is an example of the waveform of the load current of the DC motor when the mover is in the second abnormal state while the rotating portion is moving the mover. FIG. 5 is a cross-sectional view of an elliptical tubular mover, a rotating portion (rod-shaped member), a conductor, and an annular sliding member, perpendicular to the length direction of the rod-shaped member. FIG. 5 is a cross-sectional view of a polygonal tubular mover, a rotating portion (rod-shaped member), a conductor, and an annular sliding member, perpendicular to the length direction of the rod-shaped member.

The gas-insulated switchgear according to the present invention includes at least one of a ground switchgear, a ground disconnector, and a disconnector as the switchgear. In ground switches, ground disconnectors, and disconnectors, the mover is moved linearly by rotating the rotating shaft connected to the mover with a DC motor (DC motor), and the mover moves in and out of the stator. By doing so, it opens and closes. In the gas-insulated switchgear according to the present invention, the mover can be provided with a configuration in which the mover does not rotate together with the rotation shaft even if the slit for preventing rotation is not provided. In the present invention, it is possible to perform an abnormality diagnosis of a mover of a gas-insulated switchgear, particularly a mover having such a configuration.

Hereinafter, the gas-insulated switchgear according to the embodiment of the present invention will be described with reference to the drawings. The examples shown below are merely examples of embodiments of the present invention, and the contents of the present invention are not limited to the following aspects.

FIG. 1 is a cross-sectional view showing the configuration of a gas-insulated switchgear 10 according to an embodiment of the present invention. The gas-insulated switchgear 10 includes a ground switch 11, a disconnector 12, a circuit breaker 13, a current transformer 14 for an instrument, a voltage transformer 15 for an instrument, and a ground tank 16. The gas-insulated switchgear 10 may also include a ground disconnector. SF ₆ gas having high insulation performance is sealed in the grounding tank 16. A gas other than SF ₆ gas may be filled in the ground tank 16.

Hereinafter, the configuration of the grounding switch 11 will be described on behalf of the grounding switch 11, the disconnector 12, and the grounding disconnector. The following description can also be applied to the disconnector 12 and the ground disconnector.

FIG. 2 is a cross-sectional view showing the configuration of the grounding switchgear 11 included in the gas-insulated switchgear 10 according to the present embodiment. FIG. 2 shows a cross-sectional view of the grounding switch 11 in a state where the voltage and the current are cut off, as viewed from the front.

The grounding switch 11 includes a mover 4, a stator 2, a conductor 3, a rotating unit 5, a DC motor 6, a load current measuring device 7, and a computer 8.

The mover 4 is a cylindrical member, includes a hollow portion extending in the length direction, a rotating portion 5 is connected to the hollow portion, and a recess 4a is provided on the surface of the hollow portion (inner surface of the mover 4). .. The mover 4 forms a ball screw structure together with the rotating portion 5, and can be linearly moved by the rotation of the rotating portion 5. The mover 4 can be brought into contact with and detached from the stator 2 by linearly moving due to the ball screw structure. An annular sliding member 9 is installed around the mover 4. The annular sliding member 9 is an annular member and comes into contact with the mover 4 to guide the linear movement of the mover 4.

The stator 2 has a ground potential, and the ground switch 11 is opened and closed by contacting and separating from the mover 4.

The conductor 3 is in contact with the mover 4. The conductor 3 and the mover 4 on the high voltage side of the ground switch 11 are grounded when the mover 4 moves linearly and comes into contact with the stator 2.

The mover 4, the stator 2, the conductor 3, and the annular sliding member 9 are held by the solid insulator 1.

The rotating portion 5 is held between a rod-shaped member 5a having a thread (or a thread groove) on the outer surface, between the threads (or the thread groove) of the rod-shaped member 5a, and a recess 4a on the inner surface of the mover 4. It includes a spherical member 5b and is connected to a DC motor 6. At least a part of the rod-shaped member 5a is located in the hollow portion of the mover 4, and is connected to the mover 4 via the spherical member 5b. The rod-shaped member 5a is a rotating shaft driven by the DC motor 6 and is rotatable around the central axis of the rod-shaped member 5a.

The rotating unit 5 converts the rotational motion of the rod-shaped member 5a into a linear motion of the mover 4. By rotating the rod-shaped member 5a, the mover 4 is linearly moved in the length direction of the rod-shaped member 5a via the spherical member 5b. When the rod-shaped member 5a rotates, the mover 4 moves linearly because the spherical member 5b is guided by the thread (or thread groove) of the rod-shaped member 5a and moves in the length direction of the rod-shaped member 5a. .. The rod-shaped member 5a rotates according to, for example, a predetermined program.

The DC motor 6 is operated by a DC power supply (not shown) to rotate the rod-shaped member 5a of the rotating portion 5.

The load current measuring device 7 measures the load current of the DC motor 6 (current flowing through the DC motor 6).

The computer 8 is connected to the load current measuring device 7 and inputs the load current of the DC motor 6 measured by the load current measuring device 7. The computer 8 uses the input load current of the DC motor 6 to perform an abnormality diagnosis (diagnosis of an operating state) of the mover 4.

If the mover 4 rotates together with the rod-shaped member 5a during the opening / closing operation (when the mover 4 moves linearly), the grounding switch 11 may malfunction. In the grounding switch provided by the conventional gas-insulated switchgear, the mover is provided with a slit (slit-shaped opening) on the side surface, and a protrusion member for preventing rotation is fitted into the slit to prevent rotation.

In the gas-insulated switchgear 10 according to the present embodiment, the mover 4 is not provided with a rotation prevention slit in order to prevent the concentration of the electric field, relax the electric field, and improve the withstand voltage. That is, the cylindrical mover 4 does not have a portion (slit) interrupted in the circumferential direction on the outer surface, and the outer surface is continuous in the circumferential direction as a whole in the length direction. The mover 4 has a configuration that does not rotate together with the rod-shaped member 5a even if the mover 4 is not provided with a slit.

FIG. 3 is a cross-sectional view of the mover 4, the rotating portion 5 (rod-shaped member 5a), the conductor 3, and the annular sliding member 9 perpendicular to the length direction of the rod-shaped member 5a. An annular sliding member 9 is installed around the cylindrical mover 4, and a rod-shaped member 5a is connected to a position slightly displaced in the radial direction from the central axis of the mover 4. That is, the position of the rod-shaped member 5a is different from the position of the central axis of the mover 4. In such a configuration, even if the mover 4 rotates due to the rotation of the rod-shaped member 5a, the mover 4 rotates around the rod-shaped member 5a as a rotation axis, so that the outer circumference contacts the annular sliding member 9 and the rotation stops. To do. Therefore, the mover 4 does not rotate together with the rod-shaped member 5a.

Since the rod-shaped member 5a is installed at a position slightly deviated from the central axis of the mover 4, the grounding switch 11 can prevent the mover 4 from rotating even if the mover 4 does not have a slit. Since the mover 4 does not have a slit, the electric field is not concentrated and the electric field can be relaxed. Therefore, the gas-insulated switchgear 10 according to the present embodiment can be made smaller by shortening the distance between the high voltage side and the ground side as compared with the conventional case.

It has been experimentally confirmed that even if the rod-shaped member 5a is installed at a position slightly deviated from the central axis of the mover 4, the mover 4 can move linearly by the rotation of the rod-shaped member 5a. The distance at which the rod-shaped member 5a deviates from the central axis of the mover 4 can be appropriately determined according to the configuration of the grounding switch 11.

In the gas-insulated switchgear 10 according to the present embodiment, since the rod-shaped member 5a is installed at a position slightly deviated from the central axis of the mover 4, the rod-shaped member 5a is installed at the same position as the central axis of the mover 4. Compared to the above configuration, there is a high possibility that an abnormality will occur in the operation of the mover 4. Therefore, in the gas-insulated switchgear 10 according to the present embodiment, the abnormality diagnosis (diagnosis of the operating state) of the mover 4 is performed so that the abnormality can be detected immediately even if the abnormality occurs in the mover 4.

The mover 4 makes an abnormality diagnosis by measuring the load current of the DC motor 6 that drives the rotating portion 5 that moves the mover 4. The load current of the DC motor 6 is measured by the load current measuring device 7 and input to the computer 8.

FIG. 4 is an example of the waveform of the load current of the DC motor 6 when the mover 4 is in the normal state and the rotating portion 5 is moving the mover 4. When the rotating unit 5 starts moving the mover 4 and the mover 4 starts, the load applied to the DC motor 6 increases, so that the load current increases. When the mover 4 moves stably, the load current decreases to a constant value Ia. In FIG. 4, the time t is the time range when the mover 4 in the normal state is stably moving and the load current shows a substantially constant value Ia. When the mover 4 is stopped by the rotating portion 5, the load applied to the DC motor 6 is increased and the load current is increased again. When the mover 4 is stopped, the load current becomes zero. The DC motor 6 stops operating when the load current exceeds the overcurrent limit value IL.

FIG. 5 is an example of the waveform of the load current of the DC motor 6 when the mover 4 is in the first abnormal state while the rotating portion 5 is moving the mover 4. FIG. 5 shows an example of the waveform of the load current when the mover 4 is rotating due to wear of the contact portion with the annular sliding member 9. When the contact portion of the mover 4 with the annular sliding member 9 is worn and rotated, the speed of linear movement of the mover 4 decreases, and it takes longer to move than in the normal state. The mover 4 is in the first abnormal state in which the moving speed is reduced.

The time Δt1 shown in FIG. 5 is a time range when the rotating unit 5 is moving the rotating mover 4. The load current shows a value Ia when the mover 4 is stably moving in a normal state, but increases from the value Ia when the mover 4 moves while rotating at time t1. That is, during the time Δt1, the load current is larger than the value Ia when the mover 4 is stably moving in the normal state. Further, the load current shows a value larger than a predetermined threshold value Is because the mover 4 is moving while rotating within the range of the time Δt1. The threshold value Is can be arbitrarily determined according to the configuration of the mover 4, the rotating unit 5, the DC motor 6, and the like.

FIG. 6 is an example of the waveform of the load current of the DC motor 6 when the mover 4 is in the second abnormal state while the rotating portion 5 is moving the mover 4. FIG. 6 shows an example of the waveform of the load current when the mover 4 rubs against the rotating portion 5 and is deformed, the rod-shaped member 5a of the rotating portion 5 idles, and the mover 4 stops linear movement. ing. The mover 4 is in a second abnormal state in which the rod-shaped member 5a is rotating but the linear movement is stopped.

The time Δt2 shown in FIG. 6 is a time range when the rotating portion 5 is rotating the rod-shaped member 5a but the mover 4 is not linearly moving. The load current shows a value Ia when the mover 4 is moving stably in a normal state, but increases from the value Ia when the mover 4 is deformed and stops moving at time t2. That is, during the time Δt2, the load current is larger than the value Ia when the mover 4 is stably moving in the normal state. At this time, the mover 4 has stopped moving, but the rod-shaped member 5a continues to rotate for a predetermined time according to a predetermined program, and is idling. Further, the load current shows a value smaller than a predetermined threshold value Is because the rod-shaped member 5a is idling within the range of the time Δt2.

When the DC motor 6 is rotating the rod-shaped member 5a of the rotating portion 5, the computer 8 uses the load current of the DC motor 6 to perform an abnormality diagnosis of the mover 4. In the computer 8 when the load current is larger than the load current value Ia when the mover 4 is stably moving in the normal state for a predetermined time Δt or more in the above-mentioned time t range. Determines that the mover 4 is abnormal. The reason why the mover 4 is determined to be abnormal when the load current is continuously larger than Ia for a time Δt or more is to exclude the instantaneous increase in the load current due to noise from the increase in the load current used for the determination.

As described above, the time t is the time range in which the DC motor 6 rotates the rod-shaped member 5a and the normal mover 4 moves stably (the mover 4 that completes the movement without causing an abnormality is stable. It is a time range for moving the rod-shaped member 5a), and can be obtained from a program for driving the rod-shaped member 5a, an experiment conducted in advance, or the like. The predetermined time Δt can be arbitrarily determined in advance, and for example, a value of 1 second or more is a general numerical value. In the examples shown in FIGS. 5 and 6, it is assumed that Δt1 ≧ Δt and Δt2 ≧ Δt.

In the example shown in FIG. 5, the computer 8 determines that the mover 4 is abnormal because the load current is larger than Ia and Δt1 ≧ Δt within the time t range. At this time, since the value of the load current during the time Δt1 is larger than the threshold value Is, the computer 8 can also determine that the mover 4 moves linearly while rotating and the moving speed decreases.

In the example shown in FIG. 6, the computer 8 determines that the mover 4 is abnormal because the load current is larger than Ia and Δt2 ≧ Δt within the time t range. At this time, since the value of the load current during the time Δt2 is smaller than the threshold value Is, the computer 8 determines that the rod-shaped member 5a is idling and the mover 4 has stopped moving.

In this way, the computer 8 can determine whether or not the mover 4 is abnormal, and can also determine the type of abnormality (decrease in movement speed and stop of movement) of the mover 4. The computer 8 includes a display unit, and can display the determination result of the mover 4 and the type of abnormality of the mover 4 on the display unit.

The configuration in which the mover 4 does not rotate together with the rod-shaped member 5a even if it does not have a slit is not limited to the configuration shown in FIG. In the following, an example of a configuration different from that shown in FIG. 3 in which the mover 4 having no slit does not rotate together with the rod-shaped member 5a will be shown.

7 and 8 are cross-sectional views of the mover 4, the rotating portion 5 (rod-shaped member 5a), the conductor 3, and the annular sliding member 9 perpendicular to the length direction of the rod-shaped member 5a.

In the configuration shown in FIG. 7, the mover 4, the conductor 3, and the annular sliding member 9 have an elliptical shape in a cross section perpendicular to the length direction of the rod-shaped member 5a. That is, the mover 4 has an elliptical cylinder shape.

In the configuration shown in FIG. 8, the mover 4, the conductor 3, and the annular sliding member 9 have a polygonal shape in a cross section perpendicular to the length direction of the rod-shaped member 5a (in FIG. 8, a quadrangle as an example). Is. That is, the mover 4 has a polygonal tubular shape. In the configuration shown in FIG. 8, the mover 4, the conductor 3, and the annular sliding member 9 have rounded corners in order to alleviate the electric field concentration.

In the configurations shown in FIGS. 7 and 8, even if the mover 4 rotates due to the rotation of the rod-shaped member 5a, the outer circumference of the mover 4 comes into contact with the annular sliding member 9 and the rotation stops. Therefore, the mover 4 does not rotate together with the rod-shaped member 5a.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the embodiment including all the described configurations. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configurations of each embodiment and add / replace other configurations.

1 ... Solid insulator, 2 ... Disconnector, 3 ... Conductor, 4 ... Movable, 4a ... Recess, 5 ... Rotating part, 5a ... Rod-shaped member, 5b ... Spherical member, 6 ... DC motor, 7 ... Load current measuring device , 8 ... computer, 9 ... annular sliding member, 10 ... gas insulated switch, 11 ... ground switch, 12 ... disconnector, 13 ... circuit breaker, 14 ... current transformer for instrument, 15 ... voltage transformer, 16 ... Grounding tank.

Claims (7)

A grounding switchgear, a grounding disconnector, and at least one of the disconnectors are provided as an opening / closing device.
The switchgear
With a movable element that can move in a straight line,
A rod-shaped member connected to the mover and rotating to move the mover linearly,
A motor that rotates the rod-shaped member and
A current measuring device that measures the load current of the motor, and
A computer that inputs the load current measured by the current measuring device, and
With
The computer uses the load current when the normal mover stably moves within a time range in which the normal mover moves stably for a predetermined time or longer arbitrarily determined. If it is larger than, it is configured to determine that the mover is abnormal.
A gas-insulated switchgear characterized by this. The mover has a tubular shape, and its outer surface is continuous in the circumferential direction in the entire length direction.
The gas-insulated switchgear according to claim 1. When the computer determines that the mover is abnormal and the load current is larger than an arbitrarily determined threshold value, the computer determines that the moving speed of the mover has decreased.
The gas-insulated switchgear according to claim 1. When the computer determines that the mover is abnormal and the load current is smaller than an arbitrarily determined threshold value, the computer determines that the mover has stopped moving.
The gas-insulated switchgear according to claim 1. The mover has a cylindrical shape and has a cylindrical shape.
The rod-shaped member is connected to the mover at a position different from the position of the central axis of the mover.
The gas-insulated switchgear according to claim 2. The mover has an elliptical cylinder shape.
The gas-insulated switchgear according to claim 2. The mover has a polygonal tubular shape.
The gas-insulated switchgear according to claim 2.

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