High speed earthing switch of gas insulated switchgear

The present disclosure relates to a high speed earthing switch of a gas insulated switchgear and, more specifically, to a high speed earthing switch of a gas insulated switchgear, which includes an air blower so as to secure an improved arc interruption performance. A high speed earthing switch of a gas insulated switchgear according to an embodiment of the present disclosure comprises: an outer case; a cylinder member installed inside the outer case and having a ventilation hole formed along the lower circumferential surface; and a piston member installed to be inserted into the cylinder member, and moving backward and forward by means of a force transferred from a driving unit so as to inject air inside the cylinder member to a contact part when the cylinder member is opened.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2019/013403, filed on Oct. 14, 2019, which claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2018-0131206, filed on Oct. 30, 2018, the contents of which are all hereby incorporated by reference herein in their entirety.

FIELD

The present disclosure relates to a high-speed (or high speed) earthing switch of a gas insulated switchgear, and more particularly, a high-speed earthing switch of a gas insulated switchgear having an air blower to improve the arc interruption performance.

BACKGROUND

A gas insulated switchgear (GIS) is an electric device that is usually installed between a power supply side and a load side of an electric system to protect a power system and load equipment by interrupting current when the circuit is opened or closed intentionally or deliberately in normal conditions, or when a fault current such as a ground fault and a short circuit occurs.

Such a GIS generally includes a bushing unit that receives power from a high-voltage power source, a gas circuit breaker (CB), a disconnect switch (or disconnector), an earthing switch, a moveable part, a control unit, and the like.

Here, the earthing switch is a device that is installed in a portion of a circuit to manually ground a main circuit during maintenance and inspection, and to remove the remaining current in a conductor upon conducting maintenance or inspection.

FIG. 1shows an internal structure of a gas insulated switchgear according to the related art.

As illustrated, a disconnect/earthing switch (DS/ES)2and a high-speed earthing switch (HSES)5,9,10are installed inside an enclosure1. A drive or operation unit3is provided at an outside of the enclosure1.

The HSES is mainly divided into a fixed part5and a movable (or moving) part.

The fixed part5is provided at a conductor4disposed in the enclosure1. The fixed part5includes a fixed contact5aand a fixed contact holder5b(seeFIG. 2).

The movable part includes a movable (or moving) shaft6that is connected to the drive unit3to rotate, a connector link7that is connected to the moveable shaft6by a crank, a movable contact holder8aand a movable contact8bthat are fixedly installed inside the enclosure1, and a mover8cthat is connected to the connector link7so as to connect or disconnect the movable contact8band the fixed contact5awhile moving forward and backward. In addition, a bus bar9that connects the movable part and an earth (or ground) terminal8dis provided. The bus bar9may connect the movable contact holder8aand the earth terminal8d.

As such, the HSES consists of the fixed part and the movable part in contact with or separated from the fixed part and is usually installed at a power supply input end to discharge current of a power line. The HSES should have electrostatic induction current switching performance, electromagnetic induction switching performance, fast acting capacity (class E1 HSES with a capability to perform two closing operations), fast conduction performance, etc.

The performance of the HSES according to the related art is determined by a switching speed, and interruption failure may occur even if the switching speed is fast depending on a type of insulating gas. For example, interruption failure is more likely to occur in an air insulated switchgear than in a SF6 gas insulated switchgear.

FIGS. 2 and 3illustrate how an HSES of the gas insulated switchgear according to the related art works.FIG. 2shows an open state of the HSES, andFIG. 3shows a ground state of the HSES.

In the HSES of the gas insulated switchgear according to the related art, a movable shaft6is rotated by power transferred from the drive unit3, and the mover8cthat is connected to the movable shaft6connects (closes) a ground circuit (connection between the movable contact and the fixed contact), or disconnects (opens) the ground circuit (disconnection between the movable contact and the fixed contact) while moving forward and backward.

In the closed (ground) state, current flows to an external ground through the fixed contact holder5b, the fixed contact5a, the mover8c, the movable contact8b, the movable contact holder8a, the bus bar9, and the earth terminal8d.

However, depending on a type of insulating gas, an interruption failure may occur in the conventional HSES of the gas insulated switchgear due to a prolonged arcing time during interruption.

SUMMARY

Therefore, an aspect of the present disclosure is to obviate the above-mentioned problem and other drawbacks, namely, to provide a high-speed earthing switch of a gas insulated switchgear equipped with an air blower to achieve improved arc interruption performance.

A high speed earthing switch of a gas insulated switchgear according to an implementation of the present disclosure may include: an enclosure; a cylinder member that is installed inside the enclosure and has a vent hole formed at a lower portion along a circumferential surface thereof; and a piston member that is insertedly installed in the cylinder member and moves forward and backward by receiving force from a drive unit so as to inject air inside the cylinder member to a contact portion when in an open state.

A cylinder hole may be formed in a lower surface of the cylinder member so as to allow the piston member to move along a lengthwise direction.

A plurality of vent holes may be formed at the lower portion of the cylinder member along the circumferential surface thereof.

A lateral hole may be formed at an intermediate portion of the piston member.

The piston member may be provided with a longitudinal hole that extends from the lateral hole to a lower end thereof.

A fixed plate may be installed at the intermediate portion of the piston member.

The fixed plate may be disposed below the lateral hole.

A plurality of plate through holes may be formed in the fixed plate.

A movable plate may be disposed above the fixed plate in a manner of sliding along the piston member.

The movable plate may have an outer diameter smaller than an outer diameter of the fixed plate.

The outer diameter of the movable plate may have a size that is enough to completely cover the plate through holes when the movable plate is in contact with the fixed plate.

The movable plate may be provided with a central hole that has a guide portion with a predetermined height.

Lengthwise directions of the cylinder member and the piston member may be directions other than a horizontal direction.

According to a high-speed earthing switch of a gas insulated switchgear according to an implementation of the present disclosure, an air blower that blows wind to a fixed part when the high-speed earthing switch is open is provided. This allows the arc to be quickly extinguished. Accordingly, the arc interruption performance may be achieved regardless of a type of insulating gas.

Here, a piston member applied to the air blower is integrally formed with a mover, and thus, the arc interruption performance may be improved without an increase in the number of components (parts) or occupied space.

In the air blower, as a fixed plate, a movable plate that is disposed to be spaced apart from the fixed plated, and air flow holes formed in the fixed plate and a cylinder member, the flow of air that is injected to the fixed part via the air flow holes may be achieved while preventing a reduction in movement speed of the piston member that serves as a mover.

DETAILED DESCRIPTION

Hereinafter, implementations of the present disclosure will be described in detail with reference to the accompanying drawings. Also, it should be noted that the accompanying drawings are merely illustrated to easily understand the implementations disclosed in the specification, and therefore, they should not be construed to limit the technical spirit and scope disclosed in the specification.

A high-speed earthing switch of a gas insulated switchgear according to implementations of the present disclosure will be described in detail with reference to the drawings.

FIRST EXAMPLE

A high-speed earthing switch of a gas insulated switchgear according to one implementation of the present disclosure includes an enclosure10, a movable shaft17that is installed at a portion of the enclosure10, a cylinder member30that is installed to be spaced apart from the movable shaft17, a piston member20that is insertedly installed in the cylinder member30and is connected to the movable shaft17to move forward and backward so as to allow air in the cylinder member30to be injected into a contact portion.

The enclosure (tank or outer case)10may have a box shape to accommodate a disconnect switch, an earthing switch, or the like therein. At least one of upper, lower, left, right, front, and rear portions or parts of the enclosure10may be open. The enclosure10may define a portion of the entire enclosure constructing the gas insulated switchgear. The enclosure10may be one of compartments of the entire enclosure that constructs the gas insulated switchgear. The enclosure10may be configured to be closed, except for a conductor connecting portion (socket), so as to be insulated from the outside.

Spacers11,12, and13are coupled to open portions of the enclosure10, respectively. The spacers11,12, and13serve to divide a boundary of the enclosure10and support a conductor inserted (penetrating).

A plurality of conductors14and15is installed inside the enclosure10. The conductors14and15define a portion of a circuit or are connected to a portion of the circuit. The conductors14and15may be configured as a first conductor14that is coupled to the spacer11(first spacer) and a second conductor15that is connected to the spacer12(second spacer). Each of the conductors14and15may be provided in plurality. For example, in the case of a three-phase circuit, the conductors14and15may be provided in three pairs, respectively.

A disconnect/earthing switch (DS/ES)16is provided between the first conductor14and the second conductor15.

The high-speed earthing switch is provided in the enclosure10. The high-speed earthing switch includes a fixed part40and a movable part50.

The fixed part40of the high-speed earthing switch is installed at the first conductor14. The fixed part40of the high-speed earthing switch includes a fixed part holder (or holder)41, a fixed contact42, and a fixed part shield (or shield)43(seeFIG. 6). Here, the fixed contact42may be configured as a plurality of chips arranged in a circular (radial) shape.

The movable part50is installed to be spaced apart from the first conductor14. The movable part50includes the movable shaft17, the piston member20that serves as a mover, a movable part holder (or holder)51, and a movable contact52.

A drive unit (not shown) is provided at an outside of the enclosure10. The drive unit provides a driving force for operating the high-speed earthing switch.

The movable shaft17is formed through the enclosure10. The movable shaft17is connected to the drive unit. The movable shaft17is rotated by power transferred from the drive unit. Here, the movable shaft17is provided with a first crank lever18.

A link19is connected to the first crank lever18. The link19has one end connected to the first crank lever18and another end connected to the piston member20. The link19transfers motion of the movable shaft17to the piston member20. A rotational motion or movement of the movable shaft17is converted into a linear motion of the piston member20by the first crank lever18and the link19.

The piston member20is connected to the link19. The piston member20moves back and forth (up and down). The piston member20is configured as a bar-shaped conductor.

An earth (or ground) terminal45is installed at the enclosure10. The earth terminal45may be made of a material having excellent electrical conductivity, such as aluminum (Al) and copper (Cu). The earth terminal45is inserted and installed in a manner of penetrating through the enclosure10. That is, an inner end of the earth terminal45is disposed inside the enclosure10, and an outer end of the earth terminal45is disposed outside the enclosure10. The earth terminal45is also referred to as an “earth bushing”. A portion of the earth terminal45that is exposed to the outside of the enclosure10may be protected by an insulating member. An outer side of the earth terminal45is connected to an external earth terminal (not shown).

A bus bar46that connects the earth terminal45and the piston member20is provided.

One end of the bus bar46is connected to the inner end of the earth terminal45and another end of the bus bar46is connected to the movable part holder51.

A support member55is provided to support the movable part50. The support member55is fixedly installed in the enclosure10.

The movable part holder51is installed at the support member55. The movable part holder51is installed at the support member55in a penetrating manner. The bus bar46is connected to an upper end of the movable part holder51. The movable contact52is provided at a lower end of the movable part holder51. The movable contact52may be configured as a plurality of chips arranged in a circular (radial) shape. A first wear ring53is provided between the movable part holder51and the piston member20.

When the piston member20moves downward and is brought into contact with the fixed part40, the remaining current in the first conductor14is discharged to the outside through the fixed part40, the piston member20, the movable contact52, the movable part holder51, the bus bar46, and the earth terminal45.

Air blower (or centrifugal fan) includes the movable shaft17, the piston member20, the cylinder member30, a fixed plate60, and a movable (or moving) plate70(other mechanisms or devices that transfer force from the drive unit to the piston member may be applied). Please refer toFIGS. 4 to 6.

The cylinder member30is installed at a lower portion of the support member55. The cylinder member30may be have a cylindrical shape. The cylinder member30provides a space in which the piston member20is inserted to be moved. The piston member20penetrates through the cylinder member30in a lengthwise direction to move linearly.

An upper surface of the cylinder member30is open such that an opening portion31is formed. The piston member20, the movable contact52, the movable part holder51, the fixed plate60, the movable plate70, and the like are inserted and installed through the opening portion31.

A cylinder hole32is formed in a lower surface of the cylinder member30through which the piston member20can move (enter and exit) along the lengthwise direction (longitudinal direction). Here, a second wear ring35may be provided at the cylinder hole32. The second wear ring30allows friction to be reduced when the piston member20slides through the cylinder hole32.

A plurality of vent (or ventilation) holes33is radially formed in a lower portion of the cylinder member30along a circumferential surface thereof. Air outside the cylinder member30is introduced into the cylinder member30through the vent holes33, or air inside the cylinder member30is discharged to the outside of the cylinder member30through the vent holes33.

The piston member20has a circular bar shape. The piston member20is connected to the movable shaft17through the first crank lever18and the link19so as to move forward and backward. The piston member20provides power to deliver air by moving the fixed plate60and the movable plate70. In addition, the piston member20serves as a mover that connects the movable contact52and the fixed contact42. That is, the piston member20is integrally formed with the mover.

A lateral hole21is formed at an intermediate or middle portion of the piston member20. This may allow air to flow along the lateral hole21inside the cylinder member30. Here, the lateral hole21is located above the fixed plate60.

A longitudinal hole22that extends from the lateral hole21to a lower end of the piston member20is provided in the piston member20. Accordingly, air in the cylinder member30may flow out of the cylinder member30along the lateral hole21and the longitudinal hole22. That is, the lateral hole21and the longitudinal hole22serve as air flow paths or passages.

The fixed plate60is installed at the piston member20. The fixed plate60is installed at an intermediate portion of the piston member20. The intermediate portion of the piston member20may be formed in a stepped manner to allow the fixed plate60to be more easily mounted. The fixed plate60is disposed below the lateral hole21. Accordingly, when the fixed plate60is moved upward, air at an upper part of the fixed plate60inside the cylinder member30is discharged to the outside (lower part) of the cylinder member30through the lateral hole21and the longitudinal hole22.

Since the fixed plate60is provided in the cylinder member30, air in the cylinder member30is pushed when the piston member20moves linearly in the longitudinal direction, allowing the air to flow upward or downward.

A plurality of plate through holes61is formed in the fixed plate60. The plate through holes61are formed along the longitudinal direction of the cylinder member30. Accordingly, when the piston member20linearly moves in the longitudinal direction, air may escape along the plate through holes61.

An outer diameter of the fixed plate60may be, preferably, similar to an inner diameter of the cylinder member30. A circumferential groove (no reference numeral) is formed along an outer circumferential surface of the fixed plate60, and a third wear ring65is provided at the circumferential groove. The third wear ring65allows the fixed plate60to smoothly slide along an inner surface of the cylinder member30.

The movable plate70is disposed above the fixed plate60. The movable plate70may have a plate shape in the form of a ring (disk). An outer diameter of the movable plate70is less (smaller) than the outer diameter of the fixed plate60. Accordingly, the movable plate70can move freely without friction with the inner surface of the cylinder member30.

In addition, the outer diameter of the movable plate70has a size that can completely cover the plate through holes61when the movable plate70is brought into contact with the fixed plate60. Accordingly, when the piston member20goes down, the movable plate70may be separated from the fixed plate60by pressure of air flowing through the plate through holes61. When the piston member20goes up, the movable plate70moves together with the fixed plate60in a state of closing (or covering) the plate through holes61.

The movable plate70is provided therein with a central hole (no reference numeral) so as to allow the piston member20to be installed therethrough. The movable plate70slides along the piston member20.

A guide portion71is formed along a circumference of the central hole of the movable plate70. The guide portion71is implemented as a wall having a predetermined height. The guide portion71guides such that the movable plate70may smoothly slide along the piston member20.

The movable plate70is installed above the fixed plate60to move up and down together with the fixed plate60by its own weight. When the fixed plate60moves upward, the movable plate70moves while being in contact with the fixed plate60as it is pushed by the fixed plate60. When the fixed plate60moves downward, the movable plate70moves downward in a state of being spaced apart from the fixed plate60by a predetermined distance by pressure of air flowing through the plate through holes61of the fixed plate60. When the movement of the fixed plate60is stopped, the movable plate70is brought into contact with the fixed plate60since there is no pressure by air.

The lengthwise directions (operating directions) of the cylinder member30and the piston member20are directions other than a horizontal direction. Preferably, the lengthwise directions of the cylinder member30and the piston member20may be defined in a vertical direction. Accordingly, when closing or opening action (or operation) is completed, that is, when there is no action of pneumatic pressure, the plate through holes61are closed as the movable plate70is in contact with the fixed plate60.

With reference toFIGS. 6 to 9, how the high-speed earthing switch of the gas insulated switchgear according to the one implementation of the present disclosure works will be described.

First, a closing action will be described.

FIG. 6shows an open state of the high-speed earthing switch. Since the piston member20that serves as a mover has been moved upward by the movable shaft17, the piston member20is separated from the fixed contact42. That is, as the movable contact52and the fixed contact42are disconnected from each other, the ground circuit is open.

The lower end of the piston member20is located at a position of the cylinder hole32of the cylinder member30, and the fixed plate60is located at an upper part of the cylinder member30. The movable plate70is in contact with an upper portion of the fixed plate60.

FIG. 7shows a state of proceeding with the closing action. As the movable shaft17rotates, the piston member20moves downward. The fixed plate60moves downward together with the piston member20, allowing air at a lower part of the fixed plate60is discharged to the outside of the cylinder member30through the vent holes33. In addition, air at the lower part of the fixed plate60flows upward through the plate through holes61, which acts as force to push the movable plate70upward. Accordingly, the movable plate70is moved downward while being spaced apart from the fixed plate60by a predetermined distance. When the piston member20moves downward, namely, upon the closing action, air at the lower part of the fixed plate60of the air inside the cylinder member30is discharged through the cylinder hole32and the plate through holes61. Therefore, the reaction acting on the piston member20is minimized.

FIG. 8shows a state in which the closing action is completed. As the lower end of the piston member20is brought into contact with the fixed contact42, the ground circuit is connected. The movement of the fixed plate60is stopped so that the movable plate70is in contact with the upper portion of the fixed plate60. Here, the fixed plate60is located close to the lower end of the cylinder member30but is located above the cylinder hole32.

Next, an opening action will be described.

FIG. 8shows a closed state of the high-speed earthing switch. The ground circuit remains connected. The movable plate70is in contact with the upper portion of the fixed plate60. The fixed plate60is located close to the lower end of the cylinder member30but is located above the cylinder hole32.

FIG. 9shows a state of proceeding with the opening action. As the movable shaft17rotates in a reverse direction, the piston member20moves upward. The fixed plate60moves upward together with the piston member20. Since the movable plate70is in contact with the upper portion of the fixed plate60, the plate through holes61of the fixed plate60are closed. Accordingly, air at the upper parts of the fixed plate60and the movable plate70is discharged to the outside (lower part) of the cylinder member30through the lateral hole21and the longitudinal hole22of the piston member20. That is, as the air inside the cylinder member30is delivered to the lower part of the piston member20, wind is blown to the contact portion, more precisely, the fixed part40. This allows the arc generated by the separation between the piston member20and the fixed contact42to be extinguished. As a result, the arc blocking performance is improved.

Meanwhile, as air at the outside of the cylinder member30is introduced into the cylinder member30through the cylinder hole32, depressurization of the lower part of the fixed plate60is prevented. Thus, a decrease in movement speed of the piston member20is suppressed.

It will be likeFIG. 6when the opening action is completed.

In the high-speed earthing switch of the gas insulated switchgear according to the one implementation of the present disclosure, the air blower that blows wind to the fixed part when the high-speed earthing switch is opened is provided, and thus the arc can be quickly extinguished. Therefore, the arc blocking performance can be achieved regardless of a type of insulating gas.

Here, as the piston member used in the air blower is formed integrally with the mover, the arc blocking performance can be improved without an increase in the number of components or occupied space.

Further, as the air blower is provided with the fixed plate, the movable plate disposed to be spaced apart from the fixed plate, and the air flow holes formed in the fixed plate and the cylinder member, the flow of air that is injected to the fixed part via the air flow holes is achieved while preventing a reduction in movement speed of the piston member that servers as the mover.

SECOND EXAMPLE

A high-speed earthing switch of the gas insulated switchgear according to another implementation of the present disclosure will be described with reference toFIGS. 10 and 11.

Unlike the previous example, a piston member160is separately provided from a mover120in this example.

A fixed part140that includes a fixed part holder141, a fixed contact142, and a fixed part shield143is installed at a first conductor114.

A movable part150that includes a movable part holder151, a movable contact152, and a movable part shield153is installed at a first support member155. The movable part150is installed to be spaced apart from the fixed part140.

A bus bar146is connected to an earth terminal (earth bushing)145that is installed at an enclosure110and the movable part holder141.

The mover120is connected to a movable shaft116through a first crank lever117. The mover120is installed by penetrating through the movable part150. The mover120connects or disconnects a ground circuit by connecting or separating the movable part150and the fixed part140according to rotation of the movable shaft116.

A cylinder member130is installed at a second support member156(or another portion of the first support member). The cylinder member130is installed to be spaced apart from the mover120by a predetermined distance. An injection hole131is provided at a lower portion of the cylinder member130. The injection hole131is formed toward a direction in which the fixed part140is installed.

The piston member160is inserted and installed in the cylinder member130. The piston member160includes a piston rod161that is connected to a second crank lever118installed at the movable shaft116and a piston plate162that is coupled to a lower end of the piston rod161to slide inside the cylinder member130.

The second crank lever118protrudes in a direction opposite to the first crank lever117so that moving or movement directions of the mover120and the piston member160are opposite to each other. That is, when the movable shaft116rotates in a clockwise direction, the mover120moves downward whereas the piston member160moves upward. Conversely, when the movable shaft116rotates in a counterclockwise direction, the movable member120moves upward whereas the piston member160moves downward.

An opening action in this example is as follows.

In a state as illustrated inFIG. 10, when the movable shaft116rotates counterclockwise, the mover120moves upward. Then, the mover120is separated from the fixed part140. Accordingly, the ground circuit is open. Here, the piston member160moves downward and air inside the cylinder member130is injected into the fixed part140through the injection hole131. The arc generated between the fixed part140and the mover120is extinguished by the air injected through the injection hole131.

THIRD EXAMPLE

A high-speed earthing switch of the gas insulated switchgear according to another implementation of the present disclosure will be described with reference toFIGS. 12 and 13.

Unlike the first example, a piston member220is connected to a first conductor214, which is a main circuit, and a fixed part240is connected to an earth terminal245in this example. Configurations of the piston member220and a cylinder member30are substantially the same as those of the first example.

The piston member (mover)220connects or disconnects a ground circuit by connecting or separating a movable part250and the fixed part240according to rotation of a movable shaft217.

A fixed plate260and a movable plate270are installed at the piston member220like the first example.

Closing and opening actions in this example are similar to those of the first example, so a detailed description thereof will be omitted. The arc generated in the fixed part240is extinguished by air delivered from the piston member160upon the opening action.

Although preferred implementations have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the disclosure. Therefore, it should be understood that the above-described implementations are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims. Therefore, all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.