JP2009100518A - External connection terminal and gas-insulated switchgear equipped with external connection terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an external connection terminal which can improve a degree of freedom at a mounting section and reduce the cost by reducing the parts count and simplifying the manhour in setup. <P>SOLUTION: The external connection terminal 20 has a terminal rod 21, which pierces a through-hole 10b and in which an external thread 21c is formed in either section of the inside or outside of a tank 10 and a flange section 21b is formed at the other section, insulating members 22 and 24, which are arranged between the tank 10 and the terminal rod 21, and a fastening member 26, which is screwed onto the external thread 21c. The terminal rod 21 is fastened to the tank 10, catching the periphery of the through-hole 10b with the flange section 21b and the fastening member 26, while being electrically insulated from the tank 10 with the insulating members 22 and 24. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is provided on a mounting seat formed on a wall surface of a tank filled with an insulating gas, and is electrically connected to a main circuit conductor housed in the tank via a ground switch, and the ground switch is closed. The present invention relates to an external connection terminal that electrically draws a portion having the same potential as a main circuit conductor to the outside of a tank in a state, and a gas-insulated switchgear including the external connection terminal.

  In the gas-insulated switchgear in which the main circuit conductor is housed in the tank filled with the insulating gas as described above, for the purpose of grounding the main circuit conductor, or the current ratio test of the current transformer for the instrument or the electric circuit of the main circuit. For the purpose of measuring resistance, an external connection terminal that is electrically connected to the main circuit conductor via a ground switch, and that electrically pulls out the same potential as the main circuit conductor to the outside of the tank when the ground switch is closed (Grounding terminal) is provided. Such an external connection terminal has a conductor penetrating the inside and outside of the tank, and an insulating member disposed between the conductor and the tank, and the conductor is electrically connected from the tank by the insulating member. (See, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-299022

  In the external connection terminal (the energizing terminal 17 in this document) as found in the gas insulated switchgear described in Patent Document 1 above, the insulating member is a flange (on the opposite side of the tank of the insulating member) A holding plate) and fastening bolts that pass through the flange and fasten the flange to the tank.

  However, if the insulating member is bolted to the tank via a flange (presser plate), the outer diameter of the external connection terminal will increase, so the overall diameter of the device will be increased and the installation position of the external connection terminal will be restricted. Had problems.

  Further, in the method of bolting the insulating member to the tank via the flange (pressing plate), not only is the structure complicated and the number of parts is large, but also the assembly process is complicated, so an improvement has been demanded.

  The present invention has been made to solve the above-described problems, and by eliminating the bolts for fixing the insulating member, the outer diameter of the ground terminal (external connection terminal) is reduced, and the degree of freedom of the mounting location is improved. Another object of the present invention is to provide an external connection terminal capable of reducing the number of parts and simplifying the assembly process and reducing the cost, and a gas insulated switchgear provided with the external connection terminal.

  The external connection terminal according to the present invention is disposed in a through hole formed in a wall surface of a tank filled with an insulating gas, and is electrically connected to a main circuit conductor housed in the tank via a ground switch. When the grounding switch is in a closed state, it is a terminal that electrically pulls out the part having the same potential as the main circuit conductor to the outside of the tank, and penetrates the through-hole and has a male screw part formed on either the inside or outside of the tank. A terminal rod having a flange portion formed on the portion, an insulating member disposed between the tank and the terminal rod, and a fastening member screwed into the male screw portion. The terminal rod is a tank made of an insulating member. It is characterized in that the periphery of the through hole is sandwiched between the flange portion and the fastening member while being electrically insulated from the tank, and is fastened to the tank.

  The gas-insulated switchgear according to the present invention is a gas-insulated switchgear having a tank filled with an insulating gas and a main circuit conductor housed in the tank, penetrating through a through-hole formed in the wall surface of the tank. In addition, a terminal rod having a male threaded portion formed in one of the inside and outside of the tank and a flange portion formed in the other portion, an insulating member disposed between the tank and the terminal rod, and screwed into the male threaded portion And an external connection terminal fastened to the tank by sandwiching the periphery of the through hole between the flange portion and the fastening member in a state where the fastening member is electrically insulated from the tank by the insulating member. To do.

  Here, the flange portion means a portion in which one end of the rod-shaped member has a larger diameter than the other portion, and is not necessarily limited to one integrally formed with the rod-shaped member. For example, a nut-like member that is screwed into a male screw portion formed at one end of a rod-like member to form a flange shape is also included.

  According to this invention, by making the conductor itself penetrating the inside and outside of the tank into the structure of the fastening member, it is possible to eliminate the flange and the fastening bolt for fastening to the flange of the separate part that holds the insulating member, which has been necessary conventionally. In addition, the outer diameter of the terminal can be reduced to improve the degree of freedom of the mounting location, the number of parts can be reduced, the assembly process can be simplified, and the cost can be reduced.

  Embodiments of an external connection terminal according to the present invention and a gas-insulated switchgear including the external connection terminal will be described below in detail with reference to the drawings. In this embodiment, the external connection terminal according to the present invention is described by taking a ground terminal as an example, but the present invention is not limited to this.

Embodiment FIG. 1 is a diagram showing an embodiment of a gas insulated switchgear according to the present invention, and is a cross-sectional view taken along the line AA in FIG. FIG. 2 is a bottom view of a location where a ground terminal (external connection terminal) of the gas insulated switchgear is provided. FIG. 3 is an enlarged cross-sectional view of a portion B in FIG. 1 showing details of the ground terminal. FIG. 4 is a side view of the terminal rod of the ground terminal. FIG. 5 is a cross-sectional view of the tank showing a state of connection between the ground terminal and the main circuit conductor. FIG. 6 is a longitudinal sectional view of the tank showing a state of connection of the ground terminal with the main circuit conductor.

  1 and 2, three-phase main circuit conductors 11A, 11B, and 11C are accommodated along an axis (center line) of the tank 10 in a cylindrical tank 10 filled with an insulating gas (see FIG. 1 and FIG. 2). In FIG. 1, the center line of the tank 10 is omitted). As shown in FIG. 2, the end of the tank 10 is closed by an insulating spacer 15. As shown in FIG. 1, the three-phase main circuit conductors 11 </ b> A, 11 </ b> B, and 11 </ b> C are arranged (triangular arrangement) such that each main circuit conductor is positioned at the apex of a triangle in a cross section orthogonal to the axis. The three-phase main circuit conductors 11A, 11B, and 11C are accommodated by decentering the center line of the triangular arrangement by a predetermined amount (shifted upward in FIG. 1). Three ground terminals 20A, 20B are located at positions facing the three-phase main circuit conductors 11A, 11B, 11C across the gas space in the tank 10 (downward in FIG. 1) and close to the insulating spacer 15. 20C.

  The three ground terminals 20A, 20B, and 20C correspond to the three-phase main circuit conductors 11A, 11B, and 11C, respectively. The three ground terminals 20A, 20B, and 20C are arranged in a line (in a straight line) along the interphase direction (left and right direction in FIG. 1) of the three-phase main circuit conductors 11A, 11B, and 11C, and the gas space in the tank 10 The main circuit conductors 11A, 11B, and 11C are disposed so as to face each other. The interphase distance l1 between the three ground terminals 20A, 20B, and 20C is shorter than the interphase distance l2 between the three-phase main circuit conductors 11A, 11B, and 11C. The middle phase 11 </ b> B of the main circuit conductor at a location facing the central ground terminal 20 </ b> B is disposed on the opposite side of the tank 10 from the ground terminal 20 </ b> B across the center line of the tank 10. With such a structure, the diameter of the tank 10 can be reduced by facilitating an insulation distance between the three-phase main circuit conductors 11A, 11B, and 11C and the three ground terminals 20A, 20B, and 20C. The thickness of the mounting seat 10a can be reduced.

  A mounting seat 10a is formed integrally with the tank 10 on the tank wall opposite to the side where the main circuit conductors 11A, 11B, and 11C are stored in a cross section orthogonal to the axis (center line) of the tank 10. The mounting seat 10a is formed by flattening a part of the wall surface of the cylindrical tank 10 and having a plate thickness larger than that of the periphery, and three through holes 10b are formed in a line (linearly) there. . The ground terminals 20A, 20B, and 20C are directly fastened to the tank 10 by passing through terminal holes 21 described later through the through holes 10b. The insulation distance between the ground terminals outside the tank 10 is substantially the same distance as the air insulation distance between the ground.

  An internal ground plate 12 is connected to the end of the ground terminal 20 inside the tank 10. On the other hand, an external ground plate 13 is connected to the outer end of the tank 10 of the ground terminal 20. The external ground plate 13 is connected to the ground terminal 14 after the three ground terminals 20A, 20B, and 20C are mutually connected and short-circuited.

  In FIG. 3, the connection terminal 20 is screwed into the terminal rod 21 a and a substantially rod-shaped terminal rod main body 21 a that penetrates the through hole 10 b, insulating members 22 and 24 disposed between the tank 10 and the terminal rod 21, and the terminal rod 21 a. The fastening member 26 is provided. The terminal rod main body 21a has a male threaded portion 21c at the end on the inner side of the tank and a flange 21b at the end on the other side of the tank (FIG. 4). The terminal rod 21 is fastened to the tank 10 with the flange portion 21b and the fastening member 26 sandwiching the periphery of the through hole 10b while being electrically insulated from the tank 10 by the insulating members 22 and 24. The terminal bar 21 has a cross-sectional area perpendicular to the axis so that a large current (current value is about several tens of kA) at the time of a short-circuit accident can be passed, and an AC or DC voltage of about several kV to several tens of kV is applied. Even if it is applied, an electrical insulation state is secured.

  The material of the terminal rod 21 is preferably copper or copper alloy having high conductivity. The fastening member 26 is preferably made of a nonmagnetic material such as stainless steel or nonferrous metal. This is to prevent the occurrence of local heat generation during continuous energization of about several hundred amperes when testing a current transformer for an instrument. The same applies to the material of the tank 10.

  The two insulating members 22 and 24 each made of an insulating material are sandwiched between the flange portion 21b and the tank 10 on the outer side of the through hole 10b via a gasket 23 such as an O-ring to form the through hole 10b. The first insulating member 22 is hermetically sealed, and the second insulating member 24 is sandwiched together with the washer 25 between the fastening member 26 and the tank 10 inside the through hole 10b. The first insulating member 22 has a stepped cylindrical shape having a large-diameter cylindrical portion and a small-diameter cylindrical portion, and is disposed so as to cover the end portion of the terminal rod body 21a and the flange portion 21b. By adopting such a structure, the insulation performance is improved by extending the air-to-ground insulation distance outside the tank when a voltage is applied to the terminal rod 21. In addition, the axial height of the large-diameter cylindrical portion of the first insulating member 22 is slightly lower than the flange portion 21b in consideration of the ease of mounting the external ground plate 13.

  A cylindrical surrounding space 29 is formed between the inner peripheral surface of the through hole 10 b and the outer peripheral surface of the terminal rod 21. The surrounding space 29 is formed by closing both ends in the axial direction with the first insulating member 22 and the second insulating member 24. The surrounding space 29 is filled with an insulating gas. A through hole 24a is formed in the second insulating member 24, and the insulating gas in the tank 10 enters the surrounding space 29 through the through hole 24a. With such a structure, the dielectric strength of the surrounding space 29 is improved, and the inner diameter of the through hole 10b is reduced.

  An outer ground plate fixing bolt hole 21d for fixing the external ground plate 13 to the terminal rod main body 21a by a fixing bolt 27 is formed along the center line on the end surface of the terminal rod main body 21a on the outer side of the tank. Yes. On the other hand, an inner ground plate fixing bolt hole 21e for fixing the internal ground plate 12 to the terminal rod main body 21a by the fixing bolt 28 is formed along the center line on the end surface on the inner side of the tank of the terminal rod main body 21a. Has been. Furthermore, two attachment tool engagement holes 21f for engaging a dedicated tool when the terminal rod 21 is rotated relative to the fastening member 26 are formed on the outer end surface of the flange portion 21b. .

  5 and 6, the grounding fixed contact 31 is disposed inside the tank 10. The grounding fixed contact 31 is provided with three contacts corresponding to the three-phase main circuit conductors 11A, 11B, and 11C, that is, grounding fixed contacts 31A, 31B, and 31C. The grounding fixed contacts 31A, 31B, 31C are fixed to a mounting seat provided in the tank 10 via an insulating plate 34 and a conductor 35. Internal ground plates 12 extending from the three ground terminals 20A, 20B, and 20C are fixed to the fixed contacts for grounding 31A, 31B, and 31C by fixing bolts 36, respectively.

  Furthermore, a ground switch 40 for grounding the three-phase main circuit conductors 11A, 11B, and 11C is disposed inside the tank 10. Three movable contacts 32 respectively extending from the three-phase main circuit conductors 11A, 11B, and 11C are pivotally rotated by rotation shafts 38 provided at the tips of the three-phase main circuit conductors 11A, 11B, and 11C, respectively. With this structure, the movable contact 32 rotates and contacts and separates from the grounding fixed contacts 31A, 31B, and 31C.

  In the gas-insulated switchgear having such a configuration, the three-phase main circuit conductors 11A, 11B, and 11C can be short-circuited and grounded at the outside of the tank 10 by the external grounding plate 13 as needed. By removing the external ground plate 13, the electrical resistance can be measured for each of the main circuit conductors 11A, 11B, and 11C.

  As described above, the ground terminal 20 of the present embodiment penetrates the through hole 10b formed in the mounting seat 10a, and the male screw portion 21c is formed in one of the inside and outside of the tank 10, and the flange is formed in the other portion. A terminal rod 21 formed with a portion 21b, insulating members 22 and 24 disposed between the tank 10 and the terminal rod 21, and a fastening member 26 screwed into the male screw portion 21c. Are fastened to the tank 10 with the flange portion 21b and the fastening member 26 sandwiching the periphery of the through hole 10b while being electrically insulated from the tank 10 by the insulating members 22 and 24. In this way, by making the conductor itself penetrating the inside and outside of the tank into the structure of the fastening member, it is possible to eliminate the fastening bolt for fastening to the flange or tank of another part that presses the insulating member that was conventionally required, It is possible to reduce the outer diameter of the terminal to improve the degree of freedom of the mounting location, further reduce the number of parts, simplify the assembly process, and reduce the cost.

  The ground terminal 20 of the present embodiment is intended to short-circuit the three-phase main circuit conductors 11A, 11B, and 11C at once, but the external connection terminal according to the present invention is Not limited to this, for example, for the purpose of measuring the electric resistance of each of the main circuit conductors 11A, 11B, and 11C, a portion having the same potential as the main circuit conductor is disposed outside the tank 10 when the ground switch 40 is closed. It may be a terminal that is electrically drawn out.

  The terminal rod 21 of the present embodiment is provided with a male screw portion 21c and a fastening member 26 on the inner side of the tank 10 and a flange portion 21b on the outer side of the tank 10; An effect can be obtained. Further, the flange portion 21b of the present embodiment is formed integrally with the end portion of the terminal rod main body 21a, but is not limited thereto, and is, for example, a male screw portion formed at one end of a rod-like member such as a nut. It includes those that are screwed together to form a flange shape.

  Moreover, although the insulating members 22 and 24 of this Embodiment are separate members with respect to the terminal rod 21, for example, it is fixed to the periphery of the terminal rod 21 by a single casting, and so on. May be.

  Further, the three ground terminals 20A, 20B, and 20C of the present embodiment are arranged in a line (in a straight line), but are not limited to this, and may be arranged to be, for example, the apex of a triangle. .

  Furthermore, the interphase distance l1 of the ground terminals 20A, 20B, and 20C of the present embodiment is shorter than the interphase distance l2 of the three-phase main circuit conductors 11A, 11B, and 11C, but the same interphase distance (pitch). May be arranged. Further, the three ground terminals may be arranged on the tank wall surface closest to the corresponding main circuit conductor.

  The present invention is arranged in a through hole formed in a wall surface of a tank filled with an insulating gas, and is electrically connected to a main circuit conductor housed in the tank via a ground switch. It is optimally applied to a grounding terminal (external connection terminal) that electrically draws a portion having the same potential as the main circuit conductor to the outside of the tank and a gas-insulated switchgear having the same in a closed state.

It is a figure which shows embodiment of the gas insulated switchgear of this invention, and is arrow sectional drawing which follows the AA line of FIG. It is a bottom view of the location in which the ground terminal of the gas insulated switchgear was provided. It is an expanded sectional view of B section of Drawing 1 showing details of a grounding terminal. It is a side view of the terminal rod of a ground terminal. It is a cross-sectional view of a tank showing a state of connection with the main circuit conductor of the ground terminal. It is a longitudinal cross-sectional view of the tank which shows the state of a connection with the main circuit conductor of a ground terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tank 10a Mounting seat 10b Through-hole 11A, 11B, 11C Main circuit conductor 12 Internal grounding board 13 External grounding board 14 Grounding terminal 15 Insulating spacer 20A, 20B, 20C Grounding terminal 21 Terminal bar 21a Terminal bar main body 21b Flange part 21c Male thread part 21d External ground plate fixing bolt hole 21e Internal ground plate fixing bolt hole 21f Mounting tool engagement hole 22 External insulating member (first insulating member)
23 Gasket 24 Inner side insulation member (second insulation member)
24a Punching hole 25 Washer 26 Fastening member 27, 28 Fixing bolt 29 Surrounding space 31, 31A, 31B, 31C Fixed contact for grounding 32 Movable contact 34 Insulating plate 35 Conductor 36 Fixing bolt 38 Rotating shaft 40 Grounding switch

Claims (9)

It is disposed in a through-hole formed in the wall of the tank filled with insulating gas, and is electrically connected to the main circuit conductor housed in the tank via a grounding switch, and the grounding switch is in a closed state. Sometimes it is a terminal that pulls out the same potential part as the main circuit conductor to the outside of the tank,
A terminal rod that penetrates the through-hole and has a male thread portion formed in one of the inside and outside of the tank and a flange portion formed in the other portion;
An insulating member disposed between the tank and the terminal rod;
A fastening member screwed into the male screw portion,
The terminal rod is fastened to the tank by sandwiching the periphery of a through hole between the flange portion and the fastening member while being electrically insulated from the tank by the insulating member. Terminal. The external connection terminal according to claim 1, wherein the insulating gas is filled in an enclosed space formed between an inner peripheral surface of the through hole and the terminal rod. The insulating member includes a first insulating member that is sandwiched between the flange portion and the tank on the outer side of the through hole and seals the through hole, and the fastening member and the tank on the inner side of the through hole. And a second insulating member sandwiched between
The external connection terminal according to claim 2, wherein the surrounding space is formed between the first insulating member and the second insulating member. 4. The external connection terminal according to claim 3, wherein a hole is formed in the second insulating member, and an insulating gas in the tank is filled in the surrounding space through the hole. The flange portion includes a second male screw portion provided on the opposite side of the terminal rod to the male screw portion, and a second fastening member screwed into the second male screw portion. 5. The external connection terminal according to any one of 1 to 4. In a gas insulated switchgear comprising a tank filled with insulating gas and a main circuit conductor housed in the tank,
A terminal rod that penetrates a through hole formed in the wall surface of the tank and has a male screw portion formed in one of the inside and outside of the tank and a flange portion formed in the other portion, between the tank and the terminal rod And a through hole formed between the flange portion and the fastening member in a state where the insulating member is electrically insulated from the tank by the insulating member. A gas insulated switchgear characterized by comprising an external connection terminal sandwiched around and fastened to the tank. A three-phase gas-insulated switchgear in which three-phase main circuit conductors are collectively stored in one tank;
Three external connection terminals are provided corresponding to the three-phase main circuit conductors,
The three external connection terminals are arranged in a line along the interphase direction of the three-phase main circuit conductors and so as to face the main circuit conductors with a gas space in the tank interposed therebetween. The gas insulated switchgear according to claim 6. The gas-insulated switchgear according to claim 7, wherein an interphase distance between the external connection terminals is shorter than an interphase distance between the main circuit conductors. The middle phase of the main circuit conductor at a location facing the external connection terminal is located on the opposite side of the external connection terminal across the center line of the tank. The gas insulated switchgear according to claim 1.

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