JP2006166673A - Arrestor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arrestor where arrestor elements can be cut easily off a main circuit conductor and the voltage assignment of the arrestor elements can be equalized. <P>SOLUTION: This arrestor is equipped with a bushing 2 which is arranged airtightly in the opening 1a of an equipment case 1, and an arrestor mold body 6 including an arrestor element stack 61 is mounted detachably on this busing 2. The bushing 2 is equipped with a bushing main body 3 consisting of a hard insulator and, at the tip of the bushing body 3, a high-voltage shield body 4 embedded concentrically with the bushing main body 3. The periphery of the tip of the arrestor element stack 61 is covered with a high-voltage shield body 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an arrester, and in particular, an arrester including a laminate (hereinafter referred to as an “arrestor element laminate”) of a plurality of non-linear resistance elements (hereinafter referred to as “arrestor elements”) mainly composed of zinc oxide. About.

  In general, gas insulated switchgear installed in power plants, substations, etc. are provided with arresters to protect electrical equipment such as switchgears and transformers from abnormal voltages entering from the track during lightning strikes. Yes.

  Conventionally, as such an arrester, as shown in FIG. 11, an arrester element stack 100 is erected on the bottom 110a of a tank 110 filled with an insulating gas and supported through an insulating support cylinder 120. It is known (for example, Non-Patent Document 1).

  However, in the arrester having such a configuration, a large shield 130 must be provided on the high voltage side of the arrester element stack 100 in order to equalize the voltage sharing of the arrester elements constituting the arrester element stack 100. For this reason, there is a problem that the device itself is increased in size, and when performing a withstand voltage test of the gas-insulated switchgear having the arrester element laminate 100, the arrester element laminate 100 is made to be a main circuit conductor (non-conductive). Therefore, it is necessary to provide a separating device (not shown), which causes a complicated structure of the device.

  For this reason, as shown in FIG. 12, a bushing 220 is hermetically attached to the inner wall of the device case 210, and the arrester element laminate 230 is detachably attached to the bushing 220 (for example, a patent is proposed). Reference 1).

  In the arrester having such a configuration, since it is not necessary to provide a disconnecting device, the structure is simplified, and the operation of collecting or filling the insulating gas in the device case 210 when performing a withstand voltage test is performed. It can be unnecessary.

  However, in such a plug-in type arrester, since the device case 210 as a ground layer exists on a part of the outer periphery of the arrester element stack 230, it is difficult to make the voltage sharing of the arrester element 230a uniform. For this reason, the application is limited to a medium-voltage line of about 22/33 kV.

IEEJ Technical Report No. 851 7 (Fig. 2.10) Japanese Patent Laid-Open No. 1-232681 (FIG. 1)

  The present invention was made to solve the above-mentioned problems, and provides an arrester in which the arrester element can be easily separated from the main circuit conductor and the voltage sharing of the arrester element can be made uniform. It is aimed.

  The arrester according to the first aspect of the present invention has a bushing disposed so as to cover the opening in an airtight manner in an opening of the equipment case that houses the electrical equipment, and is detachably mounted in the bushing from the outside of the equipment case. The outer periphery of the tip portion of the arrester element laminate is covered with a high-pressure shield body.

  According to a second aspect of the present invention, in the arrester according to the first aspect, a solid insulating layer is provided on the outer periphery of the high-pressure shield body.

  According to a third aspect of the present invention, in the arrester according to the first aspect or the second aspect, the rear end portion of the arrester element stacked body is led out of the device case through the opening of the device case. Is.

  According to a fourth aspect of the present invention, in the arrester according to any one of the first to third aspects, the electric field in the middle portion of the arrester element stack is formed between the rear end portion of the high-voltage shield body and the device case. It is controlled by adjusting the distance between the inner surfaces.

  According to a fifth aspect of the present invention, in the arrester according to any one of the first to fourth aspects, the rear end of the bushing is formed of an insulating cylindrical member, and the cylindrical member is an equipment case. And is led out of the device case.

  According to a sixth aspect of the present invention, in the arrester according to any one of the first to fifth aspects, the bushing is formed of a hard plastic resin.

  According to a seventh aspect of the present invention, in the arrester according to any one of the first to sixth aspects, the arrester element laminated body is integrated by a rubber mold provided on the outer periphery of the arrester element laminated body. It is what has been.

  According to an eighth aspect of the present invention, in the arrester according to any one of the first to seventh aspects, the high-pressure shield body includes a metal fitting having substantially the same shape as the tip of the bushing. Is embedded concentrically with the bushing at the tip of the bushing.

  According to a ninth aspect of the present invention, in the arrester according to any one of the first to seventh aspects, the high-voltage shield body is formed of a conductive coating layer applied to the outer periphery of the tip of the bushing. It is what.

  According to a tenth aspect of the present invention, in the arrester according to any one of the first to seventh aspects, the high-pressure shield body has a cylindrical metal fitting, and the metal fitting is around the tip of the bushing. The bushing is disposed so as to surround the tip of the bushing.

  According to an eleventh aspect of the present invention, in the arrester according to the seventh aspect, the high-pressure shield is provided at the tip of the rubber mold so as to surround the tip of the arrester element laminate.

  According to the arresters of the first to eleventh aspects of the present invention, the following effects are obtained.

  First, since the arrester element laminate is detachably mounted from the outside of the equipment case to the bushing that is airtightly arranged in the opening of the equipment case, the disconnecting device is provided like a conventional gas-insulated arrester. Therefore, the structure of the device can be simplified, and the operation of collecting or filling the insulating gas in the device case when performing a withstand voltage test can be eliminated. .

  Secondly, since the outer periphery of the tip of the arrester element laminate is covered with a high-voltage shield body, the voltage sharing of the arrester element can be made uniform, and as a result, an arrester applicable to a 66/77 kV class high-voltage line. Can be provided.

  Third, since a part of the arrester element stack is led out of the device case, the device can be reduced in size.

Hereinafter, preferred embodiments to which the arrester of the present invention is applied will be described with reference to the drawings. Here, the “tip portion” of the arrester element laminated body and the “tip portion” of the bushing refer to the high-pressure side end portions of the arrester element laminated body and the bushing, and correspond to the upward direction in the drawing. Further, the “rear end portion” of the arrester element laminate and the “rear end portion” of the bushing are the end portions on the opposite side to the front end portion, and correspond to the downward direction in the drawing.
[Example 1]
FIG. 1 is a partial cross-sectional view showing an example of a 66/77 kV class arrester of the present invention.

In the figure, an electric device having an arrester according to the present invention includes a device case 1 that hermetically accommodates an electric device (not shown) such as a switch, and the device case 1 includes, for example, SF _6. It is filled with an insulating gas such as a gas. Also, an opening 1a is provided at the bottom of the device case 1, and the opening 1a has its own front end located in the device case 1, and the opening 1a is formed at the rear end of itself. A bushing 2 is disposed so as to be hermetically covered, and an arrester mold body 6 including an arrester element stack 61 described later is detachably mounted in the bushing 2.

  The bushing 2 includes a hard and insulating bushing body 3 made of an epoxy resin molded body and the like, and a high-pressure shield body 4 embedded concentrically with the bushing body 3 at the tip of the bushing body 3.

  The bushing body 3 has an upper end closed cylindrical portion (hereinafter referred to as “upper cylindrical portion”) 51 having an insertion hole (hereinafter referred to as “upper insertion hole”) 51 a for receiving the upper half portion of the arrester mold body 6. A cylindrical portion (hereinafter referred to as “lower cylindrical portion 52”) 52 having an insertion hole (hereinafter referred to as “lower insertion hole”) 52a for receiving the lower half of the arrester mold body 6; A cylindrical portion (hereinafter referred to as “intermediate cylindrical portion”) 53 having an insertion hole (hereinafter referred to as “tapered insertion hole”) 53a for receiving a conical portion 67b described later. An annular mounting flange 52b projecting in the radial direction is connected to the outer periphery of the tip end portion. Here, the diameter of the lower insertion hole 52a is larger than the diameter of the upper insertion hole 51a, and the tapered insertion hole 53a extends from the lower end of the upper insertion hole 51a to the upper end of the lower insertion hole 52a. The upper insertion hole 51a and the lower insertion hole 52a are communicated with each other through the tapered insertion hole 53a. Further, the outer diameter of the lower cylindrical portion 52 is substantially the same as or slightly smaller than the diameter of the opening 1a of the device case 1, and the outer diameter of the mounting flange 52b is larger than the diameter of the opening 1a of the device case 1. It is said that.

  The high-pressure shield body 4 includes a bell-shaped shield body 41 concentrically embedded in the upper cylindrical portion 51 from the closed portion 51 b to the lower end portion of the upper cylindrical portion 51, and the horizontal direction of the shield main body 41. A cylindrical part (hereinafter referred to as “connection conductor insertion part”) 42 protruding above the closing part 51b at the center of the part, and connected to the main circuit conductor (not shown) connected to the tip of the connection conductor insertion part 42 The main circuit connector 43 is provided. Here, the side wall portion 41 a of the shield body 41 is formed so as to expand in a conical shape from the upper end portion toward the lower end portion, and the axial length thereof is from the closing portion 51 b of the upper cylindrical portion 51 to the intermediate cylindrical portion 53. It is set as the length which reaches the upper end part vicinity. The connection conductor insertion portion 42 functions as an insertion hole for a connection conductor 62 (described later) of the arrester mold body 6, and the main circuit connector 43 provided at the upper end of the connection conductor insertion portion 42 is the arrester mold body 6. It also has a function as a stopper for a coiled spring 63 described later.

  As shown in the figure, the high-voltage shield body 4 having such a configuration causes the main circuit connector 43 to protrude from the closed portion 51b of the upper cylindrical portion 51, and the side wall portion 41a is positioned within the side wall portion 51c of the upper cylindrical portion 51. In this way, it is buried concentrically with the upper cylindrical portion 51.

  In the bushing 2 having such a configuration, the upper cylindrical portion 51 and the intermediate cylindrical portion 53 of the bushing 2 are positioned in the device case 1, and the lower cylindrical portion 52 is led out of the device case 1 through the opening 1a. Thus, the upper surface of the mounting flange 52b is brought into contact with the lower surface of the peripheral edge portion of the opening 1a of the device case 1. Therefore, the bushing 2 is attached to the device case 1 by interposing an O-ring 1c in an annular groove 1b provided at the peripheral edge of the opening 1a of the device case 1 and fastening a bolt 52c disposed on the mounting flange 52b. It can attach to the opening part 1a of this.

  As shown in FIG. 2, the arrester mold body 6 includes an arrester element laminated body 61 formed by laminating a plurality of arrester elements 61a mainly composed of zinc oxide, and the upper end side (high-pressure side) of the arrester element laminated body 61. ), A coiled spring (hereinafter referred to as “high-pressure side spring”) 63 disposed on the upper end side (high voltage side) of the connection conductor 62, and the arrester element laminate 61. A pressing member 65 disposed on the lower end side (low pressure side), a coiled spring (hereinafter referred to as “low pressure side spring”) 66 disposed on the lower surface side of the pressing member 65, and an arrester element laminate 61. And a rubber mold body 67 made of silicone rubber or the like that is integrally molded across the connection conductor 62 and the pressing metal 65. Here, the outer surface shape of the rubber mold 67 is formed to correspond to the inner peripheral surface shape of the insertion hole (the upper insertion hole 51a, the lower insertion hole 52a, and the tapered insertion hole 53a) of the bushing 2. Specifically, a small-diameter portion 67a that contacts the inner peripheral surface of the upper insertion hole 51a is formed on the upper end side (high pressure side) side of the rubber mold body 67, and an inner peripheral surface of the tapered insertion hole 53a is formed on the intermediate portion. The conical portion 67b that abuts is provided with a large-diameter portion 67c that abuts against the inner peripheral surface of the lower insertion hole 52a on the lower end side (low pressure side). Further, the number of arrester elements 61a corresponding to the system voltage is determined in consideration of a predetermined varistor voltage. This embodiment is applied to a 66 kV high-voltage line.

  The connection conductor 62 includes a disk portion 62a that is substantially the same shape as the arrester element 61a that is in contact with the high-voltage side of the arrester element stack 61, and a cylinder that protrudes upward from the center of the upper surface of the disk portion 62a. 62b, and an annular groove 62c for fitting a tape-shaped conductor connector (multi-contact) (not shown) is provided on the outer periphery of the cylindrical portion 62b. A coiled high-pressure spring 63 having the same diameter as that of the cylindrical portion 62b is mounted so as to protrude from the upper half.

  The pressing metal 65 includes an annular member 65a having a diameter slightly smaller than the outer diameter on the lower end side (low pressure side) of the rubber mold body 67. The center of the lower surface of the annular member 65a is substantially the same shape as the arrester element 61a. The disk-shaped pressing portion 65b is provided, and in the vicinity of the outer peripheral edge on the lower surface side, for example, twelve recessed portions 65c are provided so as to be equally distributed along the circumferential direction. In the figure, 65d is, for example, four screw holes provided so as to be equally distributed along the circumferential direction on the inner peripheral side of the annular member, and 65e is a large-diameter recessed portion provided in the lower central portion. Show.

  The outer periphery of the arrester element laminate 61 having such a configuration is connected in a state where the lower surface of the disk portion of the connection conductor 62 is brought into contact with the upper end portion thereof and the pressing portion 65b of the press fitting 65 is brought into contact with the lower end portion thereof. A rubber mold 67 such as silicone rubber is provided across the upper surface of the disk portion 62a of the conductor 62 and the outer periphery of the pressing metal 65. The rubber mold 67 allows the arrester element laminate 61 to be connected to the connecting conductor 62 and the pressing metal. 65 is integrated.

  Next, a method for detachably mounting the arrester mold body 6 having the arrester element stack 61 in the bushing 2 will be described.

  First, as shown in FIG. 2, the high-pressure side spring 63 is disposed in the cylindrical portion 62 b of the connecting conductor 62, and the low-pressure side spring 66 is disposed in the recessed portion 65 c of the pressing metal 65. The distal end portion (high pressure side) of the arrester mold body 6 is inserted into the bushing 2 and pushed in until the distal end portion of the high pressure side spring 63 contacts the inner wall surface of the main circuit connector 43. Thereby, a tongue piece (not shown) constituting a conductor connector (multi-contact) disposed in the cylindrical portion 62b comes into contact with the inner peripheral surface of the connection conductor insertion portion 42, and the small diameter portion 67a of the rubber mold body 67 On the inner peripheral surface of the upper insertion hole 51a of the bushing 2, the conical portion 67b of the rubber mold body 67 is on the inner peripheral surface of the tapered insertion hole 53c, and the large diameter portion 67c of the rubber mold body 67 is on the inner side of the lower insertion hole 52a. It will contact the peripheral surface.

  Next, a seal lid F made of a disk-shaped metal fitting is brought into contact with the lower surface of the lower cylindrical portion 52 of the bushing 2, and a plurality of bolts B arranged in the circumferential direction in the vicinity of the outer peripheral edge of the seal lid F. And fasten to the lower surface of the lower cylindrical portion 52. As a result, a predetermined spring force is applied to the high-pressure side spring 63 and the low-pressure side spring 66. Specifically, a predetermined surface pressure is applied between the arrester element 61a and the connection conductor 62, between the arrester element 61a, and between the arrester element 61a and the pressing portion 65b by the high-pressure side spring 63, and these members are reliably brought into contact with each other. be able to. Further, the arrester mold body 6 is pressed toward the tip by the low-pressure side spring 66, and the conical portion 67b of the rubber mold body 67 is pressed against the inner peripheral surface of the tapered insertion hole 53, whereby the rubber mold body A predetermined surface pressure is applied between the 67 conical portion 67 b and the tapered insertion hole 53.

  As described above, by mounting the arrester mold body 6 including the arrester element multilayer body 61 in the bushing 2, the shield in which the periphery of the distal end side (high voltage side) of the arrester element multilayer body 61 is embedded in the upper cylindrical portion 51. As a result, the voltage distribution of the arrester element 61a can be made uniform as will be described later.

  FIG. 3 shows an equipotential distribution diagram of the arrester in this embodiment. From the figure, the tip of the arrester element stack 61 is shielded by the high-voltage shield body 4 so that the electric field does not concentrate on the tip, and the rear end of the arrester element stack 61 serves as a grounding body. By being arranged outside the device case 1, the electric field is not concentrated on the rear end portion, and the middle part of the arrester element laminate 61 is between the high-voltage shield body 4 and the device case 1 as a grounding body. It can be seen that the electric field is appropriately controlled by adjusting the interval, so that the electric field is not concentrated in the intermediate portion.

  Here, the influence which the shield case 41 and the apparatus case 1 as a grounding body have on the arrester element laminated body 61 will be described. First, when the distance between the lower end of the shield body 41 and the inner surface of the device case 1 is shortened, the electric field in the middle portion of the arrester element laminate 61 becomes dense due to the influence of the shield body 41 and the device case 1. If the distance between the two is increased, the electric field in the intermediate portion becomes sparse. Accordingly, it is difficult to make the voltage sharing of the arrester element 61a uniform only by simply increasing the distance between the two. In this regard, in this embodiment, the tip of the arrester element stack 61 (about one third of the length of the arrester element stack 61) and the middle part (about one third of the length of the arrester element stack 61). Is positioned in the device case 1 and the rear end portion of the arrester element stack 61 (about one third of the length of the arrester element stack 61) is positioned outside the device case 1 so that the high-voltage shield 4 The distance from the device case 1 as the grounding body is appropriately adjusted, the electric field in the middle part of the arrester element stack 61 can be appropriately controlled, and the voltage sharing of the arrester element 61a can be made uniform. .

As described above, according to the arrester of the present invention, the arrester element stack 61 can be detachably mounted from the outside of the device case 1 in the bushing 2 that is airtightly attached to the opening 1 a of the device case 1. Thus, unlike the conventional gas-insulated arrester, it is not necessary to provide a separation device, the structure of the equipment can be simplified, and the insulation gas in the equipment case 1 can be recovered when performing a withstand voltage test. Or filling work can be made unnecessary. Furthermore, since the outer periphery of the tip of the arrester element stack 61 is covered with the high-voltage shield body 4, the voltage sharing of the arrester element 61a can be made uniform, and thus also applicable to 66 / 77kV class ultrahigh-voltage lines. An arrester that can be provided can be provided, and a part (low-pressure side) of the arrester element stack 61 can be led out of the device case 1 to reduce the size of the device.
[Example 2]
FIG. 4 shows a partial sectional view of the arrester in the second embodiment of the present invention. In the figure, parts common to those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  In this embodiment, a conductive coating layer 75 is provided on the outer peripheral surface of the tip of the bushing 7 as indicated by a dotted line.

  First, the bushing 7 in the second embodiment has an intermediate cylindrical portion 71 provided with an annular recessed portion 71a in the vicinity of the outer peripheral edge of the upper surface thereof, and is concentric with the intermediate cylindrical portion 71 at the upper end portion of the intermediate cylindrical portion 71. An upper cylindrical portion 72 having a tapered conical portion 72a that is smaller than the outer diameter of the intermediate cylindrical portion 71 and closed at the upper end, and an intermediate cylinder near the outer peripheral edge of the lower surface of the intermediate cylindrical portion 71. A lower cylindrical portion 73 concentrically connected to the portion 71 and having a diameter smaller than the outer diameter of the intermediate cylindrical portion 71 and a central portion of the closed portion 72b of the upper cylindrical portion 72 are provided with a tip portion protruding from the closed portion 72b. And a main circuit connector 74 embedded therein. In this embodiment, the bushing 7 has an outer diameter of the lower cylindrical portion 73 larger than that of the opening 1 a of the device case 1, and the lower surface of the outer peripheral edge of the lower cylindrical portion 73 is airtightly placed on the upper surface of the device case 1.・ It is fixed.

  Reference numeral 75 denotes a conductive coating layer (for example, a coating layer made of silver paint) as a high-voltage shield body. The conductive coating layer 75 is formed from the outer surface of the closing portion 72 b of the upper cylindrical portion 72. The outer peripheral surface of the conical portion 72 a and the outer peripheral surface of the semicircular portion 71 b constituting the recessed portion 71 a of the intermediate cylindrical portion 71 are provided.

  FIG. 5 shows the potential distribution of the arrester in the second embodiment. From this figure, in this embodiment as well as the arrester in the first embodiment, the tip of the arrester element stack 61 is shielded by a conductive coating layer 75 as a high-voltage shield, so that the tip The electric field does not concentrate on the portion, and the rear end portion of the arrester element stack 61 is disposed outside the device case 1 as a grounding body, so that the electric field does not concentrate on the rear end portion. In the middle part of the arrester element laminate 61, the electric field is controlled by adjusting the distance between the conductive coating layer 75 and the device case 1 as the grounding body, so that the electric field is not concentrated in the middle part. I understand.

Therefore, also in the arrester in the second embodiment, the voltage sharing of the arrester element 61a can be made uniform. Further, in the arrester in this embodiment, a conductive coating layer 75 is provided instead of the high-voltage shield body 4 made of the metal fitting in the first embodiment, so that it is lighter than the arrester in the first embodiment. And cost reduction can be achieved. Note that the arrester in this embodiment is suitable for gas-insulated or air-insulated type electrical equipment.
[Example 3]
FIG. 6 shows a partial cross-sectional view of an arrester in the third embodiment of the present invention. In the figure, parts common to those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  In this embodiment, a separate high-voltage shield body 10 is placed and fixed at the tip of the bushing 8.

  First, the bushing 8 in the third embodiment includes a tapered intermediate cylindrical portion 81 and an upper portion having a diameter smaller than the outer diameter of the intermediate cylindrical portion 81 connected to the upper end portion of the intermediate cylindrical portion 81 concentrically with the intermediate cylindrical portion 81. A cylindrical portion 82, and a lower cylindrical portion 83 that is concentrically connected to the lower end portion of the intermediate cylindrical portion 81 and concentrically with the intermediate cylindrical portion 81. An annular mounting flange 83a is continuously provided on the outer periphery of the tip portion 83.

  The high-voltage shield body 10 includes a cylindrical metal fitting 11 whose upper end is closed, and a main circuit connector 13 erected upward from the closing portion 12 at the center of the closing portion 12 of the metal fitting 11.

  In the high-voltage shield body 10 having such a configuration, as shown in the figure, the main circuit connector 13 is disposed above the upper cylindrical portion 82, and the side wall portion 14 of the metal fitting 11 is connected to the side wall portion 82 a of the upper cylindrical portion 82. It is placed and fixed concentrically with the upper cylindrical portion 82 at the tip of the upper cylindrical portion 82 so as to be positioned around.

  FIG. 7 shows the potential distribution of the arrester in the third embodiment. From this figure, in this embodiment as well as the arrester in the first embodiment, the tip of the arrester element stack 61 is shielded by the cylindrical metal fitting 11 that constitutes the high-pressure shield body 10. The electric field does not concentrate on the tip, and the rear end of the arrester element stack 61 is disposed outside the device case 1 as a grounding body, so that the electric field does not concentrate on the rear end. Further, the electric field is controlled in the middle part of the arrester element laminate 61 by adjusting the distance between the cylindrical metal fitting 11 and the device case 1 as the grounding body, so that the electric field is not concentrated in the middle part. I understand.

Therefore, also in the arrester in the third embodiment, the voltage sharing of the arrester element 61a can be made uniform as a whole. Note that the arrester in this embodiment is suitable for oil-insulated, gas-insulated, or air-insulated type electrical equipment.
[Example 4]
FIG. 8 shows a partial cross-sectional view of the arrester in the fourth embodiment of the present invention. In the figure, parts common to those in FIGS. 1 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, the high-voltage shield body 10 shown in FIG. 6 is placed and fixed at the tip of the bushing 9, and the periphery of the high-voltage shield body 10 is covered with a solid insulating layer 91b as follows. ing.

  First, the bushing 9 according to the fourth embodiment has an upper cylindrical portion 91 provided with an annular recessed portion 91a in the vicinity of the outer peripheral edge of the upper surface of the bushing 9 and a lower cylindrical portion of the upper cylindrical portion 91 concentric with the upper cylindrical portion 91. And a lower cylindrical part 92 having a diameter smaller than the outer diameter of the upper cylindrical part 91. The high-pressure shield body 10 having the same configuration as that shown in FIG. 6 is disposed concentrically with the upper cylindrical portion 91 so that the side wall portion 14 is located in the recessed portion 91 a of the upper cylindrical portion 91. . In this embodiment, the bushing 9 has an outer diameter of the upper cylindrical portion 91 larger than that of the opening 1a of the device case 1, and the lower surface of the outer peripheral edge of the upper cylindrical portion 91 is airtightly placed on the inner surface of the device case 1.・ It is fixed.

  FIG. 9 shows the potential distribution of the arrester in the fourth embodiment. From this figure, in this embodiment as well as the arrester in the first embodiment, the tip of the arrester element stack 61 is shielded by a cylindrical metal fitting 11 as a high-pressure shield, so that the tip In addition, the rear end portion of the arrester element stack 61 is disposed outside the device case 1 as a grounding body so that the electric field does not concentrate on the rear end portion. It can be seen that the electric field is controlled in the intermediate part of the arrester element laminate 61 by adjusting the distance between the cylindrical metal fitting 11 and the device case 1 as the grounding body, so that the electric field is not concentrated in the intermediate part. .

Therefore, also in the arrester in the fourth embodiment, the voltage sharing of the arrester element stack 61 can be made uniform as a whole. Further, in the arrester in this embodiment, the side wall portion 14 of the high-voltage shield body 10 is disposed in the recessed portion 91 a of the upper cylindrical portion 91, so that the solid insulating layer 91 b is disposed around the cylindrical metal fitting 11. As a result, the insulation distance between the phases or the insulation distance from the device case 1 can be shortened, and as a result, the device can be reduced. Note that the arrester in this embodiment is suitable for oil-insulated, gas-insulated, or air-insulated type electrical equipment.
[Example 5]
FIG. 10 shows a partial cross-sectional view of the arrester in the fifth embodiment of the present invention. In the figure, parts common to those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, the high-pressure shield body 20 is embedded at the tip of the arrester mold body 6 as follows.

  First, in the bushing 30 in the fifth embodiment, the connection conductor insertion portion 42 shown in FIG. 1 is embedded in the center of the closing portion 51b of the upper cylindrical portion 51, and the main portion shown in FIG. A circuit connector 43 is provided continuously. Further, a tapered hole 31 is provided on the inner periphery of the upper cylindrical portion 51 so as to conically extend from the closed portion 51b toward the lower end portion. The tapered hole 31 is inserted into the intermediate portion having the same diameter as the lower insertion hole 52a shown in FIG. It communicates with the hole 32.

  The high-voltage shield body 20 includes a reverse cup-shaped shield body 21 having a disc-shaped horizontal portion 21a and a side wall portion 21b extending so as to spread conically from the outer peripheral edge of the horizontal portion 21. A cylindrical portion 62b shown in FIG. 2 projects from the center of the upper portion of the horizontal portion 21a of the shield body 21.

  In the high-voltage shield body 20 having such a configuration, as shown in the figure, the horizontal portion 21 a is in contact with the tip end side (high-pressure side) of the arrester element stack 61, and in this state, on the outer periphery of the arrester element stack 61. The rubber mold body 67 is integrated. In addition, a conical portion 67 d that comes into contact with the inner peripheral surface of the tapered hole 31 is provided on the outer periphery of the distal end portion of the rubber mold body 67.

  Also in this embodiment, since the outer periphery of the tip end portion of the arrester element laminate 61 is covered with the high-voltage shield body 20, the voltage sharing of the arrester element 61a can be made uniform.

  In the fifth embodiment, the case where the high-voltage shield body 20 is embedded in the rubber mold body 67 is described. However, the high-pressure shield body 20 may be disposed on the outer periphery of the rubber mold body 67.

  The present invention can be changed and modified as follows within the scope of the claims.

  1stly, in the above-mentioned Example, although the case where a bushing was arrange | positioned in the bottom part of the apparatus case 1 was demonstrated, you may arrange | position a bushing in the side wall of the apparatus case 1. FIG.

  Secondly, in the above-described embodiment, the case where the arrester of the present invention is applied to a 66/77 kV high-voltage line is described. May be.

The partial sectional view of the arrester in the 1st example of the present invention. The partial sectional view of the arrester mold object in the 1st example of the present invention. The equipotential distribution map of the arrester in the first embodiment of the present invention. The partial sectional view of the arrester in the 2nd example of the present invention. FIG. 6 is an equipotential distribution diagram of an arrester in a second embodiment of the present invention. The partial sectional view of the arrester in the 3rd example of the present invention. FIG. 7 is an equipotential distribution diagram of an arrester in a third embodiment of the present invention. The partial sectional view of the arrester in the 4th example of the present invention. The equipotential distribution map of the arrester in the 4th Example of this invention. The partial sectional view of the arrester in the 5th example of the present invention. The partial cross section figure of the conventional arrester. The partial cross section figure of the conventional arrester.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Equipment case 1a ... Opening part 2 ... Bushing 4 ... High voltage | pressure shield body 6 ... Arresta mold body 61 ... Arrester element laminated body 67 ... Rubber mold body 11 ... Cylindrical metal fitting 75... Conductive coating layer 91b... Solid insulation layer

Claims (11)

A bushing disposed in an opening of a device case that houses an electric device so as to cover the opening in an airtight manner, and an arrester element laminate that is detachably mounted in the bushing from the outside of the device case. ,
The arrester, wherein the outer periphery of the tip of the arrester element laminate is covered with a high-pressure shield.   The arrester according to claim 1, wherein an insulating layer made of a solid is provided on an outer periphery of the high-voltage shield body.   3. The arrester according to claim 1, wherein a rear end portion of the arrester element laminated body passes through an opening of the device case and is led out of the device case. 4.   4. The electric field in the intermediate portion of the arrester element laminate is controlled by adjusting the distance between the rear end portion of the high-voltage shield body and the inner surface of the device case. The arrester according to item 1.   The rear end portion of the bushing is formed of an insulating cylindrical member, and the cylindrical member passes through an opening of the device case and is led out of the device case. The arrester according to claim 4.   The arrester according to any one of claims 1 to 5, wherein the bushing is made of a hard plastic resin.   The arrester according to any one of claims 1 to 6, wherein the arrester element laminate is integrated by a rubber mold provided on an outer periphery of the arrester element laminate.   The high-pressure shield body includes a metal fitting having substantially the same shape as the tip of the bushing, and the metal fitting is embedded concentrically with the bushing at the tip of the bushing. The arrester according to any one of claims 1 to 7.   The arrester according to any one of claims 1 to 7, wherein the high-voltage shield body is formed of a conductive coating layer applied to an outer periphery of a tip end portion of the bushing.   The high-voltage shield body has a cylindrical metal fitting, and the metal fitting is disposed around the tip of the bushing so as to surround the tip of the bushing. Item 8. The arrester according to any one of Items 7. The arrester according to claim 7, wherein the high-pressure shield body is provided at a distal end portion of the rubber mold body so as to surround the distal end portion of the arrester element laminated body.

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