CN101902020B - Gas-insulated switchgear apparatus - Google Patents

Abstract

A gas-insulated switchgear apparatus includes a center conductor 2, a current transformer 4 surrounding the center conductor 2, an electric field shield 5, and a metallic vessel 1. The electric field shield 5 is located between the center conductor 2 and the current transformer 4 and surrounds the center conductor 2. The current transformer 4 and the electric field shield 5 constitute a tubular part that outputs a signal representing an electric physical quantity. The metallic vessel 1 is filled with an insulating gas 19. The tubular part has an opening 6 formed therein. In a posture in which the center axis of the tubular part about which the tubular part surrounds the center conductor 2 is substantially horizontal, the opening 6 is located in a surface of the tubular part, which surface is included in a lower portion of the tubular part and faces the center conductor 2.

Description

Gas Insulated Switchgear

technical field

The present invention relates to a gas insulated switchgear, and more specifically, to a gas insulated switchgear having a cylindrical equipment element mounted around a central conductor.

Background technique

Gas-insulated switchgear is used in the field of power generation and transformation of power systems. Gas insulated switchgear is a pressure vessel filled with arc-extinguishing gas that contains switchgear, busbars, current transformers or voltage transformers.

Hitherto, attempts have been made to miniaturize the gas insulated switchgear. One method of miniaturization is to increase the designed electric field value near the gas insulation target part to reduce the insulation distance, and the appearance of the equipment can be reduced. However, if the designed electric field value in the vicinity of the insulation target portion is increased, foreign matter (metal foreign matter) in the equipment, which has been harmless in the past, will become a factor that reduces the insulation reliability.

Japanese Patent Application Laid-Open No. 2004-56927 discloses a gas insulated switchgear having a function of making internal foreign matter harmless. The content of this document is incorporated into this specification.

In the gas insulated switchgear disclosed in the above publication, a hole is provided in the metal adapter (support member) for mounting the current transformer in the pressure vessel. The foreign matter between the current transformer and the center conductor of the gas insulated switchgear moves to the low electric field part due to falling down from the hole formed in the metal adapter or the end of the current transformer on the opposite side, and as a result, To achieve harmless. In this structure, in order to drop the foreign matter toward the low electric field portion, it needs to move toward the end portion of the current transformer in the axial direction. Therefore, it takes a relatively long time until the metal foreign matter is rendered harmless. The metal foreign matter causes a decrease in the dielectric strength of the gas insulated switchgear and a decrease in the reliability of the gas insulated switchgear.

Contents of the invention

An object of the present invention is to provide a gas insulated switchgear capable of moving a foreign object between a central conductor and a cylindrical device element surrounding it to a low electric field portion in a short time.

In addition, another object of the present invention is to provide a gas insulated switchgear with high insulation reliability.

The gas insulated switchgear according to the present invention includes: a central conductor through which current flows; a cylindrical equipment element disposed around the central conductor; and a support member provided at at least one end of the cylindrical equipment element to support the a cylindrical equipment element; and a container containing the above-mentioned center conductor, the above-mentioned cylindrical equipment element, and the above-mentioned support member and filled with an insulating gas, the above-mentioned cylindrical equipment element having at least one opening on a surface opposite to the above-mentioned center conductor, the above-mentioned The cylindrical device element includes at least one sensor; and an electric field shield disposed between the central conductor and the sensor, wherein the at least one opening is formed in the electric field shield.

According to the present invention, foreign matter mixed between the central conductor and the cylindrical device element surrounding it can move from the opening of the cylindrical device element to a position where the electric field is small. As a result, the reliability of the gas insulated switchgear can be improved.

Description of drawings

FIG. 1 is a longitudinal sectional view showing the structure of a gas insulated switchgear according to Embodiment 1 of the present invention. Fig. 2 is a transverse sectional view taken along line AA of Fig. 1 .

Fig. 3 is a diagram for explaining the shape and formation position of openings.

FIG. 4 is a partially enlarged view of FIG. 2 .

Fig. 5 is an enlarged cross-sectional view showing an application example of the foreign matter removing structure shown in Fig. 2 .

(a) to (f) of FIG. 6 are diagrams showing modified examples of openings.

7 is a longitudinal sectional view showing the structure of a gas insulated switchgear according to Embodiment 2 of the present invention.

FIG. 8 is a transverse cross-sectional view taken along line CC of FIG. 7 .

Fig. 9 is an enlarged cross-sectional view showing an application example of the foreign matter removing structure shown in Fig. 8 .

10 is a vertical cross-sectional view illustrating a modified example of the foreign matter removal structure according to Embodiment 2. FIG.

Fig. 11 is a transverse cross-sectional view taken along line EE in Fig. 10 .

12 is a longitudinal sectional view showing the structure of a gas insulated switchgear according to Embodiment 3 of the present invention.

Fig. 13 is a transverse cross-sectional view taken along line G-G in Fig. 12 .

Fig. 14 is an enlarged cross-sectional view showing an application example of the foreign matter removing structure shown in Fig. 13 .

15 is a longitudinal sectional view showing the structure of a gas insulated switchgear according to Embodiment 4 of the present invention.

Fig. 16 is a transverse sectional view taken along line II of Fig. 15 .

Fig. 17 is an enlarged cross-sectional view showing an application example of the foreign matter removing structure shown in Fig. 16 .

Detailed ways

(Embodiment 1)

Next, gas insulated switchgear 101 according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a gas insulated switchgear 101 according to the first embodiment. Fig. 2 is a transverse sectional view taken along line AA of Fig. 1 . FIG. 1 is a cross-sectional view corresponding to line BB in FIG. 2 . In addition, in each drawing, UD indicates an upward direction, DD indicates a downward direction (direction of gravity), and HD indicates a horizontal direction.

As shown in FIGS. 1 and 2 , a gas insulated switchgear 101 according to this embodiment is composed of a metal container 1 , a central conductor 2 , an insulating spacer 3 , a current transformer 4 , an electric field shield 5 , and a switch 29 .

The metal container 1 has a metal layer that surrounds the whole and is grounded. An insulating gas 19 (for example, SF ₆ gas) is filled inside the metal container 1 .

The central conductor 2 is the main circuit conductor of the gas insulated switchgear 101 and is fixed in the metal container 1 by the insulating spacer 3 . The central conductor 2 is connected to a switch 29 . In the state where the switch 29 is closed, a current flows through the central conductor 2 .

The current transformer 4 is fixed in the metal container 1 by the fixing piece 30 and the supporting member (base) 31 . The current transformer 4 surrounds the central conductor 2 and outputs the current induced by the alternating magnetic field caused by the alternating current flowing through the central conductor 2 .

The current transformer 4 is composed of annular iron cores 4a, 4b, 4c. The cores 4a, 4b, and 4c are arranged along the axial direction of the central conductor 2 so as to surround the central conductor 2, respectively.

The electric field shield 5 is made of a cylindrical conductive metal, and is disposed around the central conductor 2 between the central conductor 2 and the cores 4a, 4b, and 4c. The electric field shield 5 is arranged to reduce electric field concentration due to the corners of the current transformer 4 or surface irregularities, and is connected to the ground potential. The electric field shield 5 is integrally formed with a support member 31 fixed in the metal container 1 by the support member 31 .

The electric field shield 5 divides two spaces S1 and S2. The space S1 is the area between the central conductor 2 and the electric field shield 5 , and the space S2 is the space between the electric field shield 5 and the metal container 1 . In the space S1, when a current flows through the central conductor 2, a large electric field is generated. On the other hand, in the space S2, even if a current flows through the central conductor 2, an electric field is hardly generated. This is because both the electric field shield 5 and the metal container 1 are grounded.

The current transformer 4 and the electric field shield 5 surround the central conductor 2 and constitute a cylindrical device element that outputs a signal representing an electrical physical quantity, that is, a cylindrical sensor. In this embodiment, the signal output by the cylindrical device element is an induced current (or an electromotive force caused by electromagnetic induction). The central axis of the cylindrical device element (the central axis of the current transformer 4 and the central axis of the electric field shield 5 ) substantially coincides with the central axis of the central conductor 2 .

The switch 29 is a device for switching the circuit of the central conductor 2 .

In the gas insulated switchgear 101, the central axis of the central conductor 2 and the current transformer 4 surrounding it is provided in a horizontal posture.

As shown in FIG. 3 , a slit-shaped opening 6 is formed in the lower portion of the electric field shield 5 . The opening 6 is formed along the lowermost position LP from one axial end E1 to the other end E2 of the electric field shield 5 in the region including the lowermost position LP in the installed state of the electric field shield 5 . The foreign matter in the high electric field space S1 between the central conductor 2 and the electric field shield 5 falls downward from the opening 6 due to gravity, and is guided to the low electric field space S2.

The distance between the central conductor 2 and the electric field shield 5 is relatively small. Therefore, when a current flows through the center conductor 2 in the space S1 between the center conductor 2 and the electric field shield 5 , the electric field increases. Under such a high electric field, the foreign matter floats up due to the electrostatic force caused by the applied electric field, reaches the center conductor 2 whose electric field is higher than the bottom of the electric field shield 5, and becomes a main cause of a decrease in dielectric strength. In addition, even if the foreign matter does not reach the central conductor 2, it becomes a factor of localized electric field concentration. Therefore, when an overvoltage such as an opening surge voltage due to the operation of a circuit breaker (not shown) or a lightning pulse voltage due to lightning occurs, it becomes a factor of a decrease in dielectric strength. In addition, foreign matter is, for example, metal particles, etc., which are generated during assembly or operation of the equipment and enter into the electric field shield 5 .

FIG. 4 is an enlarged cross-sectional view of a part of FIG. 2 . Referring to FIG. 4 , the behavior of a foreign object entering the space S1 between the central conductor 2 and the electric field shield 5 will be described. The foreign object 7 in the space S1 repeatedly floats and falls due to the buoyancy force and the effect of gravity caused by the electrostatic induction or electric polarization caused by the applied electric field, as indicated by the locus of the arrow AR. The foreign matter 7 finally reaches the opening 6 and falls downward from the opening 6 . In other words, the foreign matter 7 falls to the recess formed by the opening 6 and the inner surface of the current transformer 4 . The concave portion is a part of the space S2 and has a low electric field. Therefore, the foreign matter 7 no longer floats or falls, but stays on the bottom of the recess (the inner bottom surface of the current transformer 4). That is, the foreign matter 7 is caught in the bottom of the concave portion, and harmlessness is achieved. The electric field at the bottom of the opening 6 of the electric field shield 5 is determined by the circumferential width W of the opening 6 shown in FIG. 4 and the distance D between the electric field shield 5 and the inner surface of the current transformer 5. By forming the width The relationship of W<distance D, that is, by making the circumferential width W of the cylindrical device element of the opening 6 smaller than the inner surface of the electric field shield 5 opposite to the center conductor 2 and the center conductor 2 of the current transformer 4 With the distance D of the opposite inner surface, the electric field is greatly reduced, and the effect of trapping the foreign matter 7 is enhanced.

As shown in FIG. 5 , an adhesive layer 20 may be provided on the inner bottom surface of the current transformer 4 , more specifically, at a position facing the center conductor 2 across the opening 6 . As a method of forming the adhesive layer 20 , a method of pasting a sheet of a gel-like material, a method of pasting an adhesive double-sided tape, or a method of applying an adhesive paint can be used. By providing the adhesive layer 20 on the inner bottom surface of the iron cores 4a, 4b, 4c located at the bottom of the concave shape, the falling foreign matter 7 can be captured more reliably. In order to securely capture the foreign matter 7 falling from the opening 6, it is desirable that the adhesive layer 20 is formed so that its circumferential width WA is larger than the circumferential width W of the opening 6. In addition, the axial length of the adhesive layer 20 It is longer than the axial length of the opening 6 .

As described in detail above, according to the gas insulated switchgear 101 of the first embodiment, the foreign matter 7 that enters the space S1 between the center conductor 2 and the electric field shield 5 falls to the low electric field part (from the opening 6 and the current transformer). 4 constitute the recess), thus being removed. The foreign matter is quickly removed without moving a long distance to the end of the current transformer 4, and the gas insulated switchgear 101 with high insulation reliability can be realized.

In addition, according to Embodiment 1, the distance between the central conductor 2 and the electric field shield 5 can be reduced, thereby reducing the external volume of the metal container 1 . Therefore, the amount of materials constituting each part can be reduced, and the amount of processing can be reduced. In addition, since the volume of the metal container 1 can be reduced, the amount of the insulating gas 19 used can be reduced accordingly.

Furthermore, the mean time between failures (MTBF) of the gas insulated switchgear 101 becomes longer, and the operating rate is also improved. Therefore, the number of times to open the device to check the inside is reduced, and the number of times to recover and refill the insulating gas 19 is reduced, and its usage can be reduced.

As described above, according to the first embodiment, it is possible to reduce the environmental load of the gas insulated switchgear 101 at each stage of its service life.

In addition, in Embodiment 1, the current transformer 4 was demonstrated as the example of the cylindrical equipment element which surrounds the center conductor 2. As shown in FIG. However, the same effect can be obtained even if it is a cylindrical device element that surrounds the central conductor 2 and extracts a signal of an electrical physical quantity, except for the current transformer 4 . For example, the cylindrical device element can also be a voltage transformer or a voltage-current transformer surrounding the central conductor 2 . In addition, the present invention is not limited to converters (transformers) such as current transformers and voltage transformers, but can also be applied to other sensors such as pressure gauges and thermometers. The voltage transformer outputs the voltage caused by the electromagnetic induction caused by the applied magnetic field to the outside. A manometer measures pressure and a thermometer measures temperature. In the case of using the sensor described above, by providing the opening 6 at the lower end portion of the electric field shield 5 , the same effect as that of the first embodiment can be obtained.

The shape or number or positions of the openings 6 formed on the electric field shield 5 are arbitrary.

For example, as shown in FIGS. 6( a ) to 6 ( f ), the openings 6 ( 6 a to 6 c ) may be rectangular slits, oval slits, or the like. Alternatively, it may be circular. In addition, as shown in FIGS. 6( b ) to 6 ( f ), a plurality of openings 6 ( 6 a to 6 c ) may be formed. The plurality of openings 6 ( 6 a to 6 c ), as shown in FIGS. 6( b ) to 6 ( f ), are preferably arranged continuously from one axial end of the electric field shield 5 to the other end. Moreover, as shown in FIG. 6(c), FIG. 6(e), and FIG. 6(f), the shapes of the openings 6 (6a to 6c) may be different from each other. In addition, the positions of the openings 6 (6a to 6c) are also arbitrary. However, at least one opening 6 (6a to 6c), as shown in FIGS. 6(a) to 6(e), is preferably formed in the position including the position LP at the lowermost end of the electric field shield 5 in the installed state. Location. In addition, at least one opening 6 (6a to 6c) may be formed in the vicinity of the lowermost position LP as shown in FIG. 6(f). It is desirable that the size of the opening 6 is larger than the expected size of the foreign object 7 .

(Embodiment 2)

7 is a longitudinal sectional view showing the structure of a gas insulated switchgear 102 according to Embodiment 2 of the present invention. FIG. 8 is a transverse cross-sectional view taken along line CC of FIG. 7 . In addition, FIG. 7 is a cross-sectional view corresponding to line DD in FIG. 8 .

Gas insulated switchgear 102 according to Embodiment 2 also includes a foreign matter removal mechanism.

In Embodiment 2, as shown in FIGS. 7 and 8 , annular inter-core spacers 8 a , 8 b are provided between the cores 4 a , 4 b , 4 c of the current transformer 4 . The iron cores 4a, 4b, and 4c are partial elements constituting the current transformer 4, which is a part of cylindrical equipment elements. The inter-core spacers 8a, 8b are spacers for maintaining the space between the cores 4a, 4b, 4c. In addition, the intervals between the cores 4a, 4b, and 4c may be equal to or different from each other.

The inner diameters of the inter-core spacers 8a, 8b are larger than the inner diameters of the iron cores 4a, 4b, 4c. In addition, their central axes coincide. Therefore, recesses are formed by the cores 4a, 4b and the inter-core spacer 8a, and the iron cores 4b, 4c and the inter-core spacer 8b. That is, in the vicinity of the lower end of the current transformer 4 , the surfaces (inner surfaces) of the inter-core spacers 8 a and 8 b facing the central conductor 2 are located below the inner surface of the current transformer 4 .

A cylindrical electric field shield 9 is arranged between the iron cores 4 a , 4 b , 4 c and the center conductor 2 to relieve the electric field concentration caused by the corners of the current transformer 4 or the irregularities on the surface. The current transformer 4 is fixed on the outside of the electric field shielding member 9 by the fixing member 30 . The electric field shield 9 is fixed in the metal container 1 by the supporting member 31 . Openings 10a, 10b for dropping and removing foreign matter are formed at portions facing the inter-core spacers 8a, 8b in the lower end portion of the electric field shield 9. As shown in FIG. The electric field shield 9 is connected to ground potential. Preferably, the axial length of the openings 10a, 10b is smaller than the size of the recess (the width (the axial length) of the inter-core spacers 8a, 8b). The other structures are the same as those of the first embodiment. The current transformer 4 , the inter-core spacers 8 a and 8 b , and the electric field shield 9 surround the central conductor 2 and constitute a cylindrical device element for extracting a signal of an electrical physical quantity.

As in Embodiment 1, a foreign object entering the space S1 between the central conductor 2 and the electric field shield 9 repeatedly floats and falls due to the buoyancy force and the effect of gravity caused by the generated electric field, and finally reaches the opening 10a or 10b , falls to the recess formed by the openings 10a, 10b, the current transformer 4, and the spacers 8a, 8b between cores. The space S2 is outside the electric field shield 9, and the electric field is small. Therefore, the electric field in the concave portion is also small, and the falling foreign matter is caught in this position.

As shown in FIG. 9 , an adhesive layer 20 may be provided on the lower end portions of the inner surfaces of the inter-core spacers 8a, 8b, that is, at positions facing the central conductor 2 across the openings 10a, 10b. By providing the adhesive layer 20 on the upper surfaces of the inter-core spacers 8a and 8b located at the bottom of the concave shape, it is possible to more securely capture falling foreign objects. At this time, the adhesive layer 20 may be provided in the openings 10a and 10b, respectively, or one adhesive layer 20 may be arrange|positioned so that the dimension may oppose both openings 10a and 10b. The method of forming the adhesive layer 20 is the same as above, and a method of pasting a sheet of a gel-like material, a method of pasting an adhesive double-sided tape, or a method of applying an adhesive paint can be used.

In addition, in the second embodiment, the ring-shaped inter-core spacers 8a, 8b whose inner diameter is larger than the inner diameter of the current transformer 4 are described. But the present invention is not limited thereto. The shapes of the inter-core spacers 8a, 8b are arbitrary as long as recesses are formed under the openings 10a, 10b. For example, as shown in FIG. 10 and FIG. 11, even if the radius R1 of the upper end portion of the inter-core spacer 8a, 8b is formed to be the same as the radius R1 of the current transformer 4, the lower end portion of the inter-core spacer 8a, 8b The radius R2 is formed larger than the radius R1 of the current transformer 4, and the same effect of foreign matter removal can be obtained.

In addition, FIG. 10 is a longitudinal sectional view of the gas insulated switchgear 102, and FIG. 11 is a transverse sectional view along line EE of FIG. 10 . In addition, FIG. 10 corresponds to the cross section taken along line FF of FIG. 11 . In addition, in this example, the connection openings 10 a and 10 b are regarded as one opening 10 .

As described above, according to the gas insulated switchgear 102 of the second embodiment, the foreign matter mixed between the center conductor 2 and the electric field shield 9 falls to the low electric field portion and is removed. Foreign objects are quickly removed without moving a long distance to the end of the current transformer 4 . Therefore, the gas insulated switchgear 102 with high insulation reliability can be realized. Furthermore, since the concave shapes of the openings 10a, 10b are made deep by the inter-core spacers 8a, 8b, the effect of trapping foreign matter is high. In addition, the effect of reducing the environmental load of the gas insulated switchgear 102 at each stage of its service life is the same as or even better than that of the first embodiment.

In addition, the present invention is not limited to the structures shown in FIGS. The same effect can be obtained even if the distance is greater than the distance R1 between the surfaces of the cores 4a, 4b, and 4c facing the central conductor 2 and the central axis of the central conductor 2 .

(Embodiment 3)

FIG. 12 is a longitudinal sectional view showing the structure of a gas insulated switchgear 103 according to Embodiment 3 of the present invention. Fig. 13 is a transverse cross-sectional view taken along line G-G in Fig. 12 . In addition, FIG. 12 is a cross-sectional view corresponding to line HH in FIG. 13 .

Gas insulated switchgear 103 according to Embodiment 3 also includes a foreign matter removal mechanism.

In Embodiment 3, as shown in FIGS. 12 and 13 , inter-core spacers 11 a , 11 b are arranged between cores 4 a , 4 b , 4 c of current transformer 4 . The inter-core spacers 11a, 11b are ring-shaped, and openings 14a, 14b are formed at their lower ends. The iron cores 4a, 4b, and 4c are partial elements constituting the current transformer 4, which is a part of cylindrical equipment elements. The inter-core spacers 11a, 11b are spacers for maintaining the space between the cores 4a, 4b, 4c.

A cylindrical electric field shield 12 is arranged between the iron cores 4 a , 4 b , 4 c and the center conductor 2 to alleviate the electric field concentration caused by the corners of the current transformer 4 or the irregularities on the surface. The current transformer 4 is fixed on the outside of the electric field shielding member 12 by the fixing member 30 . The electric field shield 12 is fixed in the metal container 1 by the supporting member 31 . Openings 13a, 13b for dropping and removing foreign matter are formed at portions of the lower end portion of the electric field shield 12 facing (overlapping) the openings 14a, 14b of the inter-core spacer. Preferably, the circumferential width W2 of the openings 14a, 14b is larger than the circumferential width W of the openings 13a, 13b. Likewise, it is desirable that the axial length of the openings 14a, 14b be longer than the axial length of the openings 13a, 13b. The electric field shield 12 is connected to ground potential. Other structures are the same as those in Embodiment 1. The current transformer 4, the inter-core spacers 11a, 11b, and the electric field shield 12 surround the central conductor 2, and constitute a cylindrical device element for extracting a signal of an electrical physical quantity.

As in Embodiment 1, a foreign object entering the space S1 between the electric field shield 12 and the central conductor 2 repeatedly floats and falls due to the buoyancy force and gravity caused by the applied electric field, and finally reaches the opening 13a or 13b. fall by gravity. Since the openings 14 a and 14 b of the inter-core spacers 11 a and 11 b are provided under the openings 13 a and 13 b , the foreign matter falls to the bottom of the metal container 1 . The bottom of the metal container 1 where the foreign matter falls is located in the space S2, and since the electric field shield 12 and the metal container 1 are both grounded, the electric field is relatively weak. As a result, falling foreign matter stays in this position without being lifted up by electrostatic force, making it harmless.

As shown in FIG. 14 , an adhesive layer 20 may be provided on the bottom of the metal container 1 , that is, at a position facing the central conductor 2 across the openings 13 a and 13 b. By providing the adhesive layer 20 on the surface of the metal container 1 located at the bottom of the concave shape, it is possible to more securely capture falling foreign matter. In addition, the openings 13a and 13b may be connected as one opening. The method of forming the adhesive layer 20 is the same as above, and a method of pasting a sheet of a gel-like material, a method of pasting an adhesive double-sided tape, or a method of applying an adhesive paint can be used.

As described above, according to the third embodiment, the foreign matter entering between the central conductor 2 and the electric field shield 12 falls from the openings 13 a and 13 b to the low electric field portion in the metal container 1 and is removed. Foreign objects are quickly removed without moving a long distance to the end of the current transformer 4 . Therefore, the gas insulated switchgear 103 with high insulation reliability can be realized. Furthermore, since the openings 14a, 14b are provided in the inter-core spacers 11a, 11b, the concave bottoms of the openings 13a, 13b can be made as deep as the inner surface of the metal container 1, so the effect of trapping foreign matter is better. In addition, the effect of reducing the environmental load of the gas insulated switchgear 103 at each stage of its service life is the same as or even better than that of the first embodiment.

(Embodiment 4)

Fig. 15 is a longitudinal sectional view of a gas insulated switchgear 104 according to Embodiment 4 of the present invention. Fig. 16 is a transverse sectional view taken along line II of Fig. 15 . FIG. 15 is a cross-sectional view corresponding to line JJ of FIG. 16 .

Gas insulated switchgear 104 according to Embodiment 4 also includes a foreign matter removal mechanism.

In Embodiment 4, as shown in FIG. 15 , inter-core spacers 15 a , 15 b are disposed between cores 4 a , 4 b , 4 c of a current transformer 4 . As shown in FIG. 16, the inter-core spacer 15a is composed of a plurality of members 21 to 28 arranged in the circumferential direction. The members 21 to 28 are arranged with gaps provided. The gap 18a between the member 21 and the member 28 of the inter-core spacer 15a corresponds to the opening 14a in the third embodiment. The inter-core spacer 15b is also composed of a plurality of members similarly to the inter-core spacer 15a, and is disposed by providing a gap 18b corresponding to the opening 14b of the third embodiment. In addition, the intervals between the members 21 to 28 may be constant or different.

A cylindrical electric field shield 16 is arranged between the iron cores 4 a , 4 b , 4 c and the center conductor 2 to alleviate the electric field concentration caused by the corners of the current transformer 4 or the irregularities on the surface. The current transformer 4 is fixed on the outside of the electric field shielding member 16 by the fixing member 30 . The electric field shield 16 is fixed in the metal container 1 by the support member 31 . In the lower end portion of the electric field shield 16, openings 17a, 17b for dropping and removing foreign matter are provided at portions facing the gaps 18a, 18b between the inter-core spacers 15a, 15b. The electric field shield 16 is connected to ground potential. Other structures are the same as those in Embodiment 1.

The iron cores 4a, 4b, and 4c are partial elements constituting the current transformer 4, which is a part of cylindrical equipment elements. The inter-core spacers 15a, 15b are spacers for maintaining the space between the cores 4a, 4b, 4c. The current transformer 4, the inter-core spacers 15a, 15b, and the electric field shield 16 surround the center conductor 2, and constitute a cylindrical device element that outputs a signal of an electrical physical quantity.

As in Embodiment 1, the foreign matter in the space S1 between the electric field shield 16 and the central conductor 2 repeatedly floats and falls due to the buoyancy force and gravity caused by the applied electric field, and finally reaches the opening 17a or 17b, and due to the gravity force And whereabouts. A gap 18a of the inter-core spacer 15a or a gap 18b of the inter-core spacer 15b is formed at the bottom of the openings 17a and 17b to form a concave portion. Therefore, the foreign matter falls to the bottom of the metal container 1 . The bottom of the metal container 1 where the foreign matter falls is located in the space S2, and since it is located between the electric field shield 16 at the ground potential and the metal container 1 at the ground potential, the electric field is relatively weak. As a result, falling foreign matter stays in this position without being lifted up by electrostatic force, making it harmless.

As shown in FIG. 17 , an adhesive layer 20 may be provided on the bottom of the metal container 1 , that is, on the surface facing the central conductor 2 across the openings 17 a and 17 b. By providing the adhesive layer 20 on the surface of the metal container 1 located at the bottom of the concave portion, it is possible to more securely capture falling foreign matter. In addition, the openings 17a and 17b may be connected as one opening. The method of forming the adhesive layer 20 is the same as above, and a method of pasting a sheet of a gel-like material, a method of pasting an adhesive double-sided tape, or a method of applying an adhesive paint can be used.

As described above, according to the gas insulated switchgear 104 according to the fourth embodiment, the foreign matter mixed between the central conductor 2 and the electric field shield 16 falls from the openings 17a and 17b to the low electric field part in the metal container 1 and is removed. . Since the foreign matter is quickly removed without moving a long distance to the end of the current transformer 4, the gas insulated switchgear 104 with high insulation reliability can be realized. Furthermore, since the gaps 18a, 18b are formed in the inter-core spacers 15a, 15b, the concave bottoms of the openings 17a, 17b can be made as deep as the inner surface of the metal container 1, so the effect of trapping foreign matter is better. In addition, the effect of reducing the environmental load of the gas insulated switchgear 104 at each stage of its service life is the same as or even better than that of the first embodiment.

In the above-described embodiments, various forms of the opening formed on the surface facing the central conductor 2 in the lower portion of the cylindrical device element surrounding the central conductor 2 have been shown. The present invention is not limited to the above-mentioned embodiment, and the shape and size of the opening and the opening are arbitrary as long as the foreign matter between the central conductor 2 and the cylindrical device element can be moved to a portion with a low electric field.

In addition, the structure of the gas insulated switchgear can be changed arbitrarily. In the above embodiment, one phase of the gas insulated switchgear was described, but the gas insulated switchgear may be a single phase type or a three phase combination type. In addition, the type of the insulating gas enclosed in the metal container 1 may be SF6 gas, carbon dioxide, nitrogen, or a mixture of these gases or other alternative gases having insulating and arc-extinguishing properties.

The shape and installation position of the central conductor 2 can be changed arbitrarily. In addition, the internal structure of the metal container 1 can be changed arbitrarily. The present invention can be applied as long as an opening can be formed on the surface of the lower part of the cylindrical device on the side of the central conductor 2 in a structure in which the central axis of the cylindrical device around the central conductor 2 is substantially horizontal. In addition, the switchgear connected to the center conductor 2 can be configured arbitrarily.

In addition, the material and structure of the fixing tool 30 and the support member 31 which fix the cylindrical equipment element in the metal container 1 are arbitrary. For example, in the above-described embodiment, the supporting member 31 is provided at one axial end portion of the cylindrical equipment element (current transformer 4, electric field shield 5, etc.), and supports the cylindrical equipment element. However, it is not limited thereto, and both axial ends of the cylindrical device element may be supported by the support member 31 . In addition, the electric field shield 5 and the supporting member 31 may also be formed separately. In addition, openings for foreign matter removal may be formed not only in the cylindrical device element but also in the supporting member 31 .

In addition, the current transformer 4, the electric field shield 5, and other members constituting the cylindrical equipment element may not necessarily completely surround (one circle) the central conductor 2, but may have a structure that only surrounds a part (partially).

Various embodiments and modifications are possible without departing from the broader concept and scope of the invention. The above-mentioned embodiments are for explaining the present invention, and do not narrow the scope of the invention. The concept of the present invention is determined not by the embodiments but by the terms of the claims.

Industrial Applicability

The invention is applicable to insulated switchgear having a cylindrical device element arranged around a center conductor.

This application is based on Japanese Patent Application No. 2008-307155 filed on December 2, 2008 and Japanese Patent Application No. 2009-252490 filed on November 2, 2009. Each application includes description, claims, drawings and summary. The disclosures of these Japanese applications are incorporated into this specification.

Claims (16)

1. A gas insulated switchgear, characterized in that it comprises: a center conductor through which current flows; a cylindrical device element disposed around the center conductor; a support member disposed at at least one end of the cylindrical equipment element and supporting the cylindrical equipment element; and a container accommodating the center conductor and the cylindrical device element and the support member and filled with an insulating gas, said cylindrical device element has at least one opening on a surface opposite to said central conductor, said cylindrical device element comprising at least one sensor; and an electric field shield disposed between said center conductor and said sensor, The at least one opening is formed in the electric field shield. 2. The gas insulated switchgear according to claim 1, wherein: The at least one opening is formed at or near a lowermost end of a surface of the cylindrical device element that faces the center conductor when the center conductor is placed in a substantially horizontal posture. 3. The gas insulated switchgear according to claim 2, wherein: The at least one opening is formed along the lowermost end of the surface of the cylindrical device element facing the central conductor, or a plurality of openings including the at least one opening are formed along the lowest end of the cylindrical device element. Arranged at the bottom. 4. The gas insulated switchgear according to claim 1, wherein: The at least one opening extends in a direction substantially parallel to the central axis of the cylindrical device element, or a plurality of openings including the at least one opening extend in a direction substantially parallel to the central axis of the cylindrical device element. direction. 5. The gas insulated switchgear according to claim 1, wherein: The at least one opening continues from one axial end to the other end of the cylindrical device element. 6. The gas insulated switchgear according to claim 1, wherein: The sensor and the electric field shield surround the center conductor. 7. The gas insulated switchgear according to claim 1, wherein: A circumferential width of the cylindrical device element of the at least one opening is smaller than a distance between a surface of the electric field shield facing the central conductor and a surface of the sensor facing the central conductor . 8. The gas insulated switchgear according to claim 1, wherein: The at least one sensor constituting the cylindrical device element includes a transformer surrounding the central conductor. 9. The gas insulated switchgear according to claim 1, wherein: The electric field of the first space between the central conductor and the cylindrical device element is larger than the electric field of the second space under the at least one opening when a current flows through the central conductor, and foreign matter can be removed from the central conductor due to gravity. The at least one opening drops into the second space. 10. The gas insulated switchgear of claim 1, wherein: There are two or more sensors, and the cylindrical device element includes a spacer that is arranged between the two or more sensors and keeps the distance between the sensors, In the vicinity of the opening, the distance between the surface of the spacer that is opposite to the central conductor and the central axis of the central conductor is greater than the distance between the surface of the sensor that is opposite to the central conductor and the distance between the two or more sensors. The distance from the center axis of the center conductor. 11. The gas insulated switchgear of claim 1, wherein: The sensor has more than two, and the cylindrical device element includes a spacer arranged between the two or more sensors and maintaining a distance between the sensors, The spacer has an opening at a position facing the opening of the cylindrical device element. 12. A gas insulated switchgear as claimed in claim 11, characterized in that, The spacer is composed of two or more members arranged in the circumferential direction of the cylindrical device element, Two or more members constituting the spacer have a gap forming the opening. 13. A gas insulated switchgear as claimed in claim 12, characterized in that, A circumferential width of the opening of the spacer is larger than a circumferential width of the opening of the cylindrical device element. 14. The gas insulated switchgear of claim 1, wherein: A sticky adhesive layer is included at a position of the sensor facing the central conductor across the opening. 15. A gas insulated switchgear as claimed in claim 14, characterized in that, A circumferential width of the adhesive layer is greater than a circumferential width of the opening of the tubular device element, or an axial length of the adhesive layer is greater than an axial length of the opening. 16. A gas insulated switchgear as claimed in claim 15, characterized in that, The adhesive layer is formed of a gel-like raw material sheet, an adhesive double-sided tape, or an adhesive paint.

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