WO2001093393A1

WO2001093393A1 - Gas insulated switchgear and lighting arrester

Info

Publication number: WO2001093393A1
Application number: PCT/JP2000/003499
Authority: WO
Inventors: Masatomo Kobayashi; Tokio Yamagiwa; Kazuhiro Saito; Fumihiro Endo; Tomoaki Utsumi
Original assignee: Hitachi, Ltd.
Priority date: 2000-05-31
Filing date: 2000-05-31
Publication date: 2001-12-06

Abstract

In order to prevent a gas insulated switchgear from growing in size and reduce the consumption of sulfur hexafluoride gas used in the switchgear; sulfur hexafluoride gas is used as an insulation medium for a unit provided with a mechanism of electrically breaking an electric circuit, a nitrogen gas or a nitrogen-mixed gas is used as an insulation medium for a unit provided with an arrester of restricting overvoltage applied to an electric circuit, a discharge gap is electrically connected in parallel with the arrester, and the gas pressure of the nitrogen gas or nitrogen-mixed gas for insulating the unit provided with the arrester is set to 0.4 to 0.6 MPa.

Description

Specification

Gas insulated switchgear and lightning arrester

Technical field

The present invention relates to a gas-insulated switchgear and a lightning arrester installed in electric stations such as a substation and a switchgear.

Background art

A conventional gas insulated switchgear uses a sulfur hexafluoride gas as an insulating medium of a circuit breaker unit, as described in, for example, Japanese Patent Application Laid-Open No. Nitrogen gas, which has a lower global warming potential than sulfur hexafluoride gas, is used as the insulating medium. As a result, the amount of sulfur hexafluoride gas used is reduced without degrading the current interrupting performance of the interrupting section of the circuit breaker unit.

Since the insulation performance of nitrogen gas is about 1 Z 3 of the insulation performance of sulfur hexafluoride gas, when nitrogen gas is used as the insulation medium, the diameter of the container in which the nitrogen gas is sealed must be increased. Alternatively, it is necessary to increase the pressure of the nitrogen gas and increase the pressure of the nitrogen gas, thereby increasing the thickness of the storage container. Therefore, when nitrogen gas is used as the insulating medium, the size of the gas-insulated switchgear increases.

The size of the diameter of the container in which the insulating medium is enclosed is determined by the ability to suppress the largest overvoltage propagating through the gas-insulated switchgear, that is, the ability to suppress the lightning surge voltage of the surge arrester and the insulation performance of the insulating medium. The surge arrester's lightning surge voltage suppression performance is determined by the surge arrester's limit voltage. The lightning surge arrester's surge voltage suppression performance improves as the surge arrester's limit voltage is reduced. Therefore, the lightning arrester By reducing the voltage limit and improving the lightning surge voltage suppression performance of the surge arrester, the dielectric strength of the gas insulated switchgear is improved and the diameter of the storage container can be reduced.

As described in JP-A-57-34683, for example, the discharge gap insulated by nitrogen gas is electrically connected to a part of the surge arrester insulated by sulfur hexafluoride gas as described in Japanese Patent Application Laid-Open No. 57-34683. Can be achieved by connecting them in parallel. Alternatively, a lightning arrester insulated by nitrogen gas, as described in the film of the microphone opening photographing the contents of the specification and drawings attached to the application form of Japanese Utility Model Application No. 53-150001 (Japanese Utility Model Application No. 55-6579). This can be achieved by electrically connecting a discharge gap to part of the vessel in parallel.

However, the discharge characteristics of the discharge gap vary. This variation is smaller in nitrogen gas than in sulfur hexafluoride gas, but is larger in nitrogen gas when the gas pressure is lower. For example, when a discharge gap set to discharge at about 300 kV is discharged in a nitrogen gas at 0.01 to 0.02 MPa, the discharge characteristics of the discharge gap are ± 500. A variation of about kV occurs. Therefore, the limiting voltage characteristic of the surge arrester is not stable, and the limiting voltage of the surge arrester cannot be reduced to a predetermined value. Disclosure of the invention

A typical object of the present invention is to reduce the amount of sulfur hexafluoride gas used in a gas-insulated switchgear while suppressing the size of the gas-insulated switchgear. Another representative object of the present invention is to stabilize the limiting voltage characteristic of the lightning arrester by suppressing the variation in the discharge characteristics of the discharge gap electrically connected in parallel to the lightning arrester. A basic feature of the present invention is that a unit provided with a lightning arrester that suppresses an overvoltage propagating through an electric circuit using sulfur hexafluoride gas as an insulating medium of the unit provided with a mechanism for electrically interrupting the electric circuit. Nitrogen gas or a mixed gas with nitrogen gas is used as an insulation medium for the arrestor, and a discharge gear is electrically connected in parallel to the arrester and mixed with nitrogen gas or nitrogen gas that insulates the unit provided with the arrester. That is, the gas pressure of the gas was set to 0.4 to 0.6 MPa.

Sulfur hexafluoride gas, which is a unit insulation medium provided with a mechanism for electrically interrupting an electric circuit, is necessary to obtain high current interruption performance, and its gas pressure is 0.4 to 0.4. It is set to 6 MPa, preferably 0.5 to 0.6 MPa. Nitrogen gas or a mixed gas of nitrogen gas, preferably nitrogen gas or a mixed gas of nitrogen gas and sulfur hexafluoride gas, which is an insulating medium of the unit provided with the lightning arrester, is likely to have an adverse effect on the environment. It is necessary to reduce the amount of sulfur hexafluoride gas used. Alternative gases to sulfur hexafluoride gas include nitrogen gas or a mixed gas of nitrogen gas, preferably nitrogen gas or a mixed gas of nitrogen gas and sulfur hexafluoride gas. In consideration of gas handling properties, it is preferable to use nitrogen gas or a mixed gas of nitrogen gas, preferably nitrogen gas or a mixed gas of nitrogen gas and sulfur hexafluoride gas.

The discharge gap electrically connected in parallel to a part of the surge arrester starts discharging when the current flowing through the surge arrester reaches a predetermined value and the voltage between the terminals of the surge arrester reaches the firing voltage. As a result, the voltage limit of the surge arrester is reduced, and the surge voltage suppression performance of the surge arrester is improved, so that the dielectric strength of the gas insulated switchgear can be improved. However, if the gas pressure of the nitrogen gas or the mixed gas with the nitrogen gas that isolates the unit provided with the lightning arrestor is low, the discharge will occur. Variations occur in the discharge characteristics of the gap, making it impossible to stabilize the limiting voltage characteristics of the surge arrester and reduce the limiting voltage of the surge arrester to a predetermined value.

If the gas pressure of the nitrogen gas or the gas mixture with the nitrogen gas is low, the insulation performance required for the nitrogen gas or the gas mixture with the nitrogen gas cannot be obtained, and the nitrogen gas or the gas mixture with the nitrogen gas is sealed. It is necessary to increase the diameter of the used container. On the other hand, if the gas pressure of the nitrogen gas or the mixed gas with the nitrogen gas that insulates the surge arrester unit is high, it is necessary to increase the mechanical strength of the container. If the gas pressure of the nitrogen gas or the mixed gas with the nitrogen gas is high, the mechanical strength of the insulating member provided between the containers needs to be increased. Furthermore, when using a mixed gas of nitrogen gas and sulfur hexafluoride gas, it is necessary to consider the problem of gas liquefaction in a low temperature region of a mixed gas of nitrogen gas and sulfur hexafluoride gas.

For this reason, the present invention sets the gas pressure of nitrogen gas or a mixed gas with nitrogen gas that insulates the unit provided with the lightning arrester to 0.4 to 0.6 MPa, preferably 0.4 MPa. It was done. Thus, according to the present invention, the variation in the discharge characteristics of the discharge gap can be suppressed to about 10 kV, the limiting voltage characteristic of the lightning arrester can be stabilized, and nitrogen gas or a mixed gas with nitrogen gas is sealed. The insulation performance required for the nitrogen gas or the mixed gas with the nitrogen gas can be obtained without changing the diameter and thickness of the container.

Here, the variation in the discharge characteristics of the discharge gap can be suppressed to about ± 10 kV by the gas pressure because the probability of repeated collisions of molecules during discharge increases with the gas pressure. One of the factors is considered to be the reliable collision between the ionized molecule and other ionized molecules. available.

Also, a unit other than the unit provided with the lightning arrestor, a unit insulated by nitrogen gas or a mixed gas with nitrogen gas, for example, a unit provided with a bus, a unit provided with a power lead-in terminal or a power lead-out terminal For example, if the gas pressure of nitrogen gas or a mixed gas with nitrogen gas that insulates each unit is set to 0.4 to 0.6 MPa, preferably 0.4 MPa In addition, the insulation performance required for the nitrogen gas or the mixed gas with the nitrogen gas sealed in the container of each unit can be obtained without changing the diameter and the thickness of the container constituting each unit.

The above gas pressure is a gauge pressure based on the reading of a pressure gauge when the insulating gas is sealed in the container, that is, the atmospheric pressure. The absolute pressure, that is, the pressure based on the absolute zero pressure, is a value obtained by adding 0.1 MPa to the above gas pressure.

According to the present invention described above, the amount of sulfur hexafluoride gas, which is likely to affect the environment, can be reduced, so that the environment resistance of the gas insulated switchgear can be improved. Further, according to the present invention, the variation in the discharge characteristics of the discharge gap electrically connected in parallel with the arrester can be suppressed to about 10 kV, the limiting voltage characteristic of the arrester can be stabilized, and the nitrogen gas can be stabilized. Alternatively, the insulation required for nitrogen gas or a mixture gas of nitrogen gas and sulfur hexafluoride gas can be maintained without changing the diameter and thickness of the container in which the gas mixture of nitrogen gas and sulfur hexafluoride gas is sealed. Since performance can be obtained, the size of the gas insulated switchgear can be suppressed, and the economical efficiency of the gas insulated switchgear can be suppressed.

In this specification, an arrester is a non-linear resistor mainly composed of zinc oxide. Refers to a stacked body in which a plurality of elements are stacked. In this specification, an arrester may be referred to as a laminate or an arrester. In this specification, the lightning arrester refers to a unit including a lightning arrester, a container for accommodating the lightning arrester, an electric field mitigation member provided in the lightning arrester, and instruments. In this specification, a lightning arrester may be referred to as a lightning arrester unit. Further, in this specification, a tank type lightning arrester refers to a lightning arrester provided in a container in which an insulating medium is enclosed. In this specification, a tank-type lightning arrester or a tank-type lightning arrester refers to a device in which a tank-type lightning arrester is provided in a container in which an insulating medium is enclosed. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing an internal configuration of a tank type lightning arrester according to a first embodiment of the present invention. FIG. 2 is a sectional view showing a configuration of a gas insulated switchgear provided with the tank type lightning arrester of FIG. FIG. 3 is a characteristic diagram showing a limiting voltage-current characteristic of the tank type arrester of FIG. FIG. 4 is a sectional view showing a configuration of a gas-insulated switchgear according to a second embodiment of the present invention. FIG. 5 is a sectional view showing an internal configuration of a tank type lightning arrester according to a third embodiment of the present invention. FIG. 6 is a sectional view showing a configuration of a gas insulated switchgear provided with the tank type lightning arrester of FIG. FIG. 7 is a sectional view showing the internal configuration of a tank type lightning arrester according to a fourth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1)

1 to 3 show the configuration of the gas insulated switchgear of the first embodiment. The gas insulated switchgear is composed of a combination of a plurality of units. From the breaker unit 200, connection unit 210, 230, 250, bus unit 220, disconnector unit 240, gas-insulated pusher 260, and lightning arrester unit 260. It is configured.

The circuit breaker unit 280 includes a circuit breaker and an operation device 3. The shut-off section cuts off the fault current.The opening / closing mechanism section 1 having a fixed contact and a movable contact disposed opposite to the fixed contact and capable of being separated from the fixed contact includes a tank. 2 is provided. The operating device 3 includes an operating mechanism for opening and closing the movable contact with respect to the fixed contact of the opening and closing mechanism 1. The operating mechanism is mechanically connected to the movable contact of the opening / closing mechanism 1 via a link mechanism. Actuator 3 is installed below the shutoff.

Tank 2 is a metal cylindrical container, which is grounded. The tank 2 is filled with sulfur hexafluoride (hereinafter, referred to as “SF ₆ ”) gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, it is sealed at a gas pressure of 0.5 to 0.6 MPa in order to obtain high current interruption performance. The above gas pressure is a gauge pressure, and when expressed as an absolute pressure, it is a value obtained by adding 0.1 MPa to the above gas pressure. In the following description, all gas pressures are indicated by gauge pressure.

A connection unit 210 is provided at the lower end on one side of the circuit breaker unit 200. The connection unit 210 electrically connects the circuit breaker unit 200 and the bus unit 220 to each other, and a current-carrying conductor 4 is provided in the tank 5. The current-carrying conductor 4 is a hollow or solid metal conductor, and a breaker unit 200 is formed through a connection conductor of an insulating spacer 6 provided between the tank 5 and the tank 2. It is electrically connected to the opening / closing mechanism 1 of the unit. The tank 5 is a metal cylindrical container and is grounded. The tank 5 is filled with nitrogen (hereinafter referred to as “N ₂ ”) gas or a mixed gas of N ₂ gas and SF ₆ gas (hereinafter simply referred to as “mixed gas”) at a gas pressure of 0.4 to 0.6 MPa. ing. Preferably, the gas is sealed at a gas pressure of 0.4 MPa lower than the gas pressure of SF ₆ gas sealed in the tank 2 of the circuit breaker unit 200.

A bus unit 220 is provided on a side of the connection unit 210 opposite to the circuit breaker unit 200 side. The bus unit 222 is provided with three buses 7 in a tank 8. The bus 7 is arranged in the tank 8 so as to be located at each of the vertices of the triangle, and is connected to the disconnecting switch 9 and the connecting conductor of the insulating spacer 10 provided between the tank 8 and the tank 5. And is electrically connected to the current-carrying conductor 4.

The tank 8 is a metal T-shaped cylindrical container and is grounded. Tank 8 is filled with N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, the gas is sealed at a gas pressure of 0.4 MPa lower than the gas pressure of SF ₆ gas sealed in the tank 2 of the circuit breaker unit 200. The disconnector 9 separates the circuit on the circuit breaker unit 200 side and the circuit on the bus unit 220 side, and is disposed opposite to the fixed conductor and is separated from the fixed conductor. A movable conductor provided so as to be capable of being operated by an operating device (not shown).

A connection unit 230 is provided at one upper end of the circuit breaker unit 200. The connection unit 230 electrically connects between the circuit breaker unit 200 and the disconnector unit 240, and a current-carrying conductor 11 is provided in the tank 12. The current-carrying conductor 11 is a hollow or solid metal conductor, and an insulating sensor provided between the tanks 12 and 2. The circuit breaker unit 200 is electrically connected to the switching mechanism 1 of the circuit breaker unit 200 via the connection conductor 13.

The tank 12 is a metal cylindrical container and is grounded. The tank 12 is filled with a N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure of the SF ₆ gas sealed in the breaker unit 2 0 0 in the tank 2.

A disconnecting unit 240 is provided on a side of the connecting unit 230 opposite to the circuit breaker unit 200 side. The disconnector unit 240 has a disconnector 14 provided in a tank 15. The disconnecting switch 14 separates the circuit on the circuit breaker unit 200 side from the circuit on the line side.The disconnecting switch 14 is arranged to face the fixed conductor and to the fixed conductor, and can be separated from the fixed conductor. And a movable conductor provided between the tank 15 and the tank 12 through a connection conductor of an insulator 17 provided between the tank 15 and the tank 12. Is electrically connected to

Tank 15 is a metal cylindrical container, which is grounded. The tank 15 is filled with N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure of the SF ₆ gas sealed in the breaker unit 2 0 0 in the tank 2. The disconnecting switch unit 240 is provided with a ground switchgear 16. The ground switchgear 16 is for grounding the line, and is provided so as to be separable from the movable conductor of the disconnector 14 and has a fixed conductor grounded.

A connection unit 250 is provided on the side of the disconnector unit 240 that is opposite to the connection unit 230 side. Connection unit 2 5 0 is disconnector unit It electrically connects between 240 and the gas-insulated pusher 260 and the lightning arrester unit 260, and a current-carrying conductor 18 is provided in the tank 19. The current-carrying conductor 18 is a hollow or solid metal conductor, and is connected to the disconnector 14 via a connection conductor of an insulator 20 provided between the tank 19 and the tank 15. Is electrically connected to

The tank 19 is a metal cylindrical container and is grounded. The tank 19 is filled with N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure of the SF ₆ gas sealed in the breaker unit 2 0 0 in the tank 2.

The connection unit 250 is divided into three by insulation spacers 21 and 22. That is, it is divided into tanks 19a to 19c. Tanks 19a to 19c are provided with corresponding current-carrying conductors 18a to 18c, and are electrically connected via the connection conductors of insulating spacers 21 and 22. Has been done.

A gas pumping unit 260 is provided on a side of the connection unit 250 opposite to the disconnector unit 240 side. The gas-insulated bushing 260 draws power from the transmission line side into the gas-insulated switchgear or draws power from the gas-insulated switchgear to the transmission line side, and is a conducting conductor that extends continuously from the connection unit 250. 18 is provided in the insulator tube 23. The gas insulation bushing 260 and the connection unit 250c are constituted by the same gas compartment.

The porcelain tube 23 is a porcelain or polymer insulating tube having a plurality of pleated protrusions formed on the outer peripheral side, formed in a truncated conical shape or a cylindrical shape, and mechanically connected to the tank 19 c. I have. N ₂ gas or mixed gas is Gas is sealed at a gas pressure of 0.4 to 0.6 MPa. Preferably, the circuit breaker unit 200 is sealed at a gas pressure of 0.4 MPa, which is lower than the gas pressure of the SF ₆ gas sealed in the tank 2. External shields 24 and 25 are provided on the upper and lower ends of the insulator 23 so as to surround the upper and lower ends of the insulator 23.

A lightning arrester unit 70 is provided on the side of the connection unit 250 opposite to the disconnector unit 240 side. The lightning arrester unit 720 discharges the overvoltage transmitted to the gas insulated switchgear to the ground to protect the gas insulated switchgear from overvoltage such as lightning surge due to lightning strike or switching surge due to power line breaker. This suppresses an overvoltage applied to the gas insulated switchgear. As shown in FIG. 1, a lightning arrester 26 is provided in a tank 27.

The lightning arrester 26 is configured by alternately stacking non-linear resistor elements 28 and metal plates 29 via insulating rods not shown in the drawing, and is provided on a bottom plate 30 provided below the tank 27. It is fixed via an insulating plate 31. The non-linear resistive element 28 is a zinc oxide element containing zinc oxide (ZnO) as a main component, and is an annular element having an operation start voltage of 280 to 500 V Zmin. . The metal plate 29 absorbs heat generated by the non-linear resistor element 28, has the same shape as the non-linear resistor element 28, and has a thickness equal to or greater than the thickness of the non-linear resistor element 28. Having. The lightning arresters 26 are arranged in two rows in parallel, and are sandwiched by insulating support rods 32, 33 from both sides in a direction perpendicular to the arrangement direction. This improves the earthquake resistance of the lightning arrester 26. The tank 27 is a metal capsule-shaped container and is grounded. In the nozzle 27, N ₂ gas or a mixed gas is sealed at a gas pressure of 0.4 to 0.6 MPa. Preferably, in tank 2 of breaker unit 200 It is sealed at a gas pressure of 0.4 MPa, which is lower than the gas pressure of SF ₆ gas sealed in the tank.

A connection conductor 34 is provided in the lower part of the lightning arrester 26. One end of the connection conductor 34 is electrically connected to the metal plate 29a disposed at the lowest part of the laminate. The other end of the connection conductor 34 is fixed to a fixing member 35 provided insulated from the tank 27 and electrically connected to a sealed terminal 36 drawn out from the inside of the tank 27 to the outside. It is connected. A ground conductor 37 is electrically connected to the sealed terminal 36. As a result, the lightning arrester 26 is grounded, and the current flowing through the lightning arrester 26 is discharged to the ground. A cubicle 39 containing instruments such as a lightning arrester operation alarm and a recorder is provided at the sealed terminal 36 of the tank 27.

A connection plate 41 is provided on the upper end side (head) of the lightning arrester 26 via a spring 40. A conductor 42 for short-circuiting the spring 40 is provided between the bottom plate 30 and the connection plate 41. An electric field relaxation member 43 is provided above the connection plate 41. The electric field relaxation member 43 is an annular member made of metal, and is electrically connected to the connection plate 41. An upper potential sharing member 44 is provided below the connection plate 41. A lower potential sharing member 45 is provided below the upper potential sharing member 44.

The upper potential sharing member 44 and the lower potential sharing member 45 are metal annular members, which are electrically connected via conductors 46 and electrically connected to the connection plate 41. The lower potential sharing member 45 has a larger diameter than the upper potential sharing member 44, and is formed in a divergent shape by the upper potential sharing member 44, the lower potential sharing member 45, and the conductor 46. A conducting conductor 18C is electrically connected to the lower potential sharing member 45 via a connecting conductor 47 of the insulating spacer 38. A discharge gap 48 is electrically connected to a part of the lightning arrester 26 in parallel. The discharge gap 48 is composed of an upper discharge electrode 48a and a lower discharge electrode 48b opposed to the upper discharge electrode 48a via a gap. The upper discharge electrode 48a and the lower discharge electrode 48b are made of aluminum, and are composed of a sphere located at the tip of the electrode and a rod supporting the sphere. The lower discharge electrode 48 b is provided on a metal plate 29 a located at the lowest part of the lightning arrester 26. The upper discharge electrode 48a is provided on a metal plate 29b located above the metal plate 29a. Attachment of the electrode to the metal plate is performed by screwing a screw formed on a support rod portion of the electrode into a screw hole formed in the metal plate.

In this embodiment, the case where the upper discharge electrode 48 a and the lower discharge electrode 48 b are arranged vertically opposite to each other has been described, but the upper discharge electrode 48 a and the lower discharge electrode 48 b are arranged in the horizontal direction. In some cases. That is, the lower discharge electrode 48b provided in the tank 27 has the lower discharge electrode 48b, and the lower discharge electrode 48b provided in the tank 27 has a horizontal direction through a gap. This is a case where they are arranged to face each other.

Next, the operation of the arrester unit 270 will be described. Fig. 3 shows the limiting voltage-current characteristics of the surge arrester 26. When a lightning surge or a switching surge occurs on a line due to the opening and closing of a circuit breaker due to a lightning strike, the generated surge propagates to the gas insulated switchgear via the line. As a result, an overvoltage is applied to the gas-insulated switchgear, and the current flowing through the lightning arrester 26 rapidly increases (the lightning arrester 26 starts operating). When the current flowing through the surge arrester 26 reaches a predetermined value and the voltage between the terminals of the surge arrester 26 reaches the discharge starting voltage of the discharge gap 48, the discharge gap 48 starts discharging.

When discharge starts in discharge gap 48 ', it flows through surge arrester 26 The current flows from the middle through the discharge gap 48, and short-circuits a part of the surge arrester 26. Thereby, the limiting voltage-current characteristic of the arrester 26 changes from the characteristic of the curve a to the characteristic of the curve b as shown in FIG. 3, and the limiting voltage of the arrester 26 is reduced. At this time, since the gas pressure of the N ₂ gas or the mixed gas in the tank 27 is set to 0.4 to 0.6 MPa, preferably 0.4 MPa, the variation in the discharge characteristics of the discharge gap 48 is 10 k It is suppressed to about V, and the limiting voltage characteristic of the surge arrester 26 becomes stable.

According to the present embodiment described above, SF ₆ gas is used as the insulating medium of the circuit breaker unit 200, and the busbar unit 220, the disconnector unit 240, the connection units 210, 230, 250, since using N ₂ gas or mixed gas as an insulating medium of a gas insulated bushing 260 and lightning arrester Yunitto 2 7 0, breaker Yunitto 20 0 without impairing the current interrupting performance required for the blocking of the impact on the environment It is possible to reduce the amount of SF ₆ gas used.

Further, according to the present embodiment, the discharge gap 48 is electrically connected in parallel to a part of the lightning arrester 26, and the gas pressure of the N ₂ gas or the mixed gas that insulates the lightning arrester unit 27 is set to 0.4 to 0.6 MPa. As a result, the variation of the discharge characteristics of the discharge gap 48 can be suppressed to about 10 kV, the limiting voltage characteristic of the lightning arrester 26 can be stabilized, and the diameter and the diameter of the tank 27 constituting the lightning arrester unit 270 can be improved. The insulation performance required for the N ₂ gas or mixed gas sealed in the tank 27 of the lightning arrester unit 27 can be obtained without changing the thickness.

Further, according to the present embodiment, the gas pressure of the N ₂ gas or the mixed gas that insulates the bus unit 220, the connection units 210, 230, 250, the disconnector unit 240, and the gas insulating pusher 260 is set to 0.4. ~ 0.6MPa Since the setting is made, the insulation performance required for the N ₂ gas or mixed gas sealed in the tank of each unit can be obtained without changing the diameter and thickness of the tank constituting each unit.

Therefore, according to the present embodiment, it is possible to reduce the amount of SF ₆ gas that is likely to affect the environment, thereby improving the environmental resistance of the gas-insulated switchgear. Further, according to the present embodiment, the variation of the discharge characteristics of the discharge gap 48 electrically connected in parallel to the lightning arrester 26 is suppressed to about 10 kV, and the limiting voltage characteristic of the lightning arrester 26 is stabilized. it is possible, N ₂ gas or without gas mixture may varying the size of the diameter and thickness of the tank is sealed, insulating performance required for the N ₂ gas or mixed gas enclosed in the tank of each unit Therefore, the size of the gas-insulated switchgear can be suppressed, and the economical efficiency of the gas-insulated switchgear can be suppressed.

(Example 2)

FIG. 4 shows the configuration of the gas-insulated switchgear of the second embodiment. The gas insulated switchgear of this embodiment includes a circuit breaker unit 280, a bus unit 290, and a roadside unit 300.

The circuit breaker unit 280 is composed of a circuit breaker and a controller 52. The interrupting section interrupts the fault current, and includes an opening / closing mechanism section having a fixed contact and a movable contact arranged opposite to the fixed contact and provided so as to be separated from the fixed contact. 0 is provided in the tank 51 for three phases. The actuator 52 is for separating the movable contact from the fixed contact of the opening / closing mechanism 50, and is mechanically connected to the movable contact of the opening / closing mechanism 50 via a link mechanism. ing. Actuator 52 is installed below the shutoff. The tank 51 is a metal cylindrical container and is grounded. SF ₆ gas is sealed in the tank 51 at a gas pressure of 0.4 to 0.6 MPa. Preferably, the gas is sealed at a gas pressure of 0.5 to 0.6 MPa in order to obtain high current interruption performance. On both sides of the opening / closing mechanism 50, grounding opening / closing devices 53, 54 are provided. The earthing switchgear 53, 54 is for grounding the line, and has a fixed conductor and a movable conductor which is disposed to face the fixed conductor and is provided so as to be able to be separated from the fixed conductor. Operated by a vessel. In addition, the earthing switchgear 53, 54 is electrically connected to the switchgear 50 via a conductor. A control box 55 is provided on the side of the operation device 52 and below the busbar unit 190.

A bus unit 290a is provided at the upper end on one side of the circuit breaker unit 280. The bus unit 290a is a tank 57a in which buses 56a are provided for three phases. The bus bar 56a is arranged in the tank 57a so as to be located at each apex of the triangular shape, and an isolator provided between the disconnector 58a, the tank 57a and the tank 51. The circuit breaker unit 280 is electrically connected to an opening / closing mechanism 50 of a circuit breaker unit via a connection conductor and a reciprocating conductor of the pulser 60.

Tank 5 7 a is a metal T-branch type cylindrical container, is grounded, among which N ₂ gas or mixed gas is enclosed in the gas pressure of 0.4 to 0.6 MP a. Preferably, it is sealed with a gas pressure of less 0.4 MP a than the gas pressure of the SF ₆ gas sealed in the tank 5 1 of the circuit breaker Yunitto 2 8 0. The disconnector 58a separates the circuit on the circuit breaker unit 280 side and the circuit on the bus unit 290a side.The disconnector 58a is placed opposite to the fixed conductor and is open to the fixed conductor. It has a movable conductor detachably provided, and is operated by an actuator 59 provided between the tank 57 a and the tank 57 b. Is done.

At the lower end on one side of the circuit breaker unit 280, a bus unit 290 is provided. The bus unit 290b is a tank 57b in which buses 56b are provided for three phases. The bus bar 56b is arranged in the tank 57a so as to be located at each vertex of the triangular shape.

Opening / closing mechanism of the breaker unit constituting the circuit breaker unit 280 via the connecting conductor and the reciprocating conductor of the insulating spacer 61 provided between 57 b and the tank 51

It is electrically connected to 50.

Tank 5 7 b is a metal T-branch type cylindrical container, is grounded, among which N ₂ gas or mixed gas is enclosed in the gas pressure of 0.4 to 0.6 MP a. Preferably, it is sealed with a gas pressure of less 0.4 MP a than the gas pressure of the SF ₆ gas sealed in the tank 5 1 of the circuit breaker Yunitto 2 8 0. Disconnector 5 8 b is the circuit breaker unit 2 8 0 side circuit and bus unit

The circuit on the side of 290b is separated, comprising a fixed conductor, and a movable conductor disposed opposite to the fixed conductor and provided to be able to be separated from the fixed conductor. It is operated by an operation device 59 provided between the tanks 57 b. One

A circuit-side unit 300 is provided on the other side of the circuit breaker unit 280. The track side unit 300 is a track side device, that is, a disconnector 63, a grounding switch 66, a cable head 67 and a lightning arrester 68 are provided for three phases, and an instrument transformer 64 is provided in a tank 62. It is. The tank 62 is a metal cylindrical container, which is grounded and in which N ₂ gas or a mixed gas is sealed at a gas pressure of 0.4 to 0.6 MPa. Preferably, the gas is sealed at a gas pressure of 0.4 MPa, which is lower than the gas pressure of SF ₆ gas sealed in the tank 51 of the circuit breaker unit 280. The disconnector 63 separates the circuit on the circuit breaker unit 280 side from the circuit on the line side.The disconnector 63 is disposed so as to face the fixed conductor, and is provided so as to be separable from the fixed conductor. It has a movable conductor and is operated by an actuator not shown. Further, the disconnecting switch 63 is provided with an opening / closing mechanism section 50 of a breaking section constituting the circuit breaker unit 280 via a connecting conductor of an insulating spacer 70 provided between the tank 62 and the tank 51. Is electrically connected to The instrument transformer 64 measures the line voltage.It is located between the disconnecting switch 63 and the surge arrester 68 in a circuit, and can be connected to and disconnected from the line via the disconnecting device 65. It is configured.

The ground switchgear 66 is for grounding the line, has a fixed conductor, and a movable conductor which is disposed to face the fixed conductor and is provided so as to be able to be separated from the fixed conductor. Operated by The ground switchgear 66 is electrically connected to the disconnector 63. The cable head 67 is a terminal for drawing power from the gas-insulated switchgear or drawing power to the gas-insulated switchgear. 2 is pulled out airtight. A cable 71 is electrically connected to the cable head 67, and a current transformer 72 for measuring current is provided.

Each of the lightning arresters 68 is formed by alternately stacking non-linear resistor elements mainly composed of zinc oxide and metal plates via insulating rods. A ground wire connection is provided at the lower end of the lightning arrester 68. The ground wire connection part is drawn out of the tank 62 from the lower part of the tank 62 in an airtight manner, and the ground wire 73 is electrically connected. A discharge gap 69 for short-circuiting a part of the lightning arrester 68 with the current flowing through the lightning arrester 68 is electrically connected in parallel to each part of the lightning arrester 68. Configuration, function and function of the linear resistor element and metal plate And characteristics, and the configuration, function, and mounting method of the discharge gap 69 are the same as those in the previous example, and the description thereof is omitted.

According to the present embodiment described above, SF ₆ gas is used as the insulating medium of the circuit breaker unit 280, and N is used as the insulating medium of the bus unit 290a, 290b and the line side unit 300. _{The use of two} gases or a mixed gas reduces the amount of SF ₆ gas, which is likely to affect the environment, without impairing the current interrupting performance required for the breaker of the breaker unit 200. it can.

Further, according to the present embodiment, a discharge gap 69 is electrically connected in parallel to a part of the lightning arrester 68, and the gas pressure of the N ₂ gas or the mixed gas for insulating the line side unit 300 is set to 0.4 to 0.6 MP. Since it is set to a, the variation in the discharge characteristics of the discharge gap 69 can be suppressed to about ± 10 kV, the limiting voltage characteristics of the surge arrester 68 can be stabilized, and the line side unit 300 can be configured. The insulation performance required for the N ₂ gas or mixed gas sealed in the tank 62 of the track side unit 300 can be obtained without changing the diameter and thickness of the tank 62 to be used.

According to the present embodiment, the gas pressure of the N ₂ gas or the mixed gas that insulates the bus units 290 a and 290 b is set to 0.4 to 0.6 MPa, so that the bus unit 290 a, The insulation performance required for N ₂ gas or mixed gas enclosed in tanks 57a and 57b can be obtained without changing the diameter and thickness of tanks 57a and 57b constituting 290b. be able to. .

Therefore, according to the present embodiment, it is possible to reduce the amount of SF ₆ gas that is likely to affect the environment, thereby improving the environmental resistance of the gas-insulated switchgear. According to this embodiment, the lightning arrester 68 is electrically Suppressing variation in discharge characteristics of the discharge gap 6 9 connected in parallel to the soil 1 0 k V extent, with the limiting voltage characteristic of the arrester 6 8 can be stabilized, N ₂ gas or mixed gas is sealed tank The insulation performance required for the N ₂ gas or mixed gas sealed in the tank of each unit can be obtained without changing the diameter and thickness of the unit, thus suppressing the size of the gas insulated switchgear. Therefore, a reduction in the economic efficiency of the gas insulated switchgear can be suppressed.

(Example 3)

FIGS. 5 and 6 show the configuration of the gas-insulated switchgear of the third embodiment. The gas insulated switchgear of this embodiment is composed of a circuit breaker unit 310, a line side unit 3 30, a bus unit 3 20, an instrument transformer unit 340, and a lightning arrester unit 350.

The circuit breaker unit 310 includes a circuit breaker and a controller 76. The interrupting section interrupts the fault current, and includes an opening / closing mechanism section having a fixed contact and a movable contact disposed opposite to and fixed to the fixed contact. Are provided in the tank 75 for three phases. The actuator 76 is for separating the movable contact from the fixed contact of the opening / closing mechanism 74 and is mechanically connected to the movable contact of the opening / closing mechanism 74 via a link mechanism. . Actuator 76 is installed below the shutoff.

The tank 75 is a metal cylindrical container and is grounded. SF ₆ gas is sealed in the tank 75 at a pressure of 0.4 to 0.6 MPa. Preferably, it is sealed at a pressure of 0.5 to 0.6 MPa to obtain high current interrupting performance. Grounding switches 77, 78 are provided on both sides of the switching mechanism 74. The earthing switchgear 7 7, 7 8 is for grounding the track, It has a constant conductor and a movable conductor which is arranged opposite to the fixed conductor and is provided so as to be able to be separated from the fixed conductor, and is operated by an operating device (not shown). A control box 80 is provided on the side of the operation device 76 and below the bus unit 32. A current transformer 79 for measuring current is provided on the conductor electrically connected to the circuit breaker 74.

A bus unit 320a is provided at one upper end of the circuit breaker unit 310. The bus unit 320a has three phases of buses 81a in a tank 82a. The busbar 81a is arranged in the tank 82a so as to be located at each vertex of the triangular shape, and is provided with an isolator provided between the disconnector 83a, the tank 82a and the tank 75. The circuit breaker unit 310 is electrically connected to the opening / closing mechanism 74 of the circuit breaker unit via the connection conductor and the reciprocating conductor of the circuit 85.

Tank 82 a is a metal T-branch type cylindrical container, is grounded, N ₂ gas or mixed gas is enclosed in the gas pressure 0.4～0.6MP a among them. Preferably, the gas is sealed at a gas pressure of 0.4 MPa lower than the gas pressure of SF ₆ gas sealed in the tank 75 of the circuit breaker unit 310. The disconnector 8 3 a separates the circuit on the circuit breaker unit 310 side from the circuit on the bus unit 320 a side.The disconnector is placed opposite to the fixed conductor and is separated from the fixed conductor. It has a movable conductor that is provided so that it can be operated by the operating device 84a.

At one lower end of the circuit breaker unit 310, a bus unit 320b is provided. The bus unit 32 0 b is a tank 82 b in which buses 81 b are provided for three phases. The bus bar 8 lb is arranged in the tank 82 b so as to be located at each vertex of the triangular shape, and the insulating switch provided between the disconnector 83 b and the tank 82 b and the tank 75 is provided. Connection conductors The reciprocating conductor is electrically connected to an opening / closing mechanism 74 of a breaking unit constituting the circuit breaker unit 310.

Tank 8 2 b is a metal T-branch type cylindrical container, is grounded, among which N ₂ gas or mixed gas from 0.4 to 0. Is sealed with a gas pressure of 6 MP a. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure in the circuit breaker Yunitto 3 1 0 tank 7 5 SF ₆ gas sealed in. The disconnector 8 3 b separates the circuit on the circuit breaker unit 310 side from the circuit on the bus unit 3 20 b side, and is disposed opposite to the fixed conductor and the fixed conductor. It has a movable conductor detachably provided, and is operated by an operating device 84b.

On the other side of the circuit breaker unit 310, a line side unit 330 is provided. The track side unit 330 is a track side device, that is, a disconnector 88, a ground opening / closing device 89, and a cable head 90 are provided in a tank 87 for three phases. The tank 87 is a metal cylindrical container, which is grounded, and in which N ₂ gas or a mixed gas is sealed at a pressure of 0.4 to 0.6 MPa. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure in the circuit breaker Yunitto 3 1 0 tank 7 5 SF ₆ gas sealed in.

The disconnecting switch 8 8 separates the circuit on the circuit breaker unit 3110 side from the circuit on the line side.The disconnecting switch 8 is disposed opposite to the fixed conductor and is provided so as to be separable from the fixed conductor. It has a movable conductor and is operated by an actuator not shown. The earthing switchgear 89 is for grounding the line, and has a fixed conductor and a movable conductor which is disposed to face the fixed conductor and is provided so as to be able to be separated from the fixed conductor. Operated. The cable head 90 can be used to draw power from gas-insulated switchgear or A terminal for drawing electric power into the gas insulated switchgear, which is electrically connected to the disconnector 88. The cable head 88 is hermetically drawn out of the tank 87 from the lower portion of the tank 87, and a cable not shown is electrically connected.

On the opposite side of the circuit breaker unit 310 from the track side unit 330, an instrument transformer unit 340 is provided. The instrument transformer unit 340 has an instrument transformer (not shown) provided in the tank 92. The instrument transformer measures the line voltage

It is electrically connected to the disconnector 88 via the connection conductor and the conductor of the insulating spacer 93 provided between the switches 87 and 87.

The tank 92 is a metal cylindrical container and is grounded. The tank 92 is filled with N ₂ gas or a mixed gas at a pressure of 0.4 to 0.6 MPa. Preferably, is enclosed by a lower 0. Gas pressure 4 MP a than the gas pressure in the circuit breaker Yunitto 3 1 0 tank 7 5 SF ₆ gas sealed in.

A lightning arrester unit 350 is provided on the side of the track side unit 330 opposite to the circuit breaker unit 310 side. The lightning arrester unit 350 discharges the overvoltage transmitted to the gas-insulated switchgear to the ground to protect the gas-insulated switchgear from overvoltages such as lightning surges due to lightning strikes and switching surges caused by transmission line breakers. In addition, it suppresses overvoltage applied to the gas-insulated switchgear. As shown in FIG. 5, lightning arresters 94 are provided in the tank 95 for three phases.

Each of the lightning arresters 94 is a non-linear resistor element mainly composed of zinc oxide.

9 and metal plates 98 are alternately laminated via insulating rods 96, and are fixed to the bottom plate 99 of the tank 95 via insulators 100. Straight line The configurations, functions, and characteristics of the antibody element 97 and the metal plate 98 are the same as those in the previous example, and thus description thereof is omitted. A connecting conductor (not shown) is provided in the lower part of the arrester 94. One end of the connection conductor is electrically connected to a metal plate arranged at the lowest part of the laminate. The other end of the connection conductor is drawn out from the inside of the tank 95 to the outside via a sealed terminal and is grounded.

The tank 95 is a metal cylindrical container and is grounded. The tank 95 is filled with N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, the gas is sealed at a gas pressure of 0.4 MPa lower than the gas pressure of the SF ₆ gas sealed in the tank 75 of the circuit breaker unit 310. A cubicle 107 containing instruments such as an arrester operation alarm and a recorder is provided on the peripheral wall of the tank 95.

A connection plate 103 is provided on the upper end side (head) of the lightning arrester 94 via a spring 102. A conductor 104 that short-circuits the panel 102 is provided between the bottom plate 99 and the connection plate 103. An electric potential sharing member 105 is provided on the upper end side of the arrester 94. The potential sharing member 105 is a metal member surrounding the upper end side of the lightning arrester 94, and is electrically connected to the connection plate 103. In addition, the potential sharing member 105 is electrically connected to the disconnector 88 via the connection conductor of the insulating spacer 101, the disconnecting device 108, and the conductor.

A discharge gap 106 is electrically connected in parallel to a part of each lightning arrester 94. The discharge gap 106 is for short-circuiting a part of the lightning arrester 94 with the current flowing through the lightning arrester 94, and is disposed opposite the upper discharge electrode 106 a and the upper discharge electrode 106 a via a gap. And a lower discharge electrode 106b. The upper discharge electrode 106a and the lower discharge electrode 106b are made of aluminum. It is composed of a rod portion for supporting.

The lower discharge electrode 106 b is provided on a metal plate 98 a located at the lowest part of the arrester 94. The upper discharge electrode 106a is provided on a metal plate 98b located above the metal plate 98a. Attachment of the electrode to the metal plate is performed by screwing a screw formed on the support rod portion of the electrode into a screw hole formed in the metal plate.

According to the present embodiment described above, SF ₆ gas is used as the insulating medium of the circuit breaker unit 310, the bus unit 320a, 320b, the line side unit 330, the instrument Having used a transformer Yunitto 340 and lightning arrester Yunitto 3 50 N ₂ gas or mixed gas as an insulating medium, breaker Interview two Tsu preparative 3 1 0 without impairing the current interrupting performance required for the blocking of the environment It is possible to reduce the amount of SF ₆ gas used, which is likely to have an effect on CO2.

Further, according to the present embodiment, a discharge gap 106 is electrically connected in parallel to a part of the lightning arrester 94 to insulate the lightning arrester unit 350. The gas pressure of the N ₂ gas or the mixed gas is set to 0.4 to 0.6 MPa. , The variation in the discharge characteristics of the discharge gap 106 is suppressed to about 10 kV, the limiting voltage characteristic of the surge arrester 94 is stabilized, and the tank 9 constituting the line side unit 350 The insulation performance required for the N ₂ gas or the mixed gas sealed in the tank 95 of the track side unit 350 can be obtained without changing the diameter and thickness of 5.

Further, according to the present embodiment, the gas pressure of the N ₂ gas or the mixed gas that insulates the bus unit 320a, 320b, the line side unit 330, and the instrument transformer unit 34 is set to 0.4 to 4.0. Since the pressure is set to 0.6 MPa, the insulation performance required for the N ₂ gas or mixed gas filled in the tank of each unit can be maintained without changing the diameter and thickness of the tank constituting each unit. Obtainable.

Therefore, according to the present embodiment, it is possible to reduce the amount of SF ₆ gas that is likely to affect the environment, thereby improving the environmental resistance of the gas-insulated switchgear. Further, according to the present embodiment, the variation in the discharge characteristics of the discharge gap 106 electrically connected in parallel with the lightning arrester 94 is suppressed to about 10 kV, and the limiting voltage characteristic of the lightning arrester 94 is stabilized. it co If it is, the insulating N ₂ gas or mixed gas required for the diameter and without changing the size of the thickness, N ₂ gas or mixed-gas sealed in the tank of each unit of the tank which is sealed Since performance can be obtained, the size of the gas insulated switchgear can be suppressed, and the economical efficiency of the gas insulated switchgear can be suppressed.

Embodiment 4 FIG. 7 shows the configuration of a lightning arrester used for the gas insulated switchgear of the fourth embodiment. This embodiment is an improved example of the previous example, in which the lightning arresters 94 for three phases are housed in a single phase.

As in the previous example, the lightning arrester 94 is made up of a non-linear resistor element 97 mainly composed of zinc oxide and a metal plate 98 alternately stacked via insulating rods 96. A discharge gap 106 through which a discharge current flows by short-circuiting a part of the surge arrester 94 is electrically connected in parallel to a part of the lightning arrester 94. The tank 95 is filled with N ₂ gas or a mixed gas at a gas pressure of 0.4 to 0.6 MPa. Preferably, the gas is sealed at a gas pressure of 0.4 MPa, which is lower than the gas pressure of the SF ₆ gas sealed in the tank 75 of the circuit breaker unit 310.

In this embodiment, the connection plate 103 provided on the upper end side (head) of the lightning arrester 94 via the panel 102 is electrically connected to the connection conductor of the insulating spacer 101. An electric field relaxation member 109 is provided on the upper end side of the stacked body so as to surround the upper end side of the stacked body. Other configurations are the same as those of the previous example, and the description thereof is omitted.

Therefore, also in this embodiment, as in the previous example, the amount of SF ₆ gas, which is likely to affect the environment, can be reduced, and the environmental resistance of the gas insulated switchgear can be improved. . Further, according to this embodiment, the variation in the discharge characteristics of the discharge gap 106 electrically connected in parallel to the lightning arrester 94 is suppressed to about ± 10 kV, and the limiting voltage characteristic of the lightning arrester 94 is reduced. Insulation performance required for N ₂ gas or mixed gas filled in each unit tank without changing the diameter and thickness of the tank filled with N ₂ gas or mixed gas, while being able to stabilize Therefore, it is possible to suppress an increase in the size of the gas insulated switchgear, and to suppress a decrease in the economical efficiency of the gas insulated switchgear. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is useful for a gas insulated switchgear installed in an electric station such as a substation or a switchgear. Are suitable.

Claims

The scope of the claims.

1. In a container filled with sulfur hexafluoride gas, a unit in which a mechanism for electrically interrupting an electric circuit is provided, and in a container filled with nitrogen gas or a mixed gas of nitrogen gas, A unit provided with a lightning arrester that suppresses overvoltage propagating in the electric circuit and electrically connects a discharge gap electrically in parallel.The gas pressure of the nitrogen gas or the mixed gas is set to 0.4 to 0.6 MPa. A gas-insulated switchgear.

2. In a container filled with sulfur hexafluoride gas, a unit provided with a mechanism for electrically interrupting an electric circuit, and in a container filled with nitrogen gas or a mixed gas of nitrogen gas, A unit provided with a lightning arrester that suppresses overvoltage propagating in the electric circuit and electrically connects discharge gaps in parallel, wherein the gas pressure of the sulfur hexafluoride gas and the nitrogen gas or the mixed gas is 0.4 to Gas insulation characterized by being set to 0.6 MPa

3. In a container filled with sulfur hexafluoride gas, a unit provided with a mechanism for electrically interrupting an electric circuit, and in a container filled with nitrogen gas or a mixed gas of nitrogen gas, A unit provided with a lightning arrester that suppresses overvoltage propagating in the electric circuit and electrically connects discharge gaps in parallel with each other.The gas pressure of the sulfur hexafluoride gas is set to 0.5 to 0.6 MPa and The gas insulated switchgear, wherein the gas pressure of the nitrogen gas or the mixed gas is set to a gas pressure smaller by 0.1 to 0.2 MPa than the gas pressure of the sulfur hexafluoride gas.

4. In a container filled with sulfur hexafluoride gas, a unit provided with a mechanism for electrically interrupting an electric circuit, and in a container filled with nitrogen gas or a mixed gas of nitrogen gas, Suppresses overvoltage propagating in the electric circuit and discharges A unit provided with a lightning arrester electrically connected in parallel with the gap, wherein the gas pressure of the sulfur hexafluoride gas is set to 0.5 to 0.6 MPa and the nitrogen gas or the nitrogen gas A gas-insulated switchgear, characterized in that the gas pressure of the mixed gas is set to 0.4 MPa.

5. In a container filled with sulfur hexafluoride gas, a unit equipped with a mechanism for electrically interrupting the electric circuit from the bus to the power outlet or power outlet, and a nitrogen gas or In a unit in which the bus is provided in a container in which a gas mixture with nitrogen gas is enclosed, and in a container in which nitrogen gas or a gas mixture with nitrogen gas is enclosed, overvoltage propagating through the electric circuit is suppressed. A unit provided with a lightning arrester having a discharge gap electrically connected in parallel, and a power supply port or a power supply port which constitutes the power supply port and is insulated by nitrogen gas or a mixed gas of nitrogen gas. A gas insulated switchgear comprising a lead-in terminal or a power lead-out terminal, wherein the gas pressure of the nitrogen gas or the mixed gas is set to 0.4 to 0.6 MPa.

6. A unit provided with a mechanism for electrically interrupting the electric circuit from the bus to the power lead-in terminal or power lead-out terminal in a container filled with sulfur hexafluoride gas, and a gas containing nitrogen gas or nitrogen gas. A unit in which the bus is provided in a container in which the mixed gas is sealed, and a container in which nitrogen gas or a mixed gas of nitrogen gas is sealed, suppresses an overvoltage propagating through the electric circuit and also sets a discharge gap. A lightning arrester electrically connected in parallel; and a unit provided with the power lead-in terminal or the power lead-out terminal, wherein a gas pressure of the nitrogen gas or the mixed gas is 0.4 to 0.6 MP. A gas-insulated switchgear set to a.

7. In a container filled with sulfur hexafluoride gas, place a power lead-in terminal or A unit provided with a mechanism for electrically blocking an electric circuit leading to a power extraction terminal, a unit provided with the bus in a container filled with nitrogen gas or a mixed gas of nitrogen gas, and a nitrogen gas. Alternatively, a unit provided with a lightning arrestor in which a mixed gas with nitrogen gas is sealed and in which a discharge gap is electrically connected in parallel while suppressing an overvoltage propagating in the electric circuit is provided in a container filled with nitrogen gas or nitrogen gas. A power supply terminal or a unit provided with the power supply terminal in a container in which a gas mixture with the gas is sealed, wherein a gas pressure of the nitrogen gas or the gas mixture is 0.4 to 0.6 MP. a gas-insulated switchgear, characterized by being set to a.

8. A container in which nitrogen gas or a mixed gas of nitrogen gas is sealed, a lightning arrester provided in the container and having a plurality of non-linear resistor elements mainly composed of zinc oxide laminated thereon, Wherein the gas pressure of the nitrogen gas or the mixed gas is set to 0.4 to 0.6 MPa.