JPH09312110A - Bushing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an insulating medium inside a bushing capable to flow in and out without enlarging a supporting member and increasing the seal faces, simplify the maintenance work, and heighten the reliability by installing a terminal to lead out potential to the outside from a capacitor of a capacitor core in an aperture part of a supporting member and constituting the terminal as an entrance valve of the insulating medium. SOLUTION: Of the bushing 1a, a center conductor 3 as an electric conductor is inserted into an insulator tube 2 and at the same time the tube 2 is filled with an insulating medium 5. A capacitor core 4 comprising a plurality of capacitors is installed in the surrounding of the center conductor 3. Moreover, the bushing 1a is attached to an electric appliance through a supporting metal tool 7 as a supporting member. An aperture part 7a is formed in the supporting metal tool 7 and at the same time a terminal housing part 19 is so formed unitedly as to surround the aperture part 7a. A terminal 6 to lead out the potential of one electrode of the capacitor core 4 is installed in the housing part 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing used for electric equipment such as electric power equipment or overhead wire drawing.

[0002]

2. Description of the Related Art FIG. 10 is a cross-sectional view showing an example of a conventional capacitor bushing, and FIG. 11 is an enlarged cross-sectional view showing the structure in the vicinity of a support fitting when a measuring electric wire is connected by a conventional technique. As shown in FIG. 10, in a conventional capacitor bushing 1, a central conductor 3 for current flow is inserted into a porcelain bushing 2 and a plurality of electrodes (not shown) are arranged around the central conductor 1 in a coaxial cylindrical shape. By configuring the capacitor core 4 for electric field control, the electric fields in the axial direction and the radial direction are controlled to be uniform. Insulating paper is often used for the capacitor core 4, and an insulating medium 5 such as insulating oil is often enclosed in the capacitor core 4 for insulation and cooling.

When the capacitor core 4 and the insulating medium 5 enclosed in the bushing 1 are organic substances, it is necessary to measure the dielectric loss tangent and the electrostatic capacitance of the capacitor core 4 in order to confirm the soundness of the insulating ability. In order to measure these with high accuracy, a potential is drawn from the electrode inside the capacitor core 4 to the outside of the bushing 1 through the terminal 6. The electrode of the outermost layer of the capacitor core 4 is electrically connected to the support metal fitting 7 having a ground potential as a support member, acts as a guard electrode during measurement, and is less likely to be affected by the outside of the bushing 1.

Generally, the bushing 1 is used outdoors,
Exposed to the wind and rain. Since many sealing surfaces 8 are exposed on the surface of the bushing 1 as represented by the joint surface between the conductive portion and the insulating portion, moisture in the air is more likely to enter than in other high voltage devices. Therefore, a pressure gas 9 containing no moisture such as nitrogen gas is enclosed to make the internal pressure a positive pressure, and the external atmosphere 1
Prevents 0 intrusion.

When a liquid insulating medium is used as the insulating medium 5 inside the bushing 1, it is necessary to provide an expansion chamber 11 at the head of the bushing 1 in order to relieve the internal pressure due to temperature changes. Since the pressurizing gas 9 for increasing the internal pressure is lighter than the liquid, it accumulates in the upper part of the expansion chamber 11. The center conductor 3 often penetrates the expansion chamber 11 and slides on the contact surface with the through seal member 12 due to thermal expansion and contraction.
The pressurizing gas 9 stored in the inside 1 easily flows out.

Then, the liquid insulating medium 5 does not flow out,
Bushing 1 Pressurizing gas 9 for making the internal pressure a positive pressure 9
If only the gas flows out, it is possible to restore the normal bushing by simply injecting the pressurizing gas 9 into the bushing 1. However, the conventional bushing 1 has no gas injection mechanism.

By the way, in a large device such as a transformer, an internal insulating medium also serving as a cooling device is circulated, or a cooler accommodating the insulating medium is provided separately from the transformer body.
Although it is easy to pull out the insulating medium to the outside, many bushings have no means for pulling the insulating medium to the outside because the insulating medium is completely sealed. Most of the bushings in which the insulating medium is completely closed do not have a means for measuring the internal pressure or the temperature of the insulating medium.

On the other hand, the electrostatic capacitance of the capacitor core 4 may be used to constantly measure the voltage of the bushing main circuit. As shown in FIGS. 10 and 11, the measurement is performed by connecting a measurement electric wire 13 to the terminal 6 and electrically connecting the measurement electric wire 13 to a voltage conversion capacitor or transformer (not shown). . Then, the terminal 6 and the measurement electric wire 13 are installed in a closed container 14 as shown in FIG. 11, and the closed container 14 is filled with an insulating medium 5a.
This insulating medium 5a prevents insulation breakdown from the connecting portion 15 between the terminal 6 and the measuring electric wire 13.

[0009]

As described above, since the conventional bushing 1 has a large number of sealing surfaces 8 for sealing the insulating medium 5 inside, an external atmosphere 10 represented by the atmosphere is formed inside. When the insulating medium 5 flows out easily, the internal pressure may decrease or become negative.

When such a phenomenon occurs, the bushing 1
Since the insulation pressure of No. 2 decreases, which causes a ground fault, it is necessary to periodically sample the internal insulation medium 5 and inspect the infiltration state of the external atmosphere 10 and the filling pressure of the insulation medium 5.

Therefore, in a large bushing, as shown in FIG. 12, the valve 16 for collecting the insulating medium inside the support fitting 7 is provided.
In some cases, the valve 16 is larger than the flange of the support fitting 7, and cannot be attached unless the support fitting 7 is enlarged. In addition, valve 16
The new installation increases the number of new sealing surfaces 8a, which causes a new problem that the sealed state of the bushing 1 is likely to be incomplete.

On the other hand, when the measuring electric wire 13 is connected to the potential extracting terminal 6, a high voltage of several kV is generated at the terminal 6 during the bushing charging, so that the terminal 6 and the measuring electric wire 1 are connected.
It is necessary to insulate the connection part 15 with the connection part 3. In the conventional technique, as shown in FIG. 11, the insulating medium 5a is filled in the periphery of the connection portion 15 to perform the insulation treatment. Therefore, the sealed container 14 attached to the outer peripheral portion of the connection portion 15 via the seal member 17 is used. Then, the insulating medium 5a that is independent of the insulating medium 5 that fills the inside of the bushing 1 is required. When insulating oil is used as the insulating medium 5a, it is necessary to provide the air layer 18 on the upper part of the closed container 14 in order to relax the pressure in the closed container 14 due to thermal expansion. Also,
It is necessary to consider the sealing of the air layer 18 and the deterioration of the insulating medium 5a separately from the bushing.

Furthermore, when a liquid is used as the insulating medium 5 inside the bushing 1, the head of the bushing 1 relaxes the pressure due to the thermal expansion of the insulating medium 5 enclosed therein, so that it is inert such as nitrogen gas. An expansion chamber 11 enclosing a gas 9 for pressurizing the gas is installed. When only the pressurizing gas 9 flows out without the liquid insulating medium 5 flowing out, it is possible to restore the normal bushing 1 only by injecting the pressurizing gas 9 into the bushing 1.
A conventional bushing has a liquid insulating medium 5 and a pressurizing gas 9
Since there is no mechanism for injecting and adjusting both of them, it was necessary to overhaul the entire bushing 1.

The present invention has been made in consideration of the above-mentioned circumstances, and does not invite an increase in the size of the support fitting and an increase in the sealing surface.
It is an object of the present invention to allow an insulating medium to flow in and out of a bushing, simplify maintenance work, and provide a highly reliable bushing.

[0015]

In order to solve the above-mentioned problems, the first aspect of the present invention relates to a porcelain tube having an insulating medium filled therein, a conducting conductor inserted in the porcelain tube, and the energization. In a bushing having a capacitor core for electric field control, which is arranged on the outer periphery of a conductor and is composed of a plurality of capacitors, and in which at least the insulator tube, the current-carrying conductor and the capacitor core are attached to an electric device via a supporting member,
An opening is formed in the support member, and a terminal for drawing an electric potential from the capacitor of the capacitor core to the outside is provided in the opening, and the terminal is configured as a valve for the inlet / outlet of the insulating medium.

According to a second aspect of the present invention, in the bushing according to the first aspect, the terminal is fixed to a terminal plate, and a sealing member for sealing an insulating medium is attached to the opening of the support member, and the terminal is attached. A spring is provided between the plate and the support member, and the spring compresses the seal member to maintain the seal, while moving the terminal plate allows the insulating medium to flow in and out. And

According to a third aspect of the present invention, in the bushing according to the first aspect, a hermetically sealed container for shielding the opening from the outside air is attached to the outer periphery of the opening provided in the support member, and the inside of the hermetically sealed container is closed. One of the insulating medium and the gas for pressurizing the insulating medium is allowed to flow in and out.

According to a fourth aspect of the present invention, there is provided an insulator for electric field control, which comprises a porcelain insulator tube filled with an insulating medium, a conducting conductor inserted in the porcelain insulator, and a plurality of capacitors arranged on the outer periphery of the conducting conductor. A bushing having a capacitor core, and at least the insulator tube, the current-carrying conductor, and the capacitor core being attached to an electric device via a supporting member, an opening is formed in the supporting member, and the opening of the capacitor of the capacitor core is formed in the opening. A terminal for drawing an electric potential to the outside is provided, and a seal member compressed by an insulating medium sealed is attached to the terminal, and an external force is applied to the terminal to oppose the compressive force of the insulating medium on the seal member, and the opening is formed. The internal insulating medium is caused to flow out from the device, and the external pressure applied to the terminal at this time is measured to measure the internal pressure.

A fifth aspect of the present invention is for controlling an electric field, which comprises a porcelain insulator tube filled with an insulating medium, a conducting conductor inserted in the porcelain insulator, and a plurality of capacitors arranged on the outer periphery of the conducting conductor. A bushing having a capacitor core, and at least the insulator tube, the current-carrying conductor, and the capacitor core being attached to an electric device via a supporting member, an opening is formed in the supporting member, and the opening of the capacitor of the capacitor core is formed in the opening. A terminal for drawing out the electric potential is provided to the outside, and a measuring electric wire for connecting a potential measuring device is connected to this terminal, and the connecting portion between the measuring electric wire and the terminal is covered with an airtight container, and the inside is opened from the opening. The insulating medium is allowed to flow into the closed container to insulate the connection portion.

According to a sixth aspect of the present invention, in the bushing according to the second or fifth aspect, one of the terminal and the terminal plate provided in the opening via a seal member for sealing an insulating medium is used as a measuring wire. It is characterized by being operated by.

According to a seventh aspect of the present invention, there is provided an electric field control device comprising a porcelain insulator tube filled with an insulating medium, a conducting conductor inserted in the porcelain insulator pipe, and a plurality of capacitors arranged on the outer periphery of the conducting conductor. A bushing having a capacitor core, wherein at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device via a supporting member, the supporting member is electrically conductive, and an opening is formed in the opening. A terminal for drawing an electric potential from the capacitor of the capacitor core to the outside is provided, and a mechanism for flowing out the internal insulating medium to the outside is provided to this terminal, and the terminal is electrically connected to the supporting member during operation by mechanically interlocking with this mechanism. And a contact mechanism for bringing the same potential as that of the supporting member by contacting with the above, and a hermetically sealed container for shielding the opening from the outside air is attached to the outer periphery of the opening. , When the contact mechanism of the terminal is released, characterized by insulating the high voltage generated at the terminal by discharging the insulating medium in the closed vessel.

According to an eighth aspect of the present invention, there is provided an insulating field filled with an insulating medium, a conductive conductor inserted in the insulating pipe, and a plurality of capacitors arranged on the outer periphery of the conductive conductor for controlling an electric field. A bushing having a capacitor core, and at least the insulator tube, the current-carrying conductor, and the capacitor core being attached to an electric device via a supporting member, an opening is formed in the supporting member, and the opening of the capacitor of the capacitor core is formed in the opening. Two terminals for drawing out a potential are provided to the outside, one terminal is connected to the capacitor of the capacitor core by a first lead wire, and the other terminal is a first lead in the middle of the first lead wire. It is characterized in that a second lead wire made of a material having a work function different from that of the wire is connected to form a thermocouple.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a main part of a first embodiment of a bushing according to the present invention. Note that the same or corresponding portions as those of the conventional configuration will be described using the same reference numerals as those in FIGS. The same applies to each of the following embodiments.

In the overall structure of the bushing 1a of the first embodiment, the center conductor 3 as a current-carrying conductor is inserted into the porcelain bushing 2 and the insulating medium 5 is filled, as in the conventional case. Around the center conductor 3, a capacitor core 4 for controlling an electric field, which is composed of a plurality of capacitors, is arranged. Further, the bushing 1a is attached to an electric device (not shown) via a support fitting 7 as a support member.

An opening 7a is formed in the support fitting 7, and the terminal accommodating portion 19 surrounds the opening 7a.
Are integrally formed. In this terminal storage section 19,
A terminal 6 is provided for extracting the electric potential of one electrode of the capacitor core 4 to the outside. The terminal 6 is electrically connected to an electrode inside the capacitor core 4 via a lead wire 20 and attached to the support fitting 7 via a seal member 17. Thereby, the bushing 1a
The insulating medium 5 inside is sealed.

A female screw portion 21 is formed on the inner peripheral surface of the terminal accommodating portion 19 of the support fitting 7 while the female screw portion 21 is formed.
A male screw portion 22 that is screwed into is engraved on the outer peripheral surface of the terminal 6 for drawing out the potential. Then, the male screw portion 22 is screwed into the female screw portion 21 of the support fitting 7, whereby the sealing member 17 is compressed and the insulating medium 5 is sealed.

Next, the operation of the present embodiment will be described.

When the terminal 4 is rotated in the counterclockwise direction, the male screw portion 22 of the terminal 4 moves along the spiral groove of the female screw portion 21, so that the compressive force to the seal member 17 is reduced and the bushing 1a is kept inside. The sealed insulating medium 5 is attached to the bushing 1a.
Can be drained to the outside.

That is, in this embodiment, the seal member 17
By having a valve mechanism capable of easily loosening the terminal 6 attached to the support fitting 7 via the valve, the sealing function of the seal member 17 is eliminated, and the sealed insulating medium 5 is moved into and out of the bushing 1a. It can be possible.
Further, since the seal member of the terminal mounting portion and the seal member of the insulating medium inlet / outlet mechanism inside the bushing 1a can be made common, the number of sealing surfaces is the same as that of the conventional bushing having no inlet / outlet valve.

As described above, according to the present embodiment, the seal member 17 between the terminal 6 for drawing out the electric potential and the support fitting 7 of the bushing 1a also serves as the seal member for the inlet / outlet valve, so that the conventional structure as shown in FIG. The insulating medium 5 inside the bushing 1a can be taken out without further increasing the sealing surface.

In this embodiment, the method of compressing the seal member 17 by the screwing method is shown, but the compression of the seal member 17 may be performed by using other means such as a spring or a pressure difference between the inside and outside of the bushing 1a. Good.

FIG. 2 is a sectional view showing a main part of a second embodiment of the bushing according to the present invention. In the bushing 1b of the second embodiment, a terminal 6 for drawing out the potential of one electrode of the capacitor core 4 to the outside is firmly fixed to a terminal plate 23, and the terminal plate 23 is supported by a seal member 17 through a supporting metal fitting. Pressed to 7.

One end of a spring 24 is fixed to the terminal plate 23, and the other end of the spring 24 is fixed to the pressing plate 25. The pressing plate 25 is pressed by a fixing plate 26, and an oil guide port 27 is formed in the fixing plate 26, and a male screw portion 22 is engraved on the outer peripheral surface. The male screw portion 22 is screwed with the female screw portion 21 formed on the inner peripheral surface of the terminal housing portion 19 of the support fitting 7.

Then, the terminal plate 23 is pressed against the seal surface 28 of the support fitting 7 by the spring 24 biased via the holding plate 25, and the seal member 17 provided between the terminal plate 23 and the support fitting 7 is attached. It is compressed to keep the insulating medium 5 sealed inside the bushing 1b.

Next, the operation of this embodiment will be described.

When the fixing plate 26 is rotated counterclockwise,
The male screw portion 22 of the fixing plate 26 is the terminal housing portion 1 of the support fitting 7.
By moving along the spiral groove of the female threaded portion 21 engraved in 9, the terminal plate 23 moves in a direction away from the sealing surface 28 of the support fitting 7. Then, the urging force of the spring 24 on the sealing surface 28 gradually decreases, and the compressive force of the sealing member 17 disappears, and the insulating medium 5 inside the bushing 1b can flow out of the bushing 1b via the oil guide port 27.

Here, since the terminal 6 is permanently fixed to the terminal plate 23, the bushing 1 is inserted from the sealing surface 6b.
It is impossible to take out the insulating medium 5 inside the b.

As described above, according to this embodiment, the terminal 6 for drawing out the potential is fixed to the terminal plate 23, and the terminal plate 23 is fixed.
Since the conventional structure is applicable to the terminal 6, the conventional terminal can be applied to the terminal 6, and the insulating medium 5 inside the bushing 1b can be taken out without increasing the sealing surface. You can

The spring 24 that presses the terminal plate 23 against the support fitting 7 is a holding plate 25 that is pressed by a fixing plate 26.
Therefore, if the fixing plate 26 is attached while pressing the pressing plate 25 against the support fitting 7, it is possible to reduce the bolting work in a narrow portion such as between the flanges of the support fitting 7.

FIG. 3 is an enlarged sectional view showing a main part of a third embodiment of the bushing according to the present invention. The bushing 1c of the third embodiment has an opening 7a formed in the support fitting 7.
A closed container 14 for shielding the opening 7a from the external atmosphere 10 is attached to the outer circumference of the inside of the closed container 14 so that the insulating medium 5 inside or a pressurizing gas for pressurizing the insulating medium 5 can flow into and out of the closed container 14. It was done.

That is, in the third embodiment, the hermetically sealed container 1 is provided with the seal member 29 in the terminal accommodating portion 19 accommodating the terminal 6 for drawing out the potential of the capacitor core 4 to the outside.
4 is attached, and the opening 7a is shielded from the external atmosphere 10. An oil-tight container or an airtight container is applied to the closed container 14.

A fixing plate 26 is screwed into the terminal accommodating portion 19, and an oil guide port 27 is formed in the fixing plate 26. The spring 2 is provided near the opening 7a of the support fitting 7.
One end of the spring 4 is fixed, and the other end of the spring 24 is fixed to the terminal 6. The terminal 6 is provided with a seal member 17,
The sealing member 17 is pressed against the fixing plate 26 by the urging force of the spring 24, so that the insulating medium 5 inside the bushing 1c is kept sealed.

Further, the airtight container 14 has an exhaust port 30 integrally formed on the upper part thereof, and a pressurizing cylinder 31 is slidably inserted in the inner axial direction thereof. A terminal operating rod 32 for pressing the terminal 6 is attached to the center.

Next, the operation of the present embodiment will be described.

As shown in FIG. 3, when the terminal operating rod 32 is pushed and the terminal 6 is pushed, the seal member 17 separates from the fixed plate 26 against the biasing force of the spring 24, and the insulating medium 5 is attached to the support fitting 7. It flows out from the provided opening 7a through the oil guide port 27. Although the insulating medium 5 flows out into the closed container 14, it is stored in the closed container 14 because it is sealed by the seal member 29.

Before letting the insulating medium 5 flow out, the pressurizing cylinder 31 is operated to discharge the air in the closed container 14 from the exhaust port 30 to create a vacuum inside the insulating medium 5. It can be taken out without being exposed to the external atmosphere 10.

By the way, since insulating oil is often used in the insulating medium 5, the presence or absence of partial discharge inside the bushing, the deterioration of the insulating paper frequently used in the capacitor core 4, and the infiltration of outside air into the bushing are investigated. In addition, gas analysis of insulating oil is often performed. When the insulating oil inside the bushing is sampled, if the insulating oil is exposed to the external atmosphere 10, the outside air is dissolved in the insulating oil, which affects gas analysis. Since the insulating oil collected in the closed container 14 is not exposed to the outside air as in the present embodiment, accurate gas analysis can be performed.

Furthermore, if a pressure higher than the internal pressure of the bushing 1c is applied to the inside of the closed container 14, the insulating medium 5a in the closed container 14 can be made to flow back into the bushing 1c. In this case, the closed container 14 is the sealing member 29.
Foreign matter does not enter the inside of the bushing 1c from the external atmosphere 10 because it is connected via the.

The bushing 1c cannot maintain a sufficient insulating capacity when the insulating medium 5 enclosed therein flows out. When the insulating medium 5 flows out for some reason, the insulating medium 5 is injected into the bushing 1c from the potential extracting terminal 6 as a primary measure, and the insulating medium 5 is supplied with an insulating ability equivalent to the ground voltage in a steady state. Can be made.

When a liquid is used as the insulating medium 5, the pressurizing gas sealed in the expansion chamber is more likely to flow out than the insulating medium 5. Therefore, when only the pressurizing gas flows out without the liquid insulating medium 5 flowing out, the pressurizing gas is passed through the opening 7a formed in the support fitting 7 to the bushing 1c.
You can restore it to a normal bushing simply by injecting it inside. As a result, work in the expansion chamber at the head of the bushing becomes unnecessary, and work efficiency can be improved.

FIG. 4 is a sectional view showing a main part of a fourth embodiment of the bushing according to the present invention. The bushing 1d of the fourth embodiment has a terminal 6 for drawing an electric potential to the outside.
A seal member 17 that is compressed by the sealed insulating medium 5 is attached thereto, and an external force that resists the compressive force of the seal medium 17 by the insulating medium 5 is applied to the terminal 6 so that the internal portion is opened from the opening 7 a of the support fitting 7. The internal pressure of the bushing 1d is measured by flowing out the insulating medium 5 and measuring the external force applied to the terminal 6 at this time.

The terminal 6 for drawing out the potential of the capacitor core 4 to the outside of the bushing is movably accommodated in the terminal accommodating portion 19, and the fixing plate 26 is screwed into the terminal accommodating portion 19 and is fixed to the fixing plate 26. Has an oil guide port 27. A part of the terminal 6 is inserted into the oil guide port 27. A female screw portion 21 is engraved on the inner peripheral surface of the terminal housing portion 19, and a male screw portion 22 engraved on the outer peripheral surface of the fixing plate 26 is screwed into the female screw portion 21.

Further, the seal member 17 is the bushing 1
It is compressed by the pressure P1 of the insulating medium 5 sealed inside d, and keeps the bushing 1d sealed.

Next, the operation of the present embodiment will be described.

When an external force P2 in the opposite direction to the pressure of the insulating medium 5 applied to the terminal 6 is applied, the force for compressing the seal member 17 decreases, and the external force P2 and the force P1 for the insulating medium 5 to push back the terminal 6 are balanced. At that time, the insulating medium 5 starts to flow out.

Therefore, if the external force P2 that pushes the terminal 6 to take out the insulating medium 5 is measured and divided by the internal area of the seal member 17, the pressure of the insulating medium 5 inside the bushing 1d can be known. To measure the external force P2 applied to the terminal 6, it is convenient to use a spring scale or a torque wrench with a meter. In the current situation, a general bushing using insulating oil as the insulating medium 5 does not have a monitoring device other than an oil level gauge.

By the way, when the insulating medium 5 inside is liquid such as an oil-filled bushing, the measured pressure is the pressure in the vicinity of the support metal fitting 7. When the insulating medium 5 is a liquid, FIG.
As shown in 0, an expansion chamber 11 is provided in the head of the bushing, and the pressurizing gas 9 is enclosed in the expansion chamber 11.

The height from the support fitting 7 to the expansion chamber 11 and the density of the insulating medium 5 are known at the time of manufacturing the bushing and at the stage of mounting the device. Therefore, if the head pressure due to the height between the support fitting 7 and the expansion chamber 11 is reduced from the pressure measured by the support fitting 7, the pressure of the pressurizing gas 9 inside the expansion chamber 11 can be calculated.

As described above, according to this embodiment, the insulating medium 5 can be provided without providing the bushing 1d with a dedicated member for measurement.
Since the pressure of the insulating medium 5 can be measured based on the external force P2 for taking out, it is possible to monitor the soundness of the bushing 1d, which can greatly contribute to preventive maintenance.

FIG. 5 is a sectional view showing a main part of a modified example of the fourth embodiment of the bushing according to the present invention. When the bushing 1d of this modification cannot compress the seal member 17 only by the pressure P1 of the insulating medium 5 in the fourth embodiment,
The auxiliary means such as the auxiliary spring 33 is used.

Therefore, as shown in FIG. 5, the auxiliary spring 3
3 is used, if the force P3 for compressing the seal member 17 by the auxiliary means such as the auxiliary spring 33 is reduced based on the external force P2 applied to the terminal 6, the force due to the pressure of the insulating medium 5 can be known.

FIG. 6 is a sectional view showing the essential parts of a fifth embodiment of the bushing according to the present invention. In the bushing 1e of this embodiment, a measuring electric wire 13 is connected to a terminal 6 for drawing out the potential of the capacitor core 4 to the outside, and a connecting portion 15 between the measuring electric wire 13 and the terminal 6 is covered with an airtight container 14.
From the opening 7a formed in the support fitting 7 to the bushing 1e
The insulating medium 5 therein is injected into the closed container 14 to insulate the connection portion 15 between the terminal 6 and the measurement electric wire 13.

That is, in the present embodiment, the hermetically sealed container 14 is provided in the terminal accommodating portion 19 formed on the outer periphery of the opening 7a of the support fitting 7 so as to surround the connecting portion 15 between the terminal 6 and the measuring electric wire 13. It is attached via a seal member 29. A cable is often used as the measuring wire 13,
The closed container 14 fixed to the support fitting 7 has a function as a cable connection box.

Since the internal structure of the terminal accommodating portion 19 is the same as that of the third embodiment shown in FIG. 3, the description thereof will be omitted.

Next, the operation of this embodiment will be described.

The insulating medium 5 inside the bushing 1e that has flowed out of the opening 7a is sealed by the seal member 29 so that the external atmosphere 1
Since it is isolated from 0, it collects in the closed container 14, covers the connecting portion 15 between the terminal 6 and the measuring wire 13, and insulates the high voltage generated at the terminal 6.

By the way, when the line voltage is divided and measured by using the electrostatic capacity of the capacitor core 4, a high voltage is generated at the terminal 6 for extracting the potential, and the terminal 6 and the measuring wire 13 are used. Since the connecting portion 15 between the terminal 6 and the measuring wire 13 is often used, a part having an electric acute angle such as a crimping terminal or a tightening bolt is easily used. It is necessary to prevent partial discharge and dielectric breakdown.

In the prior art, the insulating medium 5a for protecting the connecting portion 15 must be prepared separately from the bushing, and the injection port 3 for the insulating medium 5a formed in the closed container 14 is required.
4 needs to have a large diameter, and there is a problem that the closed container 14 becomes large.

On the other hand, according to this embodiment, the insulating medium 5a in the closed container 14 is supplied from the bushing 1e,
When the insulating medium 5a is liquid, if the closed container 14 and the bushing 1e are made to communicate with each other through the opening 7a formed in the support fitting 7, the thermal expansion of the insulating medium 5a in the closed container 14 is provided at the head of the bushing 1e. Since the air is absorbed in the expanded chamber 11, the air container 18 need not be provided at the inlet 34 of the closed container 14, and the closed container 14 can be downsized.

Further, since the hermetic container 14 is provided so as to surround the connection portion 15 between the terminal 6 and the measuring electric wire 13, the insulating medium 5 in the bushing 1e can be made to flow from the terminal 6 into the hermetic container 14. , Bushing 1 for connecting part 15
e It can be insulated by the insulating medium 5 inside.

FIG. 7 is a sectional view showing a main part of a sixth embodiment of the bushing according to the present invention. In the bushing 1f of this embodiment, the measurement wire 13 for connecting the terminal 6 and the potential measuring device is mechanically and firmly coupled so that external force can be transmitted in addition to electrical connection. Is to operate the valve mechanism of the terminal part.

That is, in the present embodiment, the hermetically sealed container 14 is provided in the terminal accommodating portion 19 formed on the outer periphery of the opening 7a of the support fitting 7 so as to surround the connecting portion 15 between the terminal 6 and the measuring electric wire 13. It is attached via a seal member 29. The measuring wire 13 is electrically joined to the terminal 6, and the measuring wire 13 is firmly coupled to the terminal 6 by the wire pushing nut 35 so that the mechanical force can be transmitted.

Next, the operation of the present embodiment will be described.

When an external force is applied to the terminal 6 via the measuring electric wire 13, the compressive force of the seal member 17 for sealing the inside of the bushing 1f is reduced, and the inside of the bushing 1f is opened from the opening 7a formed in the support member 7. The insulating medium 5 is the oil guide 27
Flow out into the closed container 14 through the terminal 6 and the measuring wire 1
3. Insulate the connection part 15 with the connection part 3.

As described above, according to the present embodiment, it is not necessary to provide an inlet / outlet valve operating mechanism penetrating the closed container 14 as in the third embodiment, so that the structure of the closed container 14 can be simplified. Further, since the valve operating mechanism penetrating the closed container 14 is unnecessary, the sealing surface is reduced and the leakage probability of the insulating medium 5 can be reduced. Further, since the inlet / outlet valve can be operated after the close-packed container 14 is attached, it is possible to prevent mixing of moisture in the atmosphere into the insulating medium 5 filled in the vicinity of the connecting portion 15 between the terminal 6 and the measuring electric wire 13. it can.

Further, as shown in FIG. 7, if the mechanism for pressing the potential drawing terminal 6 which is the insulating medium inlet / outlet valve with the measuring electric wire 13 to flow out the insulating medium 5 in the bushing 1f, the closed container 14 is removed. If you do, the measurement wire 13
Since the valve opening / closing operation force is eliminated, the erroneous work of automatically closing the valve and removing the closed container 14 with the valve open can be avoided.

The present embodiment is also applicable to the second embodiment in which the terminal plate 23 is used instead of the terminal 6.

FIG. 8 is a sectional view showing the essential parts of a seventh embodiment of the bushing according to the present invention. In the bushing 1g of this embodiment, a valve for the inside of the insulating medium 5 and a grounding mechanism for the terminal 6 for drawing out the potential are interlocked.

The terminal 6 has a conductive portion 36 made of a conductive material.
The seal member 17 made of a conductive material such as carbon rubber is attached to the conductive portion 36. A spring 24 is provided near the opening 7a of the support fitting 7.
One end of the spring 24 is fixed, and the other end of the spring 24 is made of an insulating material and is fixed to the insulating portion 37 joined to the conductive portion 36. Therefore, since the fixing plate 26 and the support fitting 7 are made of a conductive material, the terminal 6 is electrically connected to the support fitting 7. A terminal support portion 38 is provided on the fixed plate 26.

Therefore, in this embodiment, the mechanism for causing the insulating medium 5 inside the bushing 1g to flow out to the terminal 6 to the outside and the terminal 6 is brought into electrical contact with the support metal 7 during operation to have the same potential as the support metal 7. And an electrical contact mechanism for mechanically connecting them. Also,
Airtight container 14 for shielding the periphery of the opening 7a from the outside
Is attached to the terminal housing portion 19 via the seal member 29. The electrical contact mechanism of the terminal 6 is released and the terminal 6
When a high voltage is generated in the
4 is configured to flow out.

Next, the operation of this embodiment will be described.

In a normal state where the partial pressure is not measured by the capacitor core 4, the conductive portion 36 of the terminal 6 that draws an electric potential from the capacitor core 4 to the outside is electrically connected to the support fitting 7 through the seal member 17 and the fixing plate 26. To be grounded.

On the other hand, when the terminal 6 is pushed in order to generate a high voltage and the grounding mechanism is released, the compressive force of the seal member 17 is lost at the same time, and the insulating medium 5 inside the opening 7a of the support metal fitting 7 is removed from the terminal 6. It flows out to the vicinity and insulates the terminal 6 and the connecting portion 15.

By the way, the terminal 6 for drawing out the potential is mainly used for verifying the insulation performance of the capacitor core 4, and during the bushing operation, the terminal 6 is normally electrically connected to the supporting member 7 which is at the ground potential. It At the time of charging the bushing, a high voltage of several kV appears at the potential extracting terminal 6 which is not connected to the supporting member 7, which is dangerous. As described above, when the measuring electric wire 13 is connected to the potential extracting terminal 6 to take out a high voltage, the insulating medium 5a is often filled in the vicinity of the connection portion 15 so as not to cause dielectric breakdown from the connection portion 15.

In this embodiment, when a high voltage is generated at the terminal 6, the insulating medium 5a inside the bushing 1g always flows out to the vicinity of the terminal 6, so that the hermetically sealed container 14 that receives the insulating medium 5a is placed in the terminal accommodating portion. It is attached to 19. As a result, it is possible to prevent accidents such as a high voltage being generated in the terminal 6 in the atmosphere to cause a dielectric breakdown of the terminal 6 or a person touching the terminal 6 having a high voltage. Further, after the insulation performance test of the capacitor core 4 is completed, when the outflow mechanism of the insulating medium 5 is closed to remove the closed container 14, the terminal 6 is grounded at the same time, so that it is possible to prevent forgetting to ground after measurement.

FIG. 9 is an enlarged sectional view showing the essential parts of an eighth embodiment of the bushing according to the present invention. The bushing 1h of this embodiment is provided with two terminals 39 and 40 for extracting the potential of at least one capacitor of the capacitor core 4 composed of a plurality of capacitors to the outside, and one terminal 39 is a single lead on the capacitor core. Wire (first lead wire) 41 is directly connected, and the other terminal 40 is lead wire 4
A lead wire (second lead wire) 42 having a work function different from that of 1 is electrically connected to the middle of the lead wire 41 to form a thermocouple, and the temperature of the insulating medium 5 enclosed therein is measured. It is a thing.

That is, the lead wire 41 connects between the electrode of the capacitor core 4 and the terminal 39, one end of the lead wire 42 having a work function different from the material of the lead wire 41 is connected to the terminal 40, and the other end is It is connected to the lead wire 41. For the lead wire 41, for example, chromel is used, and for the lead wire 42, for example, alumel is used, and a thermocouple is constituted by both of them.

Next, the operation of this embodiment will be described.

Since the lead wire 41 and the lead wire 42 have different work functions, the lead wires 41 and 42 on both sides of the connection point 43.
Has a potential difference that is uniquely determined by the temperature of the connection point 43, and a thermocouple is formed. Two lead wires 41, 42
Are drawn to the outside of the bushing 1h by the separate terminals 39 and 40 for drawing the potential, so that the internal temperature can be observed without disassembling the bushing 1h by measuring the potential difference between the terminals 39 and 40. .

If the connection point 43 is arranged on the surface of the capacitor core 4, the temperature of the capacitor core 4 can be measured,
If the connection point 43 is arranged in the insulating medium 5 inside the bushing 1h, the temperature of the insulating medium 5 can be measured. Usually, since a high impedance measuring device is connected to the potential extracting terminal 6, a large current does not flow through the lead wires 41 and 42. Therefore, even if the lead wires 41, 42 are made of a material having high electric resistance to form a thermocouple, an error does not occur in the measured potential of the bushing main circuit due to the voltage drop of the lead wires 41, 42.

The thermoelectromotive force generated by the thermocouple is several meters.
Since it is as small as V, the thermoelectromotive force does not affect the bushing main circuit voltage measurement. Further, if the lead wire 41 is connected to the support fitting 7 to be at the ground potential, the ground voltage of the terminal 40 to which the lead 42 is connected is equivalent to the thermoelectromotive force, so that the temperature during energization can be measured.

[0093]

As described above, according to the first aspect of the present invention.
According to this, an opening is formed in the support member, a terminal for drawing an electric potential from the capacitor of the capacitor core to the outside is provided in the opening, and the terminal is configured as a valve for ins / outs of the insulating medium. Without increasing
Since a mechanism for moving in and out the insulating medium inside can be added, there is no possibility of leakage of the insulating medium or foreign matter such as rainwater entering the inside, and reliability can be improved.

According to a second aspect of the present invention, in the bushing according to the first aspect, the terminal is fixed to the terminal plate, and the terminal plate is provided with a seal member for sealing the insulating medium in the opening of the supporting member. A spring is provided between the support member and the support member, and this spring compresses the seal member to maintain the seal, while the terminal plate is moved to allow the insulating medium to flow in and out. Since the bolt tightening work in the narrow space as described above is eliminated, the bushing can be easily manufactured.

According to a third aspect, in the bushing according to the first aspect, a closed container for shielding the opening from the outside air is attached to the outer periphery of the opening provided in the support member, and the inside of the closed container is attached to the closed container. By allowing either of the insulating medium and the gas for pressurizing the insulating medium to flow in and out, the insulating medium can be taken out without being exposed to the external atmosphere. If the pressure inside the closed container is set higher than the internal pressure of the bushing, the insulating medium or the pressurized gas can be easily injected into the bushing.

According to the present invention, the terminal is provided with the seal member which is compressed by the sealed insulating medium, and the terminal is provided with an external force which opposes the compressive force applied to the seal member by the insulating medium. The soundness of the bushing can be easily investigated by flowing out the insulating medium and measuring the external force applied to the terminal at this time to measure the internal pressure.

According to the present invention, a measuring electric wire for connecting a potential measuring device is connected to the terminal, the connecting portion between the measuring electric wire and the terminal is covered with a hermetically sealed container, and the insulating medium inside is opened from the opening. By flowing out into the closed container to insulate the connection portion, it is not necessary to provide a large-diameter insulating medium injection port in the closed container, and the closed container can be downsized.

According to a sixth aspect of the present invention, in the bushing according to the second or fifth aspects, one of a terminal and a terminal plate provided in the opening via a seal member for sealing an insulating medium is used as a measuring wire. By operating
It is not necessary to provide an inlet / outlet valve operation mechanism penetrating the closed container, the structure of the closed container can be simplified, the sealing surface is reduced, and the leakage probability of the insulating medium can be reduced.

According to the present invention, a support member is made of a conductor, a contact mechanism for electrically connecting the terminals to the support member is provided, and a mechanism for letting the internal insulating medium in and out through an opening provided in the support member. When mechanically interlocking the contact mechanism and the contact mechanism of the terminal and releasing the contact mechanism of the terminal, a high voltage is generated in the atmosphere by insulating the high voltage generated at the terminal by flowing out the insulating medium into the closed container. It is possible to prevent erroneous operation that causes insulation breakdown of terminals and the like.

According to claim 8, two terminals are provided,
One terminal is connected to the capacitor of the capacitor core by the first lead wire, and the other terminal is made of a material having a work function different from that of the first lead wire in the middle of the first lead wire. By configuring the thermocouple by connecting the lead wires of, the potential difference between the two terminals is determined by the temperature of the connecting portion of the two types of lead wires, so that the internal insulating medium The temperature can be measured.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of a first embodiment of a bushing according to the present invention.

FIG. 2 is a sectional view showing a main part of a second embodiment of a bushing according to the present invention.

FIG. 3 is an enlarged sectional view showing a main part of a third embodiment of a bushing according to the present invention.

FIG. 4 is a sectional view showing an essential part of a fourth embodiment of a bushing according to the present invention.

FIG. 5 is a sectional view showing an essential part of a modified example of the fourth embodiment of the bushing according to the present invention.

FIG. 6 is a sectional view showing a main part of a fifth embodiment of a bushing according to the present invention.

FIG. 7 is a sectional view showing a main part of a sixth embodiment of a bushing according to the present invention.

FIG. 8 is a sectional view showing an essential part of a seventh embodiment of a bushing according to the present invention.

FIG. 9 is an enlarged cross-sectional view showing the main parts of an eighth embodiment of a bushing according to the present invention.

FIG. 10 is a sectional view showing an example of a conventional capacitor bushing.

FIG. 11 is an enlarged cross-sectional view showing a structure in the vicinity of a support fitting when a measuring electric wire is connected by a conventional technique.

FIG. 12 is a front view of relevant parts showing a state in which a valve for collecting an insulating medium is separately installed on a support fitting in a conventional bushing.

[Explanation of symbols]

 1,1a to 1h Bushing 2 Insulator tube 3 Central conductor (conducting conductor) 4 Capacitor core 5, 5a Insulating medium 6 Terminal 7 Supporting metal fitting (supporting member) 7a Opening 9 Pressurizing gas 10 External atmosphere 11 Expansion chamber 13 Measurement wire 14 Airtight container 15 Connection part 17 Sealing member 19 Terminal housing part 21 Female screw part 22 Male screw part 23 Terminal plate 24 Spring 25 Holding plate 26 Fixing plate 27 Oil guide port 28 Sealing surface 29 Sealing member 30 Exhaust port 31 Pressurizing cylinder 32 Terminal operating rod 33 Auxiliary spring 34 Injection port 35 Electric wire pushing nut 36 Conductive part 37 Insulating part 38 Terminal support part 39 Terminal 40 Terminal 41 Lead wire (first lead wire) 42 Lead wire (second lead wire) 43 Connection point

Claims (8)

[Claims] 1. A porcelain insulator tube filled with an insulating medium, a current-carrying conductor inserted in the porcelain insulator pipe, and a capacitor core for electric field control, which is arranged on the outer circumference of the conductor and comprises a plurality of capacitors. A bushing in which at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device through a supporting member, an opening is formed in the supporting member, and a potential of the capacitor of the capacitor core to the outside is formed in the opening. Is provided with a terminal to pull out
A bushing in which this terminal is configured as a valve for moving the insulating medium in and out. 2. The bushing according to claim 1, wherein the terminal is fixed to a terminal plate, and a sealing member that seals an insulating medium is attached to the opening of the supporting member, the terminal plate and the terminal plate. A bushing is provided between the support member and the support member, and the spring compresses the seal member to maintain the seal, while moving the terminal plate to allow the insulating medium to flow in and out. . 3. The bushing according to claim 1, wherein a closed container for shielding the opening from the outside air is attached to the outer periphery of the opening provided in the support member, and an insulating medium inside the closed container and A bushing capable of flowing in or out any one of gases for pressurizing the insulating medium. 4. A porcelain insulator tube filled with an insulating medium, a conducting conductor inserted in the porcelain insulator, and a capacitor core for electric field control, which is arranged on the outer periphery of the conducting conductor and comprises a plurality of capacitors. A bushing in which at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device through a supporting member, an opening is formed in the supporting member, and a potential of the capacitor of the capacitor core to the outside is formed in the opening. Is provided with a terminal to pull out
A sealing member that is compressed by the sealed insulating medium is attached to the terminal, and an external force that opposes the compressive force of the insulating medium on the sealing member is applied to the terminal to cause the insulating medium inside to flow out from the opening. A bushing characterized in that an internal pressure is measured by measuring an external force applied to the terminal. 5. A porcelain insulator tube filled with an insulating medium, a conducting conductor inserted in the porcelain insulator, and a capacitor core for electric field control, which is arranged on the outer periphery of the conducting conductor and comprises a plurality of capacitors. A bushing in which at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device through a supporting member, an opening is formed in the supporting member, and a potential of the capacitor of the capacitor core to the outside is formed in the opening. Is provided with a terminal to pull out
A measurement electric wire for connecting a potential measuring device to this terminal is connected, the connection portion between the measurement electric wire and the terminal is covered with a closed container, and the insulating medium inside is allowed to flow out to the closed container from the opening. A bushing, which insulates the connection portion by means of an insulating layer. 6. The bushing according to claim 2 or 5, wherein one of the terminal and the terminal plate provided in the opening via a sealing member for sealing an insulating medium is operated by a measuring electric wire. Bushing characterized by that. 7. A porcelain insulator tube filled with an insulating medium, a current-carrying conductor inserted in the porcelain insulator pipe, and a capacitor core for electric field control, which is arranged on the outer periphery of the conductor conductor and is composed of a plurality of capacitors. A bushing in which at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device via a supporting member, the supporting member has conductivity and an opening is formed, and the capacitor core is provided in the opening. Is provided with a terminal for drawing an electric potential from the capacitor to the outside, and a mechanism for discharging the internal insulating medium to the outside is provided to this terminal, and the terminal is brought into electrical contact with the supporting member during operation by mechanically interlocking with this mechanism. And a contact mechanism for keeping the same potential as the supporting member, and a hermetically sealed container for shielding the opening from the outside air is attached to the outer periphery of the opening. When the contact mechanism of (1) is released, an insulating medium is caused to flow into the closed container to insulate high voltage generated at the terminal. 8. A porcelain insulator tube filled with an insulating medium, a current-carrying conductor inserted in the porcelain insulator pipe, and a capacitor core for electric field control, which is arranged on the outer periphery of the conductor conductor and comprises a plurality of capacitors. A bushing in which at least the porcelain bushing, the current-carrying conductor, and the capacitor core are attached to an electric device through a supporting member, an opening is formed in the supporting member, and a potential of the capacitor of the capacitor core to the outside is formed in the opening. Is provided with two terminals, one of which is connected to the capacitor of the capacitor core by a first lead wire, and the other terminal of which is different from the first lead wire in the middle of the first lead wire. A bushing in which a second lead wire made of a material having a work function is connected to form a thermocouple.