JPH08339920A - Bushing - Google Patents

Abstract

PURPOSE: To achieve the simplification of the maintenance and inspection work and to contribute to the shortening of the maintenance time and the reduction of the maintenance cost by estimating tan δ of a single bushing body without separating and shearing the bushing from the main body of an electric apparatus. CONSTITUTION: A divided-voltage measuring foil 12 is provided at the outside of a conductive electrode 3. Furthermore, a grounding foil 13 is provided at the outside of the measuring foil. For these foils, thermocouples 14a and 14b are connected to the divided-voltage measuring foil 12, and thermocouples 16a and 16b are connected to the grounding foil 13. Furthermore, a temperature measuring instrument 18, which measures the temperatures of the divided-voltage measuring foil 12 and the grounding foil 13, are connected to the thermocouples 14b and 16b through relay terminals 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor type bushing, and more particularly to a bushing which simplifies maintenance work by measuring a temperature change inside the bushing.

[0002]

2. Description of the Related Art Generally, capacitor type bushings are used for the output of electric equipment having a relatively high voltage such as transformers and gas-sealed switchgears. This bushing controls an electric field in the axial direction and the radial direction, and a conventional example having a structure as shown in FIG. 9 is known.

As shown in the figure, the airtight container 11 is filled with an insulating medium 10 such as insulating oil and the core insulating portion 4 is provided.
Is housed. The core insulating portion 4 includes a central conductor 1 for energization and an organic insulator 2 continuously wound around the outer periphery of the central conductor 1 (relatively thin insulator such as insulating paper).
And a plurality of conductive electrodes 3 which are concentrically arranged in the organic insulator 2 in a predetermined size. Such a core insulating portion 4 forms a capacitor between the central conductor 1 and the conductive electrode 3.

A support metal fitting 5 having a flange 5a is fixed to the outer periphery of the longitudinal intermediate portion of the core insulating portion 4. An upper porcelain bushing 6 is fixed to the upper side of the support fitting 5 so as to cover the core insulating portion 4. Further, an expansion chamber 7 is fixed on the upper porcelain bushing 6. On the other hand, a lower porcelain tube 8 is also fixed to the lower end of the support fitting 5 so as to cover the core insulating portion 4. Further, a lower clamp 9 is attached to the lower end of the lower porcelain tube 8. The base end of the central conductor 1 is fixed to the lower clamp 9. In addition, the tip of the center conductor 1 is connected to the expansion chamber 7 via a gasket (not shown).
Has been penetrated into the atmosphere and is being drawn to the atmosphere.

[0005]

By the way, in a bushing using an organic insulator as a main insulator, it is required to maintain and secure its electrical insulation property for a long period of time. To meet this requirement, it is necessary to stabilize the organic insulator. That is, when the organic insulator deteriorates, the dielectric loss tangent tan δ of the bushing increases,
This causes the temperature of the organic insulator to rise. When the temperature of the organic insulator rises, the tan δ may increase more and thermal runaway may occur, and thermal runaway causes dielectric breakdown. Therefore, in order to confirm the stability of the organic insulator, maintenance and inspection work such as periodically measuring tan δ of the bushing is important.

However, ta during operation of the bushing is
In order to measure nδ, it is necessary to remove the bushing from the main body of the electric device such as the transformer and form the bushing as a single body before measuring nδ. In such a conventional bushing, a work for disconnecting the bushing from the main body of the electric device is added, resulting in complicated maintenance and inspection work. as a result,
There were problems such as long maintenance time and high maintenance cost.

The present invention has been proposed to solve the above problems, and its main purpose is to estimate tan δ of a bushing alone without disconnecting the bushing from the electric equipment body. The purpose of the present invention is to provide a bushing that simplifies maintenance and inspection work and contributes to shortening maintenance time and maintenance cost.

Another object of the present invention is to provide a bushing capable of measuring a temperature change inside the bushing by a thermocouple. Another object of the present invention is to provide a bushing capable of measuring a temperature change inside the bushing by using a liquid crystal scintillator whose light transmittance changes with temperature. Still another object of the present invention is to provide a bushing capable of measuring a temperature change inside the bushing by using a thermosensitive color changing member whose color changes with temperature.

[0009]

In order to achieve such an object, the invention of claim 1 has a core insulating portion housed in a closed container, and the core insulating portion has a central conductor for conducting electricity. In a bushing composed of an organic insulator for insulating the central conductor and a plurality of conductive electrodes arranged concentrically in the organic insulator, a temperature measurement for measuring the temperature of the core insulating portion during operation. It is characterized by having means.

According to a second aspect of the present invention, the conductive electrode has a ground foil and a partial pressure measuring foil, a thermocouple is connected to the ground foil and the partial pressure measuring foil, and the thermocouple is connected to the core. It is characterized in that it is drawn out of the insulating portion and connected to the temperature measuring means.

According to a third aspect of the present invention, a light-emitting body is provided on the ground foil of the conductive electrode, a transmission hole for transmitting light from the light-emitting body is formed in the ground foil, and the transmission hole is exposed to light depending on temperature. A liquid crystal scintillator having a variable transmittance, a light receiving body for receiving light from the liquid crystal scintillator, and a temperature conversion unit for obtaining the temperature of the grounding foil from the amount of light received by the light receiving body as the temperature measuring means. Is characterized by.

According to a fourth aspect of the present invention, a light emitter that emits light is provided in the central conductor, the liquid crystal scintillator is provided so as to transmit the light from the light emitter, and a light receiver that receives the light transmitted through the liquid crystal scintillator. And a temperature conversion device for determining the temperature of the central conductor from the amount of light received by the light receiver as the temperature measuring means.

According to a fifth aspect of the present invention, there is provided a core insulating portion housed in a closed container, and the core insulating portion has a central conductor for conducting electricity, an organic insulator for insulating the central conductor, and In a bushing consisting of a plurality of conductive electrodes concentrically arranged in an organic insulator, a thermosensitive color changing member whose color changes with temperature is provided on the surface of the core insulating portion, and the hermetically sealed container is provided in the hermetically sealed container. A window portion for visually observing the thermosensitive color change member from outside is provided.

[0014]

In the invention of claim 1, the temperature measuring means measures the temperature of the core insulating portion during operation. Therefore, from the temperature change of the core insulating portion, it is possible to estimate the increase amount of tan δ which could not be measured without using the bushing alone. Therefore, in the unlikely event that an abnormal temperature rise occurs in the core insulating portion, and if this is measured by the temperature measuring means, it can be expected that tan δ of the bushing is increasing, and the possibility of dielectric breakdown of the bushing increases. It is believed that Therefore, the damage can be minimized by stopping the operation of the bushing and investigating the bushing before the electric device body is affected.

Moreover, since the temperature measuring means can measure the temperature inside the bushing without removing the bushing from the main body of the electric device to form a single body, the work of disconnecting the bushing from the main body of the electric device can be omitted. Minutes,
Maintenance and inspection work of the bushing can be simplified.

According to the second aspect of the invention, the thermocouple detects the temperature change of the grounding foil and the partial pressure measuring foil, and the temperature measuring means measures this.

According to the third aspect of the invention, when the temperature of the ground foil changes, the light transmittance of the liquid crystal scintillator changes. Therefore, the amount of light transmitted through the liquid crystal scintillator changes, and the amount of light received by the light receiver changes. Based on this change in the amount of received light, the temperature conversion device can determine the temperature of the ground foil.

In the third aspect of the invention, the temperature of the grounding foil is obtained, whereas in the fourth aspect of the invention, the temperature of the central conductor can be obtained by using the liquid crystal scintillator and the temperature conversion device.

In the invention of claim 5, when the temperature of the surface of the core insulating portion changes, the color of the thermosensitive discoloration member changes accordingly. By visually observing the color change of the heat-sensitive color change member through the window, it is possible to confirm the temperature change on the surface of the core insulating portion even from the outside of the closed container.

[0020]

【Example】

(1) Configuration of Embodiment One embodiment of the present invention will be specifically described below with reference to FIGS. This embodiment includes claim 2. FIG. 1 is a lateral cross-sectional view of an essential part of this embodiment applied to the XX cross-sectional view of the bushing shown in FIG. 9, and FIG. 2 is the surface of the core insulating portion 4. 3 is a graph showing an example of a temperature distribution curve from to the surface of the central conductor 1, and FIG. 3 is a transverse cross-sectional view of a main part when the PD 20 is used in FIG. In this embodiment, the same members as those in the conventional example shown in FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, a divided voltage measuring foil 12 is provided on the outer side of the conductive electrode 3, and a grounding foil 13 is further provided on the outer side thereof. Among them, the divided voltage measuring foil 12 is used for the drawer bushing 17 except when the bushing divided voltage is always used for measurement or protection.
It is grounded externally via.

The characteristic feature of the present embodiment is that thermocouples 14a and 14b are connected to the divided voltage measuring foil 12 and thermocouples 16a and 16b are connected to the grounding foil 13.
The thermocouples 14a, 14b, 16a, 16b are formed by joining both ends of dissimilar metal wires, and are configured so that a thermoelectromotive force (potential difference) is generated between the contacts due to a temperature difference.

A relay terminal 15 is attached to the support fitting 5, and the ends of the thermocouples 14a and 16a are connected to the relay terminal 15. Furthermore, the relay terminal 15
Are connected to thermocouples 14b and 16b, both of which extend to the outside of the support fitting 5 and are connected to the temperature measuring device 18. The temperature measuring device 18 measures the temperatures of the divided voltage measuring foil 12 and the grounding foil 13 from the thermoelectromotive force of the thermocouples 14b and 16b. The thermocouple 14b is connected to the thermocouple 14a, and the thermocouple 16b is connected to the thermocouple 16a.

(2) Operation and effect of the embodiment The operation of this embodiment having the above-mentioned structure is as follows. That is, the thermocouples 14a and 14b detect the temperature change of the partial pressure measuring foil 12, and further the thermocouples 16a and 16b.
Captures the temperature change of the ground foil 13. Then, the temperature measuring device 18 measures these temperature changes. In this way, the temperature measuring device 18 measures the temperature of the core insulating portion 4 at two different points in the radial direction, and estimates the temperature distribution inside the core insulating portion 4 from FIG.

According to the present embodiment as described above, by grasping the temperature change of the partial pressure measuring foil 12 and the grounding foil 13, the increase amount of the tan δ of the bushing, which has been conventionally measured after being made as a single body, can be obtained. It is possible to make a prediction without removing the bushing from the main body of the electric device. Therefore, if the core insulating part 4 has an abnormal temperature rise and this is understood from the measurement result of the temperature measuring device 18, the tanning of the bushing will occur.
Considering that δ is increasing, it is possible to perform a work to minimize the damage, such as stopping the operation of the bushing and investigating the bushing before the electric device body is affected.

Moreover, the temperature measuring device 18 does not have to be a single unit by removing the bushing from the main body of the electric device, but the core insulating portion 4
Since the temperature can be measured, it is possible to omit the work of disconnecting the bushing from the electric device body in the maintenance and inspection work of the bushing. Therefore, the maintenance and inspection work of the bushing can be simplified, the maintenance time can be significantly shortened, and the maintenance cost can be reduced.

By the way, as shown in FIG. 3, when the PD 20 is connected to the drawer bushing 17 to constantly measure the divided voltage, the thermocouple 14b is removed and the relay terminal 15 is covered with the cap 19 to insulate the earth. Secure. That is, when the drawer bushing 17 is used, a voltage of several kV is applied between the divided voltage measuring foil 12 and the grounding foil 13, so that the temperature measuring device 18 uses the divided voltage measuring foil 1.
This is because it is impossible to measure the temperature of 2.

(3) Other Embodiments In the above embodiment, thermocouples are connected to the ground foil and the divided voltage measuring foil, but the present invention is not limited to such an embodiment. Examples including the following configurations are also included.

Embodiment for Measuring Temperature of Ground Foil by Liquid Crystal Scintillator ... See FIGS. 4 and 5 This embodiment includes claim 3, FIG. 4 is a longitudinal sectional view of an essential portion, and FIG. 5 is FIG. 2 is a vertical sectional view showing the overall configuration of the embodiment shown in FIG.

As shown in FIG. 4, a luminous body 23 is provided between the organic insulator 2 and the ground foil 13. Ground foil 1
3, a transmission hole 25 for transmitting light from the light emitting body 23 is formed at a position corresponding to the light emitting body 23. The liquid crystal scintillator 22 is provided so as to face the light emitting body 23 with the transmission hole 25 interposed therebetween. The liquid crystal scintillator 22 changes its light transmittance depending on the temperature. Outside the liquid crystal scintillator 22, a light receiver 21 that receives the light transmitted through the liquid crystal scintillator 22 is provided. An optical cable 24 is connected to each of the light emitter 23 and the light receiver 21.

Further, as shown in FIG. 5, the optical cable 24
Is drawn out of the core insulating portion 4 via the relay terminal 15, and the arithmetic device 25, the temperature conversion device 26, the storage device 27, and the alarm device 28 are sequentially connected. The calculation device 25 is a device that performs a calculation that omits changes in the outside air temperature and the temperature of the insulating medium 10, and the temperature conversion device 26 is a device that obtains the temperature of the ground foil 13 from the amount of light received by the light receiver 21. Further, the storage device 27 stores data on the normal temperature state of the ground foil 13, and is configured to compare this data with the data on the actual temperature state of the ground foil 13 from the temperature conversion device 26. . Further, the alarm device 28 issues an alarm when an abnormal temperature rise occurs in the ground foil 13.

In the above embodiment, the light emitting body 23
After passing through the transmission hole 25, the light from the liquid crystal scintillator 22
However, the light transmittance of the liquid crystal scintillator 22 changes in the ground foil 13 according to the temperature change. Therefore, when the temperature of the ground foil 13 changes, the amount of light that passes through the liquid crystal scintillator 22 changes, and the amount of light received by the light receiving body 21 that receives the light from the liquid crystal scintillator 22 also changes. The change in the amount of received light is carried as data by the optical cable 24 to the arithmetic unit 25, and the arithmetic unit 25 performs the arithmetic operation omitting the outside air temperature and the temperature change of the insulating medium 10. Then, the temperature conversion device 26 obtains the temperature of the ground foil 13 from the calculation result of the calculation device 25. At this time, the storage device 27 stores the temperature data obtained by the temperature conversion device 26 and the ground foil 13 stored in the storage device 27 itself.
Compare with normal temperature data. Further, as a result of comparing the two data, when an abnormal temperature rise occurs in the ground foil 13, the alarm device 28 operates and issues an alarm. According to such an embodiment, an abnormal temperature rise in the ground foil 13 can be surely grasped, and the reliability of the bushing is further improved.

Example in which the temperature of the central conductor is measured by a liquid crystal scintillator. See FIGS. 6 and 7. This example includes claim 4, and the temperature of the ground foil 13 is obtained in the above example. On the other hand, the temperature of the central conductor 1 is obtained here. 6 is a vertical cross-sectional view of the main part, and FIG. 7 is a vertical cross-sectional view showing the overall configuration of the embodiment shown in FIG.

As shown in FIG. 6, a photoconductor 21 is attached to the central conductor 1, and a liquid crystal scintillator 22 is fixed on the photoconductor 21. Liquid crystal scintillator 2
A light-emitting body 23 is fixed on the surface 2. An optical cable 24 is connected to each of the light emitter 23 and the light receiver 21. Further, as shown in FIG. 7, the optical cable 24 is pulled out to the outside of the core insulating portion 4 via the relay terminal 15, and like the embodiment shown in FIG.
5, temperature conversion device 26, storage device 27 and alarm device 2
8 are sequentially connected.

In this embodiment, the liquid crystal scintillator 22 is used to obtain the temperature of the central conductor 1 to obtain the same effects as those of the other embodiments in which the temperature of the ground foil 13 is measured. You can

Embodiment for Monitoring Internal Temperature of Core Insulation Part by Using Thermo Label ... See FIG. 8 This embodiment includes claim 5, and FIG. 8 is a longitudinal sectional view of an essential part. As shown in FIG. 8, on the surface of the core insulating portion 4, a thermo label 29 whose color changes with temperature is provided. Further, the support fitting 5 is provided with a window portion 30 through which the thermolabel 29 can be seen. The window 30 is configured such that a seat 31 is provided on the support fitting 5 and a lid 32 is fixed to the seat 31 via a gasket (not shown) to hermetically seal.

In such an embodiment, when the surface temperature of the core insulating portion 4 changes, the color of the thermo label 29 changes accordingly. Therefore, by visually observing the change of this color from the window 30, The change in the surface temperature of the core insulating portion 4 can be monitored from the outside of the metal fitting 5. Therefore, there is an effect that the temperature state of the surface of the core insulating portion 4 can be always grasped.

[0038]

As described above, according to the bushing of the present invention, by estimating the increase amount of tan δ that cannot be measured during the bushing operation from the temperature change inside the bushing obtained by the temperature measuring means, the bushing insulation can be obtained. Since the condition can be monitored and the temperature inside the bushing can be measured without using a single bushing, it is not necessary to disconnect the bushing from the main body of the electrical equipment, greatly shortening the maintenance time and reducing the maintenance cost. Can be cheap.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a bushing according to an embodiment of the present invention.

FIG. 2 is a graph showing an example of a distribution curve of the internal temperature of the core insulating portion.

FIG. 3 is a lateral cross-sectional view of a main part when a PD 20 is used in FIG.

FIG. 4 is a longitudinal cross-sectional view of the main part of another embodiment of the present invention, in which the temperature of the ground foil is measured using a liquid crystal scintillator.

5 is a vertical cross-sectional view showing the overall configuration of the embodiment shown in FIG.

FIG. 6 is a longitudinal sectional view of a main part of another embodiment of the present invention in which the temperature of the central conductor is measured using a liquid crystal scintillator.

7 is a longitudinal sectional view showing the overall configuration of the embodiment shown in FIG.

FIG. 8 is a vertical cross-sectional view of a main part of another embodiment of the present invention, in which the thermolabel is used to monitor the internal temperature of the core insulating portion.

FIG. 9 is a vertical sectional view of a conventional general capacitor type bushing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Central conductor 2 ... Organic insulator 3 ... Conductive electrode 4 ... Core insulating part 5 ... Supporting metal 5a ... Flange 6 ... Upper insulator tube 7 ... Expansion chamber 8 ... Lower insulator tube 9 ... Lower clamp 10 ... Insulating medium 11 ... Sealed container 12 ... Foil for measuring divided voltage 13 ... Ground foil 14a, 14b, 16a, 6b ... Thermocouple 15 ... Relay terminal 17 ... Drawer bushing 18 ... Temperature measuring device 19 ... Cap 20 ... PD 21 ... Photoreceptor 22 ... Liquid crystal scintillator 23 ... Light emitter 24 ... Optical cable 25 ... Computing device 26 ... Temperature conversion device 27 ... Storage device 28 ... Warning device 29 ... Thermo label 30 ... Window part 31 ... Seat 32 ... Lid

Claims (5)

[Claims] 1. A core insulating portion housed in a hermetically sealed container, the core insulating portion having a central conductor for conducting electricity, an organic insulator for insulating the central conductor, and a middle portion of the organic insulator. A bushing comprising a plurality of concentrically arranged conductive electrodes, wherein the bushing is equipped with temperature measuring means for measuring a temperature of the core insulating portion during operation. 2. The conductive electrode has a grounding foil and a partial pressure measuring foil, a thermocouple is connected to the grounding foil and the partial pressure measuring foil, and the thermocouple is external to the core insulating portion. The bushing according to claim 1, wherein the bushing is pulled out and connected to the temperature measuring means. 3. A light-emitting body is provided on the ground foil of the conductive electrode, a transparent hole for transmitting light from the light-emitting body is formed in the ground foil, and the light transmittance of the transparent hole changes with temperature. A liquid crystal scintillator is provided, a light receiving body for receiving light transmitted through the liquid crystal scintillator is provided, and a temperature conversion device for obtaining the temperature of the grounding foil from the amount of light received by the light receiving body is provided as the temperature measuring means. The bushing according to claim 1 or 2. 4. A light-emitting body that emits light is provided on the center conductor, the liquid crystal scintillator is provided so as to transmit light from the light-emitting body, and a light-receiving body that receives light transmitted through the liquid crystal scintillator is provided. The bushing according to claim 1, 2 or 3, further comprising a temperature conversion device for measuring the temperature of the central conductor from the amount of light received by the light receiver as the measuring means. 5. A core insulating part housed in a hermetically sealed container, the core insulating part having a central conductor for conducting electricity, an organic insulator for insulating the central conductor, and an organic insulator among the organic insulators. In a bushing consisting of a plurality of conductive electrodes arranged concentrically with each other, a thermosensitive color change member whose color changes depending on temperature is provided on the surface of the core insulating portion, and the thermosensitive color changing member from the outside of the hermetic container to the thermosensitive discoloring member. A bushing provided with a window for visually observing the sex change member.