JP2002025371A - Bushing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bushing which can make collection work of insulating oil in a short time. SOLUTION: The bushing is provided with an upper porcelain tube 3, a support fitting 4 at a ground potential, a bushing main body integrally structured with a lower porcelain tube and a lower clamp combined in an axial direction, a center conductor 1 for electricity arranged on a center axial line of the bushing body, an insulating oil 9 filled in the bushing body, an expansion chamber 7 which seals in inert gas in a space for absorbing pressure fluctuation due to expansion or compression of the insulating oil, a switching valve 10 fitted to the support fitting in free communication with the insulating oil in the bushing body and closing during oil pumping, an oil tank 12 connected to the switching valve and normally storing the insulating oil in the bushing body flowing in through the switching valve, and a valve 13 which, fitted at an upper part of the oil tank, opens during pumping of the insulating oil stored in the oil tank or during replenishing of the insulating oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing having an improved structure for extracting insulating oil.

[0002]

2. Description of the Related Art In the case of electrical equipment such as a transformer and a gas-sealed switchgear, when a high-voltage lead conductor is led out to the outside, the electrical equipment case and the conductor are insulated from each other and are kept airtight. Therefore, a bushing is used. 60 of these
For high voltages of about KV or more, oil-filled bushings filled with insulating oil are widely used.

FIG. 6 is a view showing a general structure of an oil-filled bushing. This bushing is composed of a bushing main body including a center conductor 21 arranged on the center axis thereof, an upper insulator 22 covering the periphery of the center conductor, a support fitting 26 and a lower insulator 27. And this center conductor 21
The space between the bushing and the bushing body is filled with insulating oil 23. An expansion chamber 24 is provided at the upper part of the bushing body. The expansion chamber 24 is used to reduce the influence of expansion and contraction of the insulating oil 23, and the upper space is filled with an inert gas for absorbing pressure fluctuation. Further, the support metal 26 at the ground potential at the lower part of the bushing main body.
Is connected to an on-off valve 25 for sampling the insulating oil 23.

In order for the oil-filled bushing to be able to maintain a normal function without causing a failure, it is necessary to periodically grasp the degree of deterioration of the insulating oil and to take appropriate measures. . In general, when an insulating oil generates muddy substances by oxidation, not only does the insulating ability decrease, but also the cooling performance decreases. This phenomenon is likely to occur when the temperature of the insulating oil is high. Also, when insulating oil absorbs moisture, the dielectric strength is significantly reduced. For this reason, it is necessary to periodically collect the insulating oil, measure its properties (eg, acid value, viscosity, moisture content, etc.) and replace the insulating oil if the insulating oil is significantly deteriorated.

Conventionally, to collect the insulating oil 23 from the bushing, the insulating oil 23 is sampled through the on-off valve 25. However, even when the on-off valve 25 is opened, the insulating oil does not flow out. May be. This is because the expansion chamber 2
If the inert gas of No. 4 dissolves into the insulating oil 23 over time, the pressure in the gas space decreases, and the pressure in the bushing becomes negative with respect to the atmosphere. Therefore, in order to prevent such a problem from occurring, a valve (not shown) attached to the expansion chamber 24 is opened when the insulating oil 23 is collected, and the pressure in the inert gas space is returned to the atmospheric pressure. Then, after the pressure in the bushing is eliminated from becoming negative with respect to the atmosphere, the on-off valve 25 is opened to collect the insulating oil.

[0006]

As described above, when the insulating oil 23 is collected in the conventional oil-filled bushing, the pressure in the bushing is returned to the atmospheric pressure by opening the valve of the expansion chamber 24 as described above. Had to be kept. However,
Since the expansion chamber 24 is located at a high place, scaffolds, wreckers, cranes and the like for working at high places are required for working at high places, and it takes a long time to prepare for collecting insulating oil. After collecting the insulating oil from the bushing, it is necessary to replenish the same amount of the deaerated new insulating oil as the collected insulating oil. Since the replenishment is performed through the valve of the chamber 24, the operation requires a long time. On the other hand, since it is necessary to stop the electrical equipment such as transformers and gas-sealed switchgear for safety, these operations must be stopped for a long time. I had to.

[0007] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bushing capable of easily and easily collecting and replenishing insulating oil and reducing the downtime of electric equipment. Aim.

[0008]

(1) In order to solve the above-mentioned problems, a bushing according to the present invention comprises an upper porcelain pipe, a support fitting at a ground potential, a lower porcelain pipe, and a lower clamp connected in an axial direction to be integrated. A bushing body,
A central conductor for energization arranged on the central axis of the bushing main body, insulating oil filled in the bushing main body, and a pressure fluctuation caused by expansion and contraction of the insulating oil arranged on the upper insulator tube. An expansion chamber in which an inert gas is sealed in a space for absorption, an on-off valve which is provided in the support fitting so as to be able to circulate with the insulating oil in the bushing body and is closed at the time of oil collection, and which is connected to the on-off valve; An oil collecting tank for storing insulating oil in the bushing body flowing through the on-off valve; and an oil collecting tank provided at an upper portion of the oil collecting tank, which is opened at the time of collecting the insulating oil accumulated in the oil collecting tank or refilling the insulating oil. And a valve provided with the valve.

[0009] With this configuration, it is possible to perform the oil collecting operation without requiring the work at a high place.

(2) A bushing according to the present invention comprises a bushing body integrally formed by connecting an upper porcelain tube, a support fitting at a ground potential, a lower porcelain tube, and a lower clamp in an axial direction, and a central shaft of the bushing body. A central conductor for energization arranged on a wire, insulating oil filled in the bushing main body, and a space arranged above the upper porcelain tube for absorbing pressure fluctuation due to expansion and contraction of the insulating oil. An expansion chamber filled with an inert gas, an on-off valve that is provided in the support fitting so as to be able to circulate with the insulating oil in the bushing body and is closed at the time of oil collection, and is connected to the on-off valve, and always flows through the on-off valve. An oil collecting tank for accumulating insulating oil in the bushing body; a valve provided at an upper portion of the oil collecting tank and opened when pressurizing the oil collecting tank; Provided in the lower part, and a oil extraction valve and which is opened when collecting the insulating oil of the oil extraction tank.

[0011] With the above configuration, the time required for the oil collecting operation can be shortened.

(3) The bushing according to the present invention is the bushing according to (1) or (2), wherein the oil collection tank is provided with insulating oil in a bushing main body at a plurality of positions at different heights of the support bracket. The configuration is such that they are connected via on-off valves provided respectively so as to be able to flow.

With this configuration, when the convection of the insulating oil occurs due to the temperature difference, the insulating oil in the oil collecting tank and the bushing main body are connected to each other by using the on-off valve communicating at two or more locations above and below as a flow path. Is replaced with the insulating oil. Therefore, since the properties of the insulating oil collected in the oil collecting tank and the properties of the insulating oil in the bushing main body can be made uniform, the degree of deterioration of the insulating oil in the bushing main body can be determined by analyzing the properties of the insulating oil collected in the oil collecting tank. Can be accurately grasped.

(4) Next, in the bushing according to the present invention, in the bushing according to any one of (1) to (3), the oil collecting tank can monitor oil discoloration from an oil thermometer or from outside. In this configuration, at least one of the viewing windows is provided.

With this configuration, the state of the insulating oil can be grasped without oil sampling.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a first embodiment of a bushing according to the present invention in a half section.

In FIG. 1, reference numeral 1 denotes a central conductor, and a core insulating portion 2 composed of an organic insulator and a conductive electrode is formed on the outer peripheral surface of the central conductor 1. A bushing body 11 is integrally formed around the center conductor 1 by integrally connecting the upper porcelain tube 3, the support fitting 4, the lower porcelain tube 5, and the lower clamp 6 in the axial direction. The expansion chamber 7 is fixed. In this case, the upper insulator 3, the support fitting 4, the lower insulator 5, the lower clamp 6, and the expansion chamber 7 are joined via a gasket (not shown). Further, the interior of the bushing body 11 and the expansion chamber 7 is filled with insulating oil 9, and the upper space of the expansion chamber 7 is filled with an inert gas 17 such as nitrogen gas, so that the thermal expansion and contraction of the insulating oil 9 are prevented. It is a gas space for relaxation. Further, the expansion chamber 7 is provided with an exhaust sealing valve 8 for exhausting or sealing the inert gas 17. On the other hand, the support fitting 4 at the ground potential has a communication hole for collecting insulating oil, and an oil collection tank 12 is connected to the communication hole via an on-off valve 10. This oil collecting tank 12 is shown in FIG.
As shown in detail, a valve 13 for communicating with the atmosphere and collecting or replenishing the insulating oil is provided at an upper portion, and the sealing of the oil collecting tank 12 can be opened by the valve 13.

In the bushing having such a configuration, by opening the on-off valve 10 at all times, the inside of the oil collecting tank 12 is in a state where the insulating oil 9 during the bushing flows in and is filled. In such a state, to collect the insulating oil 9, the on-off valve 10 is closed, the bushing body 11 is isolated from the oil collecting tank 12, and then the valve 13 above the oil collecting tank 12 is opened. It is done by collecting. When replenishing the amount of the degassed new insulating oil corresponding to the amount of the collected insulating oil, the new insulating oil is injected through the valve 13 with the on-off valve 10 kept closed. When the oil in the oil collecting tank 12 is filled, the valve 13
Is closed to open the on-off valve 10 and the insulating oil 9 in the bushing is closed.
And distribute it.

As described above, according to the present embodiment, the insulating oil in the bushing main body 11 can be collected from the oil collecting tank 12 connected to the support fitting 4 at the ground potential via the on-off valve 10. It is not necessary to collect the insulating oil from the expansion chamber 7 as in the related art, and the oil collecting operation can be performed in a short time. Therefore, there is no need to stop the electric equipment for a long time.

FIG. 3 is a structural view showing a second embodiment of the bushing according to the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the oil collecting tank 1
An oil sampling valve 14 is connected to a lower portion of the fuel tank 2, and a valve 13 provided at an upper portion of the oil sampling tank 12 is used as a valve for filling an inert gas.

In the bushing having such a configuration, to collect the insulating oil 9, first, the on-off valve 10 is closed,
An inert gas is injected from the valve 13 to pressurize the inside of the oil collecting tank 12, and then, when the oil collecting valve 14 is opened, the insulating oil in the oil collecting tank 12 is quickly collected by the pressurized pressure (not shown). Can be transferred to Therefore, by shortening the contact time between the insulating oil and the air, oxidation of the insulating oil by the air can be reduced, and the deterioration state of the insulating oil can be grasped more accurately.

FIG. 4 is a structural view of a bushing showing a third embodiment of the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

This bushing is an improvement of the first and second embodiments. The bushing body 11 is connected between the upper and lower side surfaces of the oil collecting tank 12 and the support fittings 4 by open / close valves 10a and 10b, respectively. This allows the insulation oil to flow in and out.

In this structure, when the convection of the insulating oil occurs due to a temperature difference, the on-off valves 10a and 10b communicating with the upper and lower side surfaces of the oil collecting tank 12 are used as a flow path to form the insulating oil in the oil collecting tank. And the insulating oil in the bushing main body are exchanged, so that the properties of the insulating oil in the oil collecting tank 12 and the properties of the insulating oil in the bushing main body can be made uniform. Therefore, by analyzing the properties of the insulating oil collected in the oil collecting tank, the degree of deterioration of the insulating oil in the bushing main body can be accurately grasped. This on-off valve is 2
With the above arrangement, replacement of the insulating oil can be further promoted.

FIG. 5 is a structural view showing a fourth embodiment of the bushing according to the present invention. The same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

In the fourth embodiment, the oil collecting tank 12 is provided with an oil temperature gauge 15 and a viewing window 16 for monitoring the color change of the oil from outside.

With this configuration, it is possible to confirm the discoloration due to the deterioration of the oil temperature and the insulating oil at the time of the patrol inspection, so that the abnormality of the bushing can be prevented beforehand. In the above embodiment, only one of the oil temperature gauge 15 and the viewing window 16 may be provided in the oil collecting tank 12.

Further, if at least one of the oil thermometer 15 and the viewing window 16 is provided in the oil collecting tank 12 having a plurality of on-off valves according to the third embodiment, circulation of the insulating oil is promoted. So the insulation oil in the oil tank is
Further, highly accurate information on the properties of the insulating oil can be obtained.

The temperature of the insulating oil can be monitored not only at the time of inspection but also at all times by using a sensor.

[0031]

As described above, according to the present invention, it is possible to carry out oiling and replenishing work in the vicinity of the lower support bracket without having to work in the expansion chamber at a high place of the bushing. Since the working time can be reduced, it is not necessary to stop the electric equipment for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a bushing according to the present invention.

FIG. 2 is a configuration diagram showing a first embodiment of a bushing according to the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of a bushing according to the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of a bushing according to the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of a bushing according to the present invention.

FIG. 6 is a diagram showing a configuration of a conventional bushing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Center conductor 2 ... Core insulating part 3 ... Upper insulator 4 ... Support metal fitting 5 ... Lower insulator 6 ... Lower clamp 7 ... Expansion chamber 8 ... Exhaust sealing valve 9 ... Insulating oil 10 ... On-off valve 10a ... On-off valve 10b ... On-off valve DESCRIPTION OF SYMBOLS 11 ... Bushing main body 12 ... Oil sampling tank 13 ... Valve 14 ... Oil sampling valve 15 ... Oil temperature gauge 16 ... Viewing window 17 ... Inert gas 19 ... Partition valve 21 ... Center conductor 22 ... Upper insulator tube 23 ... Insulating oil 24 ... Expansion chamber 25 open / close valve 26 support bracket 27 lower insulator tube

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Takashi Ishii 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term inside the Toshiba Hamakawasaki Plant (reference) 2G050 AA02 BA03 BA04 BA10 CA01 DA01 EA01 EC05 5E059 JM03 JM09 5G331 AA08 BC19 DA01 FA03

Claims (4)

[Claims] 1. A bushing body integrally formed by connecting an upper porcelain pipe, a support fitting at a ground potential, a lower porcelain pipe, and a lower clamp in an axial direction, and an energizing power supply arranged on a central axis of the bushing main body. A central conductor, insulating oil filled in the bushing body, and an expansion filled with an inert gas in a space disposed above the upper porcelain tube for absorbing pressure fluctuations caused by expansion and contraction of the insulating oil. A chamber, an on-off valve provided in the support fitting so as to be able to circulate with the insulating oil in the bushing body, and closed at the time of oil collection; and an insulating oil in the bushing body connected to the on-off valve and always flowing through the on-off valve. An oil collecting tank that accumulates, and a valve that is provided at an upper portion of the oil collecting tank and that is opened when the insulating oil accumulated in the oil collecting tank is collected or the insulating oil is supplied. Bush to be characterized. 2. A bushing body integrally formed by connecting an upper porcelain pipe, a support fitting at a ground potential, a lower porcelain pipe, and a lower clamp in an axial direction, and an energizing means arranged on a central axis of the bushing body. A central conductor, insulating oil filled in the bushing body, and an expansion filled with an inert gas in a space disposed above the upper porcelain tube for absorbing pressure fluctuations caused by expansion and contraction of the insulating oil. A chamber, an on-off valve provided in the support fitting so as to be able to circulate with the insulating oil in the bushing body, and closed at the time of oil collection; and an insulating oil in the bushing body connected to the on-off valve and always flowing through the on-off valve. An oil collecting tank that accumulates; a valve provided at an upper part of the oil collecting tank, which is opened when pressurizing the oil collecting tank; and a valve provided at a lower part of the oil collecting tank, Bushing, characterized in that a oil extraction valve which is opened when collecting the insulating oil in the tank. 3. The bushing according to claim 1, wherein the oil collecting tank is provided at a plurality of positions at different heights of the support bracket so as to be able to communicate with the insulating oil in the bushing body. A bushing connected via the bushing. 4. The bushing according to claim 1, wherein the oil collecting tank is provided with at least one of an oil thermometer and a viewing window that can monitor discoloration of oil from outside. Bush to be characterized.