JPH05199645A - Lubrication structure - Google Patents

Abstract

PURPOSE:To detect insulation oil positively in safety by providing an outer tube having gas detecting section and an inner tube longer than the outer tube and fixing the inner tube such that the lower part thereof is inserted into a joint box such as an OF cable. CONSTITUTION:The lubrication structure comprises an outer tube 43 having a gas detecting chamber 56 at the upper part thereof, and an inner tube 41 longer than the outer tube 43, wherein the inner tube 41 is fixed such that the lower part thereof is inserted into a joint box part of an OF cable, for example. The inner tube 41 is made of fluororesin excellent in oil resistance, gas permeability, heat resistance and mechanical characteristics. The outer tube 43 is provided with a large number of heat radiation fins 44 and secured through a seal packing 34 to the upper oil inlet 32 of the joint box part 30. According to the constitution, insulation oil 35 can be detected in safety without causing leakage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil circulation structure of a sensor for detecting dissolved gas in oil, which is attached to an OF cable joint box.

[0002]

2. Description of the Related Art A technique has been developed in which a gas dissolved in insulating oil in an OF cable is separated by some method and the gas is detected by an electrical or optical method. In other words, although it is gas sensing, such gas detectors, that is, sensors, have reached the practical level at present.
However, it should be confirmed here that the gas sensor is in direct contact with the filter, although the gas dissolved in the insulating oil is separated by the oil-gas separator called a filter. It is desirable that the insulating oil has movement such as convection.

For example, if the above sensor is applied to the joint box portion of an OF cable, it will be attached to each of the upper and lower oiling holes provided in the joint box portion. In order to perform the above-mentioned convection of the insulating oil, a convection method in which two oil-filling holes are connected by one pipe and the temperature change above and below the joint box is utilized is conceivable.

That is, in FIG. 5 showing the joint box portion, the joint boxes 12 and 12 'of the left and right OF cables 11 and 11' have respective flanges 13 and 1, respectively.
3'is butted and connected. Then, the upper port oil inlet 14a of the right joint box 12 'and the lower port oil inlet 14b of the left joint box 12 are connected by an oil circulation pipe 15 via a gas sensor 16.

Incidentally, this technical means is the transformer case 2 of the transformer 23 in the oil-filled transformer shown in FIG.
This is the same as the method of connecting the upper and lower sides of 1 with a cooling pipe 22 to form a communication pipe structure and using natural convection of the insulating oil 24 to mitigate the temperature rise of the insulating oil 24. That is, when the insulating oil 24 is heated by the internal transformer 23, the transformer case 2
1 rises to the upper part, but is guided to the cooling pipe 22 here, cooled by the outside air, flows downward, and forms convection that flows to the lower part of the transformer 23, and this is repeated.

[0006]

By the way, such a conventional technique has the following problems.

In the element structure of the OF cable,
Although it can be applied to the ordinary joint box part, there is no problem if the oil circulation pipe 15 is made of a plastic material for the insulating joint box part, but if a metal pipe is used, an electrical insulating part is provided in the middle. It is necessary to provide. However, there is a problem in that the plastic material lacks reliability.

Joint box part lower port lubrication port 14b
When connecting the oil circulation pipe 15 and the oil circulation pipe 15, there is a risk that the outside air (air) will be held.

Since there are at least two joints of the oil circulation pipe 15, there is more concern about in-leak (liquid entry) of the outside air compared to one.

[0011] The appearance is damaged and the product value is reduced.

Providing the oil circulation pipe 15 along the joint box portion is troublesome and reduces workability in a narrow human hole or the like.

If the plastic pipe described in the above item is used, the plastic material is more or less preferable because it allows gas to pass therethrough. That is, O ₂ and N ₂ in the air permeate into the interior in proportion to time.

The present invention has been made in view of the above circumstances, and solves the technical problem that it is difficult to apply to a real line with an oil circulation structure of a dissolved gas separation / detection device, which is a conventional idea. The purpose is to provide a highly reliable oil circulation structure.

[0014]

According to the present invention, in a structure in which a device for separating / detecting dissolved gas in insulating oil is attached to a joint box part, an outer tube having a gas detecting part holding a sensor in the upper part, and an inner tube The oil circulation structure is characterized in that an inner pipe longer than the outer pipe length is provided at the bottom, and the lower part is attached so as to be inserted into a joint box portion such as an OF cable. The inner tube is made of a fluorine resin material having excellent oil resistance, gas permeability, heat resistance and mechanical properties. A large number of heat radiation fins are provided on the outer pipe and are fixed to the upper inlet oil inlet of the joint box portion by a screw joint or the like.

[0015]

[Function] Basically, the mounting position of the sensor is only the joint box part upper port oiling port, and the pipe to be attached to this oiling port is formed in a double structure, and the heated insulating oil is passed through the inner pipe to raise the insulation. The oil makes a U-turn in the filter part and returns while cooling the outer pipe (between the inner pipe and the outer pipe). And by providing cooling radiating fins on the outer tube,
It improves the flow effect of insulating oil.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing an oil circulation structure of a dissolved gas separation / detection device according to an embodiment, in which an oil circulation part composed of a double pipe is installed in an existing pipe joint 32 which is an upper oil injection port of an existing joint box part 30. 40 and a sensor unit 50 by a light detection method
Is attached. In addition, in FIG. 5 described in the related art, it is installed in the joint box upper port oiling port 14a.

The oil circulation portion 40 is composed of an outer pipe 43 and a double pipe of an inner pipe 41 inserted therein, and the lower end portion of the outer pipe 43 is fitted into the pipe joint 32 of the joint box and sealed. The cap nut 35 is configured to be screwed and fixed via the packing 34.

A sensor case 5 is provided on the outer tube 43.
1 is integrally formed, and the inside thereof is downwardly oriented with a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (P
It is divided into two chambers, an upper chamber and a lower chamber, by an oil-gas separator composed of a sintered plate 52 provided with a coating layer 53 of FA). The upper part becomes a gas detection chamber 56, and optical fibers 55 are connected to the optical connectors 54 provided on both sides thereof. The lower part is a chamber for returning the insulating oil 35.

Cooling radiating fins 44 are formed on the outer periphery of the outer tube 43, the lower end of which is inserted into a pipe joint 32 provided on the upper portion of the case 31 of the joint box portion 30, and a cap nut is inserted via a seal packing 34. It is fixed by screwing in 33.

Inside the outer tube 43, flare portions 42 and 42 'are formed at the upper and lower ends to form a funnel-like flare portion, which is made of a fluororesin material excellent in oil resistance, gas permeability, heat resistance and mechanical characteristics. The pipe 41 is inserted so as to form a double pipe, the upper portion forms a stepped flange at the peripheral edge shown in FIG. 2A, and the inner pipe 4 is formed at the center.
A spacer 45 having one insertion hole 92 and a plurality of insulating oil passage holes 91 around the insertion hole 92 is fitted and fixed so as to fulfill the functions of centering and slip-off prevention. 2B, the lower part is fixed by fitting a lower spacer 45 'having a through hole 92 of the inner pipe 41 in the center and a plurality of insulating oil passage holes 91 around the inner hole, as shown in FIG. 2B.

The inner tube 41 is made of a fluoropolymer such as tetrafluoroethylene resin (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), PFA, etc., and has a funnel shape at the upper and lower ends. Flare portions 42, 42 'that are widened to the upper side of the outer tube 43 are formed.
The lower flare portion 42 ′ is inserted in the lower folding chamber of the joint 1 so as to project into the case 31 of the joint portion 30.

Next, the procedure for mounting the oil circulation structure thus constructed will be described. First, the joint box part 3
Loosen the cap nut 33 of the upper port oil injection port of 0, and insert the inner pipe 41, to which the upper spacer 45 and the lower spacer 45 'having the centering and slip-off preventing functions are attached, into the outer pipe 43. Then, the cap nut 34 is tightened through the seal packing 34 to easily assemble.

Next, FIG. 3 shows an overall view after assembly. That is, the left and right cable cores 66 are connected by the cable connecting portion 63. A joint box 64 is provided around the connecting portion 63, and the space between the cable bodies 65 is made liquid-tight by the lead portion 61 and the anticorrosion reinforcing portion 62.
Is filled and insulated. In this figure, the gas detection sensor 71 is attached to the upper inlet oil inlet of the joint box portion 64, but the lower end of the plastic inner pipe 41 is inserted into the joint box 64. A flare portion 42 'is formed at the lower end of the inner pipe 41, and is open to the insulating oil in the joint box portion 64.

On the premise of such an arrangement, the circulating mechanism of insulating oil will be described below with reference to FIG. In FIG. 4, which is a cross-sectional view of the joint portion of the OF cable, the conductor 84 at the center is heated by energization,
The insulating oil 81 heated through the insulating paper 83 rises, is cooled by the wall portion 82 of the copper joint box portion on the outer periphery, moves downward, and starts convection as shown by the arrow.

Therefore, when the inner pipe 41 is located above the joint box portion 30 as shown in FIG. 1, if there is dissolved gas in the joint box portion due to the convection of the insulating oil, it is diffused and gradually begins from the flare portion 42 'at the lower end. Inner tube 41
It moves up inside. The dissolved gas that has moved is SUS
An oil-gas separation filter 53 formed by coating a sintered plate 52 made of 316 with a layer of a fluorine-based tetrafluoroethylene-perfluoroalkylvinyl ether copolymer.
Through the gas detection cell 56. On the other hand, the insulating oil that has reached the above-mentioned filter is stored in the inner pipe 41 as indicated by the arrow.
By moving around the flare portion 42 at the upper end and moving downward through the oil passage hole 91 of the upper spacer 45, the fin 44
While cooling is accelerated by the lower spacer 4 along the pipe wall
Return to the joint box through the oil passage hole 91 in 5 '. At this time, the flare 42 acts to bring the insulating oil 35 into contact with the entire surface of the filter 53, and enhances the gas separation effect. Hereinafter, the movement of the insulating oil will be continuously repeated. Although an optical method has been described as a method for detecting the separated gas, it goes without saying that this may be detected by an electric gas sensor.

[0026]

As described above, according to the oil circulation structure of the present invention, the sensor section for detecting the dissolved gas in the insulating oil has the simple structure of the oil circulation section including the double pipe and the existing upper port is provided. Only by mounting it on the oil inlet, it is possible to reliably detect. Further, it can be made extremely compact, and no device such as a pump for forcibly circulating insulating oil is required, and effective continuous measurement can be performed only by convection of insulating oil. Then, it suffices to connect to only one existing upper-port lubrication port, and it is possible to safely detect the insulating oil without the risk of leakage.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an oil circulation structure according to an embodiment of the present invention,

2A and 2B are cross-sectional views of an upper spacer and a lower spacer,

FIG. 3 is an overall view of the joint box part after assembly,

FIG. 4 is a transverse cross-sectional view showing the convection state of insulating oil in the joint box section,

FIG. 5 is an overall view showing an oil circulation structure of a conventional dissolved gas separation / detection device,

FIG. 6 is a vertical sectional view showing an oil circulation structure of a conventional oil-filled transformer.

[Explanation of symbols]

 30 Joint box part 31 Joint box case 32 Pipe joint (upper inlet) 33 Cap nut 34 Seal packing 41 Inner pipe 42, 42 'Inner pipe flare part 43 Outer pipe 45, 45' Vertical spacer 50 Oil gas separation / detection Device sensor 51 Sensor case

Claims (3)

[Claims] 1. An outer tube having a detection chamber holding a sensor section in an upper part in a structure in which a device for separating and detecting dissolved gas in insulating oil is attached to a joint box section, and an inner tube longer than the outer tube length in the outer tube. The oil circulation structure is characterized by being installed so that the lower part thereof is inserted into a joint box part such as an OF cable. 2. The oil circulation structure according to claim 1, wherein a fluorine-based resin having excellent oil resistance, gas permeability, heat resistance, and mechanical properties is used as the material of the inner tube. 3. The oil circulation structure according to claim 1, wherein an outer pipe is attached to the joint box oil injection port by a screw joint or the like, and a large number of heat radiation fins are provided on the outer periphery of the outer pipe.