JPH066323Y2 - Insulator with built-in optical fiber - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to an insulator with a built-in optical fiber in which an optical fiber for transmitting a signal obtained from a transmission line side to a ground side is embedded in the insulator. is there.

(Prior Art) An insulator with a built-in optical fiber in which a through hole having a small hole diameter is formed in the shaft center of an insulator, an optical fiber is penetrated therein, and a resin such as an epoxy resin is filled, is disclosed in Japanese Patent Laid-Open No. 60-158.
It is conventionally known as shown in Japanese Patent Publication No. 402, etc. This resin plays an important role in preventing leakage current from flowing along the surface of the optical fiber and in reducing the surface leakage insulation distance of the insulator. Due to the difference in the coefficient of thermal expansion between the resin and epoxy resin, the resin such as epoxy resin largely squeezes out in the axial direction to apply tension to the optical fiber, and the adhesiveness with the porcelain is lost. It was Further, if it is attempted to increase the adhesiveness between the resin and the porcelain to prevent the resin from squeezing out, the inner surface pressure of the insulator becomes too high at a high temperature, and the insulator may be cracked due to thermal expansion of the resin.

(Problems to be solved by the invention) The present invention solves the above-mentioned conventional problems and prevents the resin from protruding in the axial direction even at a high temperature, thereby changing the transmission loss of the optical fiber or the insulator. It was completed for the purpose of providing an optical fiber-embedded insulator that does not deteriorate the penetration withstand voltage characteristics and has no risk of damage to the insulator due to thermal expansion.

(Means for Solving the Problems) The present invention inserts an optical fiber core wire into the through hole formed in the insulator body in the axial direction, and fills both ends of the through hole with non-foaming resin. Further, the invention is characterized in that a portion other than both end portions in the through hole is filled with a foamed resin having an excellent expansion / contraction property alone or together with a non-foaming resin.

(Embodiment) Next, the present invention will be described in detail with reference to the illustrated embodiment.
In the first embodiment shown in FIG. 1, (1) is a porcelain insulator main body, (2) is a through hole formed in the central portion of the insulator, and (3) is inside the through hole (2). It is the inserted optical fiber core wire. Both ends of the through hole (2) are filled with a non-foaming resin (4) such as silicone resin or epoxy resin. The non-foaming resin (4) in this portion has a role of maintaining airtightness in order to prevent outside air, moisture and the like from entering the inside of the through hole (2). Since an electric field is concentrated on both ends of the insulator, it is preferable to use a resin having a high insulation performance such as silicone resin or epoxy resin. On the other hand, the resin other than the both ends of the through hole (2) is filled with the foamed resin (5). Foam resin
As (5), foamed polystyrene resin, foamed polyethylene resin, foamed silicone resin or the like is used. The foamed resin (5) has excellent expansion and contraction properties and can be easily expanded or contracted depending on the pressure, so that even when the non-foaming resin (4) is thermally expanded at high temperature, 5) absorbs this, and the protrusion of the non-foaming resin (4) and the disconnection of the optical fiber core wire (3) due to this are prevented. The inner peripheral surface of the through hole (2) is preferably made of a non-glazing agent in order to improve the adhesiveness with the resin.

In the second embodiment shown in FIG. 2, the non-foaming resin (4) is filled at both ends of the through hole (2) as in the first embodiment, but the through hole ( The portion other than both ends of 2) is filled with the foamed resin (5) in combination with the non-foaming resin (4). That is, in order to prevent the poor adhesion of the foamed resin (5), only the portion in contact with the inner peripheral surface of the through hole (2) and the portion in contact with the optical fiber core wire (3) are non-foamed resin (4). ,
The other part is filled with the foamed resin (5).

(Operation) In this structure, the insulator main body (1) supports the transmission line and other high-voltage electric wires, and the signals detected by the voltage sensor, current sensor, temperature sensor, etc. attached to the electricity applying section are optically transmitted. The signal is converted into a signal and then used to transmit the signal to the ground side through the optical fiber core wire (3) inserted into the through hole (2), as in the conventional case. However, in the present invention, the non-foaming resin (4) is provided at both ends of the through hole (2) and the foaming resin (5) is provided at the other portions.
Since it is filled alone or together with the non-foaming resin (4), even when the entire insulator is heated to a high temperature and the non-foaming resin (4) is thermally expanded, the foamed resin (excellent in expansion and contraction due to the internal pressure caused by it) ( 5) shrinks and absorbs thermal expansion. As a result, in the present invention, the non-foaming resin (4) at both ends of the insulator body (1) does not protrude outside or exert a tension on the optical fiber core wire (3), and the optical fiber core wire (3) is disconnected. And the tension does not change the transmission loss. Further, in the present invention, since the adhesiveness between the non-foaming resin (4) filled in the both ends of the through hole (2) and the insulator body (1) is not lost, the through voltage resistance of the entire insulator is reduced. The characteristics are not deteriorated, and there is no possibility that the optical fiber core wire (3) is deteriorated by salt, dust, water, corrosive outside air, or the like. Moreover, the rise in the internal pressure of the through hole (2) is moderated by the gas inside the bubbles of the foamed resin (5), so the insulator body (1)
Is not damaged by internal pressure, foam resin (5)
Since the filling amount of the non-foaming resin (4) can be reduced by the amount filled with the above, this also has an advantage such as an increase in internal pressure can be prevented.

(Effect of the Invention) As is apparent from the above description, the present invention absorbs the thermal expansion of the non-foaming resin by filling the portion other than the both ends of the through hole with the foaming resin, and the disconnection of the optical fiber core wire, It is possible to reliably prevent a change in transmission loss, a decrease in penetration withstand voltage characteristics of an insulator, a deterioration of an optical fiber core wire, and the like, and to eliminate the risk of insulator damage. Therefore, the present invention has an extremely great practical value as an insulator with a built-in optical fiber that eliminates the conventional problems.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing a first embodiment of the present invention, and FIG. 2 is a central longitudinal sectional view showing a second embodiment of the present invention. (1): Insulator body, (2): Through hole, (3): Optical fiber core wire,
(4): Non-foaming resin, (5): Foaming resin.

Claims (3)

[Scope of utility model registration request] 1. A through hole formed in the insulator body (1) in the axial direction.
While inserting the optical fiber core wire (3) inside the (2), both ends of the through hole (2) are filled with a non-foaming resin (4), and other than both ends inside the through hole (2). An insulator with a built-in optical fiber, characterized in that a portion is filled with a foamed resin (5) having excellent expansion / contraction properties, either alone or together with a non-foaming resin. 2. An insulator with a built-in optical fiber according to claim 1, wherein the foamed resin (5) is a polystyrene foam resin, a foamed polyethylene resin or a foamed silicone resin. 3. The optical fiber built-in insulator according to claim 1, wherein the non-foaming resin (4) is a silicone resin or an epoxy resin.