JPH05264825A - Production of optical fiber composite insulator - Google Patents

Abstract

PURPOSE:To decrease expansion or contraction of an org. insulating material during curing and to obtain an optical fiber composite insulator having good transmitting performance of light by wholly preheating the insulator and then heating the org. insulating material at specified temp. for curing. CONSTITUTION:A through hole 2 is formed in the center part of an insulator 1 and at least one optical fiber 3 is introduced to the through hole 2. Then the whole body of the insulator 1 is preheated at >=70 deg.C and the through hole 2 is filled with a specified org. insulating material 4. The insulating material 4 is preferably silicone rubber, urethane rubber, or the like. Then, the insulating material 4 is heated for curing at temp. between >=75 deg.C and <=90 deg.C. Thereby, transmission loss due to expansion or contraction of the insulating material 4 can be prevented and good transmitting performance of the insulator 1 can be obtd. in the temp. range allowed for the use environment of the insulator 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber composite insulator which is mainly used when forming a fault point detection system in a transmission / distribution line network, a substation or the like.

[0002]

2. Description of the Related Art It has been desired to develop a system for promptly detecting and recovering from a fault occurring in a power transmission / distribution line or a substation at a power transmission / distribution line or a power substation due to a lightning accident or the like. Therefore, conventionally, an abnormal current / abnormal voltage detection device using an optical sensor having the Faraday effect and the Pockels effect has been used. In these devices, the sensor attached to the distribution line and the fault point detector need to insulate the transmission voltage and the transmission current. Therefore, it is necessary to perform insulation through an insulator. Therefore, it is necessary to use an optical fiber composite insulator in order to transmit only an optical signal and maintain electrical insulation.

As an optical fiber composite insulator used for this purpose, a through hole is provided in the insulator body, at least one optical fiber is inserted into the through hole to fill the organic insulator, and then the organic insulator is used. It is known that an organic insulating material is cured by heating, and various curing temperatures of the organic insulating material are known, from normal temperature to over 100 ° C. For example, Japanese Patent Application Laid-Open No. 2-106823 discloses that the curing temperature is 60 ° C. or higher when the organic insulator is silicone rubber. As a method for heat-curing an organic insulator, there is known a method in which an insulator at room temperature is filled with the organic insulator and then the entire insulator is heated to cure the organic insulator.

[0004]

The organic insulator filled in the insulator through-hole expands and contracts as the ambient temperature changes.
At this time, with the curing temperature of the organic insulator as a boundary, the optical fiber is compressed in the insulator radial direction on the high temperature side as the organic insulator expands. On the low temperature side, the optical fiber is compressed due to the contraction of the organic insulator. Therefore, when the insulator becomes hot due to direct sunlight in summer and the influence of electricity, etc., if the curing temperature of the organic insulator is too low, the optical insulator expands, causing minute distortion (microbending) in the optical fiber. However, there is a problem that the optical transmission loss increases. vice versa,
If the temperature of the insulator becomes low due to the cold wind in winter, and the curing temperature of the organic insulator is too high, the optical insulator contracts, causing minute distortion (microbending) in the optical fiber.
There is also a problem that the optical transmission loss increases.

When the insulator is heated at room temperature and then the whole insulator is heated, the heat capacity of the insulator is large and it takes a long time to heat the insulator, so that the temperature of the insulator is lower than the intended curing temperature. There is a problem that the optical transmission loss increases when the insulator is hardened and the temperature of the insulator becomes high.

The object of the present invention is to solve the above problems,
An object of the present invention is to provide a method for manufacturing an optical fiber composite insulator that can achieve good optical transmission performance.

[0007]

According to the method for manufacturing an optical fiber composite insulator of the present invention, a through hole is provided in an insulator body, and at least one optical fiber is inserted into the through hole and sealed by an organic insulator. In a method for manufacturing an optical fiber composite insulator consisting of a single substance or a stack of two or more insulators, after preheating the entire insulator to 70 ° C. or higher, the organic insulator is filled in the insulator through holes, and the filled organic insulator is It is characterized by being heated and cured at a temperature of 75 ° C. or higher and 90 ° C. or lower.

[0008]

In the above structure, when the organic insulator is heated at a temperature of 75 ° C. or higher and 90 ° C. or lower, optical transmission loss occurs due to expansion of the organic insulator at high temperature, and optical loss due to contraction of the organic insulator at low temperature It is possible to prevent the occurrence of transmission loss,
It is possible to obtain an optical fiber composite insulator having a good optical transmission performance within a temperature change range in the usage environment of the insulator.
In addition, since the insulator is preheated to 70 ° C. or higher and then the insulator insulator is filled in the insulator through-hole and the organic insulator is cured by heating, the temperature of the insulator is 75 ° C. or higher and 90 ° C. or lower. It is possible to obtain an optical fiber composite insulator which can be cured by heating within the range and has a good optical transmission performance. Here, the curing temperature of the organic insulating material is limited to 75 ° C. or more and 90 ° C. or less, and the preheating temperature is limited to 70 ° C. or more, as will be apparent from the examples described later, in other temperature ranges. When,
This is because good optical transmission loss cannot be obtained at low temperatures and high temperatures.

[0009]

1 and 2 are longitudinal sectional views showing the structure of an example of an optical fiber composite insulator to which the present invention is applied.
Shows an example of a single product, and FIG. 2 shows an example of two-stage stacking. In FIGS. 1 and 2, 1 is an insulator, 2 is a through hole provided in a central portion of the insulator 1, 3 is an optical fiber inserted into the through hole 2, and 4 is an optical fiber 3 sealed in the through hole 2. It is an organic insulator for. The method of manufacturing the optical fiber composite insulator of the present invention will be described below with reference to FIG. First, the through hole 2 is provided in the central portion of the insulator 1. next,
At least one, 2 in this embodiment, is provided inside the through hole 2.
The optical fiber 3 of the book is inserted. In this state, the whole insulator 1 is kept at a predetermined temperature of 70 ° C. or higher and preheated,
A predetermined organic insulator 4 is filled in the through hole 2. As the organic insulator 4, silicone rubber, urethane rubber,
Epoxy resin and the like can be preferably used. Then, the filled organic insulator 4 is heated and cured at a temperature of 75 ° C. or higher and 90 ° C. or lower to obtain an optical fiber composite insulator.

An actual example will be described below. In order to investigate the influence of the preheating temperature of the whole insulator and the curing temperature of the organic insulator, these conditions were variously changed as shown in Table 1 below to obtain an optical fiber composite insulator, and the influence was evaluated. .. At that time, the total length of the insulator is 950m.
m, body diameter 105 mm, cap diameter 205 mm, and through hole inner diameter 5-10 mm. As the optical fiber, an optical fiber having a quartz glass in the light guide portion coated with an ultraviolet curable resin was used. In manufacturing, after inserting the optical fiber into the through hole of the insulator, the entire insulator was preheated at a predetermined temperature of 70 ° C. or higher for 3 hours or more.

After the preheating of the insulator is completed, the temperature of the insulator is prevented from lowering to 70 ° C. or lower, and liquid silicone rubber is put in the through hole of the insulator so that the degree of vacuum is 5 torr or less and the pressure is 3 to 10 kgf / cm ^2. It was vacuum pressed in. Here, when the preheating temperature of the insulator and the curing temperature of the silicone rubber are different, it is preferable to fill the silicone rubber after several hours or more have passed since the temperature of the heating furnace was set to the predetermined curing temperature. If the preheating temperature is higher than 90 ° C., it takes time for the insulator to reach a predetermined rubber curing temperature, so that the preheating temperature is 90%.
It is preferably not higher than ° C. After the filling of the silicone rubber was completed, the silicone rubber was heated and cured at the curing temperature for 3 hours or more. Finally, the optical transmission loss at the low temperature (−20 ° C.) and the high temperature (80 ° C.) of the obtained optical fiber composite insulator was obtained as an average value of 10 levels.
Results are shown in FIG. The optical transmission loss was determined as the ratio of the amount of light transmission at each temperature (−20 ° C. and 80 ° C.) to the amount of light transmission at room temperature.

[0012]

[Table 1]

From the results of FIG. 3, the inventive examples in which the preheating temperature is 70 ° C. or higher and the curing temperature of the organic insulator is 75 ° C. or higher and 90 ° C. or lower It can be seen that the optical transmission loss amount is excellent at both low temperature and high temperature as compared with the example.

[0014]

As is apparent from the above description, according to the present invention, since the whole insulator is preheated to 70 ° C. or higher, the organic insulator is heated and cured at a temperature of 75 ° C. to 90 ° C. Further, expansion and contraction of the organic insulating material at the time of curing can be reduced, and an optical fiber composite insulator having good light transmission performance can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of an example of an optical fiber composite insulator targeted by the present invention.

FIG. 2 is a vertical cross-sectional view showing the structure of another example of the optical fiber composite insulator targeted by the present invention.

FIG. 3 is a graph showing the relationship between the curing temperature of an organic insulator and the optical transmission loss in the present invention.

[Explanation of symbols]

 1 insulator 2 through hole 3 optical fiber 4 organic insulator

Claims (1)

[Claims] 1. An optical fiber composite insulator in which a through hole is provided in an insulator body, and at least one or more optical fibers are inserted into the insulator body and sealed by an organic insulating material, or two or more insulators are stacked. In the manufacturing method, after the entire insulator is preheated to 70 ° C. or higher, an organic insulator is filled in the insulator through hole, and the filled organic insulator is 75 ° C. or higher and 90 ° C. or higher.
A method for manufacturing an optical fiber composite insulator, which comprises heat-curing at the following temperature.