JPH08289455A - Joint of power cable - Google Patents

Abstract

PURPOSE: To detect abnormality in a joint constantly with high sensitivity by winding a nonmagnetic metal tube incorporating an optical fiber for measuring the temperature around the outer shield layer formed on a joint reinforcing insulation layer thereby forming an outer electrode and then taking out the nonmagnetic metal tube to the outside of outer case at the joint. CONSTITUTION: A joint reinforcing insulation layer 4 is formed on a cable insulator 1 and an outer shield layer 2 is formed on the opposite sides. A nonmagnetic metal tube 10 incorporating an optical fiber 11 for measuring the temperature is then wound around the outer shield layer 2 thus forming an outer electrode 8. A joint outer case 6, having the opposite ends coupled hermetically with the cable sheath 3, is disposed on the outside of the reinforcing insulation layer 4 and the inner space of the outer case 6 is filled with insulation oil. The nonmagnetic metal tube 10 incorporating an optical fiber 11 is taken out to the outside of the outer case 6 and the internal optical fiber 11 is connected with an optical fiber temperature measuring unit and a monitoring system. With such structure, abnormality in the joint can be detected constantly with high sensitivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable connecting portion capable of highly sensitively detecting heat generation due to an abnormality in a power cable connecting portion such as an OF cable or a CV cable.

[0002]

2. Description of the Related Art As a conventional method of detecting an abnormality in a power cable connecting portion, for example, in the case of an OF cable, a method of collecting oil from the connecting portion and analyzing the oil to evaluate the generation of flammable gas is used. In the case of a CV cable, it was evaluated by measuring partial discharge.

[0003]

In the above-mentioned conventional abnormality detection method, it is difficult to always carry out in the case of the OF cable, the measurement is not always established even in the CV cable, and the abnormality other than the discharge is not known. there were.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and provides a connecting portion of a power cable capable of detecting abnormality in the connecting portion constantly and with high sensitivity. Is formed by winding a non-magnetic metal tube with a built-in temperature measurement optical fiber around the external shielding layer on the reinforcing insulation layer of the connection part to form an external electrode, and taking out the non-magnetic metal tube to the outside of the connection part external case. There is something.

[0005]

In the above-mentioned power cable connecting portion of the present invention, the non-magnetic metal tube containing the temperature measuring optical fiber is wound around the outer shielding layer portion on the connecting portion reinforcing insulating layer, and moreover, outside the connecting portion. It is taken out of the case. Therefore,
Utilizing an optical fiber inside a metal tube taken out of the external case of the connection part, injecting pulsed light from one end of the optical fiber, and then detecting Raman scattered light included in the light irregular light. With this, it is possible to constantly detect the temperature of the surface of the reinforcing insulating layer of the connection portion, and it is possible to detect heat generation due to an abnormality in the connection portion. In addition, the temperature of the connection part can be measured when the cable is overloaded, and the integrity of the cable and the connection part can be evaluated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a) is a longitudinal sectional view of a main part of a concrete example of an OF cable connecting portion to which the present invention is applied, and FIG. 1 (b) is a transverse sectional view of a non-magnetic metal tube containing an optical fiber. is there. In the drawings, 1 is a cable insulator formed by winding an oil-impregnated paper, 2 is an outer shielding layer of the cable, 3 is a corrugated aluminum sheath, and a cable sheath such as a lead sheath. Cable insulator 1
A reinforcing insulating layer 4 formed by winding oil-impregnated paper is formed on the upper part to enclose a conductor connecting portion (not shown), and taper parts on both sides of the reinforcing insulating layer 4 are usually an external shielding layer formed by dense winding of copper wire. However, in the present invention, instead of the copper wire, as shown in FIG. 1B, a non-magnetic metal tube 10 such as a stainless pipe having an optical fiber for temperature measurement is wound. External electrode 8
Is formed. A connecting portion outer case 6 is provided outside the reinforcing insulating layer 4, both ends of which are hermetically connected to the cable sheath 3 by lead work or the like, and an inner space of the outer case 6 is filled with insulating oil. . Further, the non-magnetic metal tube 10 containing the optical fiber 11 is taken out of the outer case 6, and the internal optical fiber 11 is connected to an optical fiber temperature measuring device and a monitoring system.

The non-magnetic metal tube 10 having the optical fiber 11 built therein is filled with O in the outer case 6 in order to eliminate the influence when the metal tube 10 is broken.
It is desirable to fill the same insulating oil as the F cable insulating oil, or an insulating material that does not affect the performance of the cable even if mixed.

FIG. 2 is a vertical cross-sectional view of the essential parts of a concrete example of the CV cable connection part to which the present invention is applied. In the drawings, 1
Is a cable insulator of cross-linked polyethylene, 2 is an outer semiconductive layer of the cable, and 3 is a cable sheath of aluminum, polyvinyl chloride or the like. A reinforcing insulating layer 4 is formed on the cable insulator 1 by encapsulating a conductor connecting portion (not shown) by extrusion molding of a plastic material such as cross-linked polyethylene, and the outer periphery of the connecting portion is semiconductive. A layer 5 is provided. Then, a non-magnetic metal tube 10 such as a stainless pipe having the optical fiber 11 for temperature measurement built therein is wound on the outer semiconductive layer 5 to form an outer electrode. A connecting portion outer case 6 is provided outside the reinforced insulating layer 4, both ends of which are hermetically connected to the cable sheath 3, and a space 7 inside the outer case 6 is filled with a compound. Further, the non-magnetic metal tube 10 containing the optical fiber 11 is taken out of the outer case 6, and the internal optical fiber 11 is connected to an optical fiber temperature measuring device and a monitoring system.

The non-magnetic metal tube 10 containing the optical fiber 11 is preferably filled with a compound 12 of the same quality as the compound filled in the outer case 6, but in the case of a CV cable, it is filled. It doesn't matter if you don't.

[0010]

As described above, according to the connection portion of the power cable of the present invention, it is possible to constantly detect the heat generation due to the abnormality inside the connection, and the connection portion of the cable during the overload operation can be detected. Since the temperature rise can be measured, the integrity of cables and connections can be evaluated. Therefore, when it is used for a connection portion such as an OF cable line or a CV cable line, the maintenance and inspection of the cable line becomes easy and the reliability of the cable line is significantly improved.

[Brief description of drawings]

FIG. 1 (a) is a vertical cross-sectional view of a main part of a specific example of an OF cable connection part to which the present invention is applied, and FIG. 1 (b) is a cross-sectional view of a non-magnetic metal tube containing an optical fiber. is there.

FIG. 2 is a vertical cross-sectional view of a main part of a specific example of a CV cable connection part to which the present invention is applied.

[Explanation of symbols] 1 cable insulator 2 cable outer shield layer 3 cable sheath 4 reinforcing insulation layer 5 connecting part semi-conductive layer 6 connecting part outer case 7 outer case inner space 8 outer electrode 10 non-magnetic metal tube 11 optical fiber 12 Filling

Claims (2)

[Claims] 1. An external electrode is formed by winding a non-magnetic metal tube containing a temperature measuring optical fiber around an external shielding layer section on a connecting section reinforcing insulating layer to form an external electrode. The power cable connection, which is characterized by being taken out. 2. The electric power cable connecting portion according to claim 1, wherein the non-magnetic metal pipe is filled with the same filling material as the space portion inside the connecting portion outer case.