JPH022335B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fault point search method for an optical submarine cable system.

Optical submarine cables have a distance of several tens of kilometers in each repeater.

Occurrence of cable failure, e.g. cable breakage,
In the event that seawater enters the cable or insulation failure occurs, it is important to search for the failure point, and measurements must be taken to locate it.

Optical submarine cable systems are different from conventional coaxial submarine systems, so a new fault point detection method is required.

[Conventional technology]

In conventional coaxial submarine cable systems, cable failure points are searched as follows.

In other words, if the fault is a break in the cable, this is done by measuring the capacitance between the inner and outer conductors, and if there is seawater intrusion or poor insulation, the resistance is measured between the inner and outer conductors. I'll turn over and go. In addition, in order to simultaneously search for breaks and shorts in the cable, a method is used in which measurement pulses are sent into the coaxial line and the time difference between the sent pulse and the pulse reflected back at the fault point is measured. .

[Problem that the invention seeks to solve]

In the optical submarine cable system, the structure of the optical cable is that the line for transmitting communication information is an optical fiber, and the only conductor is a tubular power supply conductor for feeding power to the submarine repeater.

Unlike conventional coaxial cables, which have internal conductors, optical cables do not have a ground circuit.

Therefore, even if an attempt is made to search for a fault from a submarine end station, there is a problem in that the fault-search measuring device cannot be connected to the optical submarine cable.

[Means for solving problems]

The above problems are solved by the present invention.

According to the present invention, the optical submarine cable on land includes:
A coaxial external conductor is provided on the outside of the power supply tubular conductor, and at the part where the cable is inserted into the sea, the outer conductor is brought into conductive contact with seawater to prevent interference due to the coaxial line formed by the power supply tubular conductor and seawater. Enables point search.

[Function] The outer conductor installed in the section from the terminal station to the seawater forms a coaxial line together with the power supply conductor of the optical submarine cable, and by making a good conductive connection with the coaxial line made in the seawater, the measuring instrument can be connected to the end of the ocean. It can be connected to the coaxial line at the station. Cutting the cable involves cutting the power supply conductor, and intrusion of seawater into the cable will result in poor insulation or short circuit between the seawater, which serves as the external conductor, and the power supply line, so the point of failure must be searched for using conventional measuring instruments. can be carried out.

〔Example〕

Hereinafter, the gist of the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 is a block diagram showing the configuration of a fault point search method for an optical submarine cable system. In the figure, 1 is a terminal station, 2 is a measuring device for fault point detection, 3 is an optical fiber line of an optical submarine cable, 4 is a tubular conductor for power supply,
Reference numeral 5 indicates an outer conductor provided on the land portion of the optical submarine cable, 6 indicates an end portion of the outer conductor for making a good conductive connection with the seawater at the contact portion with the seawater, and 7 indicates the seawater. The measuring device 2 has its ground terminal connected to an external conductor 5 provided on the land portion of the optical submarine cable, and the other measuring terminal connected to the power supply conductor of the optical submarine cable. The thus connected measuring instruments can be used to measure capacitance, insulation resistance, or switch to pulse echo testing in the same manner as in the past, thereby making it possible to search for faults in the optical submarine cable system.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to easily and reliably search for a fault point in an optical submarine cable system, which was originally considered difficult, and its effects are significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a connection configuration of a fault point search method for an optical submarine cable system according to the present invention. In the figure, 1 is a terminal station, 2 is a measuring device for fault point detection, 3 is an optical fiber, 4 is a power supply conductor, 5 is an external conductor, 6 is an end of the external conductor that contacts seawater, and 7 is seawater. .

Claims (1)

[Claims] 1 Optical submarine cables on land are provided with a coaxial outer conductor outside the power supply tubular conductor, and at the part where the cable enters the sea, the outer conductor is brought into conductive contact with seawater, and the power supply tubular conductor and seawater are connected to each other. A fault point search method for an optical submarine cable system, which is characterized by making it possible to search for fault points using a coaxial line made by a company.