JPS6156652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-station submarine cable communication system in which a submarine cable is branched under the sea to enable communication between a plurality of land stations.

In the conventional submarine cable communication system, communication between two opposing stations is generally performed using, for example, a group-specific two-wire FDM system using a submarine coaxial cable. There is also a proposal to place a branching device in the underwater part to enable mutual communication between three stations, but this requires a complex configuration such as wave generators and modulators to branch signals within the branching device. It has not yet been put into practical use.

In recent years, submarine optical cable communication systems using optical fibers as communication media generally accommodate multi-core optical fibers because the optical fibers are small in diameter and lightweight. In this case, mutual communication between multiple stations is possible by placing submarine cable branching and connecting equipment underwater and connecting each station with optical fibers depending on the number of optical fibers. becomes. However, if the submarine section is long and repeaters need to be inserted, a system configuration that takes into consideration the power supply to these repeaters is required. Conventionally, in a submarine cable system connecting two stations, a power supply line is housed in the submarine cable, the power supply section of each repeater is connected in series by the above-mentioned power supply line, and constant current power is supplied from one land station. A constant current remote power supply method is used in which the ground is connected to the ground at the other land station, and the return path is the earth. When applying this power feeding method to a multi-station system,
If the number of stations is even, it is possible to supply power to all repeaters in the same way as in the past by determining appropriate opposing stations and connecting the feed lines between the opposing stations within the branching device. However, since the transmission path of a repeater that receives power and the power feeding path do not necessarily match, a failure in one power feeding path may cause a failure not only between the corresponding stations but also the transmission path between other stations. arise. If the number of stations is an odd number, it is necessary to supply power from at least one land station by grounding it underwater with an underwater branching device and then supplying power through a return route under the sea. Otherwise, constant current power supply is impossible.
In the above case, in order to minimize transmission line failure due to failure of one power supply line, it is desirable to connect the power supply from all stations to grounding under the sea using a branching device. Furthermore, this method is applicable regardless of the number of stations.

That is, as shown in Fig. 1, land stations A,
B, C and the underwater branching device 20 are connected by submarine cables 4, respectively. The submarine cable 4 includes, for example, four optical fibers 11 and one feeder line 1.
0, and a submarine repeater 5 is inserted in the middle of the submarine cable. The submarine repeater 5 is, for example, a land station A.
and a constant current source 30 installed at the land station A and connected in series by the power supply line 10 between the subsea branching device 20 and
The underwater branch device 20 is connected to the underwater ground. The same applies between the land stations B and C and the underwater branching device 20. That is, feeder line 1
0 are commonly connected in the underwater branching device 20 and grounded underwater. Two of the optical fibers 11 form a transmission path between land stations A and B, and similarly two optical fibers 11 each form a transmission path between land stations B and C and between land stations C and A. Ru.

FIG. 2 is an excerpt of the power feeding portion particularly related to the present invention from the configuration of FIG. 1. That is, between each land station A, B, C and the underwater branching device 20, repeaters 5 are connected in series by the respective feeder lines 10, and in the underwater branching device 20, each feeder line 10 is connected in series.
be connected to a common ground for underwater grounding. Then, by constant current sources 30 from land stations A, B, and C,
A power supply current Io is applied to the underwater branch device 20, which is grounded underwater. With the above configuration, current Io is normally supplied to each repeater 5, respectively. and,
For example, if a ground fault occurs at an intermediate point between land station C and underwater branching device 20 (point P in Figure 2), a submarine relay inserted between land stations A, B and underwater branching device 20 The power supply to the device 5 is not affected in any way, and communication between land stations A and B is ensured. That is, only land station C loses its communication function.
However, power cannot be supplied to the submarine repeater inserted between the point P and the underwater branching device 20. For this reason, the fault monitoring function normally attached to the repeater becomes inoperable, making it difficult to search for the point of fault, and requiring a great deal of time and expense to recover from the fault.

As mentioned above, an object of the present invention is to provide a multiplex system that can supply power to all repeaters even if a ground fault occurs in any submarine cable section, and facilitates and speedily searching for the fault point. Its purpose is to provide an inter-office submarine cable communication system.

The communication system of the present invention includes an underwater branching device that branches and connects submarine cables connecting a plurality of land stations under the sea, and a submarine repeater that is powered by a dual-wave rectifier circuit using a diode bridge. The feeder lines of the submarine cable and the submarine repeater are connected in series from each of the land stations, and each feeder line is commonly connected in the underwater branching device and connected to the underwater ground via a diode. shall be.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 3 is a connection diagram showing one embodiment of the present invention. However, only the power supply path relationship is shown. That is, between the land stations A, B, and C and the underwater branching device 20, there is a power supply line 10 and a submarine repeater 6, respectively.
are connected in series, and the feeder line 10 is connected to the underwater branching device 20.
are connected in common and grounded underwater via a diode 50. The repeater 6 is a submarine repeater that is supplied with power by a double-wave rectifier circuit using a diode bridge, and as described later, can be supplied with power from any direction. In this embodiment, land stations A, B, and C are normally operated by switch 40 and constant current source 30 provided in land stations A, B, and C, as in the case shown in FIG.
A power supply current Io is supplied in series from B and C, respectively, and grounded in the sea via a diode 50, so that a return path to the earth can be established. For example, when a ground fault occurs at the intermediate point between land station C and the underwater branching device 20 (point P in Figure 3), as in the case of Figure 2, land stations A, B and the underwater Since the submarine repeater 6 connected to the branching device 20 is supplied with power from land stations A and B, the transmission path between land stations A and B is not affected in any way, and only land station C loses its communication function. . However, in this embodiment, after stopping the power supply to land station B, by switching the changeover switch 40 of land station A and reversing the polarity of the constant current source 30,
Diode 50 is open and connected to the earth (underwater).
As shown by the dotted line in the figure, the current flowing from the ground fault point P passes through the submarine repeater 6 between the point P and the underwater branching device 20, reaches the underwater branching device 20, and then reaches the underwater branching device 20. Power feeder line 10 between and land station A
and a constant current source 30 flowing in series through the submarine repeater 6.
Return to That is, the ground fault point P and the underwater branching device 20
It is also possible to supply power to the submarine repeater 6 between the two. Therefore, the monitoring signal from the repeater in this section can be received by the land station A. If the power supply from land station A is stopped and the switch of land station B is reversed, the monitoring signal from the repeater in the above section can be received by land station B in the same manner as described above. In addition, the repeater between the ground fault point P and the land station C is supplied with power by grounding the ground fault point P, and the monitoring signal from the repeater in this section is transmitted from the land station C to the ground fault point P. Station C can receive it. Therefore, by receiving these monitoring signals, it becomes easy to search for the fault point, and it is possible to quickly recover from the fault.

In this embodiment, the repeater 6 is configured as shown in FIG. 4, for example. That is, diodes 100 are connected in a bridge shape between power supply lines 10 interposed in the submarine cable 4 to form a diode bridge, and the output voltage is connected to a constant voltage circuit 103 including a Zener diode and a capacitor. , the constant voltage output from the constant voltage circuit 103 provides power for operating the amplifier 101. amplifier 1
01 has four built-in optical amplifiers, each of which amplifies and regenerates the input light of the optical fiber 11 and outputs it. The diode bridge described above is a double-wave rectifier circuit, and the repeater 6 can be operated by current flowing in from either direction.
Normal operation is performed even when the direction of the feeding current is reversed.

As described above, in the present invention, submarine cables each connected to a plurality of land stations are branched and connected by an underwater branching device so as to connect arbitrary land stations, and the power feed line from each land station is , the undersea branching device is configured to be connected in common and grounded under the sea via a diode, so under normal conditions, each undersea repeater on the way from each land station is connected in series to provide a series constant current power supply. do the
If a ground fault occurs in any of the submarine cable sections, the loss of communication function can be suppressed to a minimum of only one station. Moreover, each repeater can be supplied with power from any one of the land stations by power supply operation from the land station. That is, since the monitoring signal from the repeater including the faulty section can be received by the power supply operation from the land station, it becomes easy to search for the fault point, and this has the effect of making it possible to quickly recover from the fault.

[Brief explanation of the drawing]

Fig. 1 is a system configuration diagram showing an example of a multi-station submarine cable communication system to which the present invention is applied, Fig. 2 is a diagram showing the power supply path configuration of the above system, and Fig. 3 is a diagram showing an example of the present invention. The connection diagram shown in FIG. 4 is a diagram showing an example of the configuration of a submarine repeater used in the above embodiment. In the figure, 4...submarine cable, 5, 6...
submarine repeater, 10... power supply line, 11... optical fiber, 20... underwater branching device, 30... constant current source,
40... Selector switch, 50, 100... Diode, 101... Amplifier, 103... Constant voltage circuit, A, B, C... Land station.

Claims (1)

[Claims] 1 Equipped with an underwater branching device that branches and connects submarine cables connecting multiple land stations underwater, and a submarine repeater that is supplied with power by a dual-wave rectifier circuit using a diode bridge, A multi-station submarine cable communication system characterized by connecting the feeder line of the submarine cable and the submarine repeater in series, connecting each feeder line in common within the underwater branching device, and grounding the feeder line under the sea via a diode.