JPH0437321A - Cable fault point locating system - Google Patents

Abstract

PURPOSE:To specify a fault point between cables by recording the level of a signal fed to a cable whose length is L from each feeder at both terminal stations and finding a distance up to the fault point depending on the difference T of time recorded between the terminal stations. CONSTITUTION:Voltages V1, V2 fed to a cable whose length is L including repeaters 3-7 are recorded from feeders at terminal stations 1A, 2B and the times t1, t2 when a change in the voltage due to a fault of the cable reaches the A.B terminal stations 1, 2 at a transmission speed (v) are recorded. The time difference T between the times t1, t2 recorded at the terminal A.B stations 1, 2 is calculated and a distance X from one terminal station to the fault point is calculated according to a formula of X=L-vT/2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cable failure point search method in a submarine relay system.

[Conventional technology]

The conventional cable fault detection method uses a loopback method that loops up and down lines at repeaters in a submarine relay system, and sequentially loops back the repeaters from the terminal station to find out in which relay section a cable fault has occurred. I was exploring.

[Problem to be solved by the invention]

The conventional cable failure point search method described above performs loopback from the terminal station to the repeater, so although it is possible to identify which relay section the cable failure point is, it is difficult to identify whether it is a failure point between cables. The disadvantage is that it cannot be used.

In addition, the submarine relay system has the disadvantage that if the power supply path is cut off due to a cable failure, the repeater cannot perform a loopback.

[Means to solve the problem]

The cable failure point search method of the present invention includes a means for recording the signal level fed to the cable over a distance by the respective power feeding devices of both end stations, and a means for recording the signal level fed to the cable over a distance by the respective power feeding devices of both end stations, and a change in the signal level due to a fault in the cable is determined by the transmission speed. a means for recording the time of arrival at the terminal station, and a time difference T recorded at the two terminal stations;
and the distance X from the terminal station to the failure point as X=
It has means for calculating by L-VT/2.

〔Example〕

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

1 and 2 are a block diagram and a timing diagram for explaining one embodiment of the present invention.

This embodiment includes means for recording the voltage values V, V2 supplied by the terminal stations 1 and 2 of A and B to the cables at a distance including the repeaters 3 to 7 by their respective power supply devices, and The voltage value change due to the transmission speed 1,
2, means for calculating the time difference T between tl and tz recorded in the terminal stations 1 and 2 of A and B, and the distance from one terminal station to the failure point. X=L
and means for calculating by v T / 2.

In this way, when a failure occurs at time to at failure point
and reaches the B terminal station 2 at time t21, and if the voltage transmission speed in the cable is V, then 1. The distance X can be determined by -1o-.

Note that the same implementation is possible even if the voltage of the above means is set as a current.

〔Effect of the invention〕

As explained above, the present invention records the signal level fed to the cable over a distance by the respective power feeding devices of both end stations, and records the time when the change in signal level due to a cable failure reaches both end stations at the transmission speed V. is recorded, and the time difference T recorded at both terminal stations has the effect of being able to determine the distance to the fault point even if the power supply line at the fault point is disconnected or short-circuited.

[Brief explanation of the drawing]

1 and 2 are a block diagram and a timing diagram for explaining one embodiment of the present invention. 1...A and B terminal stations, 3-7...repeater.

Claims (1)

[Claims] means for recording the signal level fed to the cable over a distance L by respective power feeding devices of both end stations; and means for recording the time when a change in signal level due to a fault in the cable reaches the both end stations at a transmission speed v. , a cable fault point search characterized by comprising means for calculating a time difference T recorded in both terminal stations, and means for calculating a distance X from the terminal station to the fault point using X=L-vT/2. method.