JPH11337607A - Method and apparatus for detection of shielding wire for cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method and an apparatus, in which the conductor of a specific cable is made to correspond to a shielding wire by a method, wherein an induction voltage is induced in one out of the shielding wire which is removed from a ground and the conductor of the specific cable and the induced voltage is detected. SOLUTION: This shielding wire 4a of one cable 1a is removed from the ground. After that, the shielding wire 4a which is removed from the ground is connected to the output terminal of a transmitter 5. A pulse signal (a pulse voltage) is applied to the shielding wire 4a. When the pulse voltage is applied to the shielding wire 4a, an induced voltage which is based on an electrostatic coupling operation is induced at a conductor 2a which faces, via an insulating layer, with a shielding layer which is set for continuity with the shielding wire 4a. Then, whether the induced voltage is induced at the conductor 2a of the cable 1a, to be detected, in order to change an interconnection or the like is detected by a receiver 9, on the basis of the electrostatic coupling operation via the insulating layer with which the conductor 2a is covered. This operation is performed, while the shielding wire 4a is removed from the ground one by one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A method and apparatus for detecting a shielded cable of a cable according to the present invention include, for example, a power station, a substation, and various factories (hereinafter referred to as "power stations").
When the wiring is changed or the like, it is used for a preparation work for searching for a specific cable from a large number of control cables or power cables.

[0002]

2. Description of the Related Art Hundreds or thousands of cables are laid in a central control panel provided in a control room of a power plant or the like. One end of each of these cables is connected to the central control panel. I have. Each of these cables has a length of several tens of meters to several hundreds of meters, and is used for a building provided with the central control panel or a machine provided with a mechanical device to which the other end of each cable is connected. It is laid so as to penetrate the wall and floor. For this reason, it is difficult to specify an intermediate portion of some of the cables in the control room or outside the building. On the other hand, in the case of renovation work at power plants,
It becomes necessary to cut and reconnect any of the cables in the middle.

For this reason, conventionally, a detection signal has been sent to a core wire or a shield layer of a cable to be detected, and a magnetic field or an electric field generated around the cable to be detected due to the sending of the detection signal has been detected by a search coil. 2. Description of the Related Art There is known a cable detecting device that detects a specific cable by detecting the cable. Conventionally, such a cable detecting device has been disclosed in Japanese Patent Application Laid-Open Nos.
Nos. 22424, 6-230057 and 6
-235747, 7-270469, 9-281175, 9-318691,
The thing described in the 9-322347 gazette etc. is known. Conventionally known cable detection devices described in these publications include an electromagnetic induction type and an electrostatic coupling type. The electrostatic coupling type includes a pulse application type and a sine wave application type. In summary, there are three types of known cable detecting devices.

Device for detecting electromagnetic induction type cable In this type of device for detecting a cable, a sinusoidal current flows through a conductor such as a core wire or a shield layer constituting a specific cable to be detected. For this purpose, a sine wave voltage is applied between one end of the conductor and the ground, and the other end of the conductor is connected (grounded) to the ground. Alternatively, the above-mentioned sine wave voltage is applied between one ends of two conductors constituting two cables whose both ends are disposed close to each other, and the other ends of the conductors constituting these two cables are connected. . It is to be noted that detecting an end of a conductor constituting a specific cable can be easily performed, unlike detecting an intermediate portion. When a sine wave current is applied to a conductor such as a core wire or a shielded wire of a cable to be specified as described above, a magnetic field is generated around the cable, and the magnetic field is measured by a detector. That is, the presence or absence and strength of the magnetic field are measured by a detector having a coiled antenna for each of a plurality of cables including the cable to be specified, and there is a significant difference from other cables (around Cable whose magnetic field is clearly stronger than other cables) is the cable to be specified.

Device for detecting a sine wave application type electrostatic coupling type cable In this type of cable detection device, a sine wave is applied between one end of a shield layer (outermost layer conductor) constituting a specific cable to be detected and the ground. A wave voltage is applied, and the other end of the shield wire is insulated from the ground (open without grounding). When a sine wave voltage is applied between the shielded wire and the ground in this way, an electric field is generated around the specific cable, so that the electric field is measured by a detector in the same manner as in the above case, and Find cables to identify.

[0006] Detecting device of pulse applied type electrostatic coupling type cable [0006] In this type of cable detecting device, a cable between one end of a shield layer constituting a specific cable to be detected and the ground.
A coded pulse voltage is applied, and the other end of the shield layer is insulated from the ground. By applying a pulse voltage between the shield layer and the ground in this way, the electric field generated around the specific cable is measured by a detector in the same manner as described above, and a code is obtained from the measured value. reading,
The cable to be identified is detected. The basic principle of detecting a specific cable by the pulse application type electrostatic coupling type cable detection device is the same as that of the sine wave application type. Especially,
In the case of the pulse application type, by changing the code of the pulse voltage applied to the shield wires of multiple cables,
It is possible to detect a plurality of cables at a time, thereby improving the efficiency of the detection work.

[0007]

It is most preferable to detect a specific cable from a large number of cables such as a power cable and a control cable from the viewpoints of efficiency and energy consumption at the time of a detection operation. , A pulse application type electrostatic coupling type. However, in the case of using an electrostatic coupling type cable detection device including a pulse application type and a sine wave application type, it is necessary to be able to detect a shield line extending from a shield layer of a cable to be specified. However, the shielded wire may be grounded below the central control panel, such as below the floor of a control room, in a state where the shielded wires for a plurality of cables are put together. That is, as shown in FIG. 4, the respective core wires 2, 2 are exposed at the ends of the plurality of cables 1, 1, and the ends of the respective core wires 2, 2 are connected to the terminal board 3 in the control room. The shield wires 4 extending from the shield layers constituting the cables 1 and 1 may be collectively grounded at a portion slightly closer to the center than the ends of the cables 1 and 1. In such a case, each of the core wires 2,
In many cases, a floor or a wall exists between the end of the cable 2 and each of the shielded wires 4 and 4, and the shielded wire corresponding to the cable to be specified cannot be detected as it is.

As described above, when the shielded cable of the cable to be specified cannot be detected, the detection device of the electrostatic coupling type cable including the pulse application type and the sine wave application type cannot be used, and the electromagnetic induction type cable cannot be used. Since the detection device must be used, the work efficiency of the cable detection work deteriorates. The method and apparatus for detecting a shielded cable of a cable according to the present invention have been made in view of such circumstances.

[0009]

SUMMARY OF THE INVENTION Among the method and apparatus for detecting a shielded cable of a cable according to the present invention, the invention of the method for detecting a shielded cable of a cable according to the first aspect of the present invention comprises the steps of: The core wire of a specific cable among a plurality of cables laid in a state where the cable is grounded via a cable, and a shield wire extended from a shield layer constituting the specific cable. In the method of detecting the shielded line of the cable according to the present invention, one of the shielded lines extending from the shield layer constituting the plurality of cables is removed from the ground. Then, by applying a pulse signal (pulse voltage) to one of the shielded wire removed from the ground and the core wire of the specific cable,
By inducing an induced voltage on the other of the shielded wire and the core of the specific cable which are removed from the ground, and detecting the induced voltage, the core of the specific cable and the specific cable are formed. With the shield wire extending from the shield layer to be formed.

According to a second aspect of the present invention, there is provided an apparatus for detecting a shielded line of a cable, wherein the apparatus for detecting a shielded line of a cable according to the first aspect is configured to be connected to the shielded line disconnected from the ground. A transmitter for applying a pulse signal to one of the core wires of the cable, and an induced voltage induced on the other of the shielded wire and the core wire of the specific cable. And a receiver for detecting

[0011]

According to the method and apparatus for detecting a shielded wire of a cable according to the present invention having the above-described configuration, the end of the core wire constituting the specific cable to be detected and the end of the shielded wire extending from the shield layer. Even if there is a floor or wall between the ends of these wires, the core wire and the shield wire that constitute the specific cable to be detected can be used. it can. For this reason, it becomes possible to use the electrostatic coupling type cable detection device including the pulse application type and the sine wave application type, and the efficiency of the cable detection operation can be improved.

[0012]

1 to 3 show an example of an embodiment of the present invention. When the method for detecting the shielded wire of the cable according to the present invention is performed, as shown in FIG. 1, the shielded wires 4a and 4b extending from the shield layer constituting the plurality of cables 1a and 1b are selected. First, the shield wire 4a for one cable 1a is disconnected from the ground. The shielded wires 4b, 4b of the other cables 1b, 1b are kept grounded. As described above, after the shield wire 4a for one cable 1a is disconnected from the ground, the shield wire 4a removed from the ground is connected to the output terminal of the transmitter 5, and a pulse signal (pulse signal) is connected to the shield wire 4a. Voltage).
As shown in FIG. 2, the transmitter 5 includes a power supply 6 and a pulse generation circuit 7, and has a repetition frequency of about 1 to 10 kHz,
A voltage pulse having a pulse duty of about 50% and a peak value of about 5 V is generated and applied to the shield line 4a. By setting the peak value of the voltage pulse to about 5 V, even when the core wire 2a of the cable 1a is energized, that is, in a so-called live state, the shield wire can be detected.

When a voltage pulse is applied to the shield wire 4a in this manner, an induced voltage based on electrostatic coupling is induced in the core wire 2a opposed to the shield layer connected to the shield wire 4a via the insulating layer and the insulating layer. Therefore, the receiver 9 determines whether or not the induced voltage is induced on the core 2a of the cable 1a to be detected for the change of the wiring through an insulating layer covering the core 2a. Detect based on As shown in FIG. 3, the receiver 9 includes a power supply 10 and a detection electrode 1.
And an amplifier 12 for amplifying the output of
A narrow-band filter 13 that passes only a signal having a frequency corresponding to the pulse signal among the signals amplified in
It comprises a determination circuit 14 for determining whether or not the induced voltage has been induced, and a display 15 for displaying whether or not the induced voltage has been induced.

The induced voltage is induced only in the core wire 2a corresponding to the shielded wire 4a to which the above-mentioned voltage pulse is applied (constituting the same cable 1a as the shield layer conducting to the shielded wire 4a). The induced voltage is not induced in the core wires 2b, 2b of the cables 1b, 1b. Therefore, if the indicator 15 indicates that an induced voltage is induced on the core wire 2a, the shield wire 4a applying the voltage pulse at that time corresponds to the specific cable 1a to be detected. It can be seen that the shield wire 4a (extended from the shield layer constituting the cable 1a). If the core wire 2a and the shield wire 4a of the specific cable 1a to be detected can be made to correspond one-to-one in this manner, the above-mentioned conventionally known electrostatic coupling type cable detection device can be used. Then, the work of detecting the intermediate portion of the specific cable 1a is performed.

On the other hand, when the indicator 15 does not indicate that the induced voltage is induced in the core wire, another shield wire is disconnected from the ground, and the above voltage pulse is applied to the shield wire. It is determined whether or not an induced voltage is induced in the core wire 2a of the specific cable 1a. Such work,
The process is repeated until it is confirmed that an induced voltage is induced on the core wire 2a, and the shield wire 4a constituting the specific cable 1a is searched for. In the illustrated example, the receiver 9 is arranged on the core wire 2a side and the transmitter 5 is arranged on the shield wire 4a side, but this arrangement may be reversed. The present invention also provides a power cable, a control cable, a cable having a shield layer and a shield wire extending from the shield layer.
It can also be used to detect shielded wires for any cable, such as instrumentation cables.

[0016]

As described above, according to the method and apparatus for detecting a shielded wire of a cable according to the present invention, a shielded wire extending from a shield layer constituting a specific cable to be detected can be reliably found. . For this reason, the detection device of the electrostatic coupling type cable can be used, and the efficiency of the cable detection operation can be improved. Further, the peak value of the voltage pulse to be applied can be small, and the operation can be performed with the cable energized, so that the operation can be performed without affecting the operation of the power plant or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of an embodiment of the present invention.

FIG. 2 is a block diagram of the transmitter.

FIG. 3 is a block diagram of the receiver.

FIG. 4 is a schematic front view showing an example of a connection state of a cable end;

[Explanation of symbols]

 1, 1a, 1b Cable 2, 2a, 2b Core wire 3 Terminal board 4, 4a, 4b Shield wire 5 Transmitter 6 Power supply 7 Pulse generation circuit 9 Receiver 10 Power supply 11 Detection electrode 12 Amplifier 13 Narrow band filter 14 Discrimination circuit 15 Display vessel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohiro Imazumi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Shinji Sakamoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo No. Mitsubishi Electric Corporation (72) Inventor Yuji Takahashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (2)

[Claims] 1. A cable extending from a core wire of a specific cable and a shield layer forming the specific cable from a plurality of cables laid with each shield layer grounded via a shield wire. A method for detecting a shielded cable of a cable, the shielded cable corresponding to the shielded cable, wherein the shielded cable for one cable is selected from the shielded cables extending from the shield layer constituting the plurality of cables. After disconnecting the shielded cable from the ground and the specific cable, a pulse signal is applied to one of the shielded cable and the core of the specific cable. An induced voltage is induced in the other of the core wire and the core wire of the specific cable and a seal forming the specific cable by detecting the induced voltage. A method of detecting the shielded wire of a cable by matching the shielded wire extending from the cable layer. 2. An apparatus for detecting a shielded cable of a cable for performing the method of detecting a shielded cable of a cable according to claim 1, wherein the shielded cable removed from ground and the core of the specific cable are connected to each other. A transmitter for applying a pulse signal to one of the lines, and a detector for detecting an induced voltage induced on the other of the shielded line and the core of the specific cable. A device for detecting a shielded wire of a cable, comprising a receiver.