JPH0713650B2 - Cable exploration device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific cable, if a plurality of cables for electric power are laid, for example.
The present invention relates to a cable search device for identifying a bull.

[0002]

2. Description of the Related Art Conventionally, for example, when a plurality of electric power cables are laid in a tunnel or a manhole, when removing a specific electric power cable from the cavern or the manhole, It is necessary to disconnect the power cable to be removed with a cable or the like. When disconnecting the power cable to be removed, it is necessary to surely identify the power cable to be removed. Therefore, the current flicker
Is used to search for the target power cable. The current flicker causes an intermittent current of 50 Hz or 60 Hz commercial frequency, for example, 10 volts, 10 amps, or 5 amps, to flow from one terminal of the target cable, and the current is applied at the cut point of the cable. The induced magnetic field generated by is detected by the hot line detector. At that time, in order to prevent the live line detector from reacting under the influence of the magnetic field due to electromagnetic induction from other cables in the live line state of the same manhole, the timer from the current flicker is prevented. Thus, for example, 5 seconds on and 10 seconds off are repeatedly energized, and the reaction time is measured on the hot line detector side.
An exploration means is adopted in which, when 0 second is off, it is determined that the cable is a target cable.

[0003]

However, the above-described conventional cable exploration means has the following problems. (1) The current flicker is about 13 kg, which is quite heavy. (2) Since the current flicker requires a commercial power source or a power source similar to that, a generator is required for exploration work in a place without a commercial power source. (3) Since the intermittent energization current from the current flicker by the timer is relatively large, deterioration of the output contact of the timer is rapid. (4) Since the intermittent energization current from the current flicker is relatively large, it is necessary to make a reliable connection to the cable. (5) Since the intermittent energizing current from the current flicker is relatively large, it is necessary to cut off the intermittent energizing current from the current flicker when disconnecting the power cable to be removed. (6) A wireless communication means such as a transceiver must be used for communication between the current flicker side and the live line finder side in switching the on / off time of the intermittent energizing current and interrupting the intermittent energizing current. , The number of times I contacted him was high. (7) The live line detector needs to frequently adjust the sensitivity according to the degree of influence of electromagnetic induction from other cables. (8) When the on / off time is measured on the hot line detector side, it is necessary to measure a plurality of times in order to ensure reliability. Therefore, in the present invention, while a battery is built in as a power source, a search signal of a small current in which a plurality of signals of frequencies different from the commercial frequency are mixed is energized to the search target cable, while at the cable identification location, By recognizing that the target cable is a probe target only when multiple signals are received simultaneously, the influence of the current in the commercial frequency band and the influence of external noise are prevented, and the target cable can be reliably connected. -Exploring the bull and displaying it is a technical issue to be solved.

[0004]

A technical means for solving the above-mentioned problems is to apply a search signal to a conductor of a cable to be searched among a plurality of laid cable groups. A transmitter and a receiver having a display function for displaying that the probe signal is a probe target cable when the probe signal is detected in the middle of the cable group. In the cable probe apparatus including a transmitter, the transmitter includes an oscillation circuit that oscillates a plurality of signals of frequencies apart from a commercial frequency band, a mixing circuit that mixes the plurality of oscillation signals, and a mixture thereof. An amplifier circuit that amplifies the mixed signal output from the circuit, energizes the amplified signal as a search signal to the conductor of the cable to be searched, and a battery power supply circuit that applies a required voltage to each of the circuits. While providing and In the receiver, a sensor which detects the search signal by the guidance detection means in a state where it is set in the middle of the cable to be searched and a process in which the signal output from the sensor is passed A first filter that cuts a frequency band, an amplifier circuit that amplifies a signal that has passed through the first filter, and a plurality of oscillators that are oscillated by the oscillator circuit in the process of passing a signal output from the amplifier circuit. A second filter that individually passes only signals having an oscillating frequency, and when all of the above signals are output from the second filter, the cable to which the sensor is located is the probe target cable. And a logic circuit that outputs a cable identification signal indicating that the cable identification signal is output from the logic circuit. A display circuit for displaying that the le, is to structure provided with a battery power supply circuit for applying a predetermined voltage to the respective circuits.

[0005]

According to the cable probe apparatus having the above-mentioned structure, when a plurality of signals having different frequencies are oscillated in the transmitter in the transmitter, the respective oscillation signals are mixed in the mixing circuit and then mixed. The signal is amplified in the amplifier circuit and is supplied to the conductor of the cable to be searched as a small current searching signal. On the other hand, on the receiver side, when the probe signal is energized in the cable set with the sensor in the proximity state, a voltage is induced in the sensor by the electromagnetic induction effect accompanying the energization of the probe signal, and the voltage signal is Applied to the first filter. When the signal from the sensor is applied to the first filter, the commercial frequency component contained in the signal is cut while the signal passes through the first filter. The signal that has passed through the first filter is amplified by the amplifier circuit, then applied to the second filter, and only signals having a plurality of oscillation frequencies oscillated in the oscillation circuit individually pass. When the respective signals are simultaneously output from the second filter, the logic circuit outputs a cable identification signal indicating that the cable to which the sensor is located is a probe target cable. . The display circuit is
When the cable identification signal is input, it is displayed that the cable brought close to the sensor is the probe target cable.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit block diagram showing the overall configuration of a cable search device according to the present invention. The cable exploration device shown in FIG. 1 is a cable installed in a manhole MH.
For example, after identifying the cable CA to be removed from the group of bulls, the cable CA to be removed is cut by a cutting machine (not shown).
Shall be used when cutting. As shown in FIG. 1, a cable search device is provided with a transmitter 1 and a receiver 2, and a receiver 2 is provided with a sensor coil 3 close to a cable CA to be removed. 4 are connected. Also, the two output lead lines 5 and 6 of the transmitter 1 are
Bull CA, for example, of the three conductors R, S, T, the conductor R,
While being connected to one end of each S, the other ends of the conductors R and S are short-circuited by the short-circuit wire 7.

Next, the transmitter 1 will be described. The transmitter 1 is provided with two oscillating circuits 11 and 12 that oscillate signals with frequencies of 210 Hz and 250 Hz, respectively. Crystal oscillators 11A and 12A are used for the oscillation circuits 11 and 12, respectively, to stabilize the oscillation frequency. 210 Hz oscillation signal 13 and 250 Hz oscillation signal 14 oscillated in the oscillation circuits 11 and 12, respectively.
Is input to the mixing circuit 15. The mixing circuit 15 is 210
The Hz oscillating signal 13 and the 250 Hz oscillating signal 14 are input and mixed, and then a mixed signal 16 having a synthetic waveform is output. The mixed signal 16 output from the mixing circuit 15 is amplified in the amplifier circuit 17. The mixed signal 16 is amplitude-amplified in the amplifier circuit 17, and then is supplied to the conductors R and S of the cable CA as a search signal from the amplifier circuit 17. Note that the current of this probe signal is limited to about 200 milliamps. Further, the transmitter 1 has a built-in battery power supply circuit 18 which uses a battery as a power supply.

Next, the receiver 2 will be described. When the sensor coil 3 is brought close to the cable CA, the sensor coil 3 is subjected to an electromagnetic induction action by the search signal supplied to the cable CA, so that an induced voltage is induced in the sensor coil 3. The induced voltage has a frequency of 210 Hz and 25
The output signal of the sensor coil 3 is a combination of two signals of 0 Hz. The output signal of the sensor coil 3 is input to the T-type filter 21 built in the main body of the receiver 2 via the lead wire 4. The T-type filter 21 has the characteristics shown in FIG. That is, the T-type filter 21 is 50H
z, 60Hz commercial frequency band cuts while 200H
Since it is configured not to cut the 250 Hz band from z, cables other than the cable CA in the manhole MH are included.
Even if the sensor coil 3 is affected by the commercial power supply current being supplied to the cable and a signal having a commercial frequency is mixed in the output signal, the commercial frequency signal is cut by the T-type filter 21 and 210 Hz. And only two signals of 250 Hz pass. Also, even if external noise comes in, it will be cut. Incidentally, FIG. 3 shows an example of a circuit of the T-type filter 21. The signal output from the T-type filter 21 is input to the amplifier circuit 22 in a state where two signals having frequencies of 210 Hz and 250 Hz are combined, amplified, and then input to the 210 Hz filter 23 and the 250 Hz filter 24. 210Hz filters 23 and 250
The Hz filter 24 is composed of a phase comparison circuit.
The 10 Hz filter 23 passes a 210 Hz signal with an accuracy of ± 15 Hz, while the 250 Hz filter 24 is 25
Pass the 0 Hz signal with an accuracy of ± 15 Hz. Therefore,
Even if external noise is mixed, the noise is blocked by the 210 Hz filter 23 and the 250 Hz filter 24. 210 Hz filter 23 and 250 Hz filter 2
210Hz signal output from each of 4 and 250
The Hz signal is converted into a logic signal at the time of output, and the logic circuit 2
Input to 5. The logic circuit 25 constitutes a logic for determining that the cable CA which is close to the sensor coil 3 is the probe target cable when the 210 Hz signal converted into the logic signal and the 250 Hz signal are inputted at the same time. Therefore, when the 210 Hz signal and the 250 Hz signal are simultaneously input, the logic "H" signal is output, the light emitting diode 26 connected to the output side of the logic circuit 25 is turned on, and the electronic buzzer 27 is activated. The output signal of the logic circuit 25 can also be used as an interlock signal of a cable cutting machine (not shown). In addition, the receiver 2
A battery power supply circuit 28, which uses a battery as a power source similar to that incorporated in the transmitter 1, is incorporated, and an external power source is not required, thereby facilitating cable search work.

The cable exploration device configured as described above has the following features. (1) The transmitter 1 and the receiver 2 have a simple built-in electronic circuit, and the electronic circuit can be configured as an integrated circuit, and the current of the search signal supplied to the cable CA is also milliamperes. Since it is the order of, the transmitter 1 and the receiver 2 can be made small and lightweight, and thus the carrying and exploration work are easy. (2) Even if there is a live-line cable in which a commercial frequency current is passed near the search target cable CA, it does not respond to the current at all, but responds only to the search signal. Only the target cable can be reliably identified. Similarly, even if external noise is mixed in, it is removed by each filter, so that it is possible to reliably identify only the target cable without being affected by it. (3) Since neither transmitter 1 nor receiver 2 requires an external power supply, it is necessary to temporarily install a power supply code from the ground, especially when an exploration signal is to be sent from the pole position of the utility pole start-up cable. Since the lead wires 5 and 6 are not provided, the lead wires 5 and 6 can be easily connected to the cable and the exploration work can be performed safely. (4) In the cable exploration work, since there is no adjustment element and the exploration signal is in milliamperes order, the cable CA can be disconnected while the exploration signal is energized. The time required for is much shorter than the conventional method.

[0010]

As described above, according to the present invention, a probe signal of a small current consisting of a plurality of signals of frequencies different from the commercial frequency is supplied to the probe target cable, and at the cable identification location, Since the configuration is such that the probe target cable is displayed only when the plurality of signals are received simultaneously, even if the cable near the probe target cable is in a live state, -Because the noise can be removed without being affected by the energizing current of the bull, or even if external noise comes in, it is possible to ensure that only the probe target cable is not affected by the noise. Moreover, there is an effect that the identification can be performed in a short time. Further, since there is no need for an external power source such as a commercial power source or a generator power source, there is an effect that the cable exploration work is easy and the working time is shortened.

[Brief description of drawings]

FIG. 1 is an electric circuit block diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a T-type filter.

FIG. 3 is a circuit diagram of a T-type filter.

[Explanation of symbols]

 1 Transmitter 2 Receiver 3 Sensor coil 11 210Hz oscillation circuit 12 250Hz oscillation circuit 15 Mixing circuit 17 Amplification circuit 18 Battery power circuit 21 T type filter 22 Amplification circuit 23 210Hz filter 24 250Hz filter 25 Logic circuit 26 Light emitting diode 27 Electronic Buzzer 28 Battery power circuit

Claims (2)

[Claims] 1. A transmitter for energizing a probe signal to a conductor of a cable to be probed out of a plurality of installed cable groups, and the probe in an intermediate part of the cable group. A cable search device comprising a receiver having a display function for displaying that the cable is a search target cable when a cable in which a signal is energized is detected. The transmitter includes an oscillating circuit that oscillates a plurality of signals having frequencies apart from the commercial frequency band, a mixing circuit that mixes the plurality of oscillating signals, and a mixed signal that is output from the mixing circuit. An amplifier circuit for energizing a conductor of a cable to be searched as a search signal using the signal as a search signal and a battery power supply circuit for applying a required voltage to each of the circuits are provided, while the receiver is provided with the search signal. In the middle of the target cable A sensor that detects the exploration signal by the guidance detection means in a state of being set in the portion, a first filter that cuts a commercial frequency band in the process of passing a signal output from the sensor, and the first filter. An amplifying circuit for amplifying a signal passing through the second filter, and a second filter for individually passing only a signal having a plurality of oscillation frequencies oscillated in the oscillating circuit in a process of passing a signal output from the amplifying circuit. When all signals having a plurality of oscillation frequencies oscillated in the oscillation circuit are output from the second filter, a cable indicating that the sensor is close to the sensor is a probe target cable. A logic circuit which outputs a cable identification signal, and when the cable identification signal is output from the logic circuit, a cable which is close to the sensor is a probe target cable. Ke wherein a display circuit for displaying that the le, by comprising a battery power supply circuit for applying a predetermined voltage to the respective circuit - Bull locator. 2. The cable identification signal output from the logic circuit is used as an interlock signal of a cable cutting system for cutting a probe target cable. Cable exploration device.