CN118011278A - Electrified cable identification method - Google Patents

Abstract

The invention provides a live cable identification method, which is implemented by a detection device, wherein the detection device comprises a signal transmitter arranged at the head end of a target cable and used for transmitting detection signals, a first current transformer and a second current transformer which are respectively sleeved at the head end and the tail end of a metal armor of the target cable, the first current transformer is electrically connected with the signal transmitter, the second current transformer is electrically connected with a signal detector which is used for receiving the detection signals and comparing the waveforms of the detection signals with the built-in waveforms so as to judge whether the current detected cable is the target cable, and the detection signals transmitted by the signal transmitter are detection signals with 400Hz of frequency synthesized by superposition of 800Hz sine waves and 1200Hz sine waves; the signal detector embeds a waveform of a forward current transmitted by the detection signal on the target cable and a waveform of a reverse current transmitted on the non-target cable. The invention can effectively solve the technical problem that the electrified cable identification method in the prior art is easy to produce misjudgment.

Description

Electrified cable identification method

Technical Field

The invention relates to the technical field of automatic identification of cables, in particular to an electrified cable identification method.

Background

As urban cables go to the ground, the number of cables in the urban cable trench is large, and the laying is complex. In the construction processes of installation, maintenance, replacement, migration and the like of a power supply cable, it is often required to identify a corresponding cable to be determined from a plurality of cables in a state where the cable is electrified. Referring to fig. 1, a first current transformer 2 electrically connected with a signal transmitter 4 is sleeved on a first end metal armor 1-2 of a target cable 1, a second current transformer 3 electrically connected with a signal detector 5 is sleeved on a tail end metal armor 1-2 of the target cable 1, and the working principle is that a detection signal is coupled to the metal armor 1-2 of the target cable 1 through electromagnetic field effect by using the signal transmitter 4, an induction current I1 is generated on the metal armor 1-2 of the target cable 1, and a specified current direction is right (namely, flows towards a detection end), and as the two ends of the metal armor 1-2 are grounded, a current loop I2 is formed with the ground; the current flow route is from the head end of the metal armor 1-2 to the tail end, flows to the ground through the grounding wire, and returns to the head end of the metal armor 1-2 through the ground to form a loop, and whether the current detected cable is the target cable can be judged by detecting whether the tail end of the target cable 1 has the same alternating current signal sent by the signal transmitter 4 through the signal detector 5. At present, the detection signal sent by the signal transmitter 4 generally adopts a sine wave signal as shown in fig. 3, and the technical problems are that: as shown in fig. 2, since the metal armor of the non-target cable 6 stacked and arranged with the target cable 1 is also connected to the earth, a part of the current I2 which is originally returned from the earth flows back from the metal armor of the non-target cable 6, so that the ac current signal I3 shown in fig. 4 can be detected when the second current transformer 3 is sleeved on the metal armor of the non-target cable 6, although the phase is opposite to that of the detection signal sent by the signal transmitter 4, since the transmitted and received signals are sine waves with the same frequency, if there is no uniform time reference, the current cannot be judged whether the current is forward or reverse, and thus the non-target cable 6 is easily misjudged as the target cable 1, and unnecessary loss is caused.

Disclosure of Invention

The purpose of the invention is that: in order to solve the problems in the prior art, the live cable identification method capable of effectively preventing erroneous judgment is provided.

The technical scheme of the invention is as follows: the invention relates to a live cable identification method implemented by a detection device, wherein the detection device comprises a signal transmitter arranged at the head end of a target cable and used for transmitting detection signals, a first current transformer electrically connected with the signal transmitter and sleeved at the head end of a metal armor of the target cable, a second current transformer sleeved at the tail end of the metal armor of the target cable, and a signal detector electrically connected with the second current transformer and used for receiving the detection signals and comparing the waveforms of the detection signals with the built-in waveforms to judge whether the current detected cable is the target cable, which is different from the prior art in that: the detection signal emitted by the signal emitter is a detection signal with 400Hz synthesized by superposition of 800Hz sine wave and 1200Hz sine wave.

The further scheme is as follows: the signal detector is internally provided with a waveform diagram of a forward current transmitted by a detection signal on a target cable and a waveform diagram of a reverse current transmitted by a non-target cable; the signal detector compares the received detection signal waveform with the two built-in waveforms to determine whether the current detected cable is a target cable or a non-target cable.

The invention has the positive effects that: the invention transmits a double sine wave superimposed detection signal through the signal transmitter, the waveform of the forward current generated by the detection signal on the target cable is different from the waveform of the reverse current generated by the non-target cable, and the signal detector can conveniently and accurately distinguish the target cable from other cables laid in a superimposed manner by comparing the received signal waveform with the built-in identification waveform. Therefore, the technical problem that the signal transmitter in the prior art sends sine wave detection signals and is easy to generate misjudgment to cause unnecessary loss is effectively solved.

Drawings

FIG.1 is a schematic diagram of the working principle of a detection device used in the prior art and the present invention;

FIG. 2 is a schematic diagram of the operation of the prior art and the detection device of the present invention when considering non-target cable factors for stacking with a target cable;

FIG. 3 is a schematic diagram of a sinusoidal waveform of forward current transmitted by a signal transmitter in the prior art after transmitting a signal on a metallic armor of a target cable;

FIG. 4 is a schematic diagram of a sinusoidal waveform of a reverse current transmitted by a signal transmitter in the prior art after transmitting a signal in a metallic armor of a non-target cable;

FIG. 5 is a schematic waveform diagram of a forward current transmitted by a metallic armor of a target cable after a signal is transmitted by a signal transmitter according to the present invention;

Fig. 6 is a schematic waveform diagram of reverse current transmitted by the signal transmitter of the present invention after transmitting a signal to the metal armor of the non-target cable.

The reference numerals in the above figures are as follows:

Target cable 1, cable conductor 1-1, metal armor 1-2; a first current transformer 2; a second current transformer 3; a signal transmitter 4; a signal detector 5; non-target cable 6.

Detailed Description

The invention will be described in further detail with reference to the drawings and the detailed description.

Example 1

Referring to fig. 1 to 6, the live cable identification method of the present embodiment is implemented by using a detection device, where the detection device includes a signal emitter 4 disposed at the head end of a target cable 1 for emitting a detection signal, a first current transformer 2 electrically connected to the signal emitter 4 and sleeved at the head end of a metal armor 1-2 provided on the target cable 1, a second current transformer 3 sleeved at the tail end of the metal armor 1-2 provided on the target cable 1, and a signal detector 5 electrically connected to the second current transformer 3 for receiving the detection signal and comparing the waveform of the detection signal with the built-in waveform to determine whether the currently detected cable is the target cable 1.

Unlike the prior art in which the signal transmitter 4 transmits a sine wave signal and the sine wave signal for judgment is built in the signal detector 5, the live cable identification method of the embodiment has the advantages that the detection signal transmitted by the signal transmitter 4 is a detection signal with 400Hz which is formed by overlapping and synthesizing an 800Hz sine wave and a 1200Hz sine wave; a waveform diagram of the forward current I1 transmitted by the detection signal on the target cable 1 is shown in fig. 5; and a waveform of the reverse current I3 transmitted by the detection signal on the non-target cable 6 laid in a stacked manner with the target cable 1 is shown in fig. 6. The signal detector 5 incorporates these two waveforms for detecting and judging whether the currently detected cable is the target cable 1 or the non-target cable 6. Comparing the two waveforms shows that the composite wave after the inversion does not generate signal overlap when shifted for any time length, i.e. the waveform of the composite wave in the inversion is completely different from that of the composite wave in the forward direction. The signal detector 5 in operation can conveniently, quickly and accurately judge whether the current detected cable is the target cable 1 or the non-target cable 6 only by comparing the received detection signal waveform with the built-in synthesized waveform, thereby effectively solving the technical problem that the signal transmitter in the prior art sends out sine wave detection signals to easily generate misjudgment and cause unnecessary loss.

It should be noted that, the superposition of sine waves with two frequencies to form a detection signal with a specific frequency is the prior art and will not be described in detail.

The above embodiments are illustrative of the specific embodiments of the present invention, and not restrictive, and various changes and modifications may be made by those skilled in the relevant art without departing from the spirit and scope of the invention, and all such equivalent technical solutions are intended to be included in the scope of the invention.

Claims (2)

1. The utility model provides a live cable identification method, utilizes detection device to implement, detection device is including locating the signal transmitter that is used for transmitting the detected signal in target cable head end, with signal transmitter electricity connection and cover establish the first current transformer at the metal armor head end that the target cable had, the second current transformer at the metal armor terminal that the target cable had is established to the cover, be connected with the second current transformer electricity and be used for receiving the detected signal and compare the detected signal waveform with built-in waveform in order to judge whether the current detected cable is the signal detector of target cable, its characterized in that: the detection signal emitted by the signal emitter is a detection signal with 400Hz synthesized by superposition of 800Hz sine waves and 1200Hz sine waves.

2. The live cable identification method of claim 1, wherein: the signal detector is internally provided with a waveform diagram of a forward current transmitted by a detection signal on a target cable and a waveform diagram of a reverse current transmitted by a non-target cable; the signal detector compares the received detection signal waveform with the two built-in waveforms to judge whether the current detected cable is a target cable or a non-target cable.