RU2386964C1 - Device to reveal, identify and diagnose multi-wire power transmission lines - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed device comprises control unit intended for coordination of operation of entire set of hardware, pulse generator to generate probing signals, receiver to receive signals from I/O of the lines to be connected, processing unit to process signals from I/O of the lines to be connected and line to be connected in between pulse generator and receiver. Note here that, in produced line formed by connected line and outer conductors in nonuniform dielectric medium, probing signal generates modes propagating in obtained structure with irregular delays. Note also that minimum difference in these delays exceeds duration of probing signal.

EFFECT: device that allows revealing, identifying and diagnosing multi-wire structures.

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Description

The invention relates to measuring equipment. Specifically, to devices for detecting, identifying, diagnosing multi-wire structures.

The closest in technical solution is the device of pulse reflectometry (http://www.reis205.narod.ru/article.htm, "The state and prospects of pulse measurements of power cable lines", author N.A. Tarasov), used to determine the location of damage in two- and multi-wire structures, selected for the prototype, containing a control unit designed to coordinate the work of all nodes included in the device, a pulse generator designed to generate probe pulses, a receiving unit designed to receive a pulse in line with the entrance reflected from the fault location and the wave impedance discontinuities processing unit for processing signals received from the input lines probed.

The disadvantage of this method is the limitation of determining the location of damage in cases where the resistance at the location of the damage is significantly higher (10 ÷ 20 times or more) than the wave impedance of the line. In this case, the reflection from the place of damage has a small amplitude and it is difficult to detect by trace on the background of interference. It should be noted that the device of pulse reflectometry requires connection to the probed line. The device for detecting, identifying and diagnosing multi-wire transmission lines does not require this.

A modal sensing device is known [RF Patent for Utility Model No. 800100], comprising a control unit for coordinating the operation of all nodes included in the device, a pulse generator for generating sounding signals, a receiving unit for receiving signals from input / output connected line, a processing unit for processing signals received from the input / output of the connected line, a connected line between the pulse generator and the receiving unit, characterized in that in p The resultant structure formed by the connected line and external conductors in an inhomogeneous dielectric filling, the probe signal excites modes propagating in the resulting structure with unequal delays, and the difference in these delays is less than the duration of the probe signal. The disadvantage of this device is the use of a probe signal with a duration greater than the difference in the delay of the modes. This leads to the fact that the probe signal does not completely decay into pulses of lower amplitude, which reduces the information content of the probe signal. The proposed device for the detection, identification and diagnosis of multi-wire transmission lines in its work uses the phenomenon of complete decomposition of pulses.

The structural diagram of the proposed device is shown in figure 1.

A device for detecting, identifying and diagnosing multi-wire transmission lines, comprising a control unit 1 for coordinating the operation of all nodes included in the device, a pulse generator 2 for generating sounding signals, a receiving unit 3 for receiving signals from the input / output of the connected lines, processing unit 4, intended for processing signals received from the input / output of the connected line, the connected line 5 between the pulse generator and the receiving unit, characterized in That the resulting structure formed by the connected line and the external conductors 6 in an inhomogeneous dielectric filling, excites the probe signal modes propagating in the resultant structure with unequal delays, the minimum difference between the delays longer than the duration of the probing signal.

The technical result is the creation of a device that allows detection, identification, diagnostics of wire structures, including without direct physical access to them.

The problem is solved due to the fact that during the propagation of a pulse in a multiconductor structure with an inhomogeneous dielectric filling, from N conductors (not counting the reference) it can undergo modal distortions, in the form of decomposition into N pulses of smaller amplitude due to the difference in the linear delays of the modes in the line . Thus, if the probed conductors have different electrical and magnetic connections with the probing conductor (which leads to a difference in mode delays), then information on the probed conductors can be obtained from the waveform in the probe line.

A brief description of the drawings, which provides a list of figures with a brief explanation of what is shown in each of them, is given below.

Figure 2 shows the waveforms at the input and output of a double-strip microstrip line. The cross section and the equivalent structure are given.

Figure 3 shows the waveforms at the input and output of a three-strip microstrip line. The cross section and the equivalent structure are given.

Figure 4 shows the cross section of the cable brand PUGNP 3 × 4 with the designation of the conductors into which the probing signal (active and reference), and the designation of the external conductor (passive). An equivalent structure diagram is given.

Figure 5 shows the waveform at the near and far ends of the active conductor of the structure shown in figure 4 without rupture of the passive wire and when it breaks at a distance of 0.5; one; 1.5 m from the start.

The principle of operation of the device for detecting, identifying and diagnosing multi-wire transmission lines is illustrated by the example of computer simulation of pulse propagation in an N-wire segment of length l of a conventional microstrip line (its parameters and modeling are described in detail in the study of modal distortion of a pulse signal in multi-wire lines with inhomogeneous dielectric filling ". Electromagnetic waves and electronic systems, No. 11. 2004. P.18-22) for N = 2, l = 1.5 m (figure 2) and N = 3, 1 = 3.0 m (figure 3 )

In both cases, the resistor values in the active conductor correspond to pseudo-matching (50-60 Ohms), and in passive ones - 10 kOhm. Thus, the boundary conditions at the ends of the passive lines are close to the idle mode, which corresponds, for example, to passive conductors torn off at the ends from the reference conductor. As can be seen from figure 2, the presence of one passive conductor will lead to the fact that at the end of the active conductor there will be not one pulse of the same amplitude as at the beginning of the line, but two pulses of half the amplitude. Thus, we can talk about solving the problem of detecting a single conductor. As can be seen from figure 3, the presence of two passive conductors will lead to the fact that at the end of the active conductor there will be three pulses. Thus, we can talk about solving the problem of detecting one and the other conductors or the identification problem, for example, determining the number of conductors in a cable.

On the example of computer simulation of the propagation of a pulse in a cable of the ПУГНП 3 × 4 brand (Fig. 4a), the possibility of diagnosis, namely the determination of line breaks, is demonstrated. The situations with a gap in a passive wire and without a gap were simulated. The situation with a break in the passive wire was modeled by two pieces of cable (Fig.4b), with R3 = R4 = 5 · 10 ⁹ Ohms. The total length of the structure is 2 m, the break point of the passive conductor was moved: 0.5; one; 1.5 m from the start of the line. (The parameters of the probe pulse: amplitude 2 V, the duration of the leading edge of 100 ps, the duration of the trailing edge of 100 ps, the duration of the flat peak of the pulse of 100 ps.) The simulation results are shown in Fig.5.

According to the simulation results, it is clear that in the case without a passive wire breaking (Fig. 5a), two pulses come to the end of the active conductor instead of one pulse, which is caused by the difference in mode delays in the structure under study. When the passive wire breaks, an increase in the number of pulses occurs at the end of the active wire (Fig.5b-d). When a passive wire breaks at a distance of 0.5 m from the beginning of the structure, the number of pulses doubles at the end of the active wire. This is due to the fact that, at the point of a break, the probe pulse decomposes into two pulses if the difference in the mode delays to the point of break is longer than the pulse duration. When a passive wire breaks at a distance of 1 m from the beginning of the structure, 3 pulses come to the end of the active wire: impulses are superimposed, so the average pulse is larger in amplitude. Thus, the information obtained at the end of the active wire allows you to determine the presence of a break in the passive wire. The reflections at the beginning of the active conductor are also informative, which allows one to determine the distance to the gap or heterogeneity.

Claims (1)

A device for detecting, identifying and diagnosing multi-wire structures, comprising a control unit for coordinating the work of all the units included in the device, a pulse generator for generating probing signals, a receiving unit for receiving signals from the input / output of the connected line, a processing unit , designed to process signals received from the input / output of the connected line, the connected line between the pulse generator and the receiving unit, characterized in that in many the probe structure, formed by the connected line and external conductors in a nonuniform dielectric filling, the probe signal excites modes propagating in the resulting structure with unequal delays, the minimum difference of these delays being longer than the probe signal duration.

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