RU80010U1 - MODAL SENSING DEVICE - Google Patents

Abstract

The invention relates to measuring equipment, specifically to devices for detecting, identifying, diagnosing multi-wire structures. A modal sensing device, comprising a control unit for coordinating the work of all nodes included in the device, a pulse generator for generating sounding signals, a receiving unit for receiving signals from the input / output of the connected line, a processing unit for processing 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 the resulting structure formed by tea line and outer conductors in a nonuniform dielectric filling, excites the probe signal modes propagating in the resultant structure with unequal delays, and the difference of these delays is less than the duration of the probing signal. The technical result is the creation of a device that allows for the detection, identification, diagnostics of wire structures, including without direct physical access to them.

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 as a 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 s from the input of the line, reflected from the place of damage and inhomogeneities of the wave resistance, a processing unit designed to process signals received from the input of the probed line.

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 modal sensing device does not require this.

A modal sensing device, comprising a control unit for coordinating the work of all nodes included in the device, a pulse generator for generating sounding signals, a receiving unit for receiving signals from the input / output of the connected line, a processing unit for processing 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 the resulting structure formed by tea line and outer conductors in a nonuniform dielectric filling, excites the probe signal 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 technical result is the creation of a device that allows for the 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 multi-wire structure with an inhomogeneous dielectric filling, from N conductors (not counting the reference) it can undergo modal distortions, up to decomposition into N pulses of smaller amplitude due to the difference in the specific mode delays 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 by the waveform in the probe line.

The principle of operation of the modal sensing device is explained by the example of computer simulation of the propagation of a pulse in an N-wire segment of length l of a conventional microstrip line (its parameters and modeling are described in detail in the work "Study of modal distortion of a pulse signal in multi-wire lines with inhomogeneous dielectric filling", Electromagnetic waves and electronic system No. 11. 2004. S.18-22) for N = 2.1 = 1.5 m (Fig. 1) and N = 3, l = 3.0 m (Fig. 2).

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 1, 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 2, 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. 3a), the possibility of diagnostics, 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 cable segments (Fig.3b), with R3 = R4 = 5 · 10 ⁹ Ohm. The total length of the structure is 2 m, the break point of the passive conductor moved: 0.5; 1; 1.5 m from the beginning of the line. (Parameters of the probe pulse: amplitude 2 V, the duration of the leading edge 100 ps, the duration of the trailing edge 100 ps, the duration of the flat peak of the pulse 100 ps). The simulation results are shown in figure 4.

According to the simulation results, it can be seen that in the case without a passive wire breaking (Fig. 4a), 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. 4b-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 modal sensing device containing a control unit for coordinating the work of all the nodes included in the device, a pulse generator for generating sounding signals, a receiving unit for receiving signals from the input / output of the connected line, a processing unit for processing 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 the resulting structure formed by tea line and outer conductors in a nonuniform dielectric filling, excites the probe signal modes propagating in the resultant structure with unequal delays, and the difference of these delays is less than the duration of the probing signal.