SU1376055A1 - Device for electric prospecting - Google Patents

Abstract

The invention relates to the exploration and detection of minerals by electric means using alternating or direct current by the method of induced polarization. The purpose of the invention - | improving the accuracy of quasi-compensation measurements by ensuring the stability of the parameters of the compensating signal. In the device for electrical prospecting, the galvanic uncoupling unit is made in the form of two toroidal cores of ferromagnetic material, enclosing the power cable. On each of the cores are wound excitation windings, connected in series and in series, and a common measuring winding. The device also contains an electronics unit. 2 Il. i (L

Description

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The invention relates to the means of reconnaissance and the detection of initial fossils by electric means using alternating or direct current and can be used in quasi-compensated measurements of nonlinear induced polarization, when external magnetic fields created by the current in the power cable are comparable to magnetic field, or significantly less than him.

The purpose of the invention is to improve the accuracy of quasi-compensation measurements by ensuring the stability of the parameters of the compensating signal.

FIG. 1 shows a block diagram of an electrical exploration device; FIG. 2 - electronics unit.

The device for electrical prospecting contains a current generator 1., The first 2-1 and the second 2-2 power cable, the first 3-1 and the second 3-2 power electrodes, the first 4-1 and the second 4-2 receiving electrodes, the regulator signal torus 5, measuring instrument 6, galvanic isolation unit 7, containing the first 8-1 and second 8-2 toroidal cores made of ferromagnetic material, the measuring coil 9, the first 10-1 and the second 10-2 excitation coils and block 11 electronics.

Unit 11 electronics contains. .

In block 7 of galvanic isolation, the output signal is formed in a grease-like manner. From the second and third outputs of the electronics unit 11, an alternating excitation current is applied to the series-opposing first and second 10-2 excitation coils. As a result, the first 8-1 and the second 8-2 toroidal cores, which are located adjacent to each other coaxially with respect to the power cable, are reversal in opposite directions. Choosing the first 8-1 and the second 8-2 cores with the same geometrical characteristics and the same magnetic and electrical

(FIG. 2) excitation generator 12, frequency doubler 13, narrow-band usi-os properties, that with the transmitter 14, amplifier 15, synchronous current in the power cable 2-2 passing through the centers of the cores, the signal in the measuring Coil 9 is absent, as it covers 40 two cores with equal and oppositely directed magnetic detectors 16 and a filter 17 of a 17 frequency band.

The device works as follows.

Current generator 1 produces mong

The alternating current (; in the form of a meander), the passage through the power cable 2-1 and 2-2, the supply electrodes 3-1 and 3-2, respectively, and the land between them, excites in the earth variable electromagnetic fields. The electric currents flowing in the ground during the excitation process create on the receiving electrodes 4-1 and 4-2 the potential difference U, the main KOhr components of which are the potential difference from the induced polarization and 5p of the rock and ore studied and the potential difference Ug , "Arising from the passage of the excitation current through the host rock, located between the receiving electrodes and possessing only active

currents. During the passage through the power cable 2-2 of the supply current 1d5 around the cable 2-2, and, consequently, inside the cores 8, a circular magnetic field of intensity H () occurs, where R is the distance from the center of the power cable 2-2 to the cores . K, for example, is equal to two radii of a power cable. This field creates an imbalance in the reversal of the first 8-1 and second 8-2 cores, as a result of which in the measuring coil 9 a signal appears at the even harmonics of the magnetization frequency G., the magnitude and phase of which depend, respectively, on the magnitude and direction current. In block 11, the electronics is highlighted.

resistance. Potential difference

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compensate in regulator 5

a signal made, for example, in the form of an ohmic resistance (in magnitude much smaller than the input resistance of the measuring device) to which a compensating signal equal to Ug is supplied through the output voltage divider of the galvanically isolated unit 7. Then, the potential difference from the receiving electrodes MN with the suppressed (or compensated) component UBM goes to the input of the measuring device 6, where the signal is further filtered and its parameters are measured.

In block 7 of galvanic isolation, the output signal is formed in a grease-like manner. From the second and third outputs of the electronics unit 11, an alternating excitation current is applied to the series-opposing first and second 10-2 excitation coils. As a result, the first 8-1 and the second 8-2 toroidal cores, which are located adjacent to each other coaxially with respect to the power cable, are reversal in opposite directions. Choosing the first 8-1 and the second 8-2 cores with the same geometrical characteristics and the same magnetic and electrical

properties, when there is no current in the power cable 2-2 passing through the centers of the cores, the signal in the measuring coil 9 is absent, since it covers two cores with equal and oppositely directed magnetic fluxes. During the passage through the power cable 2-2 of the supply current 1d5 around the cable 2-2, and, consequently, inside the cores 8, a circular magnetic field of intensity H () occurs, where R is the distance from the center of the power cable 2-2 to the cores . K, for example, is equal to two radii of a power cable. This field creates an imbalance in the reversal of the first 8-1 and second 8-2 cores, as a result of which in the measuring coil 9 a signal appears at the even harmonics of the magnetization frequency G., the magnitude and phase of which depend, respectively, on the magnitude and direction current. In block 11, the electronics is highlighted.

synchronously demodulated and filtered, for example, the second harmonic 2fg of the signal of the measuring coil 9, and the generated signal with a spectrum, for example, from O to f, is fed to the output of the galvanic isolation unit.

Unit 11 of the electronics operates as follows.

Excitation generator 12 generates an excitation signal at its outputs. This signal is sent to the second and third outputs of the electronics unit, as well as through the frequency doubler 13 and narrowband amplifier 14 (tuned to the second harmonic) to the reference input of the synchronous detector 16. To the main input of the synchronous detector 16 via the amplifier 15 (selection and amplification frequency spectrum in the range, for example, 2fg ± 0.9-fg), pos: the second harmonic signal from the measuring coil 9 blunts. As a result of synchronous detection, as well as harmonic suppression, carried out by the low-frequency filter 17, the electron at the first output of block I1 A junction is formed, the amplitude of which replicates the nature of the change in the time of current 1 dd in the power cable 2-2.

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Fore. Mule Invention

A device for electrical prospecting, containing a series-connected current generator, a power cable and supply electrodes, a series-connected galvanic isolation unit, a signal controller, and a measuring device, as well as first and second receiving electrodes, connected respectively to the second inputs of the signal controller and a measuring device, different in that, in order to increase the accuracy of quasi-compensation measurements, the galvanic isolation unit contains the first and second toroidal cores, will measure The first and the second excitation coils and the electronics unit, the first and the second excitation coils, respectively, are wound on the first and second cores, are connected in series to each other, and the second taps are connected to the second and third outputs of the electronics unit, the measuring coil covers the first and second cores, and its first and second taps are connected to the first and second inputs of the electronics unit, the first output of which is the output of the galvanic isolation unit, the power cable is passed through the core chnikov with measuring coil and katushkash vozbuddeni.

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FIG. 2

Claims (1)

SUMMARY OF THE INVENTION An electrical exploration device comprising a series-connected current generator, a power cable and * supply electrodes, a series-connected galvanic isolation unit, a signal regulator and a measuring device, as well as a first and * second— jg swarm receiving electrodes connected respectively to the second inputs signal regulator and measuring device, characterized in that, in order to improve the accuracy of quasi-compensation measurements, the galvanic isolation unit contains the first and second toroidal e cores measuring coil, the first and second excitation coils and 2Q electronics unit, the first and second excitation coils wound on the first and second cores, are connected oppositely ^series-g, and second bends their podklyu25 cheny to second and third outputs of the electronics unit, the measuring coil covers the first and second cores, and its first and second taps are connected to the first and second 20 inputs of the electronics unit, the first output of which is the output of the galvanic isolation unit, power cable - 1 b spruce is passed inside the cores with a measuring coil and excitation coils. 8-1 3 8-2 Figure 1 Fi g. 2