阅读说明：本技术 一种探测大地电性结构的方法和装置 (Method and device for detecting earth electrical structure ) 是由 陈卫营 何一鸣 薛国强 陈稳 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种探测大地电性结构的方法和装置,所述方法包括：获取输电线产生的工频电磁场信号与大地作用后的信号；从获得的信号中提取有效工频电磁场信号；对有效工频电磁场信号进行数据处理得到大地电性结构。本发明实施例基于工频电磁场信号实现对大地电性结构的测量,既消除了工频电磁场干扰,又实现了对大地电性结构的探测,提高了对大地电性结构的探测精度,降低了起伏山区的探测成本,提高了起伏山区的施工效率。(The invention discloses a method and a device for detecting a geodetic structure, wherein the method comprises the following steps: acquiring a power frequency electromagnetic field signal generated by a power transmission line and a signal after the action of the ground; extracting effective power frequency electromagnetic field signals from the obtained signals; and carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure. The embodiment of the invention realizes the measurement of the electrical structure of the earth based on the power frequency electromagnetic field signal, thereby not only eliminating the interference of the power frequency electromagnetic field, but also realizing the detection of the electrical structure of the earth, improving the detection precision of the electrical structure of the earth, reducing the detection cost of the undulating mountain area and improving the construction efficiency of the undulating mountain area.)

1. A method of exploring earth electrical structures, comprising:

acquiring a signal generated by the power frequency electromagnetic field generated by the power transmission line after the power frequency electromagnetic field acts on the ground;

extracting effective power frequency electromagnetic field signals from the obtained signals;

and carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure.

2. The method of claim 1, wherein extracting the effective power frequency electromagnetic field signal from the obtained signal comprises:

carrying out Fourier transform on the obtained signals, extracting signals with specific frequency from the signals after Fourier transform, and carrying out inverse Fourier transform on the signals with specific frequency to obtain the effective power frequency electromagnetic field signals;

wherein the specific frequency comprises a fundamental frequency and at least one of: multiple harmonics, inter-harmonics, sub-harmonics.

3. The method of claim 2, wherein the step of performing data processing on the effective power frequency electromagnetic field signal to obtain the earth electrical structure comprises:

determining the harmonic frequency current according to the vertical magnetic field component of the fundamental frequency and the vertical magnetic field component of the harmonic frequency; wherein the harmonic frequency comprises at least one of: multiple harmonic frequencies, inter-harmonic frequencies, sub-harmonic frequencies;

when the effective power frequency electromagnetic field signal meets the non-near-field condition, calculating an electromagnetic field generated by an infinite-length wire and an electromagnetic field generated by a transmission line in the layered earth according to the fundamental frequency current and the harmonic frequency current;

and inverting the effective power frequency electromagnetic field signal according to the electromagnetic field generated by the infinite long lead and the electromagnetic field generated by the transmission line in the layered earth to obtain the earth electrical structure.

4. An apparatus for detecting a geoelectrical structure, comprising:

the signal acquisition module is used for acquiring a signal generated by the power frequency electromagnetic field signal generated by the power transmission line after the signal acts on the ground;

the signal extraction module is used for extracting effective power frequency electromagnetic field signals from the obtained signals;

and the signal processing module is used for carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure.

5. An apparatus for surveying earth electrical structures, comprising a processor and a computer readable storage medium having stored therein instructions which, when executed by the processor, carry out the steps of the method of surveying earth electrical structures according to any one of claims 1-3.

6. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method for exploring earth electrical structures according to any one of claims 1 to 3.

Technical Field

The embodiment of the invention relates to an electromagnetic field and an application technology thereof, in particular to a method and a device for detecting a geoelectrical structure.

Background

The electromagnetic method is a main means for detecting the electrical structure of the earth, and has the advantages of large exploration depth, no shielding by a high-resistance layer, sensitivity to a low-resistance body, low cost and efficiency and the like, so that the electromagnetic method is widely applied to the fields of metal mineral products, oil and gas resources, hydrogeology, engineering exploration, environment assessment, shell mantle research and the like. The acquisition of the observation signal with high signal-to-noise ratio is a key factor for guaranteeing the data processing precision and the accuracy of the detection result of the electromagnetic method, and is also a primary target of data acquisition. However, data of the electromagnetic method is usually interfered by various noises, resulting in degradation of signal quality. One of the most common and serious disturbances is the power frequency electromagnetic field disturbance generated by the transmission line system, i.e. the electromagnetic wave disturbance of 50 hertz (Hz) (60 Hz in some countries) and its harmonic components. When the observation point is close to the power transmission line, the effective electromagnetic signal is almost submerged by the strong power frequency signal, 50Hz noise interference with similar amplitude is formed, and the observation data is seriously distorted.

In order to suppress or remove the interference of power frequency electromagnetic field in the electromagnetic data, people have to adopt various technical means in the data acquisition and processing process. However, the interference of the power frequency electromagnetic field has more influence ways on the observation of the electromagnetic method, the influence mechanism is more complex, the interference influence has diversity, the single data processing method is difficult to completely filter the interference, and most filtering technologies cause the loss of effective frequency spectrum information. Especially, when the power frequency electromagnetic field is close to the power transmission line and the interference intensity of the power frequency electromagnetic field is high, the interference of the power frequency electromagnetic field cannot be completely eliminated by the conventional filtering and trapping technology, and the interference caused by the frequency aliasing effect, the amplitude limiting effect, the harmonic effect and the like cannot be eliminated by a subsequent data processing method. The interference of power frequency electromagnetic field becomes an unavoidable and difficult-to-overcome interference in the measurement of electromagnetic method.

Disclosure of Invention

The embodiment of the invention provides a method and a device for detecting an earth electrical structure, which can realize the detection of the earth electrical structure under the condition of eliminating the interference of a power frequency electromagnetic field generated by a power transmission line.

The embodiment of the invention provides a method for detecting an earth electrical structure, which comprises the following steps:

acquiring a power frequency electromagnetic field signal generated by a power transmission line and a signal after the action of the ground;

extracting effective power frequency electromagnetic field signals from the obtained signals;

and carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure.

In the embodiment of the invention, the extracting the effective power frequency electromagnetic field signal from the obtained signal comprises the following steps:

carrying out Fourier transform on the obtained signals, extracting signals with specific frequency from the signals after Fourier transform, and carrying out inverse Fourier transform on the signals with specific frequency to obtain the effective power frequency electromagnetic field signals;

wherein the specific frequency comprises a fundamental frequency and at least one of: multiple harmonics, inter-harmonics, sub-harmonics.

In the embodiment of the invention, the step of carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geoelectrical structure comprises the following steps:

determining the harmonic frequency current according to the vertical magnetic field component of the fundamental frequency and the vertical magnetic field component of the harmonic frequency; wherein the harmonic frequency comprises at least one of: multiple harmonic frequencies, inter-harmonic frequencies, sub-harmonic frequencies;

when the effective power frequency electromagnetic field signal meets the non-near-field condition, calculating an electromagnetic field generated by an infinite-length wire and an electromagnetic field generated by a transmission line in the layered earth according to the fundamental frequency current and the harmonic frequency current;

and inverting the effective power frequency electromagnetic field signal according to the electromagnetic field generated by the infinite long lead and the electromagnetic field generated by the transmission line in the layered earth to obtain the earth electrical structure.

The embodiment of the invention provides a device for detecting a geodetic structure, which comprises:

the signal acquisition module is used for acquiring a signal generated by the action of a power frequency electromagnetic field signal generated by transmission electricity and the ground;

the signal extraction module is used for extracting effective power frequency electromagnetic field signals from the obtained signals;

and the signal processing module is used for carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure.

An embodiment of the present invention provides an apparatus for detecting a geodetic structure, which includes a processor and a computer-readable storage medium, wherein instructions are stored in the computer-readable storage medium, and when the instructions are executed by the processor, the steps of any one of the above methods for detecting a geodetic structure are implemented.

An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, the computer program, when being executed by a processor, implementing any one of the above-mentioned methods for detecting a geodetic structure.

The embodiment of the invention comprises the following steps: acquiring a power frequency electromagnetic field signal generated by a power transmission line and a signal after the action of the ground; extracting effective power frequency electromagnetic field signals from the obtained signals; and carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure. The embodiment of the invention realizes the measurement of the electrical structure of the earth based on the power frequency electromagnetic field signal, thereby not only eliminating the interference of the power frequency electromagnetic field, but also realizing the detection of the electrical structure of the earth, improving the detection precision of the electrical structure of the earth, reducing the detection cost of the undulating mountain area and improving the construction efficiency of the undulating mountain area.

Drawings

The accompanying drawings in the embodiments of the present invention are described below, and the drawings in the embodiments are provided for further understanding of the present invention, and together with the description serve to explain the present invention without limiting the scope of the present invention.

FIG. 1 is a flow chart of a method for detecting a geodetic structure according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a power frequency electromagnetic field signal generated by a power transmission line as observed by an apparatus of an embodiment of the present invention;

FIG. 3 is a diagram illustrating spectral information of an electromagnetic field according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a resistivity-depth profile of an embodiment of the present invention

Fig. 5 is a schematic structural composition diagram of an apparatus for detecting a geodetic structure according to another embodiment of the present invention.

Detailed Description

The following further description of the present invention with reference to the accompanying drawings is not intended to limit the scope of the present invention. In the present application, the embodiments and various aspects of the embodiments may be combined with each other without conflict.

The power frequency electromagnetic wave generated by the power transmission line also has an electromagnetic coupling effect with the earth in the transmission process and carries the resistivity information of the earth, so that the detection of the earth electrical structure by utilizing the power frequency electromagnetic field generated by the power transmission line can be considered, and the electromagnetic field generated by the power transmission line has richer frequency spectrum information. Using our country as an example, the fundamental frequency (f) of the transmission line₀) At 50Hz, multiple harmonics (f ═ nf) are also generated due to voltage and current distortions₀) And (3) components. In addition, rich inter-harmonics (f ≠ nf) are generated in the grid system₀) And subharmonic (0)<f<f₀) And (3) components. It is very advantageous if this part of the electromagnetic field can be used efficiently for detection. Firstly, the current in the power transmission line can reach hundreds to thousands of amperes generally, energy which can not be reached by a conventional artificial source can be transmitted, and signals can cover a large range; secondly, the amplitude of the power frequency electromagnetic field of the fixed power transmission line is basically stable, and repeated observation is convenient to implement; thirdly, the position and attribute information of the power transmission line can be obtained, and the electromagnetic field generated by the power transmission line is calculated; finally, power grids in China are densely distributed, and even mountainous areas with rare people smoke often have power transmission lines, so that convenience is brought to observation.

Referring to fig. 1, one embodiment of the present invention provides a method for detecting a geodetic structure, comprising:

and step 100, acquiring a power frequency electromagnetic field signal generated by the power transmission line and a signal after the action of the earth.

In the embodiment of the invention, the signals of the power frequency electromagnetic field signal after acting with the earth comprise: electric field component E parallel to the transmission line_yHorizontal magnetic field component H perpendicular to the transmission line_xAnd the magnetic field component H in the direction of the plumb_z(i.e., the vertical magnetic field component).

In the embodiment of the present invention, the instrument capable of performing measurement by the magnetotelluric method, such as V8, GMS-07e, etc., may be used to observe the power frequency electromagnetic field signal within a certain range from the power transmission line, and the instrument capable of performing measurement by the magnetotelluric method may be used to observe the power frequency electromagnetic field signal and then transmit the power frequency electromagnetic field signal to the apparatus or device implementing the method for detecting an electrical earth structure according to the embodiment of the present invention.

In an embodiment of the invention, the electric field component E parallel to the transmission line is observed by means of electrodes_yObserving the horizontal magnetic field component H perpendicular to the transmission line by means of a magnetic probe_xPerpendicular magnetic field component H in the direction of plumb_z。

And 101, extracting an effective power frequency electromagnetic field signal from the obtained signal.

In the embodiment of the invention, the obtained signals are subjected to Fourier transform, signals with specific frequency are extracted from the signals after Fourier transform, and the signals with specific frequency are subjected to Fourier inverse transform to obtain effective power frequency electromagnetic field signals.

Wherein the obtained signal can be fourier transformed using complex modulation frequency refinement techniques.

Wherein the specific frequency comprises a fundamental frequency and at least one of: multiple harmonics, inter-harmonics, sub-harmonics.

And 102, carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geodetic structure.

In an embodiment of the present invention, the geodetic structure comprises geodetic resistivity and depth information.

In the embodiment of the invention, the step of carrying out data processing on the effective power frequency electromagnetic field signal to obtain the geoelectrical structure comprises the following steps:

determining the harmonic frequency current according to the vertical magnetic field component of the fundamental frequency and the vertical magnetic field component of the harmonic frequency; wherein the harmonic frequency comprises at least one of: multiple harmonic frequencies, inter-harmonic frequencies, sub-harmonic frequencies;

when the effective power frequency electromagnetic field signal meets the non-near-field condition, calculating an electromagnetic field generated by an infinite-length wire and an electromagnetic field generated by a transmission line in the layered earth according to the fundamental frequency current and the harmonic frequency current;

and inverting the effective power frequency electromagnetic field signal according to the electromagnetic field generated by the infinite long lead and the electromagnetic field generated by the transmission line in the layered earth to obtain the earth electrical structure.