A high-power constant-voltage electromagnetic emission integrated measurement system

Abstract

The present invention provides a high-power constant-voltage electromagnetic emission integrated measurement system, comprising a high-power generator, a constant-current emission module, a constant-voltage emission module, and an electromagnetic receiving module. The high-power generator is electrically connected to the constant-current emission module and the constant-voltage emission module. The high-power generator, the constant-current emission module, and the constant-voltage emission module form a high-power electromagnetic emission control system. The high-power electromagnetic emission control system emits an excitation current signal, which uses the earth as a transmission medium and is received by the electromagnetic receiving module, thereby completing the measurement of underground geoelectric information. The present invention forms a high-power electromagnetic emission control system by using the high-power generator, the constant-current emission module, and the constant-voltage emission module. When grounding conditions are not good, a high-voltage constant-voltage emission system can be used to effectively solve the problem of sending electromagnetic signals that meet technical requirements under relatively high-resistance grounding conditions, effectively reducing field costs.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic surveying, and in particular relates to a high-power constant-voltage electromagnetic emission integrated measurement system. Background Art

[0002] Electric (magnetic) measurement is one of the important working methods of geophysical exploration, and is widely used in the fields of oil and gas exploration, solid mineral survey, groundwater, geothermal, engineering exploration and deep geological structure research. At present, the high-power electromagnetic transmission systems with a power of more than 150KW that have been put into use at home and abroad are the T200 transmitter of Phoenix Geophysical Company of Canada, the TFEM-3 time-frequency transmission system of PetroChina Oriental Geophysical Exploration Co., Ltd. and the JSGY-2 wide-area electromagnetic transmission system developed by Hunan Jishan High-tech. The above-mentioned high-power electromagnetic transmission systems all use a single constant current or voltage mode. The two transmission modes have their own advantages and disadvantages. In the constant current mode, the transmission system outputs a large current, which is a steady-current emission. The output current amplitude is adjusted by excitation to less than 2%, which is suitable for time domain electromagnetic method and medium and low frequency domain electromagnetic method. The disadvantage of the magnetic method is that it has high requirements for grounding conditions. It is difficult to transmit large currents when encountering an environment with exposed bedrock in mountainous areas or accumulated gravel on the surface. In the constant voltage mode, the transmitting system uses a fixed voltage to output large currents, and the output voltage is up to 2000V. In the frequency domain electromagnetic method, the transmitted current varies with the frequency and impedance. When it reaches a certain low frequency band, the current emission gradually stabilizes, and the output current amplitude changes by less than 5% at a constant frequency. Since this mode uses larger constant voltage components, the large voltage output is more suitable for transmitting electromagnetic signals that meet construction requirements in mountainous areas, deserts or Gobi areas with poor grounding conditions.

[0003] Based on this, a high-power constant-voltage electromagnetic emission integrated measurement system is proposed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-power constant-voltage electromagnetic emission integrated measurement system in view of the deficiencies of the above-mentioned prior art, so as to solve the problems raised in the above-mentioned background technology.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a high-power constant-voltage electromagnetic emission integrated measurement system, comprising a high-power generator, a constant current emission module, a constant voltage emission module and an electromagnetic receiving module, wherein the high-power generator is used to complete power supply, and the high-power generator is electrically connected to the constant current emission module and the constant voltage emission module, and a high-power electromagnetic emission control system is formed by the high-power generator, the constant current emission module and the constant voltage emission module;

[0006] The high-power electromagnetic emission control system sends out an excitation current signal, which uses the earth as a transmission medium and is received by the electromagnetic receiving module, thereby completing the measurement of underground geoelectric information.

[0007] Furthermore, the power of the high-power generator is 150-400kw.

[0008] Furthermore, an excitation regulator is connected between the constant current transmitting module and the constant voltage transmitting module, and the excitation regulator is used to adjust and control the output current of the high-power generator in real time when the constant current transmitting module and the constant voltage transmitting module are working.

[0009] Furthermore, the high-power electromagnetic emission control system adopts a constant current mode when the grounding condition is good, and adjusts and controls the output current of the high-power generator in real time through the excitation regulator according to the impedance and the working current of the preset frequency;

[0010] If the load is too large, the emission current will decrease. At this time, the phase-shift trigger pulse of the excitation regulator will be moved forward, which will increase the conduction time of the thyristor, increase the excitation current, increase the output voltage of the high-power generator, and increase the load current. Conversely, the generator voltage will be reduced and the current will decrease, so as to maintain the generator output load current constant.

[0011] When the grounding conditions are poor, the constant voltage mode is used. Similarly, the excitation control device is used to set a fixed voltage according to the impedance and the working current of the preset frequency, and the purpose of outputting the current signal is achieved by stabilizing the higher voltage.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] The present invention comprises a high-power electromagnetic emission control system composed of a high-power generator, a constant current emission module and a constant voltage emission module. When the grounding conditions are good, a constant current mode is adopted, and the output current of the high-power generator is adjusted and controlled in real time through an excitation regulator according to the impedance and the working current of a preset frequency. If the load is too large and the emission current decreases, the phase-shift trigger pulse of the excitation regulator is moved forward, the conduction time of the thyristor is increased, the excitation current is increased, the output voltage of the high-power generator is increased, and the load current increases. Conversely, the generator voltage is reduced, the current is reduced, and the output load current of the generator is maintained constant. When the grounding conditions are poor, a constant voltage mode is adopted. Similarly, a fixed voltage is set by the excitation control device according to the impedance and the working current of the preset frequency, and the purpose of outputting a current signal is achieved by stabilizing a higher voltage. Under extreme grounding conditions, the existing high-power constant-current transmission system is difficult to transmit a large current, resulting in the detection depth not meeting the design requirements. Under poor grounding conditions, the high-power constant-current transmission mode usually consumes a lot of manpower and material resources to reduce the grounding resistance. The use of a high-voltage constant-voltage transmission system can well solve the problem of sending electromagnetic signals that meet technical requirements under relatively high-resistance grounding conditions, effectively reducing field costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an exploded view of the overall structure of the present invention;

[0015] Figure 2 This is a schematic diagram of a current square wave signal in an embodiment of the present invention;

[0016] Figure 3 This is another schematic diagram of a current square wave signal in an embodiment of the present invention.

[0017] Description of reference numerals:

[0018] 1- high-power generator; 2- constant current transmitting module; 3- constant voltage transmitting module; 4-; excitation regulator; 5- excitation current signal; 6- electromagnetic receiving module. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] like Figure 1As shown, the present invention provides a technical solution: a high-power constant-voltage electromagnetic emission integrated measurement system, comprising a high-power generator 1, a constant-current emission module 2, a constant-voltage emission module 3 and an electromagnetic receiving module 6, wherein the high-power generator 1 is used to complete power supply, and the power of the high-power generator 1 is between 150-400kw.

[0021] The high-power generator 1 is electrically connected to the constant current transmitting module 2 and the constant voltage transmitting module 3. A high-power electromagnetic transmitting control system is formed by the high-power generator 1, the constant current transmitting module 2 and the constant voltage transmitting module 3. The transmitting voltage of the constant voltage transmitting module 3 is higher than that of other devices. The rated output voltage of the existing high-power electromagnetic transmitting system is 1200-1500V. The rated voltage of the constant voltage transmitting control module integrated this time can reach 2000V. Under the same complex grounding conditions, due to the high rated voltage of the transmitter and the current is adjusted by excitation, the transmitted current is also relatively high and more stable.

[0022] The high-power electromagnetic emission control system sends out an excitation current signal 5, which is specifically two current square wave signals. Figure 2 and Figure 3 shown.

[0023] The excitation current signal 5 uses the earth as a transmission medium and is received by the electromagnetic receiving module 6, thereby completing the measurement of underground geoelectric information.

[0024] An excitation regulator 4 is further connected between the constant current transmitting module 2 and the constant voltage transmitting module 3 , and the excitation regulator 4 is used to adjust and control the output current of the high-power generator 1 in real time when the constant current transmitting module 2 and the constant voltage transmitting module 3 are working.

[0025] Specifically, the high-power electromagnetic emission control system adopts a constant current mode when the grounding conditions are good, and adjusts and controls the output current of the high-power generator 1 in real time through the excitation regulator 4 according to the impedance and the working current of the preset frequency;

[0026] If the load is too large, the emission current will decrease. At this time, the phase-shift trigger pulse of the excitation regulator 4 will be moved forward, increasing the conduction time of the thyristor, so that the excitation current will increase, the output voltage of the high-power generator 1 will increase, and the load current will increase. Conversely, the generator voltage will be reduced, the current will decrease, and the generator output load current will be maintained constant.

[0027] When the grounding conditions are poor, the constant voltage mode is used. Similarly, the excitation control device is used to set a fixed voltage according to the impedance and the working current of the preset frequency, and the purpose of outputting the current signal is achieved by stabilizing the higher voltage.

[0028] Under extreme grounding conditions, the existing high-power constant-current transmission system is difficult to transmit a large current, resulting in the detection depth not meeting the design requirements. Under poor grounding conditions, the high-power constant-current transmission mode usually consumes a lot of manpower and material resources to reduce the grounding resistance. The use of a high-voltage constant-voltage transmission system can well solve the problem of sending electromagnetic signals that meet technical requirements under relatively high-resistance grounding conditions, effectively reducing field costs.

[0029] For example, the grounding resistance at the transmitting end of a certain mining area reaches 50Ω.m. To transmit a current of 50A, a general constant current device with a rated voltage of 1500V needs to be used, and the resistance needs to be reduced to 30Ω.m. This requires laying about 20 40*40cm aluminum plates with a spacing of 5m and a depth of more than 50cm. The estimated cost is about 3000 yuan. However, a constant voltage transmitting system with a rated voltage of 2000V only costs less than half of the cost under the same conditions.

[0030] Experimental example: In a large-scale electromagnetic exploration project for a copper polymetallic mine in Tibet, an experimental study was conducted based on the short-wave 150kw high-power electromagnetic measurement system in the embodiment;

[0031] The area is located in the central and eastern part of the Lhasa block in the Gangdise tectonic belt, at an altitude of 4,200-5,300 meters. The plateau is severely hypoxic. Due to mining construction and natural weathering, the shallow surface has a relatively complex stratigraphic structure. The exposed rocks are mainly metamorphic hornfels and limestones, some of which are intact and some are broken. The grounding conditions are poor, with a grounding resistance of 30Ω.m.

[0032] Before the experiment, two measurement methods were first used: the frequency-domain controlled source audio frequency magnetotelluric method and the time-domain induced polarization measurement in constant current mode. The experimental results showed that the controlled source audio frequency magnetotelluric method sent a maximum current of 50A in the low-frequency band of 10.6-0.75Hz, and only 12A in the high-frequency band of 1920-1024Hz due to the large impedance; the induced polarization measurement current was also 50A, and the measured resistivity and polarizability were relatively stable and repeatable.

[0033] Secondly, the same test was conducted in constant voltage mode. The test results showed that the maximum transmission current of the controlled source audio magnetotelluric method in the low frequency band of 10.6-0.75Hz can reach 65A, and the transmission current in the high frequency band of 1920-1024Hz is only 19A; the induced polarization measurement current is also 65A, and the measured resistivity and polarizability are relatively stable. However, since the transmission current in constant voltage mode is not as stable as that in constant current mode, the repeatability is not as good as the test results in constant current mode.

[0034] Based on the above test results, it can be concluded that the present invention can not only meet the electromagnetic emission measurement requirements under general geological environments, but also, especially under complex grounding conditions, through the combination or conversion of constant current and constant voltage modes, it can provide a higher emission current, meet the detection requirements of different depths, and provide convenience for electromagnetic exploration in different geological environments.

[0035] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0036] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-power constant-voltage electromagnetic emission integrated measurement system, characterized by: The invention comprises a high-power generator (1), a constant-current transmitting module (2), a constant-voltage transmitting module (3) and an electromagnetic receiving module (6), wherein the high-power generator (1) is used to complete power supply, and the high-power generator (1) is electrically connected to the constant-current transmitting module (2) and the constant-voltage transmitting module (3), and a high-power electromagnetic transmitting control system is formed by the high-power generator (1), the constant-current transmitting module (2) and the constant-voltage transmitting module (3); The high-power electromagnetic emission control system emits an excitation current signal (5), and the excitation current signal (5) uses the earth as a transmission medium and is received by the electromagnetic receiving module (6), thereby completing the measurement of underground geoelectric information; An excitation regulator (4) is also connected between the constant current transmitting module (2) and the constant voltage transmitting module (3), and the excitation regulator (4) is used to adjust and control the output current of the high-power generator (1) in real time when the constant current transmitting module (2) and the constant voltage transmitting module (3) are working; The high-power electromagnetic emission control system adopts a constant current mode when the grounding condition is good, and performs real-time regulation and control on the output current of the high-power generator (1) through the excitation regulator (4) according to the impedance and the working current of the preset frequency; If the load is too large, the emission current decreases. At this time, the phase-shift trigger pulse of the excitation regulator (4) moves forward, increasing the conduction time of the thyristor, so that the excitation current increases, the output voltage of the high-power generator (1) increases, and the load current increases. Conversely, the generator voltage is reduced, the current decreases, and the generator output load current is maintained constant; When the grounding conditions are poor, the constant voltage mode is used. Similarly, the excitation control device is used to set a fixed voltage according to the impedance and the working current of the preset frequency, and the purpose of outputting the current signal is achieved by stabilizing the higher voltage.

2. A high-power constant-voltage electromagnetic emission integrated measurement system according to claim 1, characterized in that: The power of the high-power generator (1) is 150-400kw.

3. The high-power constant-voltage electromagnetic emission integrated measurement system according to claim 1, characterized in that: The excitation current signal (5) is specifically two current square wave signals.

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