Grounding system of long-wave transmitting antenna

Abstract

The invention provides a grounding system of a long-wave transmitting antenna, and relates to the technical field of grounding systems. The system comprises a top wire ground screen, a high-voltage feeder ground screen, a tuning pavilion ground screen, an iron tower ground screen, a grounding well and a ground screen outer edge bus bar, the loss resistance of a high-voltage and high-intensity magnetic field in a grounding system is reduced aiming at the problem of the density of current borne by a top line, a high-voltage feeder line and a tuning booth, so that the grounding loss resistance is reduced to a great extent. In addition, aiming at the problem of large current density of the tuning booth, the ground net of the tuning booth is arranged by utilizing a plurality of dense and radially laid wires, so that the loss of the ground net is improved. The problem that grounding loss resistance is large due to the fact that a grounding system is designed through a large-scale dense ground net at present is solved.

Description

Technical Field

[0001] The invention relates to the technical field of grounding systems, and in particular to a grounding system for a long-wave transmitting antenna. Background Art

[0002] Long waves propagate around the world between the earth and the ionosphere in a waveguide manner. Since long wave signals have stable propagation, are less affected by nuclear explosions, have a strong ability to penetrate seawater and strata, and have low losses during atmospheric propagation, with an attenuation rate of only 2 to 3 dB per thousand kilometers, long waves have become an important means of underwater covert communication and play an irreplaceable and important role.

[0003] The structural dimensions of the long-wave transmitting antenna are relatively large, with an operating frequency of 10kHz-100kHz and a wavelength of 3km-30km. At present, the commonly used ultra-long wave transmitting antennas (also called ultra-low frequency transmitting antennas) are mainly in the form of T-shaped antennas, valley antennas, hexagonal antennas, and thirteen-tower antennas. Among them, the T-shaped antenna is widely used due to its mature and reliable technology and low cost. However, the double T antenna usually requires the erection of multiple iron towers as high as 200-300 meters, and the iron towers are also equipped with antennas 200-300 meters above the ground, which results in the antenna and grounding system occupying an area of ​​several square kilometers.

[0004] Faced with such a large antenna structure, although the radiation resistance of the long-wave transmitting antenna is low, the radiation resistance R of the double-T antenna at 20kHz is usually f is only 0.10Ω, but the loss resistance R s Usually much larger than the radiation resistance R f , which leads to the calculated long-wave antenna radiation efficiency R f / (R f +R s ) is low, affecting the propagation performance. It can be seen that the loss resistance of the long-wave transmitting antenna is very important, and the size of the loss resistance will directly affect the radiation efficiency of the long-wave antenna. s The main factor is the ground loss resistance R in the grounding system g Therefore, the ground loss resistance in the grounding system will directly affect the antenna radiation efficiency. However, since the grounding system covers an area of ​​several square kilometers, the grounding system is usually designed with a large-scale dense grid, which will make the ground loss resistance larger and affect the long-wave antenna radiation efficiency. Summary of the invention

[0005] Based on this, it is necessary to provide a grounding system for a long-wave transmitting antenna in response to the above technical problems, so as to solve the problem of large grounding loss resistance caused by the current large-scale dense ground grid design of the grounding system.

[0006] The present invention provides a grounding system for a long-wave transmitting antenna, the system comprising: The top line ground grid includes a plurality of first conductors laid parallel to the top line direction, wherein the first conductors and the second conductors cross each other and are connected through intersections; A high-voltage feeder grounding network, comprising a plurality of second conductors laid parallel to the high-voltage feeder direction, wherein the second conductors are laid at unequal intervals, and the second conductors are connected to the first conductor and the third conductor at the intersection; A tuning booth ground grid is arranged at the periphery of the tuning booth, and the tuning booth ground grid includes a plurality of third conducting wires laid radially; An iron tower ground grid is arranged at the periphery of the iron tower, and the iron tower ground grid comprises a plurality of fourth wires laid radially, and the fourth wires are connected to the first wires; The grounding well includes a deep grounding well and a shallow grounding well; the deep grounding well is arranged at the periphery of the tuning booth grounding grid; the shallow grounding well is evenly arranged at the edge of the entire area of ​​the top line grounding grid; The outer edge busbar of the grounding grid includes at least one busbar, and the busbar is laid along the edge of the top-line grounding grid.

[0007] Furthermore, the second conductors are laid at unequal intervals in the following manner: The laying density of the second conductors on the side close to the high-voltage feeder is greater than the laying density on the side far from the high-voltage feeder.

[0008] Furthermore, the third wires arranged along the regional boundary of the tuning booth ground grid are of the first size, and the plurality of third wires arranged radially inside the boundary of the tuning booth ground grid are of the second size; Among them, multiple third conductors of the second size are evenly laid in a radial shape with the outlet of the high-voltage wall insulator of the tuning booth as the center, and are connected to the third conductor of the first size at the same time.

[0009] Furthermore, the area shape of the tuning booth ground grid is square.

[0010] Furthermore, the first size is greater than the second size.

[0011] Furthermore, the length of the first conductive wire is greater than the length of the second conductive wire.

[0012] Furthermore, the area size of the tuning booth grounding network is determined according to the laying width of the high-voltage feeder grounding network.

[0013] Furthermore, the first conductor, the second conductor, the third conductor, the fourth conductor and the busbar are all made of copper.

[0014] Furthermore, the interval between the first conductive wires is 10 m.

[0015] Furthermore, the laying method includes underground setting, and the underground depth is 0.2~0.4m.

[0016] In general, the present invention provides a grounding system for a long-wave transmitting antenna, which can achieve the following beneficial effects compared with the prior art: The present invention can reduce the loss resistance of high voltage and strong magnetic field in the grounding system by setting a top line grounding network, a high-voltage feeder grounding network, a tuning booth grounding network, an iron tower grounding network, a grounding well and a grounding network outer edge busbar, aiming at the problem of the current density carried by the top line, the high-voltage feeder and the tuning booth, thereby greatly reducing the grounding loss resistance. In addition, the present invention aims at the problem of high current density of the tuning booth, and uses a plurality of densely and radially laid wires to set up the tuning booth grounding network, thereby improving the grounding network loss.

[0017] In addition, in order to address the problem of low carrying current density due to the distance between the top lines and the top lines of the ground grid being as high as 200m, the present invention not only adds an iron tower ground grid, a grounding well and a grounding busbar at the outer edge of the ground grid, but also further sets up sparse ground grid conductors with a conductor spacing of 10m, thereby reducing the ground grid loss, thereby greatly reducing the ground loss resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the system principle of a grounding system of a long-wave transmitting antenna provided by the present invention; Figure 2 It is a schematic diagram of a grounding deep well of a grounding system of a long-wave transmitting antenna provided by the present invention; Figure 3 It is a schematic diagram of a grounding shallow well of a grounding system of a long-wave transmitting antenna provided by the present invention; Figure 4 It is a schematic diagram showing the influence of the conductor diameter on the ground loss resistance of a grounding system of a long-wave transmitting antenna provided by the present invention; Figure 5 It is a schematic diagram of the effect of the spacing between the first conductors in the top line grounding network of the grounding system of a long-wave transmitting antenna provided by the present invention on the ground loss resistance; Figure 6 It is a schematic diagram showing the influence of the buried depth of the conductor on the ground loss resistance of the grounding system of a long-wave transmitting antenna provided by the present invention; 1-top line ground grid; 2-high voltage feeder ground grid; 3-tuning booth ground grid; 4-iron tower ground grid; 5-grounding deep well; 6-grounding shallow well; 7-busbar at the outer edge of the ground grid. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the drawings and embodiments of the present invention. Obviously, the described embodiments are 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 creative work belong to the scope of protection of the present invention.

[0021] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a method, step or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such method, step or system. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the method, step or system including the element.

[0022] The grounding system is a general term for a mesh structure of multiple metal grounding electrodes buried at a certain depth underground and connected by conductors. It is widely used in many industries such as electricity, construction, computers, industrial and mining enterprises, communications, etc., playing the role of safety protection and shielding. Grounding systems can be large or small, some are very complex and large, and some are composed of only one grounding electrode. They are generally designed according to needs.

[0023] In order to solve the problem of large ground loss resistance caused by the current large-scale dense ground grid design of the grounding system. Figure 1 As shown, the present invention provides a grounding system for a long-wave transmitting antenna, the system comprising: a top line grounding grid, a high-voltage feeder grounding grid, a tuning booth grounding grid, an iron tower grounding grid, a grounding well and a grounding grid outer edge busbar, and the conductors of each grounding grid are well welded at the intersection.

[0024] The top line ground grid includes a plurality of first conductors laid in parallel to the top line direction, the first conductors and the second conductors cross each other and are connected through intersections.

[0025] The top-line grounding grid mainly provides reliable ground potential for buildings, and when the building is struck by lightning, it allows the lightning current to be smoothly discharged into the earth through a larger area of ​​the grounding grid without generating dangerous step voltage and contact voltage.

[0026] Preferably, the first conductive wire and the second conductive wire cross each other perpendicularly.

[0027] The area of ​​the top-line grounding grid can be set according to the total area of ​​the grounding system. For example, if the total area of ​​the grounding network is 1800m×1600m, the top-line grounding grid can be evenly laid parallel to the top-line direction using 160 first conductors with a spacing of 10m.

[0028] As a specific embodiment of the present invention, the first conductor can be a copper wire with a diameter of Φ3mm, and the top line ground grid can be made of 160 copper wires with a diameter of Φ3mm laid parallel to the top line direction, with an interval of 10m and a conductor length of 1600m. The buried depth of the first conductor is 0.2~0.4m, preferably 0.3m, and is connected to the high-voltage feeder ground grid at the intersection.

[0029] The high-voltage feeder grounding network comprises a plurality of second conductors laid parallel to the high-voltage feeder direction, and the second conductors are laid at unequal intervals, and the second conductors are connected to the first conductor and the third conductor at the intersection.

[0030] The function of high-voltage feeder is to transmit high-voltage electric energy and high-voltage electric signals. It can be connected to any distribution network node and can be a feed-in branch or a feed-out branch. The high-voltage feeder grounding network is connected to the tuning booth grounding network and the top line grounding network at the intersection.

[0031] Furthermore, the high-voltage feeder ground grid is welded together with the tuning booth ground grid frame and the top-line ground grid at the intersection, and the end is welded to the busbar laid along the edge of the top-line ground grid.

[0032] The current under the high-voltage feeder is unevenly distributed, with large ground current in the area close to the high-voltage feeder and small ground current in the area far from the high-voltage feeder. In order to give full play to the effectiveness of the high-voltage feeder ground network, as an embodiment, the laying density of the second conductor close to the high-voltage feeder is greater than the laying density far from the high-voltage feeder. That is, the areas close to the high-voltage feeder are densely arranged, and the areas far from the high-voltage feeder are sparsely arranged.

[0033] In other words, the second conductor is arranged below the high-voltage feeder, and with the high-voltage feeder as the central axis, multiple second conductors are arranged in the vertical direction on both sides of the high-voltage feeder. The second conductors on both sides of the high-voltage feeder are densely arranged near the high-voltage feeder and sparsely arranged far away from the high-voltage feeder.

[0034] It should be noted that the second conductors on both sides of the high voltage feeder can be symmetrical or asymmetrical, preferably symmetrical.

[0035] For example, with the high-voltage feeder as the central axis, it is divided into side A and side B; the vertical distance between the two second conductors in the middle of the high-voltage feeder grounding network and the projection of the high-voltage feeder is symmetrical, that is, 0.2m on side A and 0.2m on side B; it can also be asymmetrical, that is, 0.2m on side A and 0.3m on side B. Then the two sides are laid incrementally with these two conductors as the starting point.

[0036] It should be noted that the incremental laying may be in accordance with a regular increment or in accordance with an irregular increment. That is, along the vertical direction of the high-voltage feeder, the interval between two adjacent conductors may be increased regularly or irregularly. Preferably, the interval is increased in accordance with a set regular increment.

[0037] For example, when increasing in accordance with a rule, the intervals between adjacent second conductors arranged on side A may be: 0.4m, 0.6m, 0.8m, ...; when not increasing in accordance with a rule, they may also be: 0.4m, 0.5m, 0.7m, .... When the two sides are symmetrical, the intervals between adjacent second conductors arranged on side B are consistent with those on side A; when the two sides are asymmetrical, the intervals between adjacent second conductors arranged on side B may be: 0.4m, 0.6m, 0.8m, ...; they may also be: 0.4m, 0.5m, 0.8m, ....

[0038] Preferably, the second conductors on both sides of the high-voltage feeder are symmetrical, and the projection of the high-voltage feeder directly below the ground is the symmetry axis of all the second conductors; that is, the high-voltage feeder grounding area takes the projection of the high-voltage feeder directly below the ground as the symmetry axis.

[0039] For example, the second conductor can be a copper wire with a diameter of Φ3mm. 70 copper wires with a diameter of Φ3mm are arranged parallel to the direction of the high-voltage feeder, with a width of 250m. The length can be equal to the width of the wiring system or the width of the top line ground grid area, set to 1600m, and the buried depth of the second conductor is 0.2~0.4m, preferably 0.3m; the two second conductors in the middle of the high-voltage feeder ground grid are 0.2m apart from the vertical projection of the high-voltage feeder, and the two sides are laid with these two conductors as the starting point and increased by 0.2m, that is, the intervals between the second conductors on both sides are 0.4m, 0.6m, 0.8m,... respectively.

[0040] The tuning booth ground grid is arranged at the periphery of the tuning booth, and the tuning booth ground grid includes a plurality of third conducting wires which are laid radially.

[0041] The function of the tuning booth is to make the antenna slot present a pure impedance to the transmitter at the operating frequency, so as to maximize the power radiated to the antenna. Therefore, the control requirement for the tuning booth is to be able to automatically select the shortening capacitor according to the operating frequency, complete the coarse and fine selection of the extension wire coil, and automatically adjust the fine-tuning wire coil according to the detection of the antenna resonant impedance to make the tuning booth present a pure impedance.

[0042] Since the tuning booth has high voltage and high current when the transmitter is working, the electromagnetic field strength around the tuning booth is very high, making the vicinity of the tuning booth a dangerous area when the transmitter is working. Therefore, the present invention sets up a tuning booth ground grid, which not only reduces the danger, but also reduces the ground loss resistance by laying multiple third wires of the tuning booth ground grid in a radial shape.

[0043] As a specific embodiment, the third wires arranged along the regional boundary of the tuning booth ground grid are of the first size, and the plurality of radially laid third wires arranged inside the boundary of the tuning booth ground grid are of the second size.

[0044] Among them, multiple third conductors of the second size are evenly laid in a radial shape with the outlet of the high-voltage wall insulator of the tuning booth as the center, and are connected to the third conductor of the first size at the same time.

[0045] Furthermore, the first size is greater than the second size. It should be noted that the first size and the second size may be the diameter, radius or cross-sectional area of ​​the wire.

[0046] In addition, the area shape of the tuning pavilion ground grid can be various shapes, such as square, rectangle, circle, triangle, etc. Preferably, the plurality of third wires of the second size are of the same size, that is, the diameter, radius, cross-sectional area, length, etc. are all equal. Preferably, it is square or circle.

[0047] As a specific embodiment, a tuning booth ground grid is laid near each of the two tuning booths. The regional shape of the tuning booth ground grid is a square with a side length of 250m. The first size laid along the regional boundary is a thick copper wire with a diameter of Φ6mm. A plurality of second size copper wires with a diameter of 50 copper wires of Φ3mm are arranged inside the boundary. The boundary is radially laid evenly with the outlet of the tuning booth high-voltage wall insulator as the center. The buried depth of the third conductor is 0.2~0.4m, preferably 0.3m.

[0048] The tower ground network is arranged at the periphery of the tower, and comprises a plurality of fourth conductors which are radially laid, and the fourth conductors are connected to the first conductors.

[0049] That is, the tower grounding network is located around each tower, and multiple fourth conductors are laid radially. Among them, each supporting tower should ensure that the four sides are reliably connected to the first conductor of the top line grounding network to achieve lightning protection grounding.

[0050] It should be noted that the fourth conducting wire may also be a copper wire with a diameter of Φ3 mm.

[0051] For example, each tower ground grid is connected by four copper wires with a diameter of Φ3mm and a length of about 20m, which are laid radially at the base of the tower. Each tower ground grid is located around each tower and is connected to the top-line ground grid conductor.

[0052] Since there is a certain grounding resistance between the grounding system and the soil, this resistance will increase the loss of the entire grounding system. In order to make each grounding grid in the grounding system have good contact with the earth and make the current in the earth flow smoothly back to the grounding grid, it is necessary to set up several grounding wells.

[0053] Grounding wells include deep grounding wells and shallow grounding wells.

[0054] Among them, the deep grounding well is set at the periphery of the tuning booth grounding grid; the shallow grounding well is evenly set at the edge of the entire area of ​​the top line grounding grid It should be noted that the layout depth of the grounding deep well is consistent with the groundwater, which is 20~35m; the layout depth of the grounding shallow well is 2~5m.

[0055] As a specific embodiment, the grounding deep well is as follows Figure 2 As shown, there are 2 in total, which are arranged near the ground grids of the two tuning booths. The shallow grounding wells are as follows: Figure 3 As shown, there are about 60 in total, arranged at intervals along the edge of the grounding system.

[0056] For example, deep grounding wells are set up near two tuning booths, 5m to 15m away from the tuning booths. According to soil resistivity survey data, the skin depth of very low frequency electromagnetic waves is 20m to 35m, and the depth of the deep grounding well is preferably 30m. When the depth of the deep well exceeds the skin depth, increasing the depth will have no significant effect on the grounding resistance. After the deep well is dug, a grounding body needs to be placed, such as Figure 2 As shown in the figure, a Φ90×5mm copper tube is used as the grounding body. The upper end of the grounding body is 0.1m above the ground. A well platform is built above the ground at the wellhead and protected by a well cover. The grounding body of the deep well leads 6 Φ6mm thick copper wires from different directions and is welded to the tuning booth ground grid.

[0057] For example, a shallow grounding well is set every 100m along the edge of the grounding system, with a total of 68 shallow grounding wells. The length of the shallow grounding well is 3.5m, and a vertical 25mm×3mm copper bar grounding body is arranged at each shallow grounding well. The copper bar grounding body is connected to the surrounding grounding wire through a lead wire. Furthermore, in order to ensure the reliability of the connection, Figure 3 As shown, the lead-out line of the shallow grounding well is led out at a depth of 0.3m~0.5m, and three Φ6mm thick copper wires are led out from different directions and welded to the ground grid wire nearby.

[0058] In the ground grid project, in order to make the ground loss resistance as low as possible, thereby ensuring that the antenna obtains a higher radiation efficiency, in addition to the above design and maintaining good welding at the intersections of the ground grid wires, a busbar needs to be set up.

[0059] The outer edge busbar of the grounding grid includes at least one busbar, and the busbar is laid along the edge of the top line grounding grid.

[0060] It should be noted that the busbar at the outer edge of the ground grid can be made of thicker wires or metal strips of a certain thickness, which are used to partially recover the ground current flowing in the soil between the ground grid wires to the grounding wire, or to lead the ground current outside the ground grid area to the grounding wire to reduce the current loss in the soil.

[0061] The busbar can be made of copper strip, and the buried depth is 0.2-0.4 m, preferably 0.3 m. For example, the busbar can be a copper strip with a length of 25 mm and a diameter of Φ3 mm.

[0062] As an embodiment, the busbar at the outer edge of the ground grid is formed into a bus ring using a 5×50mm copper strip, and a shallow grounding well is set every 100m at the edge, with a total of 68 shallow grounding wells.

[0063] It should be noted that the materials of the first wire, the second wire, the third wire, the fourth wire and the busbar can be various metal wires, such as gold, silver, copper, etc., preferably copper.

[0064] In addition, in order to further reduce the ground grid loss, the loss resistance of the grounding system was analyzed according to the design index requirements of the grounding system, and the conductor diameter, conductor spacing and conductor burial depth were further optimized.

[0065] According to the long-wave antenna theory, the radiation resistance of the antenna increases with the square of the frequency, while the ground loss resistance increases slowly with the increase of frequency. Therefore, the radiation efficiency of the antenna at the lowest frequency is the most concerned indicator in the design. In the normal working mode of the transmitting antenna, that is, when the two sets of antennas are dual-tuned, the antenna radiation efficiency should be no less than 15% at the working frequency of 15kHz, the antenna radiation efficiency should be no less than 20% at the working frequency of 20kHz, and so on. The antenna radiation efficiency should be no less than 30% at the working frequency of 30kHz.

[0066] The present invention designs the grounding system based on the efficiency index of 15kHz, and verifies the design of the grounding system through the efficiency index requirements at 20kHz and 30kHz. According to the effective height of the antenna, the radiation resistance of the antenna at 15kHz is about 0.05Ω. In order to achieve the goal of not less than 15% of the antenna radiation efficiency at the working frequency of 15kHz, the total loss of the antenna should not be greater than 0.283Ω.

[0067] Assuming that the sum of the tuning loop loss, antenna wire loss and other losses does not exceed 0.1Ω, then when the two sets of antennas work at the same time, the ground loss resistance relative to the total current should be no more than 0.183Ω at 15kHz. By analogy, it can be obtained that at 20kHz, the ground loss resistance should be no more than 0.26Ω, and at 30kHz, the ground grid loss resistance should be no more than 0.37Ω.

[0068] The grounding system loss resistance mainly includes magnetic field loss resistance and electric field loss resistance. Among them, the magnetic field loss resistance is the loss caused by the ground current induced by the magnetic field in the earth, which accounts for the main part of the ground loss. Therefore, in the ground grid design of the grounding system, we must first understand the distribution of the ground current induced by the transmitting antenna in the earth.

[0069] According to the current direction of high power loading to the antenna, the magnetic field strength generated by the antenna on the earth's surface is calculated. The calculation results show that the strong magnetic field area is mainly distributed near the top line, high-voltage feeder and tower.

[0070] like Figure 1 As shown, the y-direction magnetic field generates a current parallel to the top line. Therefore, the first conductor of the top line ground grid should be arranged parallel to the top line. The x-direction magnetic field generates a current parallel to the high-voltage feeder and is mainly concentrated near the high-voltage feeder. Therefore, the high-voltage feeder ground grid should be located near the bottom of the high-voltage feeder, and the second conductor should be arranged parallel to the high-voltage feeder.

[0071] Near the two tuning booths, the ground current is densely distributed, with both x and y components, which means that the ground current in this area is mainly distributed radially. Therefore, a radial third conductor should be set near the tuning booth.

[0072] In addition, there is a strong magnetic field around each supporting tower. In order to reduce the loss of this part of the magnetic field and to ensure good grounding of the tower, a tower ground grid is set at the bottom of each supporting tower.

[0073] The size of the T-shaped antenna ground grid is generally the size of the antenna curtain plus the height of the supporting tower. The projection size of the two sets of antenna curtains is 1200m×1000m, and the tower height is more than 200 meters. According to the calculation results of the ground surface magnetic field below the antenna, the current along the top line decays faster and is already very weak at the edge of the top capacitance line, while the current along the high-voltage feeder line decays relatively slowly and still has a large component beyond the edge of the antenna curtain.

[0074] Therefore, the length of the first conductor is greater than the length of the second conductor. That is, the first conductor parallel to the top line direction can be appropriately longer, and the second conductor parallel to the high-voltage feeder direction can be appropriately shorter. For example, the first conductor parallel to the top line direction is 1800m long, and the second conductor parallel to the high-voltage feeder direction is 1600m wide.

[0075] According to the calculation results of the ground surface magnetic field, the current along the high-voltage feeder is concentrated near the high-voltage feeder, and the projection of the high-voltage feeder on the ground can be used as the symmetry axis. When the distance from the high-voltage feeder exceeds 100m, the current decays quickly. Therefore, the present invention lays the high-voltage feeder ground grid with a width greater than 200m; preferably 250m.

[0076] Since the ground current is relatively large near the feeding point of the tuning booth, there is both current along the top line and current along the high-voltage feeder line, that is, the current is distributed radially with the feeding point as the origin. After moving away from the feeding point, the current gradually changes from radial to x or y. Therefore, the regional size of the tuning booth ground grid can be determined according to the laying width of the high-voltage feeder ground grid. For example, when the laying width of the high-voltage feeder ground grid is 250m, the regional size of the tuning booth ground grid is 250m×250m.

[0077] The wire diameter of the grounding system has a great influence on the electrical performance of the grounding grid, and the selection of the wire diameter is closely related to the copper consumption of the entire grounding grid project. Therefore, the present invention takes into account the engineering cost while meeting the electrical performance and reduces the copper consumption as much as possible.

[0078] Using the calculation method of ground loss, the difference in antenna ground loss when the grounding system wire has different diameters is calculated and analyzed. Figure 4 As shown in the figure, the influence of the ground grid wire diameter on the ground loss resistance under different soil apparent resistivity conditions is calculated. From the calculation results, it can be seen that the ground loss resistance decreases with the increase of the wire diameter. Increasing the wire diameter can reduce the ground loss resistance and improve the antenna efficiency, but it will also increase the amount of copper consumed in the project. When the wire diameter exceeds 3mm, the decreasing trend of the antenna ground loss becomes relatively gentle when the diameter of the ground grid wire is increased. When Φ4mm copper wire is selected, the ground loss of the antenna is only reduced by about 0.02Ω compared with the selection of Φ3mm copper wire, which has little effect on the radiation efficiency of the antenna system, reducing it by about one percentage point. However, the selection of Φ3mm copper wire will save nearly 34% of copper material compared with Φ4mm copper wire. Therefore, considering all factors, the conductor of the grounding system is preferably Φ3mm copper wire.

[0079] The top-line ground grid occupies the largest area in the entire grounding system and consumes the most copper wire. It can be seen that the conductor spacing of the top-line ground grid has a great influence on the antenna grounding loss and copper consumption. Figure 5 As shown, the variation trend of antenna ground loss resistance with the first conductor spacing in the top line ground grid area is calculated when the soil apparent resistivity takes different parameters.

[0080] It can be seen that from the perspective of electrical performance alone, 5m is a better choice for the first conductor spacing. However, when the spacing increases to 10m, the maximum reduction in ground loss resistance does not exceed 0.1Ω, which will cause the antenna radiation efficiency to decrease by about 1 to 2 percentage points, but 300km of copper wire will be saved. According to the antenna effective height design parameters, when the first conductor spacing is 10m, although the best effect of the ground grid is not achieved, the antenna radiation efficiency has met the index requirements and has a certain margin. If the conductor spacing is further increased, the ground loss value of the antenna will be too high, making the design margin of the antenna radiation efficiency insufficient, and even difficult to meet the index requirements.

[0081] Therefore, taking into account the electrical performance and engineering workload of the antenna system, the interval between adjacent first conductors of the top-line ground grid is 5m~15m, with 10m being preferred.

[0082] According to the VLF antenna theory, the buried depth of the grounding system's conductors has little effect on soil resistivity, so the antenna ground loss resistance changes very little with buried depth.

[0083] like Figure 6 As shown in the figure, it is better to place the grounding system conductor on the ground (burying depth is zero) than to bury it at a certain depth, but the difference is small. As can be seen from the figure, within the range of conductor burial depth from 0 to 0.3m, the grounding resistance slowly decreases with the increase of depth, reaching the best value when the conductor burial depth is 0.3m; and it becomes worse when the conductor burial depth is greater than 0.4m. Therefore, the conductor should not be buried too deep.

[0084] Since the influence of the buried depth of the grounding system conductor on the ground loss is negligible, considering the protection needs of the grounding system conductor, under the premise of ensuring the safety of the grounding system, the buried depth of the grounding system conductor is 0.2~0.4m, preferably 0.3m.

[0085] In summary, the present invention can address the problem of current density carried by the top line, high-voltage feeder and tuning booth by setting up a top line ground grid, a high-voltage feeder ground grid, a tuning booth ground grid, an iron tower ground grid, a grounding well and a ground grid outer edge busbar, thereby reducing the loss resistance of high voltage and strong magnetic field in the grounding system, thereby greatly reducing the grounding loss resistance.

[0086] It should be noted that, for the above-mentioned various embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0087] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0088] In the several embodiments provided in this application, it should be understood that the disclosed method or system can be implemented in other ways. For example, the above-described embodiments are only schematic, and the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0089] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0090] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0091] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the whole or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0092] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0093] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A grounding system for a long wave transmitting antenna, It is characterized in that The system comprises: The top line ground grid includes a plurality of first conductors laid parallel to the top line direction, wherein the first conductors and the second conductors cross each other and are connected through intersections; A high-voltage feeder grounding network, comprising a plurality of second conductors laid parallel to the high-voltage feeder direction, wherein the second conductors are laid at unequal intervals, and the second conductors are connected to the first conductor and the third conductor at the intersection; A tuning booth ground grid is arranged at the periphery of the tuning booth, and the tuning booth ground grid includes a plurality of third conducting wires laid radially; An iron tower ground grid is arranged at the periphery of the iron tower, and the iron tower ground grid comprises a plurality of fourth wires laid radially, and the fourth wires are connected to the first wires; The grounding well includes a deep grounding well and a shallow grounding well; the deep grounding well is arranged at the periphery of the tuning booth grounding grid; the shallow grounding well is evenly arranged at the edge of the entire area of ​​the top line grounding grid; The outer edge busbar of the grounding grid includes at least one busbar, and the busbar is laid along the edge of the top-line grounding grid.

2. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The second conductors are laid at unequal intervals as follows: The laying density of the second conductors on the side close to the high-voltage feeder is greater than the laying density on the side far from the high-voltage feeder.

3. A grounding system for a long-wave transmitting antenna according to claim 1, It is characterized in that The third wires arranged along the regional boundary of the tuning booth ground grid are of the first size, and the plurality of third wires arranged radially inside the boundary of the tuning booth ground grid are of the second size; Among them, multiple third conductors of the second size are evenly laid in a radial shape with the outlet of the high-voltage wall insulator of the tuning booth as the center, and are connected to the third conductor of the first size at the same time.

4. A grounding system for a long wave transmitting antenna according to claim 3, It is characterized in that The area shape of the tuning booth ground grid is square.

5. A grounding system for a long wave transmitting antenna according to claim 3, It is characterized in that The first size is greater than the second size.

6. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The length of the first conductive line is greater than the length of the second conductive line.

7. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The area size of the tuning booth grounding network is determined according to the laying width of the high-voltage feeder grounding network.

8. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The first conductive wire, the second conductive wire, the third conductive wire, the fourth conductive wire and the busbar are all made of copper.

9. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The interval between the first conductive wires is 10 m.

10. A grounding system for a long wave transmitting antenna according to claim 1, It is characterized in that The laying method includes underground setting, and the underground depth is 0.2~0.4m.

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