A UAV antenna and detection method for corona discharge detection

Abstract

The invention discloses a drone antenna for corona discharge detection, and relates to the field of antenna technology; the invention comprises a PCB board, and a detection antenna structure is arranged on the front of the PCB board; the detection antenna structure is composed of a plurality of fractal antenna units arranged along a serpentine line and connected in sequence head to tail; the fractal antenna unit comprises a copper-clad tape in the shape of a second-order Hilbert curve, and the copper-clad tape is attached to the surface of the PCB board; a feeding point connected to a drone signal processing circuit is arranged at either end of the head to tail of the detection antenna structure. The invention adopts a detection antenna structure for detecting corona discharge to be connected to a drone signal processing circuit through a feeding point, and the detection antenna structure can capture a unique radio frequency electromagnetic wave signal radiated by a cable when corona discharge occurs, thereby detecting the corona discharge point of the cable and helping to maintain the cable.

Description

Technical Field

[0001] The invention relates to the technical field of antennas, and in particular to an unmanned aerial vehicle antenna for corona discharge detection. Background Art

[0002] With the rapid development of my country's high-voltage and ultra-high-voltage power grids, the high-voltage discharge problem of transmission lines and electrical equipment has become increasingly serious. As an important part of the power system, overhead lines have always been the focus of fault detection. The aging of overhead line insulators and the contamination of insulator surfaces can lead to corona discharge.

[0003] In the prior art, the detection of corona discharge phenomenon usually adopts artificial vision, infrared thermal imaging and ultraviolet detection; among them, artificial visual detection depends to a large extent on the subjective experience of the observer, and it is difficult for the observer to find discharges with blind spots or low intensity. The detection of corona discharge phenomenon is inaccurate. Infrared thermal imaging detection can only detect corona discharge when the discharge develops to a certain extent and the local temperature rises significantly. At this time, the cable line has been seriously damaged, which is not conducive to the maintenance of the cable. Although ultraviolet detection is effective, it cannot be widely promoted due to its high cost. At present, ultraviolet imagers are commonly used in the market. Although the detection results are accurate and sensitive, they are expensive and not easy to be widely promoted. Ultraviolet detection needs to be carried out at night, and the requirements for the detection environment are strict. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a UAV antenna for corona discharge detection which has low cost, accurate detection and good applicability.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] Provided is a UAV antenna for corona discharge detection, comprising a PCB board, wherein a detection antenna structure is arranged on the front side of the PCB board; the detection antenna structure is composed of a plurality of fractal antenna units arranged along a serpentine line and connected end to end in sequence; the fractal antenna unit comprises a copper-clad tape in the shape of a second-order Hilbert curve, and the copper-clad tape is attached to the surface of the PCB board; a feeding point connected to a UAV signal processing circuit is arranged at one end of the detection antenna structure, and the other end of the detection antenna structure is vacant.

[0007] Furthermore, a plurality of fractal antenna units are arranged in a square array, and the array unit of the square array is an even number, and the array of the detection antenna structure is greater than or equal to 10×10; the nth row and the n+1th row in the square array are symmetrically arranged along the row spacing line, and n is an integer greater than 0; and the top of the fractal antenna unit 11 at the connection between the 2nth row and the 2n+1th row is rotated 90° in a direction away from the center point of the PCB board.

[0008] Furthermore, the array of the detection antenna structure is 14×14.

[0009] Furthermore, the fractal antenna unit is 3k×3kmm 2 square, k is a constant, and the interval between two adjacent fractal antenna units is kmm; the interval between two adjacent parallel lines in the detection antenna structure is kmm.

[0010] Furthermore, there is a gap around the detection antenna structure and the PCB board, and the width of the gap is greater than the diameter of the feeding point.

[0011] Furthermore, it also includes a packaging connection shell, the PCB board is embedded in the packaging connection shell, and the front side of the PCB board is exposed, and a signal connection ring connected to the drone is provided on the packaging connection shell, and the signal connection ring is electrically connected to the feeding point through a cable, and the cable is embedded in the packaging connection shell.

[0012] A detection method using a drone antenna for corona discharge detection comprises the following steps:

[0013] S1: Mount the antenna to the lower mount compartment of the drone;

[0014] S2: Control the UAV to fly along the cable to be inspected at a speed of v1 for initial inspection;

[0015] S3: The UAV transmits the initial signal data obtained by the initial detection to the ground;

[0016] S4: Obtain the flight route data of the UAV, divide the flight route of the UAV into line segments of equal length, and number the line segments;

[0017] S5: Compare the initial signal data with the flight route data;

[0018] If the i-th cable segment shows a radio frequency signal of corona discharge, the i-th cable segment is marked as a discharge cable and is included in the discharge set P1;

[0019] Otherwise, the i-th cable segment is marked as a non-discharging cable, and the i-th cable segment is included in the non-discharging set P2;

[0020] S6: Use a drone to fly along the cable units in the discharge set P1 at a speed of v2 to re-detect and find the corona discharge point, and the ratio of v1 to v2 is l∈[2,5].

[0021] Furthermore, when the UAV flies along the cable to be detected, the detection antenna structure is facing the cable to be detected, and when the UAV flies, the detection antenna structure is kept 5±1m away from the cable to be detected.

[0022] The beneficial effects of the present invention are:

[0023] The present invention uses a detection antenna structure for detecting corona discharge to connect with the signal processing circuit of the drone through a feeding point. The detection antenna structure can capture the unique radio frequency electromagnetic wave signal radiated by the cable when corona discharge occurs, thereby detecting the corona discharge point of the cable and helping to maintain the cable. The detection antenna structure is small in size and can be mounted on the expansion position of an existing civilian drone, without the need to design a dedicated drone, saving detection costs.

[0024] The method of the present invention is used to detect corona discharge, which can save detection time, does not require much manpower and material resources, and can quickly and accurately detect the corona discharge position. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view structural schematic diagram of a drone antenna that is not encapsulated in a packaging connection shell;

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure of the UAV antenna;

[0027] Figure 3 It is a corona discharge simulation detection platform;

[0028] Figure 4 It is the time domain signal diagram of corona discharge;

[0029] Figure 5 is the spectrum distribution diagram of the discharge signal;

[0030] Figure 6 is a return loss S11 curve diagram of the present invention;

[0031] Figure 7 is the antenna pattern of the present invention;

[0032] Figure 8 It is a structural schematic diagram of a fractal antenna unit;

[0033] Fig. 9 It is a schematic diagram of the process of the present invention;

[0034] Fig.10 This is a schematic diagram of the present invention being loaded on a drone;

[0035] Among them, 1. PCB board; 2. Detection antenna structure; 3. Feeding point; 4. Package connection shell; 5. Signal connection ring; 6. Voltage regulator; 7. Transformer; 8. Composite insulator string; 9. Test antenna; 10. Oscilloscope; 11. Fractal antenna unit. DETAILED DESCRIPTION

[0036] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0037] like Figure 1-2 As shown, a UAV antenna for corona discharge detection includes a PCB board 1, and a detection antenna structure 2 is arranged on the front of the PCB board 1; the detection antenna structure 2 is composed of a plurality of fractal antenna units 11 arranged along a serpentine line and connected end to end in sequence; Figure 8 As shown, the fractal antenna unit 11 includes a copper-clad tape in the shape of a second-order Hilbert curve, which is attached to the surface of the PCB board 1 through PCB printing technology; a feeding point 3 connected to the drone signal processing circuit is provided at the upper end of the detection antenna structure 2, and the lower end of the detection antenna structure 2 is empty.

[0038] A plurality of fractal antenna units 11 are arranged in a square array, and the array unit of the square array is an even number, and the array of the detection antenna structure 2 is greater than or equal to 10×10. The nth row and the n+1th row in the square array are symmetrically arranged along the row spacing line, and n is an integer greater than 0; and the top of the fractal antenna unit 11 at the connection between the 2nth row and the 2n+1th row is rotated 90° in a direction away from the center point of the PCB board 1.

[0039] In this embodiment, the array of the detection antenna structure 2 is 14×14. In other embodiments, the array of the detection antenna structure 2 may also be 10×10, 12×12, 16×16 or 18×18.

[0040] The fractal antenna unit 11 is 3k×3kmm 2 A square, k is a constant, and the interval between two adjacent fractal antenna units 11 is kmm; the interval between two adjacent parallel lines in the detection antenna structure 2 is kmm.

[0041] There is a gap around the detection antenna structure 2 and the PCB board 1, and the width of the gap is greater than the diameter of the feeding point.

[0042] It also includes a packaging connection shell 4, a PCB board 1 is embedded in the packaging connection shell 4, and the front side of the PCB board 1 is exposed, a signal connection ring 5 connected to the drone is provided on the packaging connection shell 4, and the signal connection ring 5 is electrically connected to the feeding point 3 through a cable, and the cable is embedded in the packaging connection shell 4.

[0043] like Fig. 9 As shown, a detection method using a drone antenna for corona discharge detection includes the following steps:

[0044] The test antenna 9 for simulation is made, the size of the PCB board is 125mm×125mm×1.6mm, the thickness of the copper tape is 0.03mm, the width is 0.4mm, and the fractal antenna unit 11 is 6.4×6.4mm 2 The diameter of the feeding point is 3 mm, and the gap between the detection antenna structure 2 and the PCB board is 5 mm. In actual settings, the sizes of the fractal antenna unit 11 and the copper clad tape are proportional to the size of the PCB board. The sizes of the fractal antenna unit 11 and the copper clad tape are set according to actual needs.

[0045] S1: Fig.10 As shown, the test antenna 9 is mounted on the lower mounting compartment of the UAV;

[0046] S2: Control the drone to fly along the cable to be tested at a speed of v1 = 20km / h for initial testing; the testing frequency band is 100MHz-500MHz;

[0047] S3: The drone transmits the initial signal data obtained from the initial detection to the ground.

[0048] S4: Obtain the flight route data of the UAV, divide the flight route of the UAV into line segments of equal length, and number the line segments;

[0049] S5: Compare the initial signal data with the flight route data;

[0050] If the i-th cable segment shows a radio frequency signal of corona discharge, the i-th cable segment is marked as a discharge cable and is included in the discharge set P1;

[0051] Otherwise, the i-th cable segment is marked as a non-discharging cable, and the i-th cable segment is included in the non-discharging set P2;

[0052] S6: Use a drone to fly along the cable units in the discharge set P1 at a speed of v2 = 5 km / h to re-detect and find the corona discharge point. The ratio l of v1 to v2 is 4. In other embodiments, l can also be 2, 3 or 5. In this embodiment, the detection frequency band of the antenna is 100MHz-500MHz.

[0053] When the UAV flies along the cable to be detected, the detection antenna structure is facing the cable to be detected, and the detection antenna structure is kept 5±1m away from the cable to be detected when the UAV flies.

[0054] Experimental data

[0055] Build a simulation testing platform, such as Figure 3As shown, it includes a voltage regulator, a transformer, a composite insulator string and an oscilloscope. When 220V industrial frequency AC is input to the voltage regulator, the voltage can be adjusted within the range of 0 to 220V. After being output to the test transformer, the voltage is increased by a transformation ratio of 1:250, and the maximum output voltage is 55kV. The composite insulator string uses two insulators with a withstand voltage of 10kV; the detection distance of the antenna is set to 5m, and the antenna is connected to the oscilloscope through a coaxial cable. The voltage regulator is adjusted to increase the voltage at both ends of the insulator. When it reaches 35kV, the test antenna captures a typical corona discharge signal, as shown below. Figure 4 The corona discharge time domain signal diagram shown is composed of Figure 4 It can be seen that at 200ns, the test antenna detected the corona discharge time domain signal, and the maximum signal strength was 10.2mV. Using the spectrum analysis function of the oscilloscope, the obtained discharge signal was analyzed and the following was obtained: Figure 5 The discharge signal spectrum distribution diagram shown in Figure 5 It can be seen that the frequency bands of the corona discharge signal obtained by the test antenna are mainly concentrated in 100MHz-130MHz, 210MHz-250MHz and 260MHz-350MHz.

[0056] The test results are as follows Figure 6 The return loss S11 graph shown in the figure and Figure 7 The antenna pattern is shown in Figure 1. Figure 6 It can be seen that there are uniform resonance points in the frequency band of 100MHz-500MHz, and the return loss of the resonance points in the frequency band of 100MHz-500MHz is lower than -5dB, which can more accurately detect corona discharge; Figure 7 It can be seen that the directivity coefficient of the antenna of the present invention is 3.0785, which has very excellent directivity; it can detect the corona discharge point more accurately and help to determine the fault location more accurately.

[0057] The prior art CN108598671A discloses an antenna, which can also detect corona discharge. However, the directivity coefficient of the antenna is 1.9984, which is significantly smaller than that of the present invention. The detection accuracy of the present invention is better than that of the prior art.

Claims

1. An unmanned aerial vehicle antenna for corona discharge detection, characterized in that: The invention comprises a PCB board (1), wherein a detection antenna structure (2) is arranged on the front side of the PCB board (1); the detection antenna structure (2) is composed of a plurality of fractal antenna units (11) arranged along a serpentine line and connected end to end in sequence; the fractal antenna unit (11) comprises a copper-clad tape in the shape of a second-order Hilbert curve, and the copper-clad tape is attached to the surface of the PCB board (1); a feeding point (3) connected to a drone signal processing circuit is arranged at one end of the detection antenna structure (2), and the other end of the detection antenna structure (2) is left vacant; The plurality of fractal antenna units (11) are arranged in a square array, and the array unit of the square array is an even number, and the array of the detection antenna structure (2) is greater than or equal to 10×10; the nth row and the n+1th row in the square array are symmetrically arranged along the row spacing line, and n is an integer greater than 0; and the top of the fractal antenna unit (11) at the connection between the 2nth row and the 2n+1th row is rotated 90° in a direction away from the center point of the PCB board (1).

2. The UAV antenna for corona discharge detection according to claim 1, characterized in that: The array of the detection antenna structure (2) is 14×14.

3. The UAV antenna for corona discharge detection according to claim 1, characterized in that: The fractal antenna unit (11) is 3k×3kmm 2 A square, k is a constant, two adjacent fractal antenna units (11) have a distance of kmm; and two adjacent parallel lines in the detection antenna structure (2) have a distance of kmm.

4. The UAV antenna for corona discharge detection according to claim 1, characterized in that: There is a gap around the detection antenna structure (2) and the PCB board (1), and the width of the gap is greater than the diameter of the feeding point.

5. A method for detecting a UAV antenna for corona discharge detection using any one of claims 1 to 4, characterized in that: The steps include: S1: Mount the antenna to the lower mount compartment of the drone; S2: Control the UAV to fly along the cable to be inspected at a speed of v1 for initial inspection; S3: The UAV transmits the initial signal data obtained by the initial detection to the ground; S4: Obtain the flight route data of the UAV, divide the flight route of the UAV into line segments of equal length, and number the line segments; S5: Compare the initial signal data with the flight route data; If the i-th cable segment shows a radio frequency signal of corona discharge, the i-th cable segment is marked as a discharge cable and is included in the discharge set P1; Otherwise, the i-th cable segment is marked as a non-discharging cable, and the i-th cable segment is included in the non-discharging set P2; S6: Use a drone to fly along the cable units in the discharge set P1 at a speed of v2 to re-detect and find the corona discharge point, and the ratio of v1 to v2 is l∈[2,5].

6. The method for detecting a UAV antenna for corona discharge detection according to claim 5, characterized in that: When the UAV flies along the cable to be detected, the detection antenna structure is facing the cable to be detected, and the detection antenna structure is kept 5±1m away from the cable to be detected when the UAV flies.

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