Microwave-based ice measurement method and device

Abstract

The present invention discloses a method and device for ice measurement based on microwave. The method includes: loading and transmitting a microwave detection signal through a microwave transmitting antenna, receiving the transmitted microwave detection signal through more than three microwave receiving antennas, calculating the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, judging whether the transmission medium is air, water or ice layer through the dielectric constant, and calculating the ice thickness through the phase change and transmission time of the received microwave detection signal. The present invention can quickly measure the equivalent ice coating thickness, greatly improving the accuracy of ice coating monitoring of transmission lines in frozen environments.

Description

Technical Field

[0001] The present invention relates to the technical field of icing and frosting detection for transmission lines, and particularly to an ice measurement method and device based on microwave. Background Art

[0002] The icing phenomenon of transmission lines has been very common. The icing and snow accumulation on transmission lines will cause a sharp decline in their mechanical and electrical properties, leading to major power accidents such as conductor galloping, tower inclination or even collapse, wire breakage, and insulator flashover, seriously affecting the safe operation of the power system. The ice disaster that occurred around the Spring Festival in China in 2008 caused large-scale and long-term power outages, with direct economic losses exceeding 150 billion yuan, and at the same time brought serious social impacts to industrial and agricultural production and people's lives. Therefore, real-time monitoring of the icing condition of transmission lines and doing a good job in de-icing have become the focus of current research.

[0003] For a long time, researchers have conducted long-term observations and studies on the icing of transmission lines and achieved many results in aspects such as icing theory, ice flashover mechanism, and related technologies for monitoring the icing of transmission lines. However, currently, the commonly used fixed image monitoring method has the problem that the camera freezes and cannot continue monitoring, the tension method can only measure the icing within one strain end, and the manual observation method cannot measure the icing on towers dozens of meters high. Summary of the Invention

[0004] The present invention provides an ice measurement method and device based on microwave to solve the technical problems that the icing monitoring of transmission lines in the existing frozen environment cannot be continuous or the accuracy is not high.

[0005] To solve the above technical problems, the technical solution proposed by the present invention is as follows:

[0006] An ice measurement method based on microwave, comprising the following steps:

[0007] Load and transmit a microwave detection signal through a microwave transmitting antenna, and receive the transmitted microwave detection signal through more than three microwave receiving antennas. Calculate the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal. Determine whether the transmission medium is air, water or ice layer through the calculation of the dielectric constant, and calculate the ice thickness through the phase change and transmission time of the received microwave detection signal.

[0008] As a further improvement of the method of the present invention:

[0009] Calculating the dielectric constant of the transmission medium through the phase difference voltage signal of the received microwave detection signal, including: directly contacting the terminal open waveguide with the surface of the substance to be measured for measurement, and then performing curve fitting calculation on the measured result to obtain an accurate value; giving the curve fitting coefficient for calculating the relative dielectric constant ε of the substance at f = 3.975 GHz through the accurate values obtained from multiple measurements. Judging the transmission medium as air, water or ice layer through the dielectric constant, including: judging as an air layer when the dielectric constant is 1, judging as an ice-covered layer when the dielectric constant is 3, and judging as a precipitation layer when the dielectric constant is 80.

[0010] Through the received Calculating the ice thickness, measuring the phase difference of the signal source to be measured by the phase discrimination method, and the measured phase change is caused by different ice thicknesses. The ice thickness is obtained by fitting the calculated phase difference. The ice thickness can also be calculated in the following way. When there is a phase difference between the received microwave detection signal and the emitted microwave detection signal, it indicates that the transmission medium has changed and is not an air medium. Thus, the dielectric constant is obtained through curve fitting, and then it is judged whether the transmission medium is an ice layer or rainfall; when it is judged to be ice-covered, by comparing the transmission time between the transmitted microwave detection signal and the received microwave detection signal with the transmission time in the air medium of the standard distance, and then according to the transmission speed of the microwave signal in different media, calculating the transmission distance of the ice layer medium causing the transmission time difference, thereby calculating the ice thickness.

[0011] The number of microwave receiving antennas is more than six, and more than six microwave receiving antennas are evenly distributed along the circumference on the circle with the microwave transmitting antenna as the center; calculating the equivalent ice thickness of the microwave measurement through the ice thickness in more than six directions, including taking the average value of the ice thickness in more than six directions as the equivalent ice thickness.

[0012] The present invention also provides a microwave-based ice measurement device, including: a detection circuit, a microwave transmitting antenna connected to the detection circuit, and more than three microwave receiving antennas connected to the detection circuit and arranged on the circumference around the microwave transmitting antenna;

[0013] The detection circuit is used to load a microwave detection signal through the microwave transmitting antenna, receive the transmitted microwave detection signal through more than three microwave receiving antennas, calculate the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, judge the transmission medium as air, water or ice layer through the dielectric constant, and calculate the ice thickness through the phase change and transmission time of the received microwave detection signal.

[0014] As a further improvement of the device of the present invention:

[0015] The number of microwave receiving antennas is six, and the six microwave receiving antennas are evenly distributed along the circumference of a circle centered on the microwave transmitting antenna. The radius of the circle is 1 to 5 cm.

[0016] Both the microwave transmitting antenna and the microwave receiving antenna are columnar antennas.

[0017] Calculating the ice thickness through phase change includes the following steps: calculating the equivalent ice thickness measured by the microwave sensor through the ice thickness in six directions, including taking the average value of the ice thickness in six directions as the equivalent ice thickness.

[0018] The present invention has the following beneficial effects:

[0019] 1. The ice thickness measurement method based on microwave of the present invention can quickly obtain the ice coating thickness of different types of conductors, greatly improving the accuracy of ice coating monitoring of transmission lines in the frozen environment, and has guiding significance for ice coating monitoring and early warning of power transmission and transformation equipment.

[0020] 2. In the preferred embodiment, the ice thickness measurement method based on microwave of the present invention can quickly measure the equivalent ice coating thickness by loading a microwave detection signal, providing quantitative data for operators to judge the severity of the ice disaster and subsequent coping strategies, making the whole process efficient, accurate and safe.

[0021] 3. The ice thickness measurement device based on microwave of the present invention, as a new type of microwave ice thickness measurement sensor, has a compact structure, simple operation, high measurement accuracy, good repeatability and stability, and can realize on-line real-time detection.

[0022] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. Description of the Drawings

[0023] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 is a flow schematic diagram of the ice thickness measurement method based on microwave of the preferred embodiment of the present invention;

[0025] Figure 2 is a structural schematic diagram of the ice thickness measurement device based on microwave of the preferred embodiment of the present invention;

[0026] Figure 3 is a position diagram of the antenna steps of the ice thickness measurement device based on microwave of the preferred embodiment of the present invention.

[0027] Each label in the figure represents:

[0028] 1. Microwave transmitting antenna; 2. First receiving antenna; 3. Second receiving antenna; 4. Third receiving antenna; 5. Fourth receiving antenna; 6. Fifth receiving antenna; 7. Sixth receiving antenna; 8. Detection circuit. Specific embodiments

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the claims.

[0030] See Figure 1 , the ice measurement method based on microwave of the present invention includes the following steps:

[0031] Load and transmit a microwave detection signal through a microwave transmitting antenna, and receive the transmitted microwave detection signal through more than three microwave receiving antennas. Calculate the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal. Determine whether the transmission medium is air, water or ice layer through the calculation of the dielectric constant. Calculate the ice thickness through the phase change and transmission time of the received microwave detection signal. The ice thickness of different conductors can be obtained quickly, greatly improving the accuracy of ice monitoring of transmission lines in the freezing environment, and having guiding significance for ice monitoring and early warning of power transmission and transformation equipment.

[0032] During implementation, calculate the dielectric constant of the transmission medium through the phase difference voltage signal of the received microwave detection signal, including: directly contacting the open-ended waveguide terminal with the surface of the substance to be measured for measurement, and then performing curve fitting calculation on the measured result to obtain an accurate value. The curve fitting coefficients for calculating the relative dielectric constant ε of the substance at f = 3.975 GHz are given. After calculating the dielectric constant, determine whether the transmission medium is air, water or ice layer through the dielectric constant, including: judging as an air layer when the dielectric constant is 1, judging as an ice-covered layer when the dielectric constant is 3, and judging as a precipitation layer when the dielectric constant is 80.

[0033] Through the received Calculate the ice thickness. Use the phase discrimination method to measure the phase difference of the signal source to be measured. The measured phase change is caused by different ice thicknesses. The ice thickness is obtained by fitting the calculated phase difference. Or, judge the medium through the phase change of the received microwave detection signal, and compare the transmission time between the transmitted microwave detection signal and the received microwave detection signal with the transmission time in the air medium of the standard distance, so as to calculate the transmission distance of the ice layer medium causing the transmission time difference according to the transmission speed of the microwave signal in different media, and thus calculate the ice thickness.

[0034] See Figure 3, in this embodiment, the number of microwave receiving antennas is six, and the six microwave receiving antennas are evenly distributed along the circumference on the circle with the microwave transmitting antenna 1 as the center; the equivalent ice thickness of the microwave measurement is calculated by the ice thickness in six directions, including taking the average value of the ice thickness in six directions as the equivalent ice thickness.

[0035] See Figure 2 , an ice thickness measuring device based on microwave provided by an embodiment of the present invention further includes: a detection circuit 8, a microwave transmitting antenna 1 connected to the detection circuit 8, and three or more microwave receiving antennas connected to the detection circuit 8 and arranged on the circumference around the microwave transmitting antenna 1; the detection circuit 8 is configured to load a microwave detection signal through the microwave transmitting antenna, receive the transmitted microwave detection signal through three or more microwave receiving antennas, calculate the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, judge whether the transmission medium is air, water or ice layer through the calculation of the dielectric constant, and calculate the ice thickness through the phase change and transmission time of the received microwave detection signal. In this embodiment, the number of microwave receiving antennas is six, and the six microwave receiving antennas are evenly distributed along the circumference on the circle with the microwave transmitting antenna as the center, namely the first receiving antenna 2, the second receiving antenna 3, and the third receiving antenna 4; the fourth receiving antenna 5, the fifth receiving antenna 6, and the sixth receiving antenna 7. During implementation, both the microwave transmitting antenna 1 and the microwave receiving antenna can be columnar antennas. In this embodiment, the radius of the circle is 1 cm. Placing this sensor in the same environment as the outdoor wire and using a cylinder with the same material and reference diameter as the wire as the transmitting and receiving antennas can make the ice thickness on the antenna surface basically the same as the ice thickness on the wire to be measured. If the diameter of the wire to be measured is different from the diameter of the antenna with the reference size, query and conversion can be performed according to the calibration table corresponding to the diameter and ice thickness calibrated in advance, and the ice thickness of the wire can be quickly obtained. During actual implementation, the result measured by using a material similarity model of the wire to be measured (monitored) is more accurate.

[0036] Calculating the ice thickness through the phase change and transmission time of the received microwave detection signal includes the following steps: judging the medium through the phase change of the received microwave detection signal, and comparing the transmission time between the transmitted microwave detection signal and the received microwave detection signal with the transmission time in the air medium of the standard distance, so as to calculate the transmission distance of the ice layer medium causing the transmission time difference according to the transmission speed of the microwave signal in different media, and thus calculate the ice thickness. Calculating the equivalent ice thickness measured by the microwave sensor through the ice thickness in six directions includes taking the average value of the ice thickness in six directions as the equivalent ice thickness.

[0037] For example:

[0038] The microwave transmitting antenna 1 sends microwaves to the receiving antennas in six directions evenly distributed at 360°. The acquisition and detection circuit 8 measures the dielectric constants h1, h2, ..., h6 in the six directions, and the measurement time is once every 1 minute.

[0039] Comparing the dielectric constant, a value near 1 indicates an air layer, a value of 3 indicates an ice-covered layer, and a value of 80 indicates a precipitation layer.

[0040] Calculate the ice-covered thicknesses d1, d2, ..., d6 in the six directions.

[0041] Calculate the actual equivalent ice thickness d = (d1 + d2 + d3 + d4 + d5 + d6) / 6.

[0042] In summary, as a new type of microwave ice-measuring sensor, the present invention can measure the equivalent ice-covered thickness, quickly obtain the ice-covered thicknesses of different conductors, provide quantitative data for operators, and judge the severity of ice disasters and subsequent coping strategies. The whole process is efficient, accurate and safe, and has guiding significance for the ice-covered monitoring and early warning of power transmission and transformation equipment.

[0043] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A microwave-based ice measurement method, characterized in that, Including the following steps: Loading and transmitting a microwave detection signal through a microwave transmitting antenna, receiving the transmitted microwave detection signal through more than three microwave receiving antennas, calculating the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, judging whether the transmitted transmission medium is air, water or ice layer through the dielectric constant, and calculating the ice thickness through the phase change and transmission time of the received microwave detection signal; Calculating the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, including: directly contacting the terminal open waveguide with the surface of the substance to be measured for measurement, and then performing curve fitting calculation on the measured result to obtain an accurate value; giving the curve fitting coefficient for calculating the relative dielectric constant ε of the substance at f = 3.975 GHz through the accurate values of multiple measurements; Calculating the ice thickness through the phase change and transmission time of the received microwave detection signal, including the steps: Judging the medium through the phase change of the received microwave detection signal, and comparing the transmission time between the transmitted microwave detection signal and the received microwave detection signal with the transmission time in the air medium of the standard distance, so as to calculate the transmission distance of the ice layer medium causing the transmission time difference according to the transmission speed of the microwave signal in different media, and thus calculate the ice thickness; Placing the microwave transmitting antenna and the microwave receiving antenna in the same environment as the outdoor wire, using a cylinder with the same material and reference diameter as the wire as the microwave transmitting antenna and the microwave receiving antenna, or when the diameter of the wire to be measured is different from the diameter of the antenna with the reference size, querying and converting according to the calibration table corresponding to the diameter and ice thickness calibrated in advance to obtain the ice thickness of the wire.

2. The microwave-based ice measurement method according to claim 1, characterized in that, Judging whether the transmitted transmission medium is air, water or ice layer through the calculation of the dielectric constant, including: judging as an air layer when the dielectric constant is 1, judging as an ice-covered layer when the dielectric constant is 3, and judging as a precipitation layer when the dielectric constant is 80.

3. The microwave-based ice measurement method according to claim 1, characterized in that, The number of the microwave receiving antennas is more than six, and the more than six microwave receiving antennas are evenly distributed along the circumference on the circumference with the microwave transmitting antenna as the center; calculating the equivalent ice thickness of the microwave measurement through the ice thickness in more than six directions, including taking the average value of the ice thickness in more than six directions as the equivalent ice thickness.

4. A microwave-based ice measurement device, characterized in that, Including: A detection circuit, a microwave transmitting antenna connected to the detection circuit, and more than three microwave receiving antennas connected to the detection circuit and arranged on the circumference around the microwave transmitting antenna; The detection circuit is used to load a microwave detection signal through the microwave transmitting antenna, receive the transmitted microwave detection signal through the more than three microwave receiving antennas, calculate the dielectric constant of the transmission medium through the voltage signal of the phase difference of the received microwave detection signal, judge whether the transmitted transmission medium is air, water or ice layer through the dielectric constant, and calculate the ice thickness through the phase change and transmission time of the received microwave detection signal; Calculating the dielectric constant of the transmission medium through the phase difference voltage signal of the received microwave detection signal includes: directly contacting the terminal open waveguide with the surface of the substance to be measured for measurement, and then performing curve fitting calculation on the measured result to obtain an accurate value; giving the curve fitting coefficient for calculating the relative dielectric constant ε of the substance at f = 3.975 GHz through the accurate values obtained from multiple measurements. Calculating the ice thickness through the phase change and transmission time of the received microwave detection signal includes the steps of: Judging the medium through the phase change of the received microwave detection signal, and comparing the transmission time between the transmitted microwave detection signal and the received microwave detection signal with the transmission time in the air medium of the standard distance, so as to calculate the transmission distance of the ice layer medium causing the transmission time difference according to the transmission speed of the microwave signal in different media, and thus calculate the ice thickness. Placing the microwave transmitting antenna and the microwave receiving antenna in the same environment as the outdoor wire, using a cylinder with the same material and reference diameter as the wire as the microwave transmitting antenna and the microwave receiving antenna, or when the diameter of the wire to be measured is different from the diameter of the antenna with the reference size, query and convert according to the calibration table corresponding to the diameter and ice cover thickness calibrated in advance to know the ice cover thickness of the wire.

5. The microwave-based ice detection device according to claim 4, characterized in that The number of the microwave receiving antennas is six, and the six microwave receiving antennas are evenly distributed along the circumference on the circumference with the microwave transmitting antenna as the center, and the radius of the circumference is 1 to 5 cm.

6. The microwave-based ice detection device according to claim 5, characterized in that, Both the microwave transmitting antenna and the microwave receiving antenna are columnar antennas.

7. The microwave-based ice detection device according to claim 4, characterized in that, Calculating the equivalent ice thickness measured by the microwave sensor through the ice thicknesses in six directions includes taking the average value of the ice thicknesses in six directions as the equivalent ice thickness.

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