Capacitive multi-loop power transmission line icing thickness sensor

Abstract

This invention discloses a capacitive multi-ring transmission line icing thickness sensor, comprising a bushing, an insulating layer, and a sensing layer; the bushing, insulating layer, and sensing layer are wrapped around the transmission line from the inside out; the sensing layer includes an insulating ring and at least n The sensor consists of several electrode rings, with adjacent rings separated by an insulating ring. In operation, a rough measurement of the ice thickness is first obtained using the maximum resolution method. Then, the icing stage is determined based on this rough measurement, and the electrode spacing is calculated using the relationship between the maximum detectable ice thickness for the corresponding stage and the electrode spacing. Using this calculated electrode spacing as a reference, while keeping the sensing electrode position unchanged, the corresponding electrode ring is switched as the excitation electrode. It is essential to ensure that the distance between the sensing electrode and the excitation electrode is greater than or equal to the calculated electrode spacing. The sensor then measures the ice thickness again, and the final ice thickness is obtained based on the sensor's capacitance value. This sensor can adaptively measure different ice thicknesses, thus expanding the measurement range.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, specifically relating to a capacitive multi-ring transmission line icing thickness sensor, which is suitable for identifying multiple thickness ranges and can be applied to environmental condition monitoring and icing disaster early warning in power transmission systems. Background Technology

[0002] Under meteorological conditions such as low temperature, rain and snow, the surface of transmission lines is prone to icing. Icing can change the stress and operating state of transmission lines. Therefore, it is necessary to monitor the icing thickness of transmission lines in real time or periodically to provide a reliable data basis for formulating anti-icing and de-icing measures.

[0003] Currently, methods for detecting icing on transmission lines mainly include video image analysis, conductor sag monitoring, and laser ranging. While these technologies can monitor icing conditions to some extent, they still have limitations in practical applications. For example, video image analysis can visually reflect the icing status of transmission lines, but it is easily affected by factors such as ambient light, weather conditions, and conductor surface reflection, leading to inaccurate and unstable monitoring results. Conductor sag monitoring indirectly reflects the icing status by detecting conductor deformation, but it is significantly affected by temperature changes and conductor tension, making it unsuitable for precise icing thickness monitoring. Laser ranging offers high measurement accuracy, but its equipment deployment is complex and costly, and it is highly sensitive to conductor vibration.

[0004] In contrast, capacitive icing detection technology has become a research hotspot due to its simple structure, fast response, low power consumption, ease of deployment, and strong environmental adaptability. When ice adheres to the vicinity of the electrodes, the dielectric constant changes due to the significant difference between air (approximately 1) and ice (approximately 3.2), causing a change in the capacitance between the electrodes, thus reflecting the ice thickness. However, most existing capacitive sensors use a fixed electrode structure, and the spacing between a single electrode can only accommodate a limited range of thickness measurements. When the ice layer is too thin or too thick, it is difficult to balance the sensor's sensitivity and resolution, and it is prone to saturation or failure, making it difficult to achieve accurate measurement of different ice thicknesses. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a capacitive multi-ring transmission line icing thickness sensor.

[0006] The present invention solves the aforementioned technical problem by adopting the following technical solution: A capacitive multi-ring transmission line icing thickness sensor includes a bushing, an insulating layer, and a sensing layer; the bushing, insulating layer, and sensing layer are wrapped around the transmission line from the inside out; the sensing layer includes an insulating ring and at least n Each electrode ring consists of two electrode rings, with an insulating ring separating adjacent electrode rings.n It is an odd number greater than 1; In use, the electrode rings at both ends are used as sensing electrodes and the electrode ring in the center is used as excitation electrodes, or the electrode rings at both ends are used as excitation electrodes and the electrode ring in the center is used as sensing electrodes. At this time, the rough measurement value of the ice thickness can be obtained based on the capacitance value of the sensor. Then, the icing stage is determined based on the rough measurement of the icing thickness. If the rough measurement of the icing thickness is within the icing thickness range of the light ice stage, the rough measurement of the icing thickness is substituted into equation (1) to obtain the calculated value of the electrode spacing. If the icing thickness is within the icing thickness range of the medium ice or thick ice stage, the rough measurement of the icing thickness is substituted into equation (2) to obtain the calculated value of the electrode spacing. (1) (2) In the formula, To the electrode spacing The maximum detectable ice thickness below, The coefficients are binomial coefficients. , The coefficient of the linear term, , It is a constant; Finally, using the calculated electrode spacing as a reference, while keeping the position of the sensing electrode unchanged, the corresponding electrode ring is switched back as the excitation electrode. It is necessary to ensure that the distance between the sensing electrode and the excitation electrode is greater than or equal to the calculated electrode spacing. At this time, the ice thickness is measured again using the sensor, and the final ice thickness is obtained based on the capacitance value of the sensor.

[0007] Furthermore, the bushing has a thickness of 0.05mm-0.3mm, the insulating layer has a thickness of 0.1mm-0.5mm, the electrode ring has a thickness of 0.1mm-0.5mm, the insulating ring has a thickness of 0.2mm-1.0mm, and the electrode ring and the insulating ring have a width of 2mm-10mm.

[0008] Compared with the prior art, the beneficial effects of the present invention are: This sensor uses a sensor array formed by alternating electrode rings and insulating rings. The electrode rings are arranged sequentially along the axis of the transmission line, ensuring mechanical stability while providing multiple combinations for measuring ice thickness. During operation, the sensor can automatically switch between different electrode combinations as working electrode pairs according to different ice thickness ranges. This allows for the formation of suitable electrode spacing within different thickness ranges, improving measurement sensitivity, expanding the measurement range, and increasing resolution, thereby enabling zoned detection and continuous monitoring.

[0009] In thin ice conditions, adjacent electrode rings with smaller spacing are preferentially selected as working electrode pairs to improve measurement sensitivity; in thick ice conditions, electrode rings with larger spacing are selected as working electrode pairs to ensure sufficient electric field penetration depth and avoid capacitance response saturation, thus maintaining measurement stability. The electrode rings are adaptively adjusted according to the ice thickness, enabling the sensor to cover the full thickness measurement range from thin to thick ice. This ensures good response characteristics and measurement accuracy under different ice thicknesses, solving the problems of existing capacitive sensors that generally use fixed electrode structures, making it difficult to balance sensitivity and measurement range under thin and thick ice conditions, and are prone to saturation or failure, lacking adaptive adjustment capabilities. Attached Figure Description

[0010] Figure 1 This is a structural diagram of the present invention. Figure 2 This is a cross-sectional view of the present invention; In the diagram, 1-transmission line; 2-shaft sleeve; 3-insulation layer; 4-electrode ring; 5-insulation ring. Detailed Implementation

[0011] Specific embodiments are given below with reference to the accompanying drawings. These specific embodiments are only used to describe the technical solution of the present invention in detail and are not intended to limit the scope of protection of this application.

[0012] like Figure 1-2 As shown, the present invention provides a capacitive multi-ring transmission line icing thickness sensor, comprising a bushing 2, an insulating layer 3, and a sensing layer; the bushing 2, the insulating layer 3, and the sensing layer are wrapped around the transmission line 1 from the inside out, with the bushing 2 in close contact with the transmission line 1; the sensing layer includes an insulating ring 5 and at least n Each electrode ring 4 is separated from an adjacent electrode ring 5 by an insulating ring 5. n It is an odd number greater than 1; the electrode ring 4 can be used as both a sensing electrode and an excitation electrode. The larger the distance between the sensing electrode and the excitation electrode, the greater the ice thickness that the sensor can measure. The sensor has the highest resolution when the electrode rings 4 at both ends are used as sensing electrodes and the electrode ring 4 at the center is used as an excitation electrode, or when the electrode rings 4 at both ends are used as excitation electrodes and the electrode ring 4 at the center is used as a sensing electrode.

[0013] The electrode ring 4 is made of conductive material. The outer surfaces of the electrode ring 4 and the insulating ring 5 are directly exposed to the operating environment, allowing for direct contact with the ice layer and a change in dielectric material during icing, thus enabling capacitance-based detection of transmission line icing thickness. Since the transmission line 1 is a steel-cored aluminum stranded wire structure with gaps due to its surface being composed of multiple strands of aluminum wire, direct installation of the electrode ring is difficult. Therefore, a bushing 2 is installed between the transmission line 1 and the sensing layer to ensure a tight fit and fixation between the electrode ring 4 and the transmission line 1. Considering that both the transmission line 1 and the electrode ring 4 are conductors, an insulating layer 3 is installed between them to prevent electrical short circuits.

[0014] The thickness of the bushing 2 and the insulating layer 3 should be minimized as much as possible while meeting the requirements of mechanical strength and electrical insulation, so as to reduce the inherent capacitance of the sensor structure and improve the signal-to-noise ratio of the sensor. Preferably, the thickness of the bushing 2 is 0.05mm-0.3mm, more preferably 0.1mm; the thickness of the insulating layer 3 is 0.1mm-0.5mm, more preferably 0.2mm.

[0015] The thickness of the electrode ring 4 is preferably 0.1mm-0.5mm, more preferably 0.2mm, to reduce parasitic coupling between electrodes and increase the capacitance change ratio caused by icing; the thickness of the insulating ring 5 is preferably 0.2mm-1.0mm, more preferably 0.2mm-0.5mm, to reduce the proportion of dielectric participation in the electric field while ensuring insulation strength; the width of the electrode ring 4 and the insulating ring 5 is preferably 2mm-10mm, more preferably 3mm-6mm, to balance electric field stability and sensitivity.

[0016] Generally, the icing process of transmission lines can be divided into three stages: light icing, medium icing, and thick icing. The icing thickness range and growth characteristics of different stages are significantly different. The icing thickness in the light icing stage is relatively small and changes rapidly. The icing thickness gradually increases in the medium and thick icing stages, and the maximum icing thickness is approximately linearly correlated with the electrode spacing.

[0017] In the light icing stage, a quadratic function is used to establish the relationship between the maximum detectable ice thickness and the electrode spacing, and its expression is: (1) In the medium and thick ice stages, as the ice thickness increases, the electric field distribution gradually stabilizes, and the maximum detectable ice thickness shows an approximately linear relationship with the electrode spacing, expressed as follows: (2) In the formula, To the electrode spacing The maximum detectable ice thickness below, The coefficients are binomial coefficients. , The coefficient of the linear term, , It is a constant; Wherein, the coefficient of the quadratic term The influence of the edge diffusion effect of the electric field and the curvature of the field lines on the detection range is characterized by its value, which is related to the radius of the transmission line, the ratio of the electrode spacing to the diameter of the transmission line, the nonlinear distribution characteristics of the electric field, and the dielectric constant of the icing layer; the coefficient of the first term. , The coupling effect of electrode spacing variation on the detection thickness under nonlinear electric field conditions is characterized, and its value is related to parameters such as electrode thickness, cross index, electrode duty cycle, insulating layer thickness, and equivalent dielectric constant. , The equivalent thickness correction, characterizing the amount when the theoretical electrode spacing approaches zero, is related to parameters such as conductor radius of curvature, electrode thickness, insulation thickness, and parasitic capacitance compensation. For transmission lines of different diameters, recalibration is required at different icing stages based on the transmission line diameter and electrode structure parameters. , , , , Therefore, this sensor can be extended to the detection of icing on power transmission lines with different diameters and electrode spacings, enabling unified measurement and calculation of icing thickness on power transmission lines of various specifications.

[0018] The working principle and workflow of this invention are as follows: The sensor forms a dual-electrode capacitor between the sensing electrode and the excitation electrode, and the capacitance value reflects the ice thickness. In actual use, the electrode rings 4 at both ends are used as sensing electrodes and the electrode ring 4 at the center is used as excitation electrodes, or the electrode rings 4 at both ends are used as excitation electrodes and the electrode ring 4 at the center is used as sensing electrodes. In this case, the sensor has the highest resolution but the sensitivity is low. The ice thickness is roughly measured based on the sensor's capacitance. Next, the icing stage is determined based on the rough measurement of the icing thickness. If the rough measurement of the icing thickness is within the range of the light icing stage, the rough measurement of the icing thickness is substituted into equation (1) to obtain the calculated value of the electrode spacing. If the icing thickness is within the range of the medium or thick icing stage, the rough measurement of the icing thickness is substituted into equation (2) to obtain the calculated value of the electrode spacing. Then, based on the calculated value of the electrode spacing, the position of the sensing electrode remains unchanged, and the corresponding electrode ring is switched as the excitation electrode. It is necessary to ensure that the distance between the sensing electrode and the excitation electrode is greater than or equal to the calculated value of the electrode spacing. Since the width (thickness along the axial direction) of the electrode ring and the insulating ring are discrete values, the distance between the sensing electrode and the excitation electrode may not be completely equal to the calculated value of the electrode spacing. Therefore, it is necessary to ensure that the distance between the sensing electrode and the excitation electrode is slightly greater than the calculated value of the electrode spacing so that the resolution of the sensor is greater than the rough measurement of the icing thickness. Finally, the icing thickness is measured again using the sensor, that is, the fine measurement value of the icing thickness is obtained based on the sensor capacitance value, which is the final icing thickness.

[0019] Matters not covered in this invention are common knowledge.

Claims

1. A capacitive multi-ring transmission line icing thickness sensor, comprising a bushing, an insulating layer, and a sensing layer; the bushing, insulating layer, and sensing layer are wrapped around the transmission line from the inside out; characterized in that, The sensing layer includes an insulating ring and at least n Each electrode ring consists of two electrode rings, with an insulating ring separating adjacent electrode rings. n It is an odd number greater than 1; In use, the electrode rings at both ends are used as sensing electrodes and the electrode ring in the center is used as excitation electrodes, or the electrode rings at both ends are used as excitation electrodes and the electrode ring in the center is used as sensing electrodes. At this time, the rough measurement value of the ice thickness can be obtained based on the capacitance value of the sensor. Then, the icing stage is determined based on the rough measurement of the icing thickness. If the rough measurement of the icing thickness is within the icing thickness range of the light ice stage, the rough measurement of the icing thickness is substituted into equation (1) to obtain the calculated value of the electrode spacing. If the icing thickness is within the icing thickness range of the medium ice or thick ice stage, the rough measurement of the icing thickness is substituted into equation (2) to obtain the calculated value of the electrode spacing. （1） （2） In the formula, To the electrode spacing The maximum detectable ice thickness below, The coefficients are binomial coefficients. , The coefficient of the linear term, , It is a constant; Finally, using the calculated electrode spacing as a reference, while keeping the position of the sensing electrode unchanged, the corresponding electrode ring is switched back as the excitation electrode. It is necessary to ensure that the distance between the sensing electrode and the excitation electrode is greater than or equal to the calculated electrode spacing. At this time, the ice thickness is measured again using the sensor, and the final ice thickness is obtained based on the capacitance value of the sensor.

2. The capacitive multi-ring transmission line icing thickness sensor according to claim 1, characterized in that, The bushing has a thickness of 0.05mm-0.3mm, the insulation layer has a thickness of 0.1mm-0.5mm, the electrode ring has a thickness of 0.1mm-0.5mm, the insulation ring has a thickness of 0.2mm-1.0mm, and the width between the electrode ring and the insulation ring is 2mm-10mm.

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