A power distribution line very low frequency ice melting parameter analysis method, system, device and medium

Abstract

This invention relates to the field of power distribution line de-icing analysis technology, and discloses a method, system, equipment, and medium for analyzing very low frequency (VLF) de-icing parameters of power distribution lines. The method includes: calculating the power required for de-icing iced conductors based on environmental parameters and line icing data; calculating the Joule heat power generated by the conductors under VLF current; calculating the dielectric loss heat power generated by the icing layer under the VLF electric field; determining the correlation between de-icing voltage and de-icing frequency, and calculating the de-icing voltage at different de-icing frequencies; considering the line insulation level and electromagnetic interference generated by VLF, selecting de-icing frequency and voltage ranges that meet insulation and anti-interference requirements. This invention can reasonably determine the technical parameters for VLF de-icing of power distribution lines, ensure that the line insulation is not broken down during the de-icing process, and effectively reduce the interference of VLF electric fields on the environment and communication, providing a scientific and reliable parameter basis for uninterrupted de-icing of power distribution lines.

Description

Technical Field

[0001] This invention relates to the field of power line de-icing analysis technology, and in particular to a method, system, equipment and medium for analyzing very low frequency de-icing parameters of power lines. Background Technology

[0002] As a key link connecting the power transmission network and users in the power system, distribution lines may suffer various ice-related accidents such as tower collapse, line breakage, and galloping when covered with ice. This can not only cause large-scale power outages, but in severe cases, it can even threaten the personal safety of people in the surrounding area.

[0003] Currently, existing power distribution line de-icing technologies mainly include transformer de-icing and mechanical de-icing. Transformer de-icing uses a dedicated transformer to adjust the output voltage, increasing the current in the iced line and utilizing the Joule heat generated by the line resistance to melt the ice; this is suitable for medium and low voltage lines. Mechanical de-icing relies heavily on manual labor or external equipment to vibrate and remove ice from the iced line, resulting in low efficiency, high safety risks, long processing times, and often requiring power outages, leading to poor reliability. Very low frequency (VLF) excitation power distribution line de-icing involves applying a VLF excitation of 3kHz-30kHz to the conductor, utilizing the combined effects of the Joule heating effect of the conductor and the dielectric loss heat effect of the ice layer to achieve de-icing without power interruption. The de-icing effect of VLF de-icing is related to the de-icing frequency and voltage, requiring comprehensive consideration of multiple factors to accurately determine the range of VLF de-icing frequency and voltage. Current research on VLF de-icing lacks specific analysis of de-icing parameters, and the determination of these parameters lacks sufficient evidence. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method, system, equipment and medium for analyzing very low frequency de-icing parameters of power distribution lines, which solves the problems of insufficient specificity in the analysis of de-icing parameters and lack of sufficient basis for determining de-icing parameters in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for analyzing very low frequency de-icing parameters of power distribution lines, including: Calculate the power required to melt the iced conductors based on the obtained environmental parameters and line icing data; Calculate the Joule heat power generated in the conductor under very low frequency current. Calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field; Based on the power required for melting the icing conductor, the Joule heat power, and the dielectric loss heat power, the correlation between the melting voltage and the melting frequency is determined, and the melting voltage at different melting frequencies is calculated. Considering the line insulation level and electromagnetic interference generated by very low frequencies, based on the correlation between the de-icing voltage and the de-icing frequency, a range of de-icing frequency and de-icing voltage that meets the insulation and anti-interference requirements is selected.

[0007] As a preferred embodiment of the method for analyzing very low frequency de-icing parameters of power distribution lines according to the present invention, the step of calculating the power required for de-icing of the iced conductors based on the acquired environmental parameters and line icing data includes: Calculate the DC resistance per unit length of the circuit to be melted; Based on the obtained environmental parameters and line icing data, the minimum de-icing current of typical conductors under the corresponding operating conditions is selected from the national standards. Based on the DC resistance per unit length of the line to be melted and the minimum melting current of the typical conductor, calculate the linear density of the heating power required for melting. Calculate the power required to melt the ice-covered conductor based on the heating power linear density and the length of the line to be melted.

[0008] As a preferred embodiment of the method for analyzing very low frequency (VLF) de-icing parameters of power distribution lines according to the present invention, the calculation of the Joule heat power generated by the conductor under the action of VLF current includes: Calculate the skin depth of the conductor under very low frequency conditions; Based on the skin depth, the equivalent resistance per unit length of the conductor under very low frequency action is calculated, and a functional relationship between the resistance per unit length of the conductor and frequency is established. Calculate the inductance per unit length of the line to be melted by combining the conductor radius and the geometric mean distance between the three phase conductors; Calculate the Joule heat power generated by the conductor under very low frequency action based on the equivalent resistance per unit length and the inductance per unit length.

[0009] As a preferred embodiment of the method for analyzing very low frequency (VLF) de-icing parameters of power distribution lines according to the present invention, the calculation of the dielectric loss heat power generated by the icing layer under the action of a VLF electric field includes: In the very low frequency range, the electric field around the conductor is regarded as an electric quasi-static field. The phase voltage of the conductor is calculated based on the integration of the electric field intensity, and the linear charge density of the conductor is inversely deduced. Based on the stated charge linear density, calculate the electric field strength inside the ice layer and the average electric field strength inside the ice layer; Calculate the volume of the ice layer based on the radius of the conductor before and after icing; The dielectric loss heat power generated by the ice layer is calculated by combining the average electric field strength, the volume of the ice layer, and the dielectric loss tangent of the ice layer.

[0010] As a preferred embodiment of the method for analyzing very low frequency de-icing parameters of power distribution lines according to the present invention, the step of determining the correlation between de-icing voltage and de-icing frequency, and calculating the de-icing voltage at different de-icing frequencies, includes: The power required to melt the ice-covered conductor is taken as the total target power. Establish a balance relationship between the total target power and the Joule heat power and the dielectric loss heat power, and determine the correlation between the melting voltage and the melting frequency based on the balance relationship. Based on the correlation between the melting voltage and the melting frequency, the melting voltage at different melting frequencies is calculated.

[0011] The beneficial effects of this preferred technical solution are: it provides a scientific and quantifiable basis for determining very low frequency de-icing parameters, overcomes the lack of frequency-voltage correlation analysis in existing technologies, and improves the rationality and adaptability of de-icing parameter selection.

[0012] As a preferred embodiment of the very low frequency de-icing parameter analysis method for power distribution lines described in this invention, the step of screening de-icing frequencies and de-icing voltage ranges that meet insulation and anti-interference requirements includes: Based on the maximum voltage limit of power distribution lines specified in national standards and the preset upper limit of de-icing voltage, and combined with the correlation between the de-icing voltage and the de-icing frequency, the minimum value of the de-icing frequency is calculated. The maximum value of the ice-melting frequency is determined based on the upper limit of the very low frequency range and the constraint of avoiding interference with power line carrier communication. Using the minimum and maximum values ​​of the melting frequency as constraint boundaries, the melting frequency and melting voltage range that satisfy the constraint boundary conditions are selected from the correspondence between different melting frequencies and melting voltages.

[0013] The beneficial effects of this preferred technical solution are: ensuring that the selected de-icing parameters can meet the safety requirements of preventing line insulation breakdown, and avoiding interference with power line carrier communication, thereby improving the safety and reliability of power distribution line operation while ensuring the de-icing effect.

[0014] In a preferred embodiment of the very low frequency de-icing parameter analysis method for power distribution lines described in this invention, the determination of the minimum and maximum values ​​of the de-icing frequency includes: Based on the maximum voltage limit of the power distribution line specified in the national standard, combined with the constraint that the de-icing voltage does not exceed the maximum voltage limit of the power distribution line, and the constraint that the de-icing voltage does not exceed the preset upper limit of the de-icing voltage, the de-icing voltage is substituted into the correlation between the de-icing voltage and the de-icing frequency, and the minimum value of the de-icing frequency is obtained by inverse solution. Based on the upper limit of the very low frequency range and the constraint of avoiding interference with power line carrier communication, 30kHz is taken as the maximum value of the ice melting frequency.

[0015] Secondly, the present invention provides a very low frequency de-icing parameter analysis system for power distribution lines, comprising: The first calculation module is used to calculate the power required to melt the iced conductors based on the acquired environmental parameters and line icing data. The second calculation module is used to calculate the Joule heat power generated by the conductor under the action of very low frequency current. The third calculation module is used to calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field. The correlation determination module is used to determine the correlation between the melting voltage and the melting frequency based on the power required for melting the ice-covered conductor, the Joule heat power, and the dielectric loss heat power, and to calculate the melting voltage at different melting frequencies. The screening module is used to consider the line insulation level and electromagnetic interference generated by very low frequencies, and based on the correlation between the de-icing voltage and the de-icing frequency, to screen the de-icing frequency and de-icing voltage range that meet the insulation and anti-interference requirements.

[0016] Thirdly, the present invention provides an electronic device, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor executes the computer-executable instructions to implement the steps of a method for analyzing very low frequency de-icing parameters of power distribution lines.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of a method for analyzing very low frequency de-icing parameters of power distribution lines.

[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention fully considers the influence of multiple factors such as environmental conditions, ice thickness, and conductor type, and performs refined calculation and analysis on the power generated by different heat sources, deeply revealing the intrinsic correlation between melting voltage and melting frequency, filling the technical gap in the selection of very low frequency (VLF) melting parameters. By comprehensively considering the line insulation level and VLF electromagnetic interference constraints, this invention can reasonably select the melting frequency and voltage range that meet the requirements of safe operation and anti-interference, ensuring that the line insulation is not broken down during the melting process, while effectively reducing the interference of VLF electric fields on the environment and communication, providing a scientific and reliable parameter basis for uninterrupted ice melting of power distribution lines. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall process logic of a method for analyzing very low frequency de-icing parameters of power distribution lines according to an embodiment of the present invention.

[0021] Figure 2 The graph shows the relationship between the resistance per unit length of conductor and frequency under the skin effect in the very low frequency de-icing parameter analysis method for power distribution lines provided in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram showing the range of de-icing voltage and de-icing frequency in a method for analyzing very low frequency de-icing parameters of power distribution lines according to an embodiment of the present invention. Detailed Implementation

[0023] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0024] Example 1, referring to Figure 1 As an embodiment of the present invention, a method for analyzing very low frequency de-icing parameters of power distribution lines is provided, such as... Figure 1 The specific steps shown are as follows: S100: Calculate the power required to melt the iced conductors based on the acquired environmental parameters and line icing data; S200: Calculate the Joule heat power generated by the conductor under very low frequency current; S300: Calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field; S400: Based on the power required for melting ice-covered conductors, Joule heat power, and dielectric loss heat power, determine the correlation between melting voltage and melting frequency, and calculate the melting voltage at different melting frequencies. S500: Considering the line insulation level and electromagnetic interference generated by very low frequencies, based on the correlation between de-icing voltage and de-icing frequency, de-icing frequency and de-icing voltage ranges that meet the insulation and anti-interference requirements are selected.

[0025] It should be noted that this invention fully considers the influence of multiple factors such as environmental conditions, ice thickness, and conductor type, and performs refined calculation and analysis on the power generated by different heat sources. It deeply reveals the intrinsic correlation between melting voltage and melting frequency, filling the technical gap in the selection of very low frequency (VLF) melting parameters. By comprehensively considering the line insulation level and VLF electromagnetic interference constraints, this invention can rationally select melting frequency and voltage ranges that meet the requirements of safe operation and anti-interference, ensuring that the line insulation is not broken down during the melting process. Simultaneously, it effectively reduces the interference of VLF electric fields on the environment and communication, providing a scientific and reliable parameter basis for uninterrupted ice melting of power distribution lines.

[0026] In this embodiment of the invention, step S100, which calculates the power required for melting the icing conductor based on the acquired environmental parameters and line icing data, includes the following sub-steps A1-A4: In A1: Calculate the DC resistance per unit length of the line to be melted; Specifically, power distribution lines typically use steel-cored aluminum stranded wire, so the resistance per unit length of the line to be melted is... r eq It can be approximated as the parallel connection of the steel core resistance and the aluminum stranded wire resistance, that is, the DC resistance per unit length of the line to be melted. r eq The calculation formula is: in, , The resistivity of steel and aluminum are respectively, in units. ; , These are the cross-sectional areas of the steel and aluminum conductors, respectively, in units. .

[0027] In A2: Based on the acquired environmental parameters and line icing data, select the minimum de-icing current of typical conductors under the corresponding operating conditions from the national standards; Specifically, the acquired environmental parameters and line icing data include icing thickness, wind speed, conductor temperature, ambient temperature, and conductor type. Based on the minimum de-icing current recommendation table for different conductor types, icing thicknesses, ambient temperatures, and wind speeds provided in the "Technical Guidelines for Current-Based De-icing of Overhead Transmission Lines," the actual collected icing thickness, wind speed, conductor temperature, ambient temperature, and conductor type are matched with the operating parameters in the recommendation table, and the recommended current value under the corresponding operating condition is selected as the minimum de-icing current for the line.

[0028] In A3: Based on the DC resistance per unit length of the line to be melted and the minimum melting current of a typical conductor, calculate the linear density of the heating power required for melting; the formula is expressed as: in, W l This is the linear density of heating power, in W / m. I This is the minimum de-icing current for a typical conductor under the corresponding operating conditions as specified in the national standard, expressed in amperes (A).

[0029] In A4: Calculate the power required to melt the iced conductor based on the linear density of the heating power and the length of the line to be melted; the formula is expressed as: in, The power required to melt ice-covered conductors, expressed in watts (W). l The length of the line is in meters (m).

[0030] It should be noted that the above step S100 calculates the power required for melting the iced conductor based on environmental parameters and line icing data. This fully considers actual operating conditions such as ice thickness, wind speed, ambient temperature, and conductor type, making the determination of melting power more consistent with the site conditions. This avoids insufficient melting or energy waste caused by power estimation deviations, and lays an accurate power basis for subsequent parameter matching.

[0031] In this embodiment of the invention, the above step S200, which calculates the Joule heat power generated by the conductor under the action of very low frequency current, includes the following sub-steps B1-B4: In B1: Calculate the skin depth of the conductor under very low frequency conditions; Specifically, the frequency is calculated based on the formula for skin depth. f Skin depth of the lower conductor d The formula is as follows: in, d For the conductor at frequency f Skin depth, in meters; Represents the free permeability, 4π × 10⁻⁶ -7 ; The relative permeability of the conductor is approximately 1; in this embodiment, the relative permeability of the steel-cored aluminum stranded wire is approximately 1. The electrical conductivity of a conductor is expressed in units of [missing information]. .

[0032] In B2: The equivalent resistance per unit length of the conductor under very low frequency action is calculated based on the skin depth, and the functional relationship between the resistance per unit length of the conductor and the frequency is established. Specifically, based on the calculated skin depth and the relationship between resistance and conductor cross-sectional area, the equivalent resistance per unit length of the conductor under very low frequency conditions is calculated. R eq The calculation formula is as follows: in, R eq r1 is the equivalent resistance per unit length of the conductor, in Ω / m; r2 is the radius of the conductor, in meters.

[0033] Specifically, by combining the skin depth and the equivalent resistance per unit length of the conductor, the functional relationship between the resistance per unit length of the conductor and the frequency is obtained, expressed by the formula: in, This represents the functional relationship between the resistance per unit length of a conductor and its frequency.

[0034] In B3: Calculate the inductance per unit length of the line to be melted, taking into account the conductor radius and the geometric mean distance between the three phase conductors. L The calculation formula is as follows: in, L The inductance per unit length of the circuit to be melted is expressed in H / m. The geometric mean distance between the three-phase conductors is expressed in meters (m). The calculation formula is as follows: , , , These represent the distances between the three-phase conductors AB, BC, and CA, respectively. Let be the relative permeability of the conductor, and lg represent the logarithmic function to the base 10.

[0035] In B4: Calculate the Joule heat power generated by the conductor under very low frequency conditions based on the equivalent resistance per unit length and the inductance per unit length. W 1. The calculation formula is as follows: Where U is the phase voltage of the conductor, in V; W1 represents the Joule heat power generated by the conductor, measured in W.

[0036] It should be noted that the above step S200, by introducing the influence of the skin effect on the frequency characteristics of the conductor resistance, can accurately reflect the heating law of the conductor itself under very low frequency excitation, and ensure that the calculation of Joule heat power is dynamically adjusted with frequency changes, thereby truly reflecting the contribution of the conductor heat source to de-icing.

[0037] In this embodiment of the invention, the above step S300, which calculates the dielectric loss heat power generated by the icing layer under the action of a very low frequency electric field, includes the following sub-steps C1-C4: In C1: In the very low frequency range, the electric field around the conductor is regarded as an electric quasi-static field. The phase voltage of the conductor is calculated based on the integration of the electric field intensity, and the linear charge density of the conductor is inversely deduced. Specifically, analyze the linear charge density of the conductor. Phase voltage of the conductor U The relationships include: In the very low frequency range, the electric field around the conductor can be regarded as a quasi-static field. The electric field around the conductor can be calculated using the electric field strength formula, and then integrated to calculate the phase voltage of the conductor. U Phase voltage of the conductor U The calculation formula is as follows: Where r1 is the radius of the conductor, in meters; r 2 is the radius of the icing conductor, in meters (m). Linear charge density of a conductor, in C / m; The vacuum permittivity is approximately 8.854 × 10⁻⁶. -12 F / m; is the relative permittivity of ice; h The distance of the conductor from the ground is expressed in meters (m); ln represents the logarithmic function with base e.

[0038] Specifically, the linear charge density of the conductor is calculated by combining the phase voltage of the conductor. The formula for calculating the linear charge density of a conductor is as follows: In C2: Calculate the electric field strength inside the ice layer and the average electric field strength inside the ice layer based on the charge linear density; Specifically, the electric field strength inside the ice layer E The calculation formula is as follows: in, E This represents the electric field strength inside the ice layer, measured in V / m.

[0039] Specifically, the average electric field strength of the ice layer The calculation formula is as follows: in, The average electric field strength inside the ice layer is expressed in V / m.

[0040] In C3: The volume of the ice layer is calculated based on the conductor radius before and after icing, expressed by the formula: in, V ice This indicates the volume of the ice layer, in meters (m). 3 .

[0041] In C4: The dielectric loss heat power generated by the icing layer is calculated by combining the average electric field strength, the volume of the icing layer, and the dielectric loss tangent of the icing layer; the formula is expressed as: in, W 2 represents the heat loss of the icing layer, in W; This represents the tangent of the dielectric loss angle of the icing layer.

[0042] It should be noted that step S300 above uses the quasi-static field assumption to analyze the electric field distribution inside the icing layer, which can quantify the self-heating effect of the icing medium in the very low frequency alternating electric field, fully explore the melting potential of the icing layer as an auxiliary heat source, and realize the synergistic utilization of the Joule heat of the conductor and the heat loss of the ice layer medium.

[0043] In this embodiment of the invention, step S400, based on the power required for melting the icing conductor, the Joule heat power, and the dielectric loss heat power, determines the correlation between the melting voltage and the melting frequency, and calculates the melting voltage at different melting frequencies, including the following sub-steps D1-D3: In D1: the power required to melt the iced conductor is taken as the total target power; In D2: Establish a balance relationship between the total target power, Joule heat power, and dielectric loss heat power, and determine the correlation between the melting voltage and the melting frequency based on the balance relationship. It should be noted that the power required to melt ice-covered conductors is equal to the sum of the Joule heat power of the conductor and the heat power lost by the dielectric layer of the ice layer. Based on this relationship, a balance relationship is established between the total target power and the Joule heat power and the dielectric loss heat power, expressed by the formula as follows: Furthermore, by performing algebraic transformation and rearranging the balance relationship between total target power, Joule heat power, and dielectric loss heat power, the correlation between melting voltage and melting frequency is finally obtained.

[0044] In D3: Based on the correlation between melting voltage and melting frequency, calculate the melting voltage at different melting frequencies; Specifically, based on project requirements, a series of discrete de-icing frequency values ​​are selected within the very low frequency range (e.g., 3kHz to 30kHz). Each frequency value is then substituted into the correlation between de-icing voltage and de-icing frequency to calculate the corresponding de-icing voltage value. This yields several sets of frequency-voltage data pairs, which can be organized into tables or plotted as curves for subsequent selection of reasonable de-icing frequency and de-icing voltage ranges based on insulation levels and electromagnetic interference constraints.

[0045] It should be noted that step S400 establishes the physical balance equation between the total melting power and the power of the two heat sources, making the relationship between the melting voltage and frequency clear and quantifiable, and providing calculable theoretical support for the flexible matching of melting parameters under multiple operating conditions.

[0046] In this embodiment of the invention, step S500, considering the line insulation level and electromagnetic interference generated at very low frequencies, and based on the correlation between de-icing voltage and de-icing frequency, selects de-icing frequency and de-icing voltage ranges that meet the insulation and anti-interference requirements, including the following sub-steps E1-E3: In E1: Based on the maximum voltage limit of the distribution line specified in the national standard and the preset upper limit of the de-icing voltage, and combined with the correlation between the de-icing voltage and the de-icing frequency, calculate the minimum value of the de-icing frequency. In this embodiment of the invention, the minimum value of the ice melting frequency The determination includes: based on the maximum voltage limit of the distribution line specified in the national standard, combined with the constraint that the de-icing voltage does not exceed the maximum voltage limit of the distribution line, and the constraint that the de-icing voltage does not exceed the preset upper limit of the de-icing voltage, the de-icing voltage is substituted into the correlation between the de-icing voltage and the de-icing frequency, and the minimum value of the de-icing frequency is obtained by inverse solution.

[0047] Specifically, according to the national standard GB 311.1-2012, the maximum voltage limit for a 10kV distribution line cannot exceed 12kV. Without affecting the normal operation of the distribution line, the de-icing voltage cannot exceed a preset upper limit. In this embodiment of the invention, the preset upper limit for the de-icing voltage is 2kV. And through voltage... U With frequency f From the relationship, we can deduce that the frequency at this point should satisfy: In E2: Determine the maximum value of the ice-melting frequency based on the upper limit of the very low frequency range and the constraint of avoiding interference with power line carrier communication; In this embodiment of the invention, 30kHz is taken as the maximum value of the ice-melting frequency.

[0048] Specifically, the de-icing frequency needs to be controlled within a certain range. If the frequency is too high, it will interfere with power line carrier communication. Furthermore, considering the very low frequency (VLF) range, which is much lower than the frequencies that would interfere with power line carrier communication, the de-icing frequency cannot exceed 30kHz. .

[0049] In E3: Using the minimum and maximum values ​​of the melting frequency as the constraint boundary, the melting frequency and melting voltage range that satisfy the constraint boundary conditions are selected from the correspondence between different melting frequencies and melting voltages. Specifically, the reasonable range of ice-melting frequency in this embodiment is: .

[0050] Furthermore, based on the ice-melting frequency range, the voltage range is obtained as follows: .

[0051] It should be noted that the above step S500 can reasonably constrain the boundaries of de-icing parameters while ensuring the safe operation of the power distribution line and without interfering with the power line carrier communication. It can effectively avoid the de-icing voltage being too high and breaking down the insulation or the frequency being too low and failing to meet the de-icing requirements. Finally, it outputs a safe and reliable de-icing parameter range that can be directly applied in engineering.

[0052] Example 2, refer to Figure 2 and Figure 3 This embodiment provides an application example of a method for analyzing very low frequency de-icing parameters of power distribution lines, and verifies and explains the technical effect of this method.

[0053] In this embodiment, the line to be de-iced is a 10kV distribution line with a total length of 5000m. The conductor type is LGJ-120 / 20, and the conductors are arranged in a triangular pattern with a phase spacing of 1m. The average height of the conductors above the ground is 10m. The temperature difference between the conductor and the outside air temperature is -3℃, the wind speed is 3m / s, and the ice thickness is 0.01m. The outer diameter of the conductor is... The cross-sectional area of ​​the aluminum stranded wire is 115.6 mm². 2 The cross-sectional area of ​​the steel core is 18.8 mm². 2 The resistivity of steel is 0.0987. The resistivity of aluminum is 0.0315. The conductivity of the conductor is .

[0054] The specific calculation process is as follows: Step 1.1, DC resistance per unit length of the circuit to be melted r eq The calculation formula is as follows: Step 1.2: Based on information such as ice thickness, wind speed, conductor temperature, ambient temperature, and conductor type, select the minimum de-icing current for typical conductors under the corresponding operating conditions from the national standard. Combined with the DC resistance per unit length of the line to be de-iced calculated in Step 1.1, calculate the linear density of the heating power required for de-icing. Then, combining the linear density of the heating power required for de-icing and the length of the line to be de-iced, calculate the power required for de-icing. The formula for calculating the linear density of the heating power required for de-icing is as follows: The formula for calculating the heating power required for the circuit to be melted is as follows: Step 2.1, calculate the skin depth d of the conductor at frequency f using the skin depth formula: Step 2.2: Using the skin depth obtained in Step 2.1, calculate the equivalent resistance per unit length of the conductor under very low frequency (VLF) conditions based on the relationship between resistance and conductor cross-sectional area. R eq : Step 2.3: Combining the skin depth obtained in Step 2.1 and the resistance per unit length of the conductor obtained in Step 2.2, calculate the function of resistance per unit length of the conductor and frequency: Figure 2 This is a graph of the resistance per unit length of a conductor as a function of frequency, plotted based on this formula. Under the same conditions, the higher the frequency, the greater the resistance per unit length of the conductor, and the more pronounced the resulting thermal effect.

[0055] Step 2.4, combining the radius of the conductor and the geometric mean distance between the conductors, calculate the inductance per unit length L of the circuit to be melted: Step 2.5: Combining the resistance per unit length of the conductor obtained in Step 2.3 and the inductance per unit length of the conductor obtained in Step 2.4, calculate the Joule heat power generated by the conductor under very low frequency conditions. W 1: Step 3.1: Within the very low frequency range, the electric field around the conductor can be considered as a quasi-static field. Calculate the electric field around the conductor using the electric field strength formula, integrate it, and calculate the phase voltage U of the conductor. Combine this with the phase voltage to calculate the linear charge density of the conductor. The formula for calculating the voltage between a conductor and ground is as follows: The formula for calculating the linear charge density of a conductor is as follows: Step 3.2: Combining the charge linear density obtained in Step 3.1, calculate the electric field intensity E and the average electric field intensity inside the ice layer. The formula for calculating the electric field strength of the ice layer is as follows: The formula for calculating the average electric field strength of the ice layer is as follows: Step 3.3: Combining the relationship between voltage and average electric field strength given in Step 3.2, and using the dielectric loss formula per unit volume, along with the volume of the icing layer, calculate the dielectric loss heat power of the icing layer. W 2. The formula for calculating the volume of the ice layer is as follows: The formula for calculating the heat power loss of the icing layer is as follows: Step 4: Combining the power required for de-icing obtained in Step 1, the Joule heat power of the conductor obtained in Step 2, and the dielectric loss heat power of the icing layer obtained in Step 3, the ultra-low frequency de-icing method proposed in this invention requires a power equal to the sum of the Joule heat power of the conductor and the dielectric loss heat power of the icing layer. Based on this, the corresponding de-icing voltage at different de-icing frequencies is calculated. The formula is as follows:

[0056] Based on the above formula, the melting voltage corresponding to different melting frequencies is calculated as shown in Table 1: Table 1: Correspondence between melting frequency and melting voltage.

[0057] Step 5.1: Based on the line insulation level specified in the national standard, calculate the minimum value of the de-icing frequency without affecting the normal power supply of the distribution line.

[0058] According to national standard GB 311.1-2012, the maximum voltage of a 10kV distribution line cannot exceed 12kV, and the de-icing voltage cannot exceed 2kV without affecting the normal operation of the distribution line. Using the relationship between voltage U and frequency f, the frequency at this point can be approximated as follows:

[0059] Step 5.2, the ice-melting frequency must not exceed 30kHz, that is... ; Therefore, according to the very low frequency de-icing method proposed in this invention, the reasonable de-icing frequency range is:

[0060] The voltage range is obtained based on the frequency range:

[0061] Figure 3 Based on the range of melting frequency and melting voltage obtained in step 5.2, and combined with the correlation between melting frequency and melting voltage in step 4, the range curves of melting frequency and melting voltage under the selected working conditions in this example are plotted.

[0062] As described above, this invention fully considers the influence of multiple factors such as environmental conditions, ice thickness, and conductor type, and performs refined calculation and analysis on the power generated by different heat sources. It deeply reveals the intrinsic correlation between melting voltage and melting frequency, filling the technical gap in the selection of very low frequency (VLF) melting parameters. By comprehensively considering the line insulation level and VLF electromagnetic interference constraints, this invention can rationally select melting frequency and voltage ranges that meet the requirements of safe operation and anti-interference, ensuring that the line insulation is not broken down during the melting process. Simultaneously, it effectively reduces the interference of VLF electric fields on the environment and communication, providing a scientific and reliable parameter basis for uninterrupted ice melting of power distribution lines.

[0063] Example 3: This example provides a very low frequency de-icing parameter analysis system for power distribution lines, including: The first calculation module is used to calculate the power required to melt the iced conductors based on the acquired environmental parameters and line icing data. The second calculation module is used to calculate the Joule heat power generated by the conductor under the action of very low frequency current. The third calculation module is used to calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field. The correlation determination module is used to determine the correlation between the melting voltage and the melting frequency based on the power required for melting ice-covered conductors, Joule heat power, and dielectric loss heat power, and to calculate the melting voltage at different melting frequencies. The screening module is used to consider the insulation level of the line and electromagnetic interference generated at very low frequencies. Based on the correlation between de-icing voltage and de-icing frequency, it screens the de-icing frequency and de-icing voltage range that meet the insulation and anti-interference requirements.

[0064] It should be noted that the technical solution of the power distribution line VLCN de-icing parameter analysis system is based on the same concept as the technical solution of the aforementioned power distribution line VLCN de-icing parameter analysis method. For details not described in detail in this embodiment, please refer to the description of the technical solution of the aforementioned power distribution line VLCN de-icing parameter analysis method.

[0065] The above-mentioned unit modules can be embedded in the processor of the electronic device in hardware form or independent of it, or they can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of the above modules.

[0066] This embodiment also provides an electronic device, which includes a processor, a memory, a communication interface, a display screen, and an input device connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through WiFi, carrier networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for analyzing very low frequency de-icing parameters of power distribution lines. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0067] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method proposed in the above embodiments.

[0068] The storage medium proposed in this embodiment belongs to the same inventive concept as the method proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0069] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory, random access memory, flash memory, hard disk, or optical disk, and includes several instructions to cause an electronic device (which may be a personal computer, server, or network device, etc.) to execute the method of the embodiments of the present invention.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for analyzing very low frequency de-icing parameters of power distribution lines, characterized in that, include: Calculate the power required to melt the iced conductors based on the obtained environmental parameters and line icing data; Calculate the Joule heat power generated in the conductor under very low frequency current. Calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field; Based on the power required for melting the icing conductor, the Joule heat power, and the dielectric loss heat power, the correlation between the melting voltage and the melting frequency is determined, and the melting voltage at different melting frequencies is calculated. Considering the line insulation level and electromagnetic interference generated by very low frequencies, based on the correlation between the de-icing voltage and the de-icing frequency, a range of de-icing frequency and de-icing voltage that meets the insulation and anti-interference requirements is selected.

2. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 1, characterized in that, The calculation of the power required for melting iced conductors based on the acquired environmental parameters and line icing data includes: Calculate the DC resistance per unit length of the circuit to be melted; Based on the obtained environmental parameters and line icing data, the minimum de-icing current of typical conductors under the corresponding operating conditions is selected from the national standards. Based on the DC resistance per unit length of the line to be melted and the minimum melting current of the typical conductor, calculate the linear density of the heating power required for melting. Calculate the power required to melt the ice-covered conductor based on the heating power linear density and the length of the line to be melted.

3. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 2, characterized in that, The calculation of the Joule heat power generated by the conductor under very low frequency current includes: Calculate the skin depth of the conductor under very low frequency conditions; Based on the skin depth, the equivalent resistance per unit length of the conductor under very low frequency action is calculated, and a functional relationship between the resistance per unit length of the conductor and frequency is established. Calculate the inductance per unit length of the line to be melted by combining the conductor radius and the geometric mean distance between the three phase conductors; Calculate the Joule heat power generated by the conductor under very low frequency action based on the equivalent resistance per unit length and the inductance per unit length.

4. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 3, characterized in that, The calculation of dielectric loss heat power generated by the icing layer under a very low frequency electric field includes: In the very low frequency range, the electric field around the conductor is regarded as an electric quasi-static field. The phase voltage of the conductor is calculated based on the integration of the electric field intensity, and the linear charge density of the conductor is inversely deduced. Based on the stated charge linear density, calculate the electric field strength inside the ice layer and the average electric field strength inside the ice layer; Calculate the volume of the ice layer based on the radius of the conductor before and after icing; The dielectric loss heat power generated by the ice layer is calculated by combining the average electric field strength, the volume of the ice layer, and the dielectric loss tangent of the ice layer.

5. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 4, characterized in that, The process of determining the correlation between melting voltage and melting frequency, and calculating the melting voltage at different melting frequencies, includes: The power required to melt the ice-covered conductor is taken as the total target power. Establish a balance relationship between the total target power and the Joule heat power and the dielectric loss heat power, and determine the correlation between the melting voltage and the melting frequency based on the balance relationship. Based on the correlation between the melting voltage and the melting frequency, the melting voltage at different melting frequencies is calculated.

6. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 5, characterized in that, The screening of de-icing frequencies and de-icing voltage ranges that meet insulation and anti-interference requirements includes: Based on the maximum voltage limit of power distribution lines specified in national standards and the preset upper limit of de-icing voltage, and combined with the correlation between the de-icing voltage and the de-icing frequency, the minimum value of the de-icing frequency is calculated. The maximum value of the ice-melting frequency is determined based on the upper limit of the very low frequency range and the constraint of avoiding interference with power line carrier communication. Using the minimum and maximum values ​​of the melting frequency as constraint boundaries, the melting frequency and melting voltage range that satisfy the constraint boundary conditions are selected from the correspondence between different melting frequencies and melting voltages.

7. The method for analyzing very low frequency de-icing parameters of power distribution lines as described in claim 6, characterized in that, The determination of the minimum and maximum values ​​of the ice melting frequency includes: Based on the maximum voltage limit of the power distribution line specified in the national standard, combined with the constraint that the de-icing voltage does not exceed the maximum voltage limit of the power distribution line, and the constraint that the de-icing voltage does not exceed the preset upper limit of the de-icing voltage, the de-icing voltage is substituted into the correlation between the de-icing voltage and the de-icing frequency, and the minimum value of the de-icing frequency is obtained by inverse solution. Based on the upper limit of the very low frequency range and the constraint of avoiding interference with power line carrier communication, 30kHz is taken as the maximum value of the ice melting frequency.

8. A very low frequency (VLF) de-icing parameter analysis system for power distribution lines, employing the VLF de-icing parameter analysis method for power distribution lines as described in any one of claims 1 to 7, characterized in that, include: The first calculation module is used to calculate the power required to melt the iced conductors based on the acquired environmental parameters and line icing data. The second calculation module is used to calculate the Joule heat power generated by the conductor under the action of very low frequency current. The third calculation module is used to calculate the dielectric loss heat power generated by the ice layer under the action of a very low frequency electric field. The correlation determination module is used to determine the correlation between the melting voltage and the melting frequency based on the power required for melting the ice-covered conductor, the Joule heat power, and the dielectric loss heat power, and to calculate the melting voltage at different melting frequencies. The screening module is used to consider the line insulation level and electromagnetic interference generated by very low frequencies, and based on the correlation between the de-icing voltage and the de-icing frequency, to screen the de-icing frequency and de-icing voltage range that meet the insulation and anti-interference requirements.

9. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store computer-executable instructions, and when the processor executes the computer-executable instructions, it implements the steps of the method for analyzing very low frequency de-icing parameters of power distribution lines as described in any one of claims 1 to 7.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the computer-executable instructions are executed by the processor, they implement the steps of the method for analyzing very low frequency de-icing parameters of power distribution lines as described in any one of claims 1 to 7.

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