Direct current ice melting self-adaptive control method and system for non-uniform icing

Abstract

The application discloses a direct-current ice melting self-adaptive control method for non-uniform icing, and comprises the following steps: identifying the icing shape characteristics of an icing section; calculating the ice melting control parameters of non-uniform icing according to the icing shape characteristics; and carrying out segmented control on ice melting within the ice melting control parameter range; the ice melting segmented control at least comprises an initial heating stage, a dynamic current ice melting stage and a safe cooling stage. The application establishes a special ice melting control method for non-uniform icing, solves the defects that the existing ice melting technology is long-term limited by the ideal uniform cylindrical hypothesis and cannot cope with actual complex micro-meteorological environments, and establishes a refined thermal field model considering the ice ridge heat dissipation enhancement effect and the non-uniform distribution of circumferential thermal resistance, so that the ice melting current calculation error is reduced.

Description

Technical Field

[0001] This invention belongs to the field of disaster prevention and mitigation technology for power system transmission lines, specifically relating to an adaptive control method and system for DC de-icing in the case of non-uniform icing. Background Technology

[0002] Fiber-optic composite overhead ground wires (OPGWs), as key equipment in modern power grids that combine lightning protection and communication functions, are highly susceptible to icing accidents during winter snow and ice disasters. DC de-icing technology is currently the most effective means to solve the icing problem of OPGWs.

[0003] However, existing de-icing solutions are all designed based on an ideal, uniform cylindrical icing model. In actual working conditions, influenced by environmental factors such as wind direction, temperature gradient, and rainfall intensity, icing on the OPGW surface often exhibits a non-uniform distribution, mainly manifesting as two morphologies: icicle-shaped icing and cone-shaped icing. Uniform icing has a significant impact on the DC de-icing process. On the one hand, conical icing significantly increases the surface area, leading to a substantial increase in heat loss to the environment through convection and radiation, resulting in reduced de-icing efficiency. Existing calculation models for critical and maximum de-icing currents based on the assumption of uniform icing have significant errors. On the other hand, conical icing causes uneven circumferential thermal resistance distribution in OPGW, with high thermal resistance in thick ice areas and low thermal resistance in thin ice areas. This results in asynchronous de-icing processes in different parts. After the thinner ice layer is de-iced prematurely, the temperature of the exposed conductor rises rapidly, which may cause the local fiber temperature to exceed the safety threshold, increasing the risk of fiber thermal damage.

[0004] In the existing technology, although there are real-time temperature monitoring schemes based on distributed optical fiber sensing, their control strategies still adopt a single current regulation mode based on the assumption of uniform icing. They fail to differentiate control for the special heat dissipation characteristics of non-uniform icing and the differences in the melting process, and thus cannot effectively solve the above problems.

[0005] In the existing technology, although there are real-time temperature monitoring schemes based on distributed optical fiber sensing, their control strategies still adopt a single current regulation mode based on the assumption of uniform icing. They fail to differentiate control for the special heat dissipation characteristics of non-uniform icing and the differences in the melting process, and thus cannot effectively solve the above problems. Summary of the Invention

[0006] To address the technical problems of low melting efficiency and difficulty in fiber temperature control of OPGW DC de-icing under non-uniform icing conditions in the prior art, this invention provides an adaptive control method and system for OPGW DC de-icing under non-uniform icing conditions through icing morphology recognition, non-uniform thermal field modeling, and staged differentiated current control.

[0007] To achieve the above objectives, the present invention provides the following technical solution: An adaptive control method for DC de-icing in cases of non-uniform icing includes the following steps: Identify the icing morphology characteristics of icing sections; Calculate the melting control parameters for non-uniform icing based on the icing morphology characteristics; Segmented control of ice melting is implemented within the range of ice melting control parameters; The segmented ice-melting control includes at least an initial heating stage, a dynamic current ice-melting stage, and a safe cooling stage.

[0008] In a preferred embodiment, the ice morphology type is obtained by acquiring multi-angle images of the ice-covered section using an image acquisition device and identifying them using an image processing algorithm.

[0009] In a preferred embodiment, the icing morphology includes icicle-shaped icing and cone-shaped icing, and a non-uniform thermal field model is constructed based on the icing morphology. The non-uniform thermal field model of the icicle-like ice cover includes a modified heat balance equation, which is:

[0010] Where Q is the Joule heat generated by the melting current; Q1 is the heat loss of the base ice layer; Q2 is the latent heat of phase change of the ice layer; Q3 is the heat required for each part to heat up; and Q4 is the additional heat loss of the ice shards. The non-uniform thermal field model for the conical icing includes a circumferential non-uniform thermal resistance distribution model. This model divides the conductor circumferentially into multiple sector regions, and the thermal resistance of each region is calculated independently based on the ice thickness and angular size. The thermal resistance of each region is:

[0011] Where, r i Let r be the outer radius of the ice layer in region i, m; o Δθ is the radius of the OPGW ground wire, in meters; Δθ is the angle of the sector region.

[0012] In a preferred embodiment, the de-icing control parameters for non-uniform icing are calculated based on a non-uniform thermal field model. The de-icing control parameters for non-uniform icing include a modified critical de-icing current and a modified maximum de-icing current.

[0013] In a preferred embodiment, the modified critical de-icing current I min1 :

[0014] In the formula, β is the correction coefficient; I min The critical current for uniform icing; L is the length of the ice ridge; d represents the average ice thickness in meters. The corrected maximum de-icing current Imax1 :

[0015] In the formula, ΔT n The additional temperature rise is due to non-uniform icing; I max T represents the maximum de-icing current under uniform icing conditions. pMAX The maximum permissible temperature; T a The ambient temperature of the icing line is K.

[0016] In a preferred embodiment, during the initial heating phase, an initial current I is applied. min1 The temperature continues until the surface temperature of the line rises to the melting point of the ice.

[0017] In a preferred embodiment, the dynamic current de-icing stage includes: Tracking the highest temperature T across the entire line max The changing trend and position of T max The current is adjusted by comparing it with multiple threshold levels. When T max In T env To T low During this period, the de-icing current is gradually increased using a positive step size, so that the current gradually increases to I. min1 ; When T max In T low To T high During this period, a closed-loop algorithm is used to fine-tune the de-icing current, T. max It remains stable within this range; When T max In T high To T trip If T occurs due to non-uniform de-icing during this period, max >T high Then, a negative step size is used to forcibly reduce the de-icing current, so that T max Falling back to T high To T trip between; When T max Greater than T trip When this occurs, the safety interlock protection is triggered, and an emergency trip shutdown is executed; Wherein: T env For ambient temperature, T low For efficient ice melting lower limit temperature, T high For the safe upper limit temperature, T trip This is the ultimate tripping temperature.

[0018] In a preferred embodiment, during the dynamic current de-icing stage, when the melting of ice crystals is detected by image recognition or temperature change, the de-icing current is increased by 10% to 15%. When the rate of temperature rise in a local area exceeds a preset rate threshold per unit time, and the ice thickness in that area has dropped to zero or below a preset de-icing thickness threshold, non-uniform de-icing is determined to have occurred.

[0019] In a preferred embodiment, during the safe cooling phase, the de-icing current is gradually reduced, and the temperature reduction rate is constrained to be less than B°C per second, where B is not greater than 2.

[0020] An adaptive control system for DC de-icing in the case of non-uniform icing includes Ice morphology recognition subsystem: includes a high-definition camera device, an image processing unit and a feature extraction module. The image processing unit is used to process images in real time and recognize ice morphology. The feature extraction module is used to extract ice geometric parameters. Non-uniform thermal field calculation subsystem: includes thermal field modeling module, parameter database and ice melting current calculation module. The thermal field modeling module calls the corresponding thermal field calculation model according to the ice cladding morphology. The parameter database stores thermal parameters of different line models and different ice cladding morphologies. The ice melting current calculation module calculates the corrected critical current and maximum current. Distributed temperature monitoring subsystem: includes a distributed fiber optic temperature measurement host and a data acquisition and processing unit, used to collect temperature distribution data in real time and send the highest temperature of the line and its location to the control unit; The adaptive current control subsystem includes a central control unit and an adjustable DC de-icing power supply. The central control unit runs a phased control algorithm and generates current adjustment commands, while the adjustable DC de-icing power supply receives the commands and precisely adjusts the output current.

[0021] The technical effects and advantages of this invention are as follows: 1. This application establishes a specialized ice-melting control method for non-uniform icing, which solves the problem that existing ice-melting technologies have long been limited by the assumption of an ideal uniform cylinder and cannot cope with the actual complex micro-meteorological environment; a refined thermal field model that considers the heat dissipation enhancement effect of ice ridges and the non-uniform distribution of circumferential thermal resistance is established, which reduces the calculation error of ice-melting current.

[0022] 2. This application, by correcting the calculation of the maximum de-icing current, fully considers the additional temperature rise effect caused by non-uniform icing, such as premature de-icing in thin ice areas, and ensures that under special working conditions of uneven icing, the maximum temperature of the optical fiber of the entire line does not exceed the safety threshold of 85°C, thus avoiding irreversible thermal damage to the optical fiber to a greater extent.

[0023] 3. This application implements a phased differentiated control strategy based on global temperature feedback. Compared with using a fixed current for de-icing, it ensures safety by using PID dynamic regulation to make the de-icing current meet the thermal tolerance of the optical fiber and the requirements for efficient de-icing. At the same time, it uses advanced technologies such as image recognition, multiphysics modeling, and adaptive control to achieve higher de-icing efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the icing morphology recognition process in this application.

[0025] Figure 2 This is a flowchart of the phased adaptive current control strategy of this application.

[0026] Figure 3 This is a temperature distribution diagram of the OPGW DC de-icing process under the conical icing condition described in this application.

[0027] Figure 4 This is the overall architecture diagram of the DC ice-melting adaptive control system of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1-2 As shown, the adaptive control method for DC de-icing in cases of non-uniform icing includes the following steps: 1. Identify the icing morphology characteristics of the icing section; acquire multi-angle images of the OPGW icing section using an image acquisition device, and use image processing algorithms to identify the icing morphology type. Common image recognition methods can be used, such as the Otsu's method, Hough transform, and convolutional neural networks. Icing morphology types include icicle-shaped icing and cone-shaped icing.

[0030] Feature parameters were extracted from the identified icing morphology, including average icing thickness d and maximum icing thickness d. max Minimum icing thickness d min The coefficient of uneven icing η = (d max - d min ) / d, icicle length L, icicle root diameter D base and tip diameter D tip The circumferential distribution angle of the ice layer is θ.

[0031] 2. Calculate the melting control parameters for non-uniform icing based on the icing morphology characteristics.

[0032] First, a non-uniform thermal field model for non-uniform icing is established based on the characteristics of icing morphology. The non-uniform thermal field model of icicle-shaped ice cover establishes a modified heat balance equation to enhance heat dissipation. In the modified heat balance equation, the heat generated by the melting current is the sum of the heat loss of the base ice layer, the heat consumed by the latent heat of phase change of the ice layer, the heat required for each part to heat up, and the heat loss of the ice ridges. The additional heat loss of the ice ridges is the heat lost by the direct heat exchange between the surface of the ice ridges and the environment. The larger the surface area of ​​the ice ridges, the more additional heat dissipation occurs.

[0033] Specifically, such as Figure 3 As shown, a modified heat balance equation considering the enhanced heat dissipation from icicles is established: (1) In the formula, Q is the Joule heat generated by the melting current; Q1 is the heat loss of the base ice layer; Q2 is the latent heat of phase change of the ice layer; Q3 is the heat required for each part to heat up; and Q4 is the additional heat loss of the ice shards.

[0034] The formula for calculating the Joule heat Q generated by the de-icing current is as follows: (2) In the formula, I is the DC de-icing current, A; r T Ω / m represents the resistivity of the OPGW line at temperature T.

[0035] The formula for calculating the heat loss Q1 due to heat dissipation from the base ice layer is as follows: (3) In the formula: Γ 01 The outer surface of the ice layer is represented by h, which is the heat exchange coefficient between the outer surface of the ice layer and the surrounding environment when the ice layer is uniformly covered, in W / (m²). 2 K); T a T i Let K be the ambient temperature and the outer surface temperature of the ice layer.

[0036] The formula for calculating the heat Q2 absorbed by the ice layer during the ice-water phase change is as follows: (4) In the formula: ρ i The density of the ice layer is kg / m³. 3 L F L is the latent heat of the ice-water phase transition. F =335000 J / m 3 ; S is the area of ​​the melted ice layer, in meters. 2 .

[0037] During the OPGW DC de-icing process, the formula for calculating the heat Q3 absorbed by the line and the surrounding ice layer due to temperature rise is as follows: (5) In the formula: θ is the area element in the two-dimensional model; ρ θ The density of the area element θ is kg / m³. 3 C θ The specific heat capacity of the area element θ, in J / kg ℃; dS is the θ-area of ​​the area element, m 2 dT is The change in temperature over time t.

[0038] The formula for calculating the additional heat loss of the ice shards is: (6) In the formula, h i Additional heat transfer coefficient for the ice surface, W / (m 2 K); Considering the enhancing effect of icicle shape on convective heat transfer: (7) In the formula, α is the heat dissipation enhancement coefficient of the icicle, which is determined by fitting simulation data and has a value range of 0.15-0.25.

[0039] The non-uniform thermal field model for conical icing is to establish a circumferential non-uniform thermal resistance distribution model. The circumferential non-uniform thermal resistance distribution model divides the conductor circumferentially into multiple sector regions, and the thermal resistance of each region is calculated independently based on the ice thickness and the angular size.

[0040] Specifically, the OPGW is divided into n sector regions circumferentially, and independent heat conduction equations are established for each region. The differences in the melting process of each region are calculated, and the thermal resistance of each region is: (8) In the formula, r i Let r be the outer radius of the ice layer in region i, m; o Δθ is the radius of the OPGW ground wire, in meters; Δθ is the angle of the sector region.

[0041] 3. Based on the non-uniform icing thermal field model, calculate the corrected critical melting current and maximum melting current: (1) Correction of critical de-icing current I min1 : (9) In the formula, β is a correction coefficient, with a value of 1.2-1.5; I min The critical current for uniform icing: (10) In the formula, T c OPGW surface temperature, K; T i is the outer surface temperature of the ice layer, °C; h is the heat exchange coefficient between the outer surface of the ice layer and the surrounding environment when uniformly covered with ice, W / (m²). 2 K); d represents the ice thickness on the OPGW surface when uniformly iced, in meters.

[0042] (2) Correction of maximum de-icing current I max1 : Consider the effect of fiber temperature rise during non-uniform icing and de-icing: (11) In the formula, ΔT n The additional temperature rise caused by non-uniform icing is obtained by querying a pre-established feature database; I max The maximum de-icing current when the ice is uniformly covered: (12) In the formula: T pMAX h is the maximum permissible temperature of the internal optical fiber of OPGW. c The heat exchange coefficient of the OPGW surface is W / (m²). 2 K); r T Ω / m represents the resistivity of the OPGW line at temperature T.

[0043] 4. Implement segmented control of ice melting within the range of ice melting control parameters; The segmented control of ice melting includes at least the initial heating stage, the dynamic current ice melting stage, and the safe cooling stage.

[0044] Phase 1: Initial Heating Phase Apply initial current I min1 Simultaneously monitor the OPGW surface temperature T c This raises the surface temperature of OPGW to around -2°C. The purpose of this stage is to rapidly increase the surface temperature of OPGW to near the melting point of ice.

[0045] The second stage: the dynamic current de-icing stage, including: Tracking the highest temperature T across the entire line max The changing trend and position of T max The current is adjusted by comparing it with multiple threshold levels. When T max In T env To T low During this period, the de-icing current is gradually increased using a positive step size, so that the current gradually increases to I. min1 ; When T max In T low To T high During this period, a closed-loop algorithm is used to fine-tune the de-icing current, T. max It remains stable within this range; When T max In T high To T trip If T occurs due to non-uniform de-icing during this period, max >T high Then, a negative step size is used to forcibly reduce the de-icing current, so that T max Falling back to T high To T trip between; When T max Greater than T trip When this occurs, the safety interlock protection is triggered, and an emergency trip shutdown is executed; Wherein: T env For ambient temperature, T low For efficient ice melting lower limit temperature, T high For the safe upper limit temperature, T trip This is the ultimate tripping temperature.

[0046] In this embodiment, dynamic current regulation is adopted, and a reference current I is selected. base =(I min1 +I max1 ) / 2, based on the distributed fiber optic temperature measurement feedback, extract the global maximum temperature T. max The PID algorithm is used to adjust the ice-melting current in real time. (13) In the formula, e(t) is the deviation function: (14) In the formula T target The reference temperature is set to 75℃.

[0047] When the melting of icicles is detected through image recognition or temperature change analysis, the melting current is increased by 10%-15% to compensate for heat loss. When the distributed fiber optic temperature measurement system detects that the temperature rise rate in a localized area exceeds a preset threshold per unit time, and the ice thickness in that area has dropped to zero or below a preset ice removal thickness threshold, non-uniform ice removal is determined to have occurred. When thin ice areas remove ice prematurely, the melting current is reduced by 15%-20% to prevent excessively high temperatures in those areas. When the ice thickness is detected to have decreased to approximately 2mm, the system enters the third stage.

[0048] Phase Three: Safe Cooling Phase By monitoring the internal fiber temperature of the OPGW through distributed optical fiber, the de-icing current is gradually reduced during the safe cooling phase. The de-icing current is gradually reduced, and the temperature reduction rate is constrained to be less than B℃ per second, with B not exceeding 2.

[0049] After the de-icing is completed, an effectiveness evaluation is conducted. The total de-icing time, the highest fiber temperature and the time of its occurrence are recorded; fiber attenuation changes are detected using an OTDR; a de-icing operation report is generated, including the icing morphology, de-icing parameters, temperature curves, etc.; and the de-icing data is stored in a feature database for optimizing subsequent de-icing parameters.

[0050] like Figure 4 As shown, an adaptive control system for DC de-icing in the case of non-uniform icing includes... Ice morphology recognition subsystem: includes a high-definition camera device, an image processing unit and a feature extraction module. The image processing unit is used to process images in real time and recognize ice morphology, and the feature extraction module is used to extract ice geometric parameters. Non-uniform thermal field calculation subsystem: includes thermal field modeling module, parameter database and ice melting current calculation module. The thermal field modeling module calls the corresponding thermal field calculation model according to the ice cladding morphology type. The parameter database stores thermal parameters of different line models and different ice cladding morphologies. The ice melting current calculation module calculates the corrected critical current and maximum current. Distributed temperature monitoring subsystem: includes a distributed fiber optic temperature measurement host and a data acquisition and processing unit, used to collect temperature distribution data in real time and send the highest temperature of the line and its location to the control unit; Adaptive current control subsystem: includes a central control unit and an adjustable DC de-icing power supply. The central control unit runs a phased control algorithm and generates current regulation commands, while the adjustable DC de-icing power supply receives the commands and precisely regulates the output current.

[0051] Example Upon receiving the ice-melting task instruction from the dispatch center, the system enters the multi-dimensional parameter acquisition phase for the ice morphology. High-definition cameras mounted on the towers control a pan-tilt unit to acquire multi-angle images of the OPGW ice morphology. The image processing module uses image recognition algorithms to extract and segment the ice contour, identifying the complex characteristics of the current ice morphology, including conical eccentricity and overhanging icicles. Further quantification extracts key morphological parameters: average ice thickness, maximum ice thickness, minimum ice thickness, ice non-uniformity coefficient, icicle length, root diameter and tip diameter of the icicle, and the circumferential distribution angle of the ice morphology. These physical morphological parameters are stored in a local database as key input conditions for calculating the ice-melting power.

[0052] Next, full-area temperature sensing and data acquisition are performed. The sensing fiber undergoes zero-point calibration, using the current ambient temperature as a reference to eliminate inherent errors in the DTS system and ensure the accuracy of the temperature measurement data. The DTS host is configured with appropriate optical pulse sampling frequency and temperature range parameters to match the requirements of ice melting monitoring. After the distributed fiber optic temperature measurement system is started, probe laser pulses are continuously injected into the idle sensing fibers inside the OPGW at a preset sampling frequency. Based on the principle of optical time-domain reflectometry (OTDR) using Raman or Brillouin scattering, backscattered light signals carrying temperature information at various points along the line are collected, achieving continuous, blind-spot-free temperature monitoring of the entire OPGW. The DTS host performs photoelectric conversion, filtering, and other processing on the collected raw light signals, demodulating them to obtain the temperature distribution curve for the entire line. The central control unit receives the temperature distribution data uploaded by the DTS host, eliminates abnormal data through a built-in module, and accurately tracks and extracts the highest temperature value T across the entire line within the current sampling period. max The system binds and stores the temperature distribution curve with the sampling timestamp. Simultaneously, it assists the micro-meteorological monitoring station in continuously collecting and uploading data such as ambient temperature, wind speed, and humidity, forming multi-dimensional operational condition information.

[0053] Then, multi-level threshold determination and initial decision-making are performed. The central control unit first loads preset multi-level temperature thresholds, which constitute the basic boundaries for subsequent dynamic control. (Combined with the attached...) Figure 2 A schematic diagram of the multi-level temperature zoning and dynamic current adjustment logic of the control strategy is shown. The safety and efficiency thresholds set by the system include at least: Ambient temperature T env The reference temperature for the circuit in a cold state. High-efficiency lower limit temperature T. low The fiber optic cable reaching this temperature indicates that the ice layer has absorbed a large amount of latent heat, ensuring a basic melting rate. Safe upper limit temperature T high This is typically set to the maximum safe operating temperature of the optical fiber to prevent aging during long-term operation, ensuring the fiber's long-term safe operation. Ultimate tripping temperature T trip : Set as the physical limit temperature to prevent instantaneous irreversible damage. When the temperature reaches this value, the power must be cut off immediately for protection.

[0054] After defining the threshold, control parameters are tuned based on the complex icing parameters obtained in the first part. Addressing the significant difference in thermal resistance caused by the substantial increase in heat dissipation due to the ice spikes, the central control unit uses its internal thermal balance equation and correction algorithm to calculate a corrected critical melting current capable of overcoming the heat loss from the ice spikes. Considering the premature detachment of thin ice zones, to prevent the fiber optic temperature from exceeding the safety limit after detachment, the system calculates a corrected maximum melting current as the output upper limit. Initially, because the line temperature is at ambient temperature T... env Below the lower limit temperature of efficient ice melting T lowThe system determines that the current de-icing power is insufficient. The central control unit sends an initial start-up current command to the adjustable de-icing power supply device. The de-icing power supply gradually and smoothly increases the output current according to the soft-start strategy to avoid damage to the OPGW optical fiber caused by the inrush current.

[0055] Then, dynamic closed-loop regulation is implemented during the ice-melting process. After ice-melting is initiated, the distributed fiber optic temperature measurement system continuously monitors temperature changes across the entire line, and the central control unit receives temperature feedback data in real time, tracking the highest temperature T across the entire line. max The changing trend and location. The central control unit will T max By comparing with multi-level thresholds, differentiated current closed-loop regulation logic is implemented: The fiber temperature is in the inefficient region (T env To T low Between: In this range, due to the stronger heat dissipation effect of the ice shards, the core temperature rises slowly. Based on the closed-loop algorithm, the positive step size is calculated, driving the power supply to steadily increase the power, causing the current to gradually increase to I. min1 .

[0056] The fiber optic temperature is within the high-efficiency and safe zone (T). low To T high Between): When the fiber optic cable reaches its highest point within this range, the central control unit fine-tunes the de-icing current using a PID closed-loop algorithm to maintain T. max The system remains stable within this range, balancing ice melting efficiency and fiber optic security. When ice melting causes changes in thermal resistance and fluctuations in ambient wind speed, the system utilizes T... max As a feedback quantity, dynamic adjustment compensates for environmental disturbances to ensure stable temperature control.

[0057] The fiber optic temperature is in the safe warning zone (T high To T trip (Between) and non-uniform de-icing forced adjustment: As de-icing continues, thin ice zones will detach before thick ice zones and ice ridges. After the thin ice detaches, this section is directly exposed to the air, causing a drastic change in the local heat dissipation environment. The DTS system quickly detects hotspots with abnormally high temperatures in this area. When T max Temperature rise greater than T high A safety warning is triggered when the system determines that localized overheating has occurred due to uneven de-icing. The central control unit calculates a negative adjustment step size and issues a command to the execution subsystem to limit power output. By reducing the de-icing current, the system limits the temperature rise of the optical fiber in that area, bringing it back to the target high-efficiency and safe zone, thus preventing damage to the optical fiber from localized overheating. At this time, the system continues to slowly melt the thick ice and ice ridges on the windward side using a lower holding current, ensuring the safe progress of de-icing on the line.

[0058] The fiber optic temperature is in the danger zone (greater than T). tripIf the highest temperature across the entire line continues to rise and exceeds the limit tripping temperature, the central control unit will immediately trigger the safety interlock protection mechanism, issue an emergency tripping and shutdown command to the de-icing power supply device, and immediately cut off the current output to prevent burnout accidents.

[0059] The above closed-loop control process is repeated cyclically, forming a dynamic negative feedback control loop until the ice layer reaches the expected melting target.

[0060] After a period of de-icing, a de-icing termination determination and shutdown procedure are initiated. The central control unit assesses the de-icing effect by integrating multi-source data: acquiring ice detachment data via an image acquisition terminal and combining this with temperature change trends provided by the DTS system. When the ice thickness across the entire line is determined to be below the set safety threshold, and the temperature across the entire line remains stable without a significant upward trend, the de-icing task is deemed essentially complete. The central control unit issues a shutdown command, and the de-icing power supply gradually reduces its output current to zero according to a soft-stop strategy, avoiding sudden current drops that could cause abrupt changes in line stress and ensuring mechanical and physical safety. After shutdown, the distributed fiber optic temperature measurement system continues to monitor the fiber optic temperature cooling process until the temperature drops to near ambient temperature. OTDR equipment is used to test the fiber optic communication performance, assessing the impact of the de-icing process on fiber optic attenuation and ensuring that communication quality is not degraded.

[0061] Finally, system standby and maintenance prompts are displayed. After cooling monitoring and communication evaluation are completed, the entire system switches to standby mode. The DTS host reduces the sampling frequency to save energy, while continuously monitoring the fiber optic temperature to ensure no subsequent abnormal temperature rise.

[0062] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0063] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive control method for DC de-icing in cases of non-uniform icing, characterized in that, Includes the following steps: Identify the icing morphology of icing sections; Calculate the melting control parameters for non-uniform icing based on the icing morphology type; Segmented control of ice melting is implemented within the range of ice melting control parameters; The segmented ice-melting control includes at least an initial heating stage, a dynamic current ice-melting stage, and a safe cooling stage.

2. The adaptive control method for DC de-icing in non-uniform icing as described in claim 1, characterized in that, The ice morphology type is obtained by acquiring multi-angle images of the ice-covered section using an image acquisition device and identifying them using an image processing algorithm.

3. The adaptive control method for DC de-icing in non-uniform icing as described in claim 1, characterized in that, The ice morphology types include icicle-shaped ice morphology and cone-shaped ice morphology, and a non-uniform thermal field model is constructed based on the ice morphology types. The non-uniform thermal field model of the icicle-like ice cover includes a modified heat balance equation, which is: Where Q is the Joule heat generated by the melting current; Q1 is the heat loss of the base ice layer; Q2 is the latent heat of phase change of the ice layer; Q3 is the heat required for each part to heat up; and Q4 is the additional heat loss of the ice shards. The non-uniform thermal field model for the conical icing includes a circumferential non-uniform thermal resistance distribution model. This model divides the conductor circumferentially into multiple sector regions, and the thermal resistance of each region is calculated independently based on the ice thickness and angular size. The thermal resistance of each region is: Where, r i Let r be the outer radius of the ice layer in region i, m; o Δθ is the radius of the OPGW ground wire, in meters; Δθ is the angle of the sector region.

4. The adaptive control method for DC de-icing in non-uniform icing as described in claim 3, characterized in that, The melting control parameters for non-uniform icing are calculated based on a non-uniform thermal field model. These parameters include a modified critical melting current and a modified maximum melting current.

5. The adaptive control method for DC de-icing in non-uniform icing according to claim 4, characterized in that, The modified critical de-icing current I min1 : In the formula, β is the correction coefficient; I min The critical current for uniform icing; L is the length of the ice ridge; d represents the average ice thickness in meters. The corrected maximum de-icing current I max1 : In the formula, ΔT n The additional temperature rise is due to non-uniform icing; I max T represents the maximum de-icing current under uniform icing conditions. pMAX The maximum permissible temperature; T a The ambient temperature of the icing line is K.

6. The adaptive control method for DC de-icing in non-uniform icing according to claim 1, characterized in that, During the initial heating phase, an initial current I is applied. min1 The temperature continues until the surface temperature of the line rises to the melting point of the ice.

7. The adaptive control method for DC de-icing in non-uniform icing as described in claim 1, characterized in that, The dynamic current de-icing stage includes: Tracking the highest temperature T across the entire line max The changing trend and position of T max The current is adjusted by comparing it with multiple threshold levels. When T max In T env To T low During this period, the de-icing current is gradually increased using a positive step size, so that the current gradually increases to I. min1 ; When T max In T low To T high During this period, a closed-loop algorithm is used to fine-tune the de-icing current, T. max It remains stable within this range; When T max In T high To T trip If T occurs due to non-uniform de-icing during this period, max >T high Then, a negative step size is used to forcibly reduce the de-icing current, so that T max Falling back to T high To T trip between; When T max Greater than T trip When this occurs, the safety interlock protection is triggered, and an emergency trip shutdown is executed; Wherein: T env For ambient temperature, T low For efficient ice melting lower limit temperature, T high For the safe upper limit temperature, T trip This is the ultimate tripping temperature.

8. The adaptive control method for DC de-icing in non-uniform icing as described in claim 1, characterized in that, During the dynamic current de-icing stage, when the melting of ice crystals is detected through image recognition or temperature change, the de-icing current is increased by 10% to 15%. When the rate of temperature rise in a local area exceeds a preset rate threshold per unit time, and the ice thickness in that area has dropped to zero or below a preset de-icing thickness threshold, non-uniform de-icing is determined to have occurred.

9. The adaptive control method for DC de-icing in non-uniform icing according to claim 1, characterized in that, During the safe cooling phase, the de-icing current is gradually reduced, and the temperature reduction rate is constrained to be less than B℃ per second, with B not exceeding 2.

10. A DC ice-melting adaptive control system for non-uniform icing, used to execute the method according to any one of claims 1-9, characterized in that, include Ice morphology recognition subsystem: includes a high-definition camera device, an image processing unit and a feature extraction module. The image processing unit is used to process images in real time and recognize ice morphology. The feature extraction module is used to extract ice geometric parameters. Non-uniform thermal field calculation subsystem: includes thermal field modeling module, parameter database and ice melting current calculation module. The thermal field modeling module calls the corresponding thermal field calculation model according to the ice cladding morphology. The parameter database stores thermal parameters of different line models and different ice cladding morphologies. The ice melting current calculation module calculates the corrected critical current and maximum current. Distributed temperature monitoring subsystem: includes a distributed fiber optic temperature measurement host and a data acquisition and processing unit, used to collect temperature distribution data in real time and send the highest temperature of the line and its location to the control unit; The adaptive current control subsystem includes a central control unit and an adjustable DC de-icing power supply. The central control unit runs a phased control algorithm and generates current adjustment commands, while the adjustable DC de-icing power supply receives the commands and precisely adjusts the output current.

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