Ice-coated area OPGW line safety distance early warning system and method

Abstract

This invention discloses a safety distance early warning system and method for OPGW lines in icing areas, specifically relating to the field of power system line operation monitoring technology. The system includes the following steps: status acquisition, spatial modeling, distance calculation, dynamic comparison, and trend prediction. By acquiring meteorological parameters in real time, a position function of the conductor and optical cable in space is constructed, the minimum spatial distance is calculated, and compared with a dynamic distance threshold to identify the risk level. Historical data and a difference evolution algorithm are combined to predict the distance change trend, triggering an early warning in advance, thus achieving dynamic assessment and proactive intervention control of distance risks under icing conditions. This invention achieves accurate dynamic monitoring, real-time risk assessment, and trend early warning of the minimum spatial distance between the fiber-optic composite overhead ground wire and the conductor in icing areas. It possesses the beneficial effects of comprehensive data acquisition, accurate modeling and calculation, timely risk identification, and proactive early warning intervention, significantly improving the safety and responsiveness of line operation.

Description

Technical Field

[0001] This invention relates to the field of power system line operation monitoring technology, and more specifically, to an early warning system and method for safe distance of OPGW lines in icing areas. Background Technology

[0002] In high-voltage and ultra-high-voltage power transmission projects, optical fiber composite overhead ground wires (OPGWs) are an important component of the lines, serving both communication transmission functions and lightning protection and grounding functions. They are typically installed at the top of towers. The conductors that work in conjunction with OPGWs are suspended at lower or middle levels, maintaining a specific vertical spatial distance between them under static conditions to meet both electrical insulation and operational safety requirements. However, in areas with severe icing, such as high-latitude mountainous regions and cold, damp depressions, the operating environment is complex and variable. OPGWs and conductors are susceptible to the coupled effects of meteorological load changes, especially under conditions of low temperatures, strong winds, and icing, causing nonlinear changes in the cable structure. These changes manifest not only as reduced tension and increased sag in individual cables but also as a coordinated imbalance between wind-induced conductor galloping and OPGW sag, further compressing the spatial safety margin between the two lines and inducing serious faults such as insufficient electrical insulation distance, phase-to-phase discharge, and even mechanical collisions.

[0003] Existing line safety monitoring methods primarily focus on single-point risks such as conductor tension changes, increased ice thickness, or tower base icing, often relying on tension limit alarms or static judgments based on fixed minimum safety distance thresholds given in design specifications. These methods have significant shortcomings: they cannot dynamically reflect the spatial coordination response between OPGW (Operating Power Wire) and conductors under different meteorological conditions, lack real-time calculation of minimum spatial distance and dynamic threshold update mechanisms, and cannot perform trend judgment and early intervention before the spatial distance approaches the limit, resulting in delayed early warning responses. Therefore, this paper proposes a safety distance early warning system and method for OPGW lines in icing areas to address the aforementioned problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] The method for early warning of safe distances to OPGW lines in icing areas includes the following steps:

[0006] Step 1, Status Acquisition: By deploying tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices on the fiber optic composite overhead ground wire and conductor respectively, real-time operating parameters under different meteorological conditions in the target section are obtained, and each set of data is timestamped.

[0007] Step 2, Spatial Modeling: Using the tower geometry parameters and the height difference information of the conductor suspension point, combined with the real-time data collected in Step 1, the catenary shape of the conductor and optical cable in the vertical plane within the target span is derived through analytical calculation, and the corresponding position function of the two lines in space is further constructed.

[0008] Step 3, Distance Calculation: Perform joint calculation on the two position functions from Step 2 to solve the minimum spatial distance between the optical cable and the conductor within the target span in real time, and record the lateral position and time point corresponding to the minimum value;

[0009] Step 4: Dynamic Comparison: Based on the insulation standards corresponding to the voltage level of overhead lines, the dynamic minimum spacing threshold under the influence of current ice load, wind speed and tension is calculated through multivariate functions. The minimum spatial distance obtained in Step 3 is compared and analyzed with this dynamic minimum spacing threshold. If the distance is insufficient, the level is immediately marked and the risk is confirmed.

[0010] Step 5: Trend Prediction: Based on the historical data from Step 4, a short-cycle evolution curve is constructed using a preset difference algorithm, and it is determined whether an early warning signal is triggered, so as to achieve proactive intervention and control of spacing risks under icing conditions.

[0011] In a preferred embodiment, status acquisition includes the following specific steps:

[0012] Within the target section, a tension sensing device is installed on the fiber optic composite overhead ground wire to obtain the tension value of the fiber optic composite overhead ground wire under different working conditions in real time; at the same time, another tension sensing device is installed on the conductor to independently record the tension change of the conductor within the target section. The two are measured independently and the physical data are not mixed.

[0013] While acquiring tension data, temperature detection devices are installed near the fiber optic composite overhead ground wire and the conductor respectively to record the ambient temperature around each cable in the target section, ensuring that the temperature information has location correspondence and data timeliness. In order to accurately identify icing conditions, an ice thickness measurement device is deployed on the fiber optic composite overhead ground wire to detect changes in surface ice thickness in real time. This ice thickness measurement device does not physically overlap with the tension sensing device.

[0014] To synchronously capture the impact of wind loads, wind speed sensing devices need to be installed in the target section to continuously record wind speed information. These devices are then fixed to the top of the towers using structural means to ensure stable and reliable data acquisition. Tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices all collect data under a unified time management mechanism. Each set of data is accompanied by a precise timestamp, generating a set of operating parameters with time series characteristics.

[0015] In a preferred embodiment, spatial modeling includes the following:

[0016] First, determine the target span length between the fiber optic composite overhead ground wire and the conductor in the target section. This target span length is the horizontal distance between the corresponding suspension points of two adjacent towers in the horizontal direction, which serves as the basis for calculating the span of the cable catenary configuration.

[0017] Based on the tension, temperature, ice thickness and wind speed information obtained from the status acquisition, the dynamic unit weight of the fiber optic composite overhead ground wire under the current meteorological conditions is calculated. This unit weight is the sum of three parts, including the unit weight of the cable body, the unit weight of the equivalent ice weight added by icing, and the unit weight of the equivalent wind load generated by wind speed.

[0018] The unit weight of the cable body is calculated based on the tension standard by multiplying the cable mass by the gravitational acceleration and then dividing by the target span length. The unit weight of the icing is expressed as a function of the ice thickness and the cable outer diameter by multiplying the volume of the cylindrical shell by the ice density and the gravitational acceleration and then dividing by the target span length. The unit weight of the wind load is calculated by multiplying the square of the wind speed by the wind resistance coefficient, air density, and cross-sectional area, then converting it to the unit length form and dividing by the target span length.

[0019] Using the aforementioned synthetic unit weight as input, and substituting it into the catenary tension-deformation relationship, the functional expression of the fiber optic composite overhead ground wire in the vertical plane is derived, forming a complete vertical plane functional expression. This process is applied independently to the conductor, using the conductor's tension value, structural parameters, and meteorological input to construct the conductor's functional expression in the vertical plane, keeping the two expressions independent and strictly corresponding to the actual input data.

[0020] In a preferred embodiment, spatial modeling further includes the following:

[0021] After completing the construction of the vertical plane function of the fiber composite overhead ground wire and the conductor within the target span length, the position expression of the two lines in the three-dimensional space of the target section is further established. By constructing a rectangular coordinate system, the position of the fiber composite overhead ground wire hanging point of one end tower in the target section is taken as the origin, the horizontal axis is defined along the span direction, the height axis is defined along the vertical direction, and the longitudinal axis is defined along the tower crossing direction.

[0022] In this coordinate system, the position function of the fiber optic composite overhead ground wire is represented by the three-dimensional function P1(x)=(x,0,y1(x)), and the position function of the conductor is represented by the three-dimensional function P2(x)=(x,d,y2(x)). Here, the variable x represents any position on the horizontal axis, the functions y1(x) and y2(x) are the vertical plane functions of the fiber optic composite overhead ground wire and the conductor, respectively, and the variable d represents the actual horizontal distance between the two in the longitudinal axis direction, which depends on the tower structure layout.

[0023] In a preferred embodiment, when performing a joint operation on the two position functions in step two, the two position functions are substituted into the spatial Euclidean distance formula to calculate the spatial distance D(x) corresponding to each position within the target span length. By traversing all values ​​of variable x in the interval [0, target span length], the minimum value of D(x) and its corresponding position coordinates are solved.

[0024] In a preferred embodiment, the first part of the dynamic comparison includes the following: Based on the actual operating voltage level of the overhead line in the target section, the air insulation safety distance design standard corresponding to that voltage level is obtained and set as the basic distance value Δ0. This value is determined according to the voltage-level insulation parameters in the national power transmission design specifications. Based on this basic distance value, the ice thickness, wind speed information, and tension values ​​corresponding to the fiber optic composite overhead ground wire and conductor, respectively, obtained from the status acquisition, are introduced and set as... and Establish a multivariable dynamic function model:

[0025] Output the dynamic minimum distance threshold at the current time. This multivariate dynamic function model is represented by a weighted addition model, and its construction form is as follows:

[0026] ;

[0027] ;

[0028] ;

[0029] and These are the design tension reference values ​​for the fiber optic composite overhead ground wire and the conductor, respectively. and All are preset parameter sensitivity weights. The output is used to perform point-by-point comparison and judgment with the spatial distance function, and incorporates the structural response characteristics of fiber optic composite overhead ground wire and conductor under the current meteorological conditions into the unified threshold judgment logic to form a judgment baseline associated with electrical insulation standards.

[0030] In a preferred embodiment, the second part of the dynamic comparison includes the following:

[0031] After generating the function for the dynamic minimum spacing threshold Δ(t), the spatial distance function D(x) is called to perform point-by-point comparison analysis. Taking all values ​​of variable x within the target span length range as input, each output value of function D(x) is compared with the corresponding Δ(t) at the current time to construct a new difference function ΔD(x) = D(x) - Δ(t).

[0032] The minimum value of ΔD(x) within the target span length range is defined as ΔDmin, and its sign status is determined. When ΔDmin≥0, ​​it means that the minimum spatial distance of the target section under the current weather conditions meets the electrical insulation standard and no alarm is required; when ΔDmin<0, it means that the spatial distance is insufficient and there is a risk of discharge. This result serves as the basis for subsequent level identification and risk confirmation. The data structure retains the specific location, D(x) value and Δ(t) value corresponding to variable x.

[0033] In a preferred embodiment, the third part of the dynamic comparison includes the following:

[0034] After determining ΔDmin, the current target section is immediately labeled according to the preset risk level standard. The risk level standard adopts a three-segment division, corresponding to low risk, medium risk and high risk respectively. ΔDmin≥0 indicates no risk and no label is triggered; p≤ΔDmin<0 indicates medium risk and triggers a yellow label; ΔDmin<p indicates high risk and triggers a red label. p is a preset negative constant. The labeling results are synchronously output to the power dispatch visualization interface and serve as input signals for the control center's operation and maintenance decisions. The labeling process records the timestamp, location index, risk level, ΔDmin value, D(x) value and Δ(t) value, forming a complete risk confirmation structure.

[0035] In a preferred embodiment, the minimum value ΔDmin of the difference function ΔD(x) constructed in step four is continuously recorded during the operation, forming a time series updated at a fixed sampling period. , where variables This represents each historical sampling time point. To extract the current trend, a short-period evolution curve is constructed by applying a fixed-step difference algorithm to this time series. A three-point equidistant sliding window center difference mode is adopted, with the step size denoted as ΔT. This is applied to the three sets of sample values ​​within the current sliding window. , , Perform difference fitting and calculate the local trend slope. :

[0036] Combining multiple consecutive slope values ​​to form a short-period evolution curve, if at any given time point... Appear Less than 0, and If the value is less than or equal to ε, where ε is a preset safety margin threshold, then the conditions for triggering an early warning are met.

[0037] In a preferred embodiment, the OPGW line safety distance early warning system for icing zones includes:

[0038] The status acquisition module acquires real-time operating parameters under different meteorological conditions in the target section by deploying tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices on the fiber optic composite overhead ground wire and conductor respectively, and timestamps each set of data.

[0039] The spatial modeling module utilizes the geometric parameters of the tower and the height difference information of the conductor suspension point, combined with the real-time data collected in step one, to deduce the respective catenary morphology of the conductor and optical cable in the vertical plane within the target span through analytical calculation, and further constructs the corresponding position function of the two lines in space.

[0040] The distance calculation module performs joint calculations on the two position functions in the spatial modeling module to solve the minimum spatial distance between the optical cable and the conductor in the target span section in real time, and records the lateral position and time point corresponding to the minimum value.

[0041] The dynamic comparison module, based on the insulation standard corresponding to the voltage level of the overhead line, calculates the dynamic minimum spacing threshold under the influence of current ice load, wind speed and tension through a multivariable function, and compares and analyzes the minimum spatial distance obtained in step three with the dynamic minimum spacing threshold. If the distance is insufficient, the level is immediately marked and the risk is confirmed.

[0042] The trend prediction module, based on historical data from the dynamic comparison module, uses a preset difference algorithm to construct a short-cycle evolution curve and determine whether an early warning signal is triggered.

[0043] The technical effects and advantages of this invention are as follows:

[0044] This invention collects tension, temperature, ice thickness, and wind speed parameters from both the fiber optic composite overhead ground wire and conductor, and adds timestamps to create a foundation of operational parameter data with temporal continuity. This effectively solves the problem of traditional monitoring methods being unable to acquire multi-source physical quantities in real time. Furthermore, by combining tower structural parameters and suspension point height differences, this invention derives the catenary morphology and constructs a corresponding position function during the spatial modeling stage. This significantly enhances the analytical capability for changes in spatial relationships, enabling the dynamic acquisition of precise positional relationships between conductors and optical cables in target sections under any weather conditions. This provides a solid foundation for subsequent comparative analysis and risk assessment.

[0045] This invention calculates the minimum spatial distance within the target span section in real time by jointly performing calculations on the corresponding position functions of two lines in space. Combined with insulation standards corresponding to voltage levels, a dynamic minimum spacing threshold calculation model is established. This process not only covers three main influencing factors—ice load, wind speed, and tension—but also achieves accurate determination of the relationship between spatial distance and safety threshold under current operating conditions through comparative analysis. If insufficient spatial distance is detected, risk level identification and confirmation can be completed immediately, ensuring the timeliness and controllability of system response and significantly enhancing the ability to identify abnormal operating conditions.

[0046] Building upon dynamic comparison, this invention further introduces a trend recognition mechanism based on historical data to construct short-cycle evolution curves and uses a difference algorithm to determine whether an early warning signal is triggered. This trend prediction method can identify potential distance risks caused by external meteorological evolution or structural deformation before insufficient distance occurs, shifting from "post-event alarm" to "pre-event warning." This enhances the system's perception of operational status under icing conditions, facilitates early deployment and scientific decision-making by the dispatch center, and strengthens the overall safety redundancy of the system. Attached Figure Description

[0047] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings;

[0048] Figure 1 This is a schematic diagram of the OPGW line safety distance early warning method in the icing zone of the present invention.

[0049] Figure 2 This is a schematic diagram of the OPGW line safety distance early warning system in the icing zone of the present invention. Detailed Implementation

[0050] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Reference Figure 1 - Figure 2 The following examples were obtained:

[0052] Example 1: A method for early warning of safe distance for OPGW lines in icing areas, comprising the following steps:

[0053] Step 1: Status Acquisition. Tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices are deployed on the fiber optic composite overhead ground wire and conductors respectively to acquire real-time operating parameters under different meteorological conditions in the target section. Each set of data is timestamped. The core significance of this step is to comprehensively, object-specifically, and index-specifically acquire the key physical states of the line under its current environment, ensuring high-precision input for subsequent modeling and analysis. By deploying tension sensing devices on the fiber optic composite overhead ground wire and conductors, the stress state of each cable can be accurately acquired. The deployment of temperature detection devices ensures the dynamic response of environmental temperature changes to material properties and suspension behavior. Ice thickness measurement devices are used to identify additional loads under icing conditions. Wind speed sensing devices can capture the probability of lateral swaying and wind-induced vibration. Each data acquisition is timestamped, giving all data a temporal sequence, providing a structured input source for subsequent dynamic modeling, trend analysis, and evolution inference, and constructing a spatiotemporally matched data support system.

[0054] Step Two: Spatial Modeling. Utilizing the tower's geometric parameters and the conductor suspension point elevation difference, combined with the real-time data collected in Step One, the catenary morphology of the conductor and optical cable within the target span in the vertical plane is derived through analytical calculation. Furthermore, the corresponding position functions of the two lines in space are constructed. This step represents a crucial transition from physical state data to geometric spatial modeling. Using the tower's geometric parameters and the conductor suspension point elevation difference as the structural basis, the boundary conditions and spatial framework for modeling are determined. Then, state data such as tension, ice thickness, and wind speed are converted into unit load inputs and introduced into the catenary formula. The sag variation curves of the conductor and optical cable are derived analytically. Ultimately, two independent but structurally related cable spatial position functions are formed, describing their path evolution and sag response in three-dimensional space, respectively. This provides an analytical functional basis for subsequent calculations of the relative distance between the two lines and is the core of the geometric derivation in the entire early warning method.

[0055] Step 3, Distance Calculation: The two position functions from Step 2 are jointly calculated to determine the minimum spatial distance between the optical cable and the conductor within the target span in real time, and the lateral position and time point corresponding to the minimum value are recorded. This step realizes the key computational behavior from modeling expression to numerical solution. By substituting the spatial position functions of the conductor and the optical cable into the Euclidean distance formula, a spatial distance function for both at any lateral position within the span is constructed. A numerical method is then used to traverse the entire range to extract the exact value of the minimum spatial distance and its corresponding position. The obtained minimum distance directly reflects the safety margin of the most unfavorable location under current meteorological conditions, which has engineering early warning significance. This data is not only used for subsequent comparison with safety standards, but also for constructing a risk location index through time point and lateral coordinate information, which is an important guarantee for the simultaneous spatial and temporal positioning.

[0056] Step 4, Dynamic Comparison: Based on the insulation standards corresponding to the voltage level of overhead lines, the dynamic minimum spacing threshold under the influence of current ice load, wind speed, and tension is calculated using a multivariate function. The minimum spatial distance obtained in Step 3 is then compared with this dynamic minimum spacing threshold. If the distance is insufficient, the risk level is immediately identified and confirmed. This step integrates spatial distance with electrical insulation standards to achieve a mapping judgment from physical distance to safety threshold. The dynamic minimum spacing threshold is not a fixed value but is dynamically generated through a function model based on current meteorological and mechanical data, reflecting the minimum safety requirements under different operating conditions in real time. Comparing the calculated actual minimum spatial distance with this threshold point by point is the process of judging whether the line operation status has "crossed the boundary." Once an insufficiency is found, the system immediately classifies the risk level, providing a tiered basis for subsequent alarm response and dispatch intervention, realizing a closed-loop engineering logic from "value" to "judgment."

[0057] Step 5, Trend Prediction: Based on the historical data from Step 4, a short-cycle evolution curve is constructed using a pre-defined difference algorithm. This determines whether a pre-warning signal is triggered, enabling proactive intervention and control of spacing risks under icing conditions. This step represents a technological expansion from static judgment to trend prediction, demonstrating the early warning system's upgrade from a "response-based" to a "predictive" approach. By calling the historical time series of the minimum difference data generated during the dynamic comparison phase, a trend curve is constructed within a short time window, extracting the decay rate and direction of the minimum spacing margin. When the evolution trend indicates that the spacing is rapidly approaching or about to exceed the threshold, the system issues an early warning signal, independent of the current critical state. This proactive early warning significantly improves the system's response time to spatial risks under sudden conditions, providing maintenance units with sufficient intervention reserves. It is the core innovation for achieving true "early detection and early decision-making."

[0058] The status acquisition includes the following specific steps: Within the target section, a tension sensing device is set up on the fiber optic composite overhead ground wire to obtain the tension value of the fiber optic composite overhead ground wire under different working conditions in real time; at the same time, another tension sensing device is set up on the conductor to independently record the tension change of the conductor within the target section. The two are measured independently and no physical data is mixed.

[0059] Fiber Optic Composite Overhead Ground Wire (OPGW) is a composite cable core that integrates communication optical fiber into the ground wire structure, serving both grounding and communication functions. Tension sensing devices are online tensile force detection modules based on strain gauges or force-sensitive elements, typically fixed to exposed cable sections using clamping structures. Due to the differences in structure and stress characteristics between OPGW and conductors, deploying tension sensing devices separately avoids misjudgments caused by data aggregation and supports subsequent separate modeling. The term "operating condition" refers to the operational status under different weather conditions and load combinations (such as sunny days, icing, wind disturbances, etc.).

[0060] While acquiring tension data, temperature detection devices are installed near the fiber optic composite overhead ground wire and the conductor respectively to record the ambient temperature around each cable in the target section, ensuring that the temperature information has location correspondence and data timeliness. In order to accurately identify icing conditions, an ice thickness measurement device is deployed on the fiber optic composite overhead ground wire to detect changes in surface ice thickness in real time. This ice thickness measurement device does not physically overlap with the tension sensing device.

[0061] Temperature detection devices, such as thermocouples or infrared thermal sensors, are preferably installed in insulated locations that do not affect the conductor's insulation performance. Temperature information is used to dynamically correct material modulus and thermal expansion / contraction deviations in catenary calculations, serving as a necessary input for spatial modeling. Ice thickness measurement devices, employing contact capacitance layer measurement or image-based contour recognition technology, are deployed on the outer surface of the bare OPGW section. This serves as a direct physical input for identifying the icing level and is further incorporated into unit weight calculations. Tension sensing devices and ice thickness measurement devices are separate structural components with independent physical locations, avoiding sensory interference or measurement errors.

[0062] To synchronously capture the impact of wind loads, wind speed sensing devices need to be installed in the target section to continuously record wind speed information. These devices are then fixed to the top of the towers using structural means to ensure stable and reliable data acquisition. Tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices all collect data under a unified time management mechanism. Each set of data is accompanied by a precise timestamp, generating a set of operating parameters with time series characteristics.

[0063] The wind speed sensing device, based on a rotor-type or ultrasonic anemometer, is installed on the main crossarm structure at the top of the tower to minimize interference from ground obstacles. Wind speed information is used to assess wind-generated lateral loads and directly affects the unit weight and cable tension correction model. A unified time management mechanism refers to all sensors synchronously acquiring data through the same controller or clock module, serializing data from different sensors using timestamps to form a data alignment basis for spatial modeling and dynamic comparison. The timestamp accuracy is no less than the second level, possessing traceability capabilities to ensure the validity of input for trend analysis and distance calculation. Each complete set of data parameters includes four dimensions: tension, temperature, ice thickness, and wind speed, possessing spatial separation, temporal consistency, and measurement independence.

[0064] Spatial modeling includes the following: First, the target span length between the fiber optic composite overhead ground wire and the conductor is determined in the target section. This target span length is the horizontal distance between the corresponding suspension points of two adjacent towers, serving as the basis for calculating the span of the catenary configuration. The target span length (denoted as L) refers to the projected distance in the horizontal direction (X-axis direction) between the corresponding suspension points of the optical cable or conductor on two towers. It is one of the geometric boundary conditions for catenary calculation, and its unit is meters (m). This parameter can be obtained from construction drawings or laser ranging, and typically ranges from tens to hundreds of meters.

[0065] Based on the tension, temperature, ice thickness and wind speed information obtained from the status acquisition, the dynamic unit weight of the fiber optic composite overhead ground wire under the current meteorological conditions is calculated. This unit weight is the sum of three parts, including the unit weight of the cable body, the unit weight of the equivalent ice weight added by icing, and the unit weight of the equivalent wind load generated by wind speed.

[0066] The unit weight (denoted as q, unit: N / m) is the vertical load on the cable per unit length, used as the load input in the catenary analysis. It consists of three parts, as follows:

[0067] Cable body unit weight According to the tension calculation standard, the cable mass is multiplied by the acceleration due to gravity and then divided by the target span length: m is the mass per unit length of the cable (kg / m), given by the cable manufacturing specifications; g is the acceleration due to gravity (9.81 m / s²); L is the target span length (m).

[0068] The target span length is determined as follows: the initial span length is set to L0, and the measured temperature change relative to the preset reference value is BH. The initial span length is then corrected using the linear thermal expansion formula, specifically: ; The linear expansion coefficient of the cable material is preset and can be obtained from the factory data;

[0069] Ice-covered unit weight The relationship between ice thickness and cable outer diameter can be expressed as the volume of a cylindrical shell multiplied by the ice density and gravitational acceleration, then divided by the target span length:

[0070] r is the radius of the bare conductor of the cable (m); h is the ice thickness collected in real time (m). This refers to the density of ice (typically around 900 kg / m³).

[0071] Wind load per unit weight The wind speed squared is multiplied by the drag coefficient, air density, and cross-sectional area, then converted to a unit length form and divided by the target span length.

[0072] ; This refers to the drag coefficient (typically 1.2–1.5 for cylinders). air density (approximately 1.225 kg / m³); v is wind speed (m / s), from a wind speed sensor; D is cable diameter (m).

[0073] Using the aforementioned composite unit weight as input, and substituting it into the catenary tension-deformation relationship, we derive the functional expression of the fiber optic composite overhead ground wire in the vertical plane, forming a complete vertical plane functional expression. The catenary function describes the hanging shape of the cable under its own weight and load. Under constant tension T and uniform load q, its standard expression is:

[0074] ; x represents the vertical sag of the cable, in meters; x represents the horizontal position, ranging from [0, L]. ; For catenary parameters; The constant reflects the initial boundary conditions and can be obtained from the height of the hanging points, or determined by calculation of the boundary conditions (e.g., when the heights of the two hanging points are symmetrical). Therefore, the final vertical plane function expression for the fiber optic composite overhead ground wire under the current operating conditions is:

[0075] This process is applied independently to the conductor, using the conductor's tension value, structural parameters, and meteorological input to construct a functional expression for the conductor in the vertical plane. The two expressions are kept independent and strictly correspond to the actual input data. The functional expression for the conductor in the vertical plane is derived using the same logic, which will not be elaborated here.

[0076] Spatial modeling also includes the following: After constructing the vertical plane function of the fiber optic composite overhead ground wire and conductor within the target span length, the positional representation of the two lines in the three-dimensional space of the target section is further established. This is achieved by constructing a Cartesian coordinate system, with the location of the fiber optic composite overhead ground wire suspension point on one end of the tower in the target section as the origin. A horizontal axis is defined along the span direction, a height axis along the vertical direction, and a longitudinal axis along the tower span direction. The Cartesian coordinate system serves as a three-dimensional spatial reference system, used to accurately describe the spatial position of the fiber optic composite overhead ground wire and conductor throughout the entire target span area. The origin is selected as the fixed suspension point of the fiber optic composite overhead ground wire on the tower near the measurement starting point, serving as the reference coordinate system for all subsequent position calculations. The horizontal axis is the direction consistent with the target span length, that is, the horizontal direction from the starting tower to the ending tower, representing the axis where the cable catenary projection is located; the height axis is the direction perpendicular to the ground, used to represent the sag height of the cable under the action of gravity; the vertical axis is the direction perpendicular to the horizontal axis, describing the horizontal distance between the fiber optic composite overhead ground wire and the conductor. This direction, together with the plane of the line running direction, forms the basis for a complete three-dimensional description.

[0077] In this coordinate system, the position function of the fiber optic composite overhead ground wire is represented by the three-dimensional function P1(x)=(x,0,y1(x)), and the position function of the conductor is represented by the three-dimensional function P2(x)=(x,d,y2(x)). Here, the variable x represents any position on the horizontal axis, the functions y1(x) and y2(x) are the vertical plane functions of the fiber optic composite overhead ground wire and the conductor, respectively, and the variable d represents the actual horizontal distance between the two in the longitudinal axis direction, which depends on the tower structure layout.

[0078] In this expression, the position of the fiber optic composite overhead ground wire is a variable with any position on the horizontal axis, while the vertical axis is fixed at zero, meaning the two wires do not coincide in the vertical direction. The height value is determined by its own vertical plane function, which is derived from the catenary derivation result after the aforementioned unit weight and tension input. The three-dimensional position function of the conductor is consistent with that of the fiber optic composite overhead ground wire, with a fixed offset only in the vertical axis direction. This offset is a constant value in the horizontal direction, representing the actual hanging distance between the conductor and the fiber optic composite overhead ground wire, which is generally several meters and determined according to the tower structure design.

[0079] For example, if the tower design in the target section allows the conductor to be laid outside the fiber optic composite overhead ground wire, and the two suspension points are four meters apart in the longitudinal direction, then the variable d is four meters. Under this structure, the spatial position of any two cables can be expressed as three-dimensional coordinate points, and the actual spatial distance between them can be solved using three-dimensional Euclidean distance, serving as the basis for distance calculation and safety threshold judgment in subsequent dynamic comparison steps. This modeling process ensures that the catenary functions of the fiber optic composite overhead ground wire and the conductor are not only independently established on the two-dimensional plane, but also have a unified calculation reference system and corresponding positional logic in three-dimensional space, avoiding misjudgments that may be caused by simplifying the projection model.

[0080] When performing the joint operation of the two position functions in step two, the two position functions are substituted into the spatial Euclidean distance formula to calculate the spatial distance D(x) corresponding to each position within the target span length. By traversing all values ​​of the variable x in the interval [0, target span length], the minimum value of D(x) and its corresponding position coordinates are solved. After completing the construction of the position functions of the fiber optic composite overhead ground wire and the conductor in three-dimensional space, it is necessary to calculate the relative spatial distance between the two within the target span length range to determine whether there is a risk of insufficient safety clearance under specific meteorological conditions.

[0081] The target span length is the effective span length obtained in the aforementioned spatial modeling based on temperature correction. It takes into account the thermal expansion effect of the cable caused by temperature changes and performs a linear correction to the actual span. Specifically, this length value is the original design span length plus the thermal expansion length calculated based on the difference between the current temperature and the reference temperature. The correction method has been disclosed in the aforementioned description using the thermal expansion formula, which forms the basis for the actual modeled span.

[0082] To perform joint calculations, the position function of the fiber optic composite overhead ground wire is represented as a three-dimensional function P1(x)=(x,0,y1(x)), and the position function of the conductor is represented as a three-dimensional function P2(x)=(x,d,y2(x)). The position variable x on the horizontal axis is any real value in the interval [0, target span length]. The two functions respectively provide the specific coordinate positions of the two cables at the same horizontal position in three-dimensional space. Functions y1(x) and y2(x) have been constructed as vertical plane functions in the spatial modeling step, and the variable d is the fixed structural distance between the two lines in the longitudinal direction given by the tower design. Under this structure, the spatial distance D(x) between the two cables at the same horizontal position can be calculated using the Euclidean distance formula, expressed as follows: For any variable x, the corresponding spatial distance is the Euclidean distance between the three-dimensional coordinate points, i.e.:

[0083] The first term is the square of the fixed distance in the longitudinal direction, and the second term is the square of the vertical sag difference. Since the lateral axis positions are the same, the lateral component is zero, so there is no need to calculate the difference. The entire distance function is determined only by the longitudinal distance and the height difference, and is a real-valued function that varies with the lateral position variable. To obtain the closest distance between two lines, the variable x needs to be iterated and evaluated within the target span length interval [0, span length after current temperature correction]. The minimum value of D(x) is taken as the minimum spatial distance, and its corresponding variable x value is recorded, which is the actual closest point position. For example, if the target span length is 400 meters, and a step size of 1 meter is used for sampling, then the number of calculated positions is 401. These are substituted into the above formula for solution, and finally the pair of spatial position points with the smallest distance and their values ​​are selected as the input for whether the insulation spacing standard is met in the dynamic comparison step. This joint operation process ensures the accuracy and adaptability of the distance calculation between the two cables in a real three-dimensional spatial structure, and provides continuous function support for subsequent dynamic threshold judgment, which is the basis for realizing the construction of the difference function and trend early warning.

[0084] The first part of the dynamic comparison includes the following: Based on the actual operating voltage level of the overhead lines in the target section, the air insulation safety distance design standard corresponding to that voltage level is obtained and set as the basic distance value Δ0. This value is determined according to the voltage classification insulation parameters in the national power transmission design specifications. Based on this basic distance value, the ice thickness, wind speed information, and tension values ​​corresponding to the fiber optic composite overhead ground wire and conductor obtained from the status acquisition are introduced and set as follows: and Establish a multivariable dynamic function model:

[0085] Output the dynamic minimum distance threshold at the current time. This multivariate dynamic function model is represented by a weighted addition model, and its construction form is as follows:

[0086] ;

[0087] ;

[0088] ;

[0089] and These are the design tension reference values ​​for the fiber optic composite overhead ground wire and the conductor, respectively. and All are preset parameter sensitivity weights. The output is used for point-by-point comparison with the spatial distance function. The structural response characteristics of fiber optic composite overhead ground wires and conductors under current meteorological conditions are incorporated into a unified threshold judgment logic, forming a judgment baseline associated with electrical insulation standards. Factors such as ice thickness and wind speed affect cable sag and spacing. The model dynamically updates the minimum safety threshold to avoid misjudgment and omission. The national standard provides a static baseline. This model superimposes the structural dynamic response on this basis, thereby transforming it into a comparable real-time judgment boundary. This model essentially "equivalently transforms" the deformation effects of the physical environment into changes in safe distance, forming a fusion quantitative expression of discharge risk. Under extreme weather conditions, cable status fluctuates significantly, and fixed threshold judgments fail. This method ensures that early warning effectiveness is maintained even under atypical operating conditions. This design does not treat the structural status as a separate analysis item, but rather transforms it into a dynamic threshold standard value through function modeling, achieving an effective mapping between physical status and electrical standards.

[0090] Parameter sensitivity weights are multiplicative coefficients used in the dynamic minimum spacing function to characterize the influence of each input variable (such as ice thickness, wind speed, and temperature difference) on the dynamic minimum spacing threshold. They are used to quantify the contribution of each factor in a multivariate weighted model. The principles for setting parameter sensitivity weights are as follows: Based on structural mechanics simulation results, finite element simulation or catenary deformation models can be used to calculate the degree of sag or tension change under different single-factor conditions (such as adding only wind or only ice). The numerical response of each variable to spacing changes under unit changes is compared, and the linear regression slope is extracted as the initial sensitivity weight. Based on field observation and operational data fitting, measured historical data (such as meteorological values ​​when a spacing alarm occurs) are collected, a regression model is established, and the optimal fitting coefficient is extracted as the initial value of the sensitivity weight using the least squares fitting method. Based on expert experience and fault tolerance control requirements, if actual data is limited, combined with the principle of engineering safety factor, professional designers set empirical values ​​(such as increasing the safety spacing by 2cm for every millimeter change in ice thickness), while setting a maximum upper limit for the weight range to ensure that misjudgment is not caused by a single abnormal input.

[0091] The second part of the dynamic comparison includes the following: After generating the function for the dynamic minimum spacing threshold Δ(t), the spatial distance function D(x) is called to perform point-by-point comparison analysis. This spatial distance function D(x) has already been constructed during the distance calculation process and represents the actual spatial distance between the fiber optic composite overhead ground wire and the conductor at any position x within the target span length range. The variable x represents the horizontal projection distance from the starting tower to the ending tower along the transverse axis, with a value range from zero to the target span length. The step size can be set according to accuracy requirements, for example, one meter as a sampling unit.

[0092] The dynamic minimum spacing threshold Δ(t) is the standard spacing value calculated by multivariable function modeling under the current meteorological conditions. This value takes into account the influence of physical parameters such as ice thickness, wind speed, temperature difference and tension on the structural state of the two lines at the current moment. It is a function output value that changes with time and is used to represent the minimum safe spacing required between the two cables under the current state.

[0093] The comparison method is as follows: taking all values ​​of variable x within the target distance range as input, each output value of the D(x) function is compared with the corresponding Δ(t) at that moment to construct a new difference function ΔD(x), whose mathematical meaning is the difference between the actual spatial distance at the target position and the minimum required distance under the current state, in the form of ΔD(x)=D(x)-Δ(t).

[0094] During the entire traversal of the variable x interval, the minimum value of the difference function ΔD(x) is recorded and named ΔDmin. This minimum difference ΔDmin is a key indicator for determining whether there are any safety hazards in the current operating state, and its sign status has clear significance for determining electrical insulation risks.

[0095] When ΔDmin is greater than or equal to zero, it means that at any lateral position within the target span length range, the spatial distance between the two cables is not lower than the safety distance threshold required under the current working conditions, the overall operating status is within the safety boundary, and the system does not need to alarm.

[0096] When ΔDmin is less than zero, it indicates that at least one lateral position exists where the actual spatial distance between the two cables is less than the current dynamic spacing threshold, posing a risk of discharge due to insufficient spacing and inadequate insulation strength. The risk identification process should be initiated immediately. Based on the determination of ΔDmin, to ensure the execution of subsequent dynamic traceability analysis and risk level identification, key data during the determination process needs to be structured and recorded. Specifically, this includes: the specific location of variable x corresponding to the minimum value of ΔDmin, used to reverse-locate the risk occurrence location; the actual spatial distance D(x) at that location, used to represent the actual physical state; and the dynamic threshold Δ(t) referenced for the determination, used to indicate the baseline judgment conditions under this condition. All of the above data items are uniformly stored in the system's internal data structure and have timestamps to support subsequent visualization and intelligent decision-making needs of the dispatch center.

[0097] The third part of the dynamic comparison includes the following: After determining ΔDmin, the current target section is immediately labeled according to the preset risk level standard. ΔDmin is the minimum value of the difference function ΔD(x) within the target span length range, representing the minimum difference between the actual spatial distance between the fiber optic composite overhead ground wire and the conductor under current weather conditions and the dynamic minimum spacing threshold. This value has been obtained in the aforementioned comparison analysis and is used to determine whether the spatial distance meets the safety spacing requirements.

[0098] To ensure the early warning mechanism has the capability to classify response levels, the system introduces a hierarchical judgment logic. This logic divides the risk into three states based on the range of ΔDmin, and assigns different level labels to each state, allowing dispatchers to intuitively identify operational risks in different areas on the interface.

[0099] The specific risk level standard adopts a three-segment division method, which is set as follows: When ΔDmin is greater than or equal to zero, it means that the minimum spatial distance between the fiber optic composite overhead ground wire and the conductor at all lateral positions within the target span length is greater than or equal to the dynamic minimum spacing threshold Δ(t) calculated under the current meteorological conditions. The operating status belongs to the risk-free range, there is no risk of insufficient spacing or insulation damage, and the system does not trigger any risk indicators.

[0100] When ΔDmin is less than zero but greater than or equal to a preset negative constant p, i.e., when p is less than or equal to ΔDmin and ΔDmin is less than zero, it indicates that the spatial distance at a certain location in the current section is slightly lower than the required minimum spacing threshold, and there is a moderate risk of discharge. At this time, a yellow risk indicator is triggered to remind dispatchers to pay attention to the section and to determine whether intervention is necessary based on trend information.

[0101] When ΔDmin is less than the preset constant p, it indicates that the minimum spatial distance is significantly lower than the current safety threshold, posing a significant risk of discharge or mechanical collision. In this case, the system automatically triggers a red risk indicator, indicating that the section is in a high-risk state and should enter the emergency handling process. The operation control center dispatchers will then intervene or implement shutdown measures based on the risk level. The variable p is a preset negative constant in the system. Its value is set by the operation and maintenance unit based on the transmission line design tolerance, safety margin requirements, and historical risk threshold experience. The unit is usually meters, and it is adjustable for engineering purposes, allowing for dynamic configuration based on regional differences or seasonal factors.

[0102] After completing the risk level assessment, the system must synchronously output the risk level result to the power dispatch visualization interface. This interface serves as a daily monitoring tool for dispatchers, featuring spatial positioning, data display, and interactive early warning functions. Red and yellow risk level indicators are rendered in real-time above the target section using color layers, creating an intuitive risk perception environment and issuing signal alerts. Simultaneously, the risk level indicator result will also serve as an input signal for the control center's operation and maintenance decisions, linking with other system modules such as the maintenance scheduling system, load allocation module, or emergency response mechanism, ensuring that operators can make scientific adjustments based on the risk level. To achieve full-process traceability, the system must record key data in a structured manner during the indicator processing. This includes: the timestamp corresponding to the assessment time; the horizontal position index of the location where the minimum spatial distance occurred (i.e., the value of variable x); the risk level to which the assessment result belongs (e.g., "no risk," "medium risk," "high risk"); the ΔDmin value on which the assessment was based; the spatial distance D(x) value at the corresponding time; and the dynamic minimum spacing threshold Δ(t) value at that time. The above data together constitute a complete risk confirmation structure, which is stored in the system data center and used as a technical basis for subsequent risk analysis, operational assessment and accident backtracking processes.

[0103] During the operation, the minimum value ΔDmin of the difference function ΔD(x) constructed in step four is continuously recorded to form a time series updated at a fixed sampling period. , where variables This represents each historical sampling time point. To extract the current trend, a short-period evolution curve is constructed by applying a fixed-step difference algorithm to this time series. A three-point equidistant sliding window center difference mode is adopted, with the step size denoted as ΔT. This is applied to the three sets of sample values ​​within the current sliding window. , , Perform difference fitting and calculate the local trend slope. :

[0104] Combining multiple consecutive slope values ​​to form a short-period evolution curve, Indicates a point in time The local rate of change of the corresponding minimum interval difference is used to measure whether the current trend is approaching a safe zone or entering a zone of increased risk. This trend value is dimensionless, and its sign indicates the direction of increase or decrease of ΔDmin, while the absolute value reflects the rate of change. Multiple consecutive slope values... By combining these parameters, a short-cycle evolution curve can be formed, reflecting the dynamic evolution trajectory of ΔDmin. Through real-time monitoring of this curve, the system can identify risk trends in advance, before spatial distance exceedances occur directly. The prediction logic is set as follows: if at any given time point... Appear A value less than zero indicates that the minimum spacing is decreasing, and A value less than or equal to ε indicates that the current minimum distance difference is close to the preset safety margin threshold, thus meeting the conditions for triggering an early warning. The variable ε is a preset safety margin threshold, set by the system based on empirical values ​​or design margins. Its value is a preset constant used to characterize the minimum safety margin of the spatial difference ΔDmin from its judgment boundary, provided that Δ(t) has not been violated. When ΔDmin is less than or equal to this preset constant, it is determined that it is in a critical risk state, meeting the conditions for triggering an early warning. The purpose of introducing this warning mechanism is to achieve "non-triggering" intervention control, that is, to respond in advance based solely on trend changes before ΔDmin becomes less than zero (i.e., before entering a high-risk zone), thereby improving the system's response speed and risk anticipation capabilities, and preventing sudden discharges or collisions.

[0105] Example 2: OPGW line safety distance early warning system in icing areas, including:

[0106] The status acquisition module acquires real-time operating parameters under different meteorological conditions in the target section by deploying tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices on the fiber optic composite overhead ground wire and conductor respectively, and timestamps each set of data.

[0107] The spatial modeling module utilizes the geometric parameters of the tower and the height difference information of the conductor suspension point, combined with the real-time data collected in step one, to deduce the respective catenary morphology of the conductor and optical cable in the vertical plane within the target span through analytical calculation, and further constructs the corresponding position function of the two lines in space.

[0108] The distance calculation module performs joint calculations on the two position functions in the spatial modeling module to solve the minimum spatial distance between the optical cable and the conductor in the target span section in real time, and records the lateral position and time point corresponding to the minimum value.

[0109] The dynamic comparison module, based on the insulation standard corresponding to the voltage level of the overhead line, calculates the dynamic minimum spacing threshold under the influence of current ice load, wind speed and tension through a multivariable function, and compares and analyzes the minimum spatial distance obtained in step three with the dynamic minimum spacing threshold. If the distance is insufficient, the level is immediately marked and the risk is confirmed.

[0110] The trend prediction module, based on historical data from the dynamic comparison module, uses a preset difference algorithm to construct a short-cycle evolution curve and determine whether an early warning signal is triggered.

[0111] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0112] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0113] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0114] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0115] 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.

Claims

1. A method for early warning of safe distance for OPGW lines in icing areas, characterized in that, Includes the following steps: Step 1, Status Acquisition: By deploying tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices on the fiber optic composite overhead ground wire and conductor respectively, real-time operating parameters under different meteorological conditions in the target section are obtained, and each set of data is timestamped. Step 2, Spatial Modeling: Utilizing the tower geometry parameters and conductor suspension point elevation differences, combined with the real-time data collected in Step 1, the catenary morphology of the conductor and optical cable within the target span in the vertical plane is derived through analytical calculations. Furthermore, the corresponding position functions of the two lines in space are constructed. Spatial modeling specifically includes the following: First, determine the target span length between the fiber optic composite overhead ground wire and the conductor in the target section. This target span length is the horizontal distance between the corresponding suspension points of two adjacent towers in the horizontal direction, which serves as the basis for calculating the span of the cable catenary configuration. Based on the tension, temperature, ice thickness and wind speed information obtained from the status acquisition, the dynamic unit weight of the fiber optic composite overhead ground wire under the current meteorological conditions is calculated. The dynamic unit weight is the sum of three parts, including the unit weight of the cable body, the unit weight of the equivalent ice weight added by icing, and the unit weight of the equivalent wind load generated by wind speed. The unit weight of the cable body is calculated based on the tension standard by multiplying the cable mass by the gravitational acceleration and then dividing by the target span length. The equivalent icing unit weight is expressed as a function of the ice thickness and the cable outer diameter by multiplying the volume of the cylindrical shell by the ice density and the gravitational acceleration and then dividing by the target span length. The equivalent wind load unit weight is calculated by multiplying the square of the wind speed by the drag coefficient, air density, and cross-sectional area, then converting it to the unit length form and dividing by the target span length. Using the aforementioned dynamic unit weight as input, and substituting it into the catenary tension-deformation relationship, we derive the functional expression of the fiber optic composite overhead ground wire in the vertical plane, and form a complete vertical plane functional expression. This expression is then independently applied to the conductor. Using the conductor's tension value, structural parameters, and meteorological input, we construct the conductor's functional expression in the vertical plane, ensuring that the two expressions are independent and strictly correspond to the actual input data. After completing the construction of the vertical plane function of the fiber composite overhead ground wire and the conductor within the target span length, the position expression of the two lines in the three-dimensional space of the target section is further established. By constructing a rectangular coordinate system, the position of the fiber composite overhead ground wire hanging point of one end tower in the target section is taken as the origin, the horizontal axis is defined along the span direction, the height axis is defined along the vertical direction, and the longitudinal axis is defined along the tower crossing direction. In this coordinate system, the position function of the fiber optic composite overhead ground wire is represented by the three-dimensional function P1(x)=(x,0,y1(x)), and the position function of the conductor is represented by the three-dimensional function P2(x)=(x,d,y2(x)), where the variable x represents any position on the horizontal axis, the functions y1(x) and y2(x) are the vertical plane functions of the fiber optic composite overhead ground wire and the conductor, respectively, and the variable d represents the actual horizontal distance between the two in the longitudinal axis direction; Step 3, Distance Calculation: Perform joint calculation on the two position functions from Step 2 to solve the minimum spatial distance between the optical cable and the conductor within the target span in real time, and record the lateral position and time point corresponding to the minimum value; Step 4: Dynamic Comparison: Based on the insulation standards corresponding to the voltage level of overhead lines, the dynamic minimum spacing threshold under the influence of current ice load, wind speed and tension is calculated through multivariate functions. The minimum spatial distance obtained in Step 3 is compared and analyzed with this dynamic minimum spacing threshold. If the distance is insufficient, the level is immediately marked and the risk is confirmed. Step 5: Trend Prediction: Based on the historical data from Step 4, a short-cycle evolution curve is constructed using a preset difference algorithm, and it is determined whether an early warning signal is triggered.

2. The method for early warning of safe distance for OPGW lines in icing areas according to claim 1, characterized in that, Status acquisition includes the following specific steps: Within the target section, a tension sensing device is installed on the fiber optic composite overhead ground wire to obtain the tension value of the fiber optic composite overhead ground wire under different working conditions in real time; at the same time, another tension sensing device is installed on the conductor to independently record the tension change of the conductor within the target section. The two are measured independently and the physical data are not mixed. While acquiring tension data, temperature detection devices are installed near the fiber optic composite overhead ground wire and the conductor respectively to record the ambient temperature around each cable in the target section. An ice thickness measurement device is deployed on the fiber optic composite overhead ground wire to detect changes in surface ice thickness in real time. The ice thickness measurement device does not physically overlap with the tension sensing device. Wind speed sensing devices are installed in the target section to continuously record wind speed information. Tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices all collect data under a unified time management mechanism. Each set of data is appended with a precise timestamp to generate a set of operating parameters with time series characteristics.

3. The method for early warning of safe distance for OPGW lines in icing areas according to claim 1, characterized in that, When performing a joint operation on the two position functions in step two, substitute the two position functions into the spatial Euclidean distance formula to calculate the spatial distance D(x) corresponding to each position within the target span length. By traversing all values ​​of variable x in the interval [0, target span length], solve for the minimum value of D(x) and its corresponding position coordinates.

4. The method for early warning of safe distance for OPGW lines in icing areas according to claim 3, characterized in that, The first part of the dynamic comparison includes the following: Based on the actual operating voltage level of the overhead lines in the target section, the air insulation safety distance design standard corresponding to that voltage level is obtained and set as the basic distance value Δ0. Based on this basic distance value, the ice thickness, wind speed information, and tension values ​​corresponding to the fiber optic composite overhead ground wire and conductor, respectively, obtained from the status acquisition, are introduced and set as follows: and Establish a multivariable dynamic function model: Output the dynamic minimum distance threshold at the current time. This multivariate dynamic function model is represented by a weighted addition model, and its construction form is as follows: ； ； ； and These are the design tension reference values ​​for the fiber optic composite overhead ground wire and the conductor, respectively. and All are preset parameter sensitivity weights. The output is used to perform point-by-point comparison and judgment with the spatial distance function.

5. The method for early warning of safe distance for OPGW lines in icing areas according to claim 4, characterized in that, The second part of the dynamic comparison includes the following: After generating the function for the dynamic minimum spacing threshold Δ(t), the spatial distance function D(x) is called to perform point-by-point comparison analysis. Taking all values ​​of variable x within the target span length range as input, each output value of function D(x) is compared with the corresponding Δ(t) at the current time to construct a new difference function ΔD(x) = D(x) − Δ(t). The minimum value of ΔD(x) within the target span length range is defined as ΔDmin, and its sign status is determined. When ΔDmin≥0, ​​it means that the minimum spatial distance of the target section under the current weather conditions meets the electrical insulation standard and no alarm is required; when ΔDmin<0, it means that the spatial distance is insufficient and there is a risk of discharge.

6. The method for early warning of safe distance for OPGW lines in icing areas according to claim 5, characterized in that, The third part of the dynamic comparison includes the following: After determining ΔDmin, the current target segment is immediately labeled according to the preset risk level standard. The risk level standard adopts a three-segment division, corresponding to low risk, medium risk and high risk respectively. ΔDmin≥0 is a risk-free state and no label is triggered; p≤ΔDmin<0 is a medium risk state and a yellow label is triggered; ΔDmin<p is a high risk state and a red label is triggered, where p is a preset negative constant.

7. The method for early warning of safe distance for OPGW lines in icing areas according to claim 6, characterized in that, During the operation, the minimum value ΔDmin of the difference function ΔD(x) constructed in step four is continuously recorded to form a time series updated at a fixed sampling period. , where variables This represents each historical sampling time point. To extract the current trend, a short-period evolution curve is constructed by applying a fixed-step difference algorithm to this time series. A three-point equidistant sliding window center difference mode is adopted, with the step size denoted as ΔT. This is applied to the three sets of sample values ​​within the current sliding window. , , Perform difference fitting and calculate the local trend slope. : ； Combining multiple consecutive slope values ​​to form a short-period evolution curve, if at any given time point... Appear Less than 0, and If the value is less than or equal to ε, where ε is a preset safety margin threshold, then the conditions for triggering an early warning are met.

8. An OPGW line safety distance early warning system for icing areas, used to implement the OPGW line safety distance early warning method for icing areas as described in any one of claims 1-7, characterized in that, include: The status acquisition module acquires real-time operating parameters under different meteorological conditions in the target section by deploying tension sensing devices, temperature detection devices, ice thickness measurement devices, and wind speed sensing devices on the fiber optic composite overhead ground wire and conductor respectively, and timestamps each set of data. The spatial modeling module utilizes the geometric parameters of the tower and the height difference information of the conductor suspension point, combined with the real-time data collected in step one, to deduce the respective catenary morphology of the conductor and optical cable in the vertical plane within the target span through analytical calculation, and further constructs the corresponding position function of the two lines in space. The distance calculation module performs joint calculations on the two position functions in the spatial modeling module to solve the minimum spatial distance between the optical cable and the conductor in the target span section in real time, and records the lateral position and time point corresponding to the minimum value. The dynamic comparison module, based on the insulation standard corresponding to the voltage level of the overhead line, calculates the dynamic minimum spacing threshold under the influence of current ice load, wind speed and tension through a multivariable function, and compares and analyzes the minimum spatial distance obtained in step three with the dynamic minimum spacing threshold. If the distance is insufficient, the level is immediately marked and the risk is confirmed. The trend prediction module, based on historical data from the dynamic comparison module, uses a preset difference algorithm to construct a short-cycle evolution curve and determine whether an early warning signal is triggered.

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