Digital Twin Evaluation Method and System for Dynamic Capacity Increase of Wind Power Transmission Lines

Abstract

The present invention discloses a digital twin evaluation method and system for dynamic capacity increase of wind power transmission lines, the method comprising: establishing a digital twin model of wind power transmission lines; conducting safety verification on transmission lines and interval transformers on both sides; determining the capacity increase dispatching interval and dispatching current carrying capacity increase gear of wind power transmission lines; when monitoring that the channel area of ​​wind power transmission lines is affected by extreme weather, comprehensively determining the operation and maintenance inspection mode based on equipment reliability and grid reliability; when monitoring that wind power prediction and micro-meteorology meet the capacity increase conditions, the wind power transmission lines enter the capacity increase dispatching operation state; during the dispatching operation of wind power transmission lines, when the temperature and sag of the transmission lines are judged to be beyond the limit through model monitoring and simulation, the current carrying capacity of the wind power transmission lines is reduced. The present invention has the advantages of high safety, strong operability, good data visualization effect, etc., which is helpful to improve the level of new energy consumption, save engineering investment, and improve economic and social benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of transmission line condition assessment, and relates to a digital twin assessment method and system for dynamic capacity increase of wind power transmission lines. Background Technique

[0002] Under the goals of "carbon peak" and "carbon neutrality", the new energy industry will embrace high-quality and leapfrog development, and the proportion of clean power installed capacity will increase significantly. However, if the problem of new energy power consumption cannot be solved, it is still difficult to form a new power ecosystem with new energy as the main body. The distribution project for new energy transmission is the connection link between the source and the grid, and its construction and operation quality restricts the large-scale development and application of new energy to a certain extent. In recent years, the problem that overhead transmission lines cannot meet the original designed transmission capacity has become more prominent. Building a new line corridor not only requires huge investment and a long construction period, but also has great difficulty in opening up a new line corridor. Therefore, scientifically and safely increasing the transmission capacity of existing transmission lines has become an urgent research topic and a technical problem to be solved. To address this, it is necessary to combine means such as wind power transmission supporting projects, dynamic capacity increase of transmission lines, digital twin transmission lines, and operation and maintenance management of transmission lines to solve the problem.

[0003] Wind power transmission supporting project: Due to the different construction periods of new energy power sources and the power grid, the lag in the construction of supporting transmission projects greatly restricts the normal grid connection of new energy projects. Taking the wind power construction in Liaoning area as an example, the western and northern regions of Liaoning are rich in wind resources. With the increase in newly built and expanded wind power projects in recent years, the problem of "choking" of the transmission line capacity has become more prominent. Taking the expansion project of a certain wind farm as an example, the original installed capacity of 50 MW was upgraded and expanded to 250 MW, while the original 220 kV wind power transmission line conductor used a JL / G1A-240 / 30 type single conductor, and the allowable transmission capacity was only 230 MVA (allowable current-carrying capacity of 600 A), which was lower than the full-load capacity of the unit. The conventional method of increasing the transmission line capacity by building a new line will incur huge project construction costs and a long construction period.

[0004] Dynamic capacity increase of transmission lines: Regarding the calculation of the conductor current-carrying capacity, abroad generally uses the IEEE Std.738 standard and the CIGRE601 technical manual for calculation, while in China, the British Morgan formula is generally used to check the maximum current-carrying capacity of the line. The conductor current-carrying capacity generally uses the following formula: In the formula, I is the allowable current-carrying capacity (A), W R is the radiation heat dissipation power per unit length of the conductor (W / m), W F is the convective heat dissipation power per unit length of the conductor (W / m), W S is the solar radiation heat absorption power per unit length of the conductor (W / m), R t ′The AC resistance (Ω / m) of the wire at the allowable temperature. The main basis for controlling the allowable current-carrying capacity of the wire is the highest allowable operating temperature of the wire and the environmental parameters of the wire operation. At present, the current-carrying capacity of domestic design departments is generally checked according to the meteorological conditions required by the national standard. The calculated value of the wire current-carrying capacity has a great relationship with the boundary condition values. China has a vast territory, with large differences in wind speed and sunshine. Especially in the Northeast region, the temperature is low, the temperature difference between morning and evening is large, and the seasonal wind speed is relatively high, which creates favorable conditions for further increasing the actual allowable current-carrying capacity of overhead transmission lines. By perceiving the wire state and environmental conditions (ambient temperature, sunshine, wind speed, etc.), without exceeding the allowable temperature of the wire specified in the current regulations, the maximum allowable current-carrying capacity of the wire can be dynamically calculated, and the hidden capacity objectively existing in the line can be fully utilized to realize the dynamic management of the line current-carrying capacity. Research shows that the wire has the ability to increase the allowable current-carrying capacity. Among environmental factors, wind speed has a greater impact on the wire temperature, while the impact of sunshine intensity on the temperature is not significant.

[0005] Digital twin transmission line: Digital twin refers to constructing an identical entity in the digital world for an object in the physical world through digital means, so as to achieve the understanding, analysis, and optimization of the physical entity. Using the digital twin method, a digital twin model of power transmission and transformation equipment can be established to carry out multi-dimensional data fusion analysis and risk assessment of power transmission and transformation equipment based on digital twins, and intuitively reflect the state of the main equipment and the external environment in real time. Applying digital twin technology to transmission lines can simulate the real operating state of the on-site line completely in the background management system. For example, the current flowing through the wire, the heating state of the joints, the inclination state of the towers, the dancing amplitude on the wire, and other real operating states are simulated and restored and then transmitted to the monitoring and analysis platform, so that the duty personnel can understand the operating state of the line in time in the monitoring room.

[0006] Operation and maintenance management of transmission lines: Since wind farms in the same wind belt need to consider the wind power simultaneity rate, the higher the simultaneity rate, the more cases of restricting the power generation output of the wind farm will be. When the wind power increases, the phenomenon of wind abandonment is extremely likely to occur due to the limitation of the transmission capacity, resulting in the ineffective consumption of new energy. In addition, extreme freezing weather such as low temperature and snow will cause disasters such as icing of transmission lines, and even cause equipment operation failures and accidents of wind turbines and booster stations, bringing pressure to the power and electricity balance. Relevant data shows that rain and snow freezing weather in late autumn and early winter is likely to lead to icing disasters of transmission lines. In summer, typhoons are the main meteorological disasters affecting the safe operation of new energy transmission. Compared with traditional power sources, wind power generation is more likely to have problems such as a sharp reduction in output and damage to power generation facilities due to extreme weather such as strong winds, low temperatures, heavy rains, and lightning.

[0007] The prior art (CN202010240637.3) proposes a method for dynamically evaluating the boundary of the current-carrying capacity of a transmission line, including the following steps: (1) Input the sensor information and environmental meteorological information collected by the transmission line into the digital twin model of the transmission line; (2) Calculate the boundary of the current-carrying capacity; (3) Calculate the steady-state value and temperature rise value of the wire temperature after the current transition; (4) Determine whether the steady-state value of the wire temperature exceeds the preset temperature value to determine whether it is necessary to reduce the boundary of the current-carrying capacity to recalculate the steady-state value of the wire temperature, and output the reduced boundary of the current-carrying capacity as a reference; (5) Calculate the maximum sag of the wire corresponding to the maximum current-carrying capacity of the transmission line; (6) Determine whether the maximum sag of the wire corresponding to the maximum current-carrying capacity of the transmission line meets the requirement of the ground clearance of the transmission line; (7) Obtain the final boundary of the current-carrying capacity of the transmission line. This technology improves the credibility and accuracy of the evaluation of the transmission capacity of the transmission line on the premise of ensuring the stable operation of the system and the safety of equipment. However, the application object of this technology is not the wind power transmission line, and the influence of the wind power coincidence rate is not fully considered in its boundary conditions. The digital twin model adopted by this technology is a simulation calculation model for calculating the current-carrying capacity of the line, rather than a three-dimensional model for real-time monitoring of the line and the channel, and it is impossible to perceive and evaluate the operation state of the transmission line in real time. Summary of the Invention

[0008] To solve the deficiencies existing in the prior art, the purpose of the present invention is to provide a digital twin evaluation method and system for dynamic capacity increase of wind power transmission lines, which have the advantages of high safety, strong operability, good data visualization effect, etc., and are helpful to improve the level of new energy consumption, save project investment, and enhance economic and social benefits.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions:

[0010] A digital twin evaluation method for dynamic capacity increase of wind power transmission lines, including the following steps:

[0011] Step 1: Establish a digital twin model of the wind power transmission line to realize line state monitoring and operation state simulation;

[0012] Step 2: Verify the safety of the transmission line and the interval substation equipment on both sides according to the target capacity increase and the target transmission current;

[0013] Step 3: Determine the capacity increase scheduling interval and the scheduling current-carrying capacity improvement gear of the wind power transmission line;

[0014] Step 4: When it is monitored by the digital twin model that the wind power transmission line channel area is affected by extreme weather, determine the operation and maintenance and repair method by comprehensively considering equipment reliability and grid reliability;

[0015] Step 5: When it is monitored by the digital twin model that the wind power prediction and micro-meteorology meet the capacity increase conditions, the wind power transmission line enters the capacity increase dispatching operation state, and the line current-carrying capacity is increased according to the gear;

[0016] Step 6: During the dispatching operation of the wind power transmission line, when it is monitored and simulated by the digital twin model that the temperature and sag of the transmission line exceed the limit, the line current-carrying capacity of the wind power transmission line is reduced.

[0017] The present invention further includes the following preferred solutions:

[0018] Preferably, in step 1, a digital twin model of the wind power transmission line is established by fusing BIM and 3D laser scanning technology, specifically including:

[0019] Step 1.1: Construct a tower structure model through BIM data;

[0020] Step 1.2: Construct a conductor and channel model through 3D laser scanning;

[0021] Step 1.3: Integrate the tower structure model with the conductor and channel model;

[0022] Step 1.4: Superimpose the transmission line state perception data on the basis of the integrated model, and perform data linkage between the instant state of the line and the model to dynamically evaluate the operation safety of the line and the channel, that is, form a digital twin model of the wind power transmission line, and realize line state monitoring, visual display and operation state simulation.

[0023] Preferably, step 1.2 is specifically: after the installation of the line equipment and facilities is completed, by carrying a lidar device on the unmanned aerial vehicle, directly collect the 3D laser point cloud of the line corridor, and then obtain the 3D line corridor terrain, landform, structures and the spatial information of the line facilities and equipment to construct the conductor and channel model;

[0024] The spatial information includes the tower height and coordinates, span, defect location, crossing angle, suspension point location, and conductor sag.

[0025] Preferably, in step 1.4, wind power prediction data is also accessed in the digital twin model of the transmission line for the use of the dispatching department;

[0026] The wind power prediction refers to calculating the output power of the wind farm by physical methods based on the data of numerical weather prediction.

[0027] Preferably, the realization of the line state monitoring in step 1.4 specifically includes:

[0028] 1) Online monitoring of the sag of the transmission line: The monitoring method includes at least one of laser ranging, Beidou differential positioning, and binocular vision distance measurement methods;

[0029] Among them, the laser ranging and Beidou differential positioning methods are to install the sensor at the lowest point of the sag on the conductor, and monitor the parameters of the vertical distance from the lowest point of the sag to the ground in real time; the binocular sight method is to install the sensor on the tower, and measure the conductor sag within the sight range based on binocular vision; superimpose the data on the fusion model to realize the online monitoring of the transmission line sag;

[0030] 2) Micro-meteorological monitoring of transmission lines: The monitoring method is: install micro-meteorological monitoring devices on poles and conductors at the same time, the monitoring devices on the poles collect the ambient temperature, humidity, air pressure, wind speed, wind direction, and rainfall parameters of the poles, and the monitoring devices on the conductors collect the ambient temperature, sunshine intensity, and wind speed parameters of the conductors; superimpose the data on the fusion model to realize micro-meteorological monitoring of transmission lines;

[0031] 3) Comprehensive status monitoring of transmission lines: The monitoring method is: install the comprehensive status monitoring device on the conductor, collect the conductor's temperature, current, ambient temperature, sunshine intensity, wind speed, and calculate the conductor's load capacity, and superimpose the data on the fusion model to achieve comprehensive status monitoring of the transmission line.

[0032] Preferably, in step 1.4, the transmission line state sensing data is obtained in the following manner to implement line state monitoring:

[0033] Install the tower body and environmental monitoring devices on the tower to realize all-round three-dimensional monitoring of the tower body, including the tower bolts, insulators, pins, and ground wires, to timely discover the defects of the tower body, and to realize the micro-meteorological monitoring and recording around the tower, including temperature, humidity, air pressure, wind speed, wind direction, and rainfall status;

[0034] Install tilt monitoring sensors on the towers to automatically collect the longitudinal and lateral tilt angles of the towers and monitor the tilt of the towers in real time;

[0035] Install a night vision card camera monitoring device on the tower to observe the external insulation of the line at night and issue an early warning when an abnormality occurs;

[0036] Install tension sensors on the pole towers to monitor and sense the dancing of the lines;

[0037] Bolt tightening monitoring sensors are installed on the tower to monitor the bolt tightening force at key nodes of the tower body;

[0038] A binocular video ranging device is installed on the tower to reconstruct the three-dimensional point cloud of the line channel to reproduce the terrain scene within the line of sight, measure the conductor sag and provide early warning;

[0039] Install temperature sensors at the key connection points of the strain tower to monitor the connection temperature of the strain clamp in real time and locate potential heating hazards;

[0040] Install a comprehensive condition monitoring device on the wire to collect the temperature, current, ambient temperature, solar radiation intensity, and wind speed of the wire, and calculate the load-carrying capacity of the wire;

[0041] Install an abnormal condition monitoring device on the wire to locate, identify, and give early warnings of insulator deterioration, floating discharge of fittings, and pollution, and find the line fault points;

[0042] Install an intelligent spacer device on the wire to monitor the galloping and ground clearance of the line in real time;

[0043] Install a sag monitoring device on the wire to monitor the parameter of the vertical distance from the lowest point of the sag to the ground in real time at the key positions of large spans, across rivers, and low sag points.

[0044] Preferably, in step 2, verify the safety of the transmission line according to the target capacity increase, and verify the safety of the interval substation equipment on both sides of the transmission line according to the target transmission current. When both verifications are passed, enter step 3;

[0045] The verification of the safety of the transmission line specifically includes:

[0046] Step A1: Determine the ratio of the capacity exceeding the line transmission capacity through the target transmission capacity and the maximum wind power installed capacity, and determine the sag intersection and crossing check gears;

[0047] Step A2: Collect and analyze the wind speed-power data of the wind turbines, and determine the corresponding wind speeds of different types of turbines at different powers according to the relationship between the single-unit capacity and the power curve of the turbines in the wind farm;

[0048] Step A3: Collect and analyze the typical meteorological data of the wind farm, and combine the historical broadcast data provided by the meteorological bureau and the measured monitoring meteorological data in the wind farm to statistically analyze the average wind speed, ambient temperature, and solar radiation intensity of each month in the past 2-3 years in the farm;

[0049] Step A4: Analyze the wire temperature-sag check data, calculate the wire temperature respectively with the current, wind speed, ambient temperature, and solar radiation intensity corresponding to each gear of the sag intersection and crossing check, and conduct sag intersection and crossing checks;

[0050] Step A5: Obtain the conclusion of line safety verification: When conducting cross-span verification for each span of the line, if the cross-span distances between the conductor and the ground, power lines, trees, and structures all meet the requirements of GB 50545-2010, it indicates that after positioning and checking the sag according to the operating conditions and environmental conditions of the line, the conductor can at least safely increase the transmission capacity by a proportion exceeding the line transmission capacity, realizing 100% transmission of the load of all wind turbines and avoiding wind curtailment; if the requirements of GB 50545-2010 cannot be met due to the influence of trees, tree felling can be adopted to meet the requirements. If the requirements of GB 50545-2010 cannot be met due to the influence of other factors, the target transmission capacity shall be reduced and the safety verification shall be carried out again.

[0051] Preferably, the safety verification of the interval substation equipment on both sides of the transmission line specifically includes:

[0052] Step B1: Verify the rated current of the circuit breakers on both sides of the interval through the target transmission current;

[0053] Step B2: Verify the rated current of the disconnectors on both sides of the interval through the target transmission current;

[0054] Step B3: Verify the protection, measurement, and metering transformation ratios of the current transformers on both sides of the interval through the target transmission current;

[0055] Step B4: According to the verification results of Step B1 - Step B3, adjust the circuit breakers, disconnectors, or current transformers that fail the verification, that is, replace or transform the equipment. After the equipment is replaced or transformed, the dispatching department shall finally verify the protection setting values of this line to complete the safety verification of the substation equipment.

[0056] Preferably, in Step 3, the method for determining the capacity increase dispatching interval and the dispatching load current increase gear of the wind power transmission line includes:

[0057] When the boundary of the capacity increase purpose is clear by using the target transmission capacity in the safety verification link, through the expected capacity increase target I exp to determine the capacity increase dispatching interval [I e , I exp and the capacity increase ratio, as well as the dispatching load current increase gear;

[0058] Among them, I e is the maximum load current of the line.

[0059] Preferably, in Step 3, the method for determining the capacity increase dispatching interval and the dispatching load current increase gear of the wind power transmission line includes:

[0060] The target transmission capacity without the security verification link is calculated to obtain the conductor ampacity boundary I by using the preset maximum conductor temperature, the measured conductor temperature, micro-meteorological parameters, conductor current, and conductor sag as fixed boundary conditions. max , thereby determining the capacity increase scheduling interval as [I e , I max , and the gear for increasing the scheduling ampacity, and determining the capacity increase ratio through I max and I e ;

[0061] Among them, I e is the maximum load current of the line.

[0062] Preferably, in step 4, it is monitored whether the wind power transmission line corridor area is affected by extreme weather through the digital twin model. Receiving an extreme weather forecast and warning is regarded as being affected. At this time, the operation and maintenance and repair method is determined by comprehensively considering equipment reliability and grid reliability, providing a decision for equipment management and dispatching operation; at the same time, if it is monitored that it is affected by cold wave weather, an ice coating state warning is given to the fan and the transmission line.

[0063] If not affected, go to step 5.

[0064] Preferably, the operation and maintenance and repair method determined by comprehensively considering equipment reliability and grid reliability in step 4 provides a decision for equipment management and dispatching operation, specifically:

[0065] When the wind power transmission line corridor area is affected by extreme weather, taking the current wind farm, wind power transmission line, and wind power receiving end collection station as a subset of meteorologically affected equipment, mainly considering strongly related station-line equipment, introducing associated station-lines and power sources, and removing weakly related station-line equipment, reconstructing the power grid fault set, realizing the data interaction from equipment reliability analysis to power grid reliability analysis, and based on this, conducting static and dynamic security and stability analysis of the power grid to determine the operation and maintenance and repair method, providing a decision for equipment management and dispatching operation.

[0066] Preferably, in step 5, it is monitored whether the wind power prediction and micro-meteorology meet the capacity increase conditions through the module. If not, the wind power transmission line maintains normal state dispatching operation; if so, the wind power transmission line enters the capacity increase dispatching operation state, and the line ampacity is increased according to the gear. Specifically:

[0067] If, through wind power prediction and micro-meteorological monitoring, it is determined that the wind speed is higher than the set value but does not exceed the operating conditions of the wind turbine, it means that the wind speed meets the condition for increasing the carrying capacity of the wind power transmission line. Then, the wind power transmission line enters the capacity increase dispatching operation state. Considering the wind power coincidence rate, the dispatching department respectively upgrades the first-level section according to the transmission line status of each wind farm and the unit load, that is, the carrying capacity of the wind power transmission line. At the same time, at the second-level section, that is, the transmission line of the receiving-end collecting substation of the wind power adjusts the carrying capacity of the second-level section dynamically according to the N-1 principle.

[0068] Preferably, in step 6, during the dispatching operation of the wind power transmission line, the operation state of the wind power transmission line is dynamically monitored and simulated through the digital twin model of the transmission line, and it is judged whether the temperature and sag of the transmission line exceed the limit. If they exceed the limit, the carrying capacity of the wind power transmission line is lowered, and step 5 is returned; if they do not exceed the limit, the current capacity increase operation state is maintained, and step 5 is returned.

[0069] The present invention also provides a digital twin evaluation system for the dynamic capacity increase of wind power transmission lines, which is used to implement the digital twin evaluation method for the dynamic capacity increase of wind power transmission lines.

[0070] The beneficial effects of the present invention are as follows: compared with the prior art:

[0071] (1) Since both the unit load of the wind farm and the transmission capacity of the transmission line are positively correlated with the wind speed, therefore, by using the method of the present invention, when the predicted wind power of the wind farm increases, it is more conducive to realizing the dynamic capacity increase of the wind power transmission line, solving the problem of "choking" of the capacity of the wind power transmission line, and helping to improve the level of new energy consumption;

[0072] (2) The digital twin model of the transmission line of the present invention superimposes and displays rich transmission line status perception data on the three-dimensional model, realizes data linkage between the instant state of the conductor and the three-dimensional modeling, dynamically evaluates the operation safety of the line and the channel, realizes the visual display of the conductor state and the simulation of the operation state, is more intuitive, can judge the operation safety of the conductor through real-time monitoring data, meets the national standard requirements, and has higher safety;

[0073] (3) The present invention conducts hierarchical dispatching of the line capacity increase according to the boundary of the capacity increase expected purpose. When the safety index exceeds the limit, it can timely lower the load capacity or even quickly return to the normal operation state, and the operability of the dispatching control is stronger;

[0074] (4) The present invention also provides a safety verification method for power transmission and transformation equipment. Before actually carrying out the dynamic capacity increase, the safety of the power transmission and transformation equipment is verified to ensure the safe, stable and efficient operation of the entire transmission project;

[0075] (5) When extreme meteorological disasters such as rain, snow, ice, and freezing occur in the region, the present invention can comprehensively analyze the reliability of the regional power grid based on equipment reliability and system reliability and provide decision-making suggestions, with closer source-network coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is a flowchart of the digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to the present invention;

[0077] Figure 2 is the monitoring and analysis interface of the digital twin transmission line according to the present invention;

[0078] Figure 3 is a flowchart of the safety verification method for the transmission line according to the present invention;

[0079] Figure 4 is a flowchart of the safety verification method for substation equipment according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0080] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the protection scope of the present invention.

[0081] As Figure 1 shown, Embodiment 1 of the present invention provides a digital twin evaluation method for dynamic capacity increase of wind power transmission lines. In the preferred but non-limiting embodiment of the present invention, the method specifically includes the following steps:

[0082] Step 1: Establish a digital twin model of the wind power transmission line to realize line state monitoring and operation state simulation;

[0083] Further preferably, a digital twin model of the wind power transmission line is established by integrating BIM and three-dimensional laser scanning technology, specifically including:

[0084] Step 1.1: Construct a tower structure model through BIM data;

[0085] Through the BIM technology applied in the early stage of the three-dimensional design stage of the transmission line, the three-dimensional digital delivery of the transmission line tower structure design can be realized.

[0086] Step 1.2: Construct a conductor and channel model through three-dimensional laser scanning;

[0087] Further preferably, after the installation of the line equipment and facilities is completed, a lidar device is carried on a drone to directly collect high-precision three-dimensional laser point clouds of the line corridor, and then high-precision three-dimensional line corridor terrain, landform, structures, and line facility equipment spatial information is obtained to construct a conductor and channel model;

[0088] The spatial information includes tower height and coordinates, span distance, defect location, crossing angle, suspension point location, conductor sag, etc.

[0089] Step 1.3: Integrate the tower structure model with the conductor and corridor models.

[0090] The 3D line design constructs a 3D simulation scenario based on multi-source geographic data and vector parameter models for engineering design. Its functions cover transmission line route planning, corridor clearance, tower ranking, electrical verification, structural calculation, digital handover, etc. By matching the tower structure model in the BIM information with the high-precision 3D laser point cloud of the line corridor collected after installation, the tower structure model is corrected. At the same time, the conductor and corridor models constructed from the line corridor terrain and structure information are superimposed, so that the accuracy after the two are integrated can reach the centimeter level.

[0091] Step 1.4: Superimpose the transmission line status perception data on the integrated model, link the instant line status with the model to realize data linkage, and dynamically evaluate the operation safety of the line and corridor, that is, form a digital twin model of the wind power transmission line to realize line status monitoring, visual display, and operation status simulation.

[0092] Further preferably, wind power prediction data is also connected to the digital twin model of the transmission line for the use of the dispatching department.

[0093] The wind power prediction data used by the dispatching department is different from the wind farm data:

[0094] The wind power prediction used for dispatching calculates the output power of the wind farm by physical methods based on the data of numerical weather forecasting; while the wind farm data is predicted by a statistical method based on the online measured data of the relationship between numerical weather forecasting and the power output of the wind farm.

[0095] The dynamic evaluation of the operation safety of the line and corridor: For example Figure 2 As shown, the digital twin model of the transmission line can superimpose the transmission line status perception data on the 3D model of the transmission line, link the instant conductor status with the 3D modeling to realize data linkage, and can be used to dynamically evaluate the operation safety of the line and corridor. For example: Figure 2 The analysis interface shown can simulate and calculate whether the conductor will discharge due to insufficient safety distance from the trees below the line under the influence of temperature and wind deflection angle based on the 3D model of the conductor and the tree models in the corridor.

[0096] The realization of line status monitoring specifically includes:

[0097] 1) Online monitoring of the sag of transmission lines: The monitoring methods include at least one of the methods such as laser ranging, Beidou differential positioning, and binocular vision distance measurement. Among them, for the laser ranging and Beidou differential positioning methods, the sensor is installed at the lowest point of the sag on the conductor, and for the binocular vision distance measurement method, the sensor is installed on the tower to calculate the sag of the conductor within the line of sight based on binocular vision. The data is superimposed on the fusion model to achieve online monitoring of the sag of transmission lines;

[0098] 2) Micro-meteorological monitoring of transmission lines: The monitoring method is as follows: The micro-meteorological monitoring device is installed on both the tower and the conductor at the same time. The micro-meteorological monitoring device on the tower is responsible for collecting meteorological state parameters such as ambient temperature, humidity, air pressure, wind speed, wind direction, and rainfall, and the micro-meteorological monitoring device on the conductor is responsible for collecting meteorological state parameters such as ambient temperature, solar radiation intensity, and wind speed. The data is superimposed on the fusion model to achieve micro-meteorological monitoring of transmission lines;

[0099] 3) Comprehensive state monitoring of transmission lines: The monitoring method is as follows: The monitoring device is installed on the conductor, which can accurately collect the temperature, current, and environmental parameters (ambient temperature, solar radiation intensity, wind speed) of the conductor and calculate the load-carrying capacity of the conductor. The data is superimposed on the fusion model to achieve comprehensive state monitoring of transmission lines. Among them, the comprehensive state monitoring device adopts the CT energy-taking method.

[0100] In specific implementation, to improve the actual application effect of the dynamic capacity increase project, it is necessary to install online monitoring devices such as environmental parameters, and based on the collected environmental parameters, dynamically verify the load flow data, realize the access of data, and conduct real-time calculation of the line transmission capacity and operation safety assessment. The calculation results are pushed to the dispatching in real time for the dispatching to refer to for the adjustment of the transmission capacity. To ensure safety, it is necessary to install at least fitting temperature sensors, sag sensors, etc. on important spans to monitor the operation status in real time.

[0101] Further preferably, the following methods are used to obtain the state perception data of transmission lines to achieve the above-mentioned line state monitoring objectives.

[0102] Install a tower body and environmental monitoring device on the tower, which can achieve all-round three-dimensional monitoring of the tower body such as tower bolts, insulators, pins, conductors and ground wires, timely discover defects in the tower body, and at the same time realize the monitoring and recording of the micro-meteorology around the tower, including meteorological states such as temperature, humidity, air pressure, wind speed, wind direction, and rainfall;

[0103] Install an inclination monitoring sensor on the tower to automatically collect the longitudinal and lateral inclination angles of the tower and monitor the inclination of the tower in real time;

[0104] Install a night vision card camera monitoring device on the tower to observe the external insulation condition of the line at night and give an early warning in time once an abnormality occurs;

[0105] Install a tension sensor on the pole tower to accurately monitor and sense the galloping condition of the line;

[0106] Install a bolt tightening monitoring sensor on the pole tower to accurately monitor the bolt tightening force at the key joints of the tower body;

[0107] Install a binocular video ranging device on the pole tower. By reconstructing the three-dimensional point cloud of the line corridor, realize the reproduction of the topographic and geomorphic scene within the line of sight, the calculation and early warning of the conductor sag;

[0108] Install temperature sensors at the key joint parts of the strain pole tower to monitor the joint temperature of the strain clamp in real time. There is no need for on-site temperature measurement by maintenance personnel, and accurately locate the hidden danger of overheating;

[0109] Install a comprehensive condition monitoring device on the conductor, which can accurately collect the temperature, current, and environmental parameters (ambient temperature, sunlight intensity, wind speed) of the conductor, and calculate the load-carrying capacity of the conductor;

[0110] Install an abnormal condition monitoring device on the conductor to locate, identify and give early warning of abnormal discharges such as insulator deterioration, fitting floating discharge, and pollution, and guide maintenance personnel to quickly find the line fault point;

[0111] Install an intelligent spacer device on the conductor to monitor the galloping and ground clearance of the line in real time;

[0112] Install a sag monitoring device on the conductor. For key positions with large spans, crossing rivers, and low sag points, monitor the parameter of the vertical distance from the lowest point of the sag to the ground in real time.

[0113] Step 2: Verify the safety of the transmission line and the interval substation equipment on both sides;

[0114] When the specific implementation of the present invention is carried out, before dynamic capacity increase, it is also necessary: A: Verify the safety of the transmission line, B: Verify the safety of the interval substation equipment on both sides of the transmission line;

[0115] A: Verify the safety of the line.

[0116] According to the target transmission capacity or transmission current, select the harsh environmental parameters of this line corridor, calculate the conductor temperature, and perform sag positioning and span crossing check according to the temperature obtained by rounding up the calculated value (further increasing the safety margin).

[0117] If the distance between the conductor and the span crossing object at a certain span of the line does not meet the national standard requirements after exploration, it can be processed by methods such as locally raising the line and felling trees to make it meet the requirements of GB 50545-2010.

[0118] As Figure 3 shown, the specific steps of the verification are as follows:

[0119] Step A1: Determine the ratio exceeding the line transmission capacity based on the target transmission capacity and the maximum installed wind power capacity, and determine the sag intersection and crossing check gears.

[0120] In the embodiment of the present invention, it is assumed that the original installed capacity of the wind farm is 50 MW, and the installed capacity after addition (i.e., the target transmission capacity) reaches 250 MW. The transmission capacity of the original 220 kV power transmission line is 230 MVA, and the installed capacity exceeds the transmission capacity (i.e., the ratio exceeding the line transmission capacity) by about 10%.

[0121] The designed transmission capacity of the original line is only about 90% of the unit load. Therefore, it can be considered in gears according to 90%, 95%, and 100% of the unit load.

[0122] Step A2: Collect and analyze the wind speed-power data of the wind turbines, and determine the corresponding wind speeds of the units (including various different models) at different powers according to the relationship between the single-unit capacity and the power curve of the units in the wind farm.

[0123] Since the entire wind farm can reach the corresponding load only when the wind speed reaches the corresponding load lower limit wind speed of all the wind turbines, in the embodiment of the present invention, it is assumed that when the wind farm reaches 90%, 95%, and 100% of the load, the corresponding wind speeds are 9 m / s, 11 m / s, and 14 m / s respectively.

[0124] Step A3: Collect and analyze the typical meteorological data of the wind farm, and combine the historical broadcast data provided by the meteorological bureau and the measured monitoring meteorological data in the wind farm to statistically analyze the average wind speed, ambient temperature (taking the high-temperature period from 12:00 to 15:00), and sunshine intensity in each month within the past 2 - 3 years in the field.

[0125] In the embodiment of the present invention, the wind speed in this area is high in spring and autumn and low in summer and winter. The higher wind speeds are mainly concentrated in March - May and October - November and the wind speed is stable; combined with the power generation data of the wind farm in the past 3 years, it is relatively consistent with the change trend of the meteorological data. The average wind speed is used to obtain the corresponding relationship among wind speed - light - air temperature in the meteorological environment elements corresponding to the geographical location of the wind farm, and it can only be statistically analyzed through the average value.

[0126] Step A4: Analyze the conductor temperature - sag check data, and calculate the conductor temperature and check the sag respectively with the currents corresponding to 90%, 95%, and 100% of the load of the wind farm (obtained in Step A1, and the current corresponds to the transmission capacity), the wind speed (the wind speed in Step A2, which refers to the lowest wind speed when all the wind turbines in the wind farm reach a certain power), the ambient temperature, and the sunshine intensity.

[0127] For the positioning temperature below 40°C of the conductor, there is no need to reposition the conductor.

[0128] Under harsh extreme environmental conditions and in accordance with the wire sag control principle, while leaving sufficient margin, the cross-span of the line can be verified at a maximum wire operating temperature of 50°C.

[0129] Step A5: Obtain the conclusion of line safety verification.

[0130] Conduct cross-span verification for each span of the line. If the cross-span distances between the wire and the ground, power lines, trees, structures, etc. all meet the requirements of GB 50545-2010, it indicates that after positioning and checking the sag according to the operating conditions and environmental conditions of the line, the wire can safely increase the transmission capacity by at least 10%, achieve 100% output of the load of all wind turbines, and avoid wind curtailment. If it cannot meet the requirements of GB 50545-2010 due to the influence of trees, the trees can be cut down to meet the requirements. If it cannot meet the requirements of GB 50545-2010 due to the influence of other factors, the target transmission capacity is reduced and the safety verification is carried out again.

[0131] B: Before dynamic capacity increase, conduct safety verification on the substation equipment.

[0132] Verify the current-carrying capacity of the interval equipment on both sides of the line, the range and accuracy of the current transformers according to the increased maximum proposed operating current (i.e., the target transmission current).

[0133] In the embodiment of the present invention, since the newly added installed capacity reaches 250 MW and the transmission capacity of the original 220 kV power transmission line is 230 MVA, with the installed capacity exceeding the transmission capacity by about 10%, the line current-carrying capacity will be increased from 600 A to 660 A.

[0134] As Figure 4 shown, the specific verification steps are as follows:

[0135] Step B1: Verify the rated current of the circuit breakers on both sides of the interval.

[0136] In the embodiment of the present invention, the rated currents of the circuit breakers on both sides of the interval are 3150 A and 4000 A respectively. Therefore, the current-carrying capacity of the circuit breakers can all meet the requirements.

[0137] Step B2: Verify the rated current of the disconnectors on both sides of the interval.

[0138] In the embodiment of the present invention, the interval on the sending end side close to the wind farm is arranged in a single-busbar mode, with a line-side disconnector rated current of 3150 A and a busbar-side disconnector rated current of 2500 A; the receiving-end interval on the opposite side is arranged in a double-busbar mode, with a line-side disconnector rated current of 3150 A and the rated currents of the two groups of busbar-side disconnectors both being 3150 A. Therefore, the current-carrying capacity of the disconnectors can all meet the requirements.

[0139] Step B3: Verify the transformation ratios of the current transformers on both sides at intervals.

[0140] In the embodiment of the present invention, for the current transformers on the side near the sending end of the wind farm, the transformation ratios for protection, measurement, and metering are 1600 / 1, 800 / 1, and 800 / 1 respectively, and the transformation ratios of the current transformers meet the requirements; for the current transformers on the receiving end side of the other side, the transformation ratios for protection, measurement, and metering are 1200 / 1, 1200 / 1, and 600 / 1 respectively. Among them, the transformation ratio of the metering winding of the current transformer does not meet the requirements. Therefore, the transformation ratio of the current transformer equipment on the receiving end side of the other side needs to be adjusted.

[0141] Step B4: Obtain the conclusion of the safety verification of the substation equipment.

[0142] In this embodiment, the circuit breakers and disconnectors on both sides of the line at intervals do not need to be adjusted (that is, no modification or replacement is required). The transformation ratio of the metering winding of the current transformer on the receiving end side needs to be adjusted to 1200 / 1, and the parameters of other current transformers do not need to be adjusted. In addition, after the equipment is replaced or modified, the dispatching department should finally verify the protection setting values of this line.

[0143] Step 3: Determine the capacity increase dispatching interval and the dispatching load current increase gear of the wind power transmission line;

[0144] Further preferably, there are two methods for determining the capacity increase dispatching interval of the line. Let the maximum load current of the line be I e .

[0145] 1) The first method: Adopt the target transmission capacity in the safety verification link, that is, determine the capacity increase ratio through the expected capacity increase target I exp . The capacity increase dispatching interval should be [I e , I exp .

[0146] For example, if the maximum load current I e of the line is 600 A and the expected capacity increase target I exp is 660 A, the load current of the line will be increased from 600 A to 660 A, and the capacity increase ratio is 10%.

[0147] 2) The second method: Do not adopt the target transmission capacity in the safety verification link, and it is necessary to calculate to find the load current boundary.

[0148] Using the preset maximum wire temperature, measured wire temperature, micro-meteorological parameters, wire current, and wire sag as fixed boundary conditions, calculate the wire load current boundary I max . Determine the capacity increase ratio through I max and I e . The capacity increase dispatching interval should be [I e , I max .

[0149] In practical applications, the scheduling operation of the first method is more feasible, and the operation of line equipment is safer.

[0150] Within the line capacity increase scheduling range of both methods, 5% of the maximum load current I of the line is used as one gear for the dispatching department to make decisions and operations on increasing the current-carrying capacity. e For example, the line load can be increased from I

[0151] to 1.05I e and then to 1.1I e or directly to 1.1I e , until the difference from I e is less than 5%I max and then no further increase is made. Similarly, when the dispatching department needs to reduce the current-carrying capacity, 5% of the maximum load current I of the line is also used as one gear for the dispatching department to reduce the current-carrying capacity. e e e Step 4: When it is monitored by the digital twin model that the wind power transmission line channel area is affected by extreme weather, determine the operation and maintenance method by comprehensively considering equipment reliability and grid reliability;

[0152] Further preferably, it is judged whether the wind power transmission line channel area is affected by extreme weather such as rain, snow and ice (receiving extreme weather forecast and early warning is regarded as being affected). If it is affected by weather such as cold wave, give an icing state early warning for the fan and the transmission line, and at the same time determine the operation and maintenance method by comprehensively considering equipment reliability and grid reliability, so as to provide a decision for equipment management and dispatching operation;

[0153] The operation and maintenance method determined by comprehensively considering equipment reliability and grid reliability in Step 4 provides a decision for equipment management and dispatching operation, specifically:

[0154] When the wind power transmission line channel area is affected by extreme weather, taking the current wind farm, wind power transmission line, and wind power receiving-end collecting station as the equipment subset affected by the weather, mainly considering the strongly related station-line equipment, introducing the associated station-line and power source points, removing the weakly related station-line equipment, reconstructing the power grid fault set, realizing the data interaction from equipment reliability analysis to power grid reliability analysis, and on this basis, conducting static and dynamic security and stability analysis of the power grid to determine the operation and maintenance method, so as to provide a decision for equipment management and dispatching operation. Specifically:

[0155]

[0156] ​Evaluate the reliability of source and network equipment under the influence of extreme weather. When the equipment reliability is low, it indicates that the equipment is likely to trip or fail, and such equipment is included in the initial set of low-reliability equipment. At the same time, according to the grid's attention to the operation of core equipment and the relevance between equipment, determine the key equipment, networks, and systems that maintain the basic functions of the power system. By integrating the physical state of the equipment with the grid security information, improve the ranking (priority) of key grid components in the initial set of low-reliability equipment, and reconstruct the low-reliability fault set of the power grid applicable to grid risk assessment. This link realizes the data interaction from equipment reliability analysis to grid reliability analysis. Based on the low-reliability fault set of the power grid, conduct static and dynamic security and stability analyses of the power grid according to the most severe situation, and propose control plans and operation and maintenance methods for "prevention and control, resistance strategies, emergency response, and rapid restoration" of the regional power grid under extreme weather disasters, so as to improve the elasticity and toughness of the new power system and provide a scientific basis for the security and stability analysis of the regional power grid under the influence of extreme weather.

[0157] Step 5: When it is monitored by the digital twin model that the wind power prediction and micro-meteorology meet the capacity increase conditions, the wind power transmission line enters the capacity increase dispatching operation state, and the line current-carrying capacity is increased according to the gear.

[0158] In Step 5, if it is judged through wind power prediction and micro-meteorological monitoring that the wind speed is higher than the set value but does not exceed the fan operating conditions, it means that the wind speed meets the conditions for increasing the current-carrying capacity of the wind power transmission line. Then the wind power transmission line enters the capacity increase dispatching operation state. Considering the wind power coincidence rate, the dispatching department respectively increases the first-level section, that is, the current-carrying capacity of the wind power transmission line, according to the transmission line status and unit load of each wind farm. At the same time, in the second-level section, that is, the transmission line of the receiving-end collecting substation of the wind power adjusts the current-carrying capacity of the second-level section (usually a double-circuit line) dynamically according to the N-1 principle.

[0159] Specifically, after the wind power transmission line enters the capacity increase dispatching operation state, the line current-carrying capacity is increased by one gear with 5% of the line maximum load as a gear.

[0160] The above wind power prediction is a prediction of the power output of the wind farm in the future for a period of time, similar to notifying the dispatching in advance to prepare for capacity increase; the micro-meteorological monitoring can confirm whether the meteorological environment at this time meets the capacity increase conditions. The former is a forecast, and the latter is real-time monitoring.

[0161] Regarding the above consideration of the wind power coincidence rate, the dispatching department respectively increases the first-level section, that is, the current-carrying capacity of the wind power transmission line, according to the transmission line status and unit load of each wind farm. At the same time, in the second-level section, that is, the transmission line of the receiving-end collecting substation of the wind power adjusts the current-carrying capacity of the second-level section (usually a double-circuit line) dynamically according to the N-1 principle. Specifically:

[0162] Since the wind speeds of relevant wind farms in the same wind belt are correlated to a certain extent and cannot be considered independent, the capacity increase scheduling of wind power transmission lines needs to consider the wind power coincidence rate. For example, three wind farms are connected to the same wind power receiving and collecting station through different transmission lines (single circuit, primary section), and the transmission line of this collecting station is double circuit (secondary section). Suppose the capacity of all three wind power transmission lines (primary section) is increased by 10% for a short time, but there is no capacity increase condition on the secondary section of the transmission line from the collecting station. At this time, the current-carrying capacity must be dynamically adjusted according to the N-1 principle on the secondary section to ensure the safe operation of other connecting lines.

[0163] Step 6: During the dispatching operation of the wind power transmission line, when it is monitored and simulated by the digital twin model that the temperature and sag of the transmission line exceed the limit, the current-carrying capacity of the wind power transmission line is reduced.

[0164] In specific implementation, after the dispatching department increases the current-carrying capacity, the operation state of the wind power transmission line is dynamically monitored and simulated through the digital twin model of the transmission line.

[0165] Because after the actual transmission capacity (current) of the wire increases, first, the operating temperature of the wire will increase. Therefore, the first prerequisite for dynamic capacity increase is to keep the wire temperature not exceeding the highest allowable temperature of 70°C designed for the line during operation;

[0166] Second, the increase in wire temperature will lead to an increase in the sag of the wire, reducing the crossing distance between the wire and the crossing object.

[0167] Therefore, at this time, the key is to focus on whether the wire temperature or sag monitored by the on-line monitoring sensor exceeds the limit. If it exceeds the limit, the line state assessment level is reduced, and the dispatching department appropriately reduces the current-carrying capacity and continues the operation monitoring; if it does not exceed the limit, the current capacity increase operation state can be continued.

[0168] The digital twin evaluation system for dynamic capacity increase of wind power transmission lines of the present invention is used to implement the digital twin evaluation method for dynamic capacity increase of wind power transmission lines described above.

[0169] The beneficial effects of the present invention are as follows compared with the prior art:

[0170] (1) Since both the load of the wind farm unit and the transmission capacity of the transmission line are positively correlated with the wind speed, therefore, by using the method of the present invention, when the predicted wind power of the wind farm increases, it is more conducive to realizing the dynamic capacity increase of the wind power transmission line, solving the "bottleneck" problem of the capacity of the wind power transmission line, and helping to improve the level of new energy consumption;

[0171] (2) The digital twin model of the transmission line of the present invention superimposes and displays rich transmission line state perception data on the 3D model, realizes data linkage between the instant state of the conductor and 3D modeling, dynamically evaluates the operation safety of the line and the corridor, realizes the visual display of the conductor state and the simulation of the operation state, which is more intuitive. The operation safety of the conductor can be judged through real-time monitoring data, meeting the requirements of national standards and having higher safety;

[0172] (3) The present invention conducts graded scheduling for line capacity increase according to the boundary of the capacity increase expected target. When safety indicators exceed the limit, the load can be timely reduced or even quickly restored to the normal operation state, and the operability of the scheduling control is stronger;

[0173] (4) The present invention also provides a method for verifying the safety of power transmission and transformation equipment. Before actually carrying out dynamic capacity increase, the safety of power transmission and transformation equipment is verified to ensure the safe, stable and efficient operation of the entire power transmission project;

[0174] (5) When the region encounters extreme meteorological disasters such as rain, snow and ice, the present invention can conduct reliability analysis on the regional power grid by comprehensively considering the equipment reliability and system reliability and provide decision-making suggestions, with closer source-network coupling.

[0175] The applicant of the present invention has made a detailed description and illustration of the embodiments of the present invention in combination with the accompanying drawings of the specification. However, those skilled in the art should understand that the above embodiments are only the preferred implementation schemes of the present invention. The detailed description is only to help readers better understand the spirit of the present invention, rather than a limitation on the protection scope of the present invention. On the contrary, any improvement or modification made based on the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. Digital Twin Evaluation Method for Dynamic Capacity Increase of Wind Power Transmission Lines Characterized in that: The method includes the following steps: Step 1: Establish a digital twin model of the wind power transmission line to realize line status monitoring and operation status simulation; Step 2: Verify the safety of the transmission line and the interval substation equipment on both sides according to the target capacity increase and the target transmission current; Step 3: Determine the capacity increase scheduling interval and the load current increase gear for the wind power transmission line. The determination method is as follows: When the target transmission capacity of the security verification link is adopted and the boundary of the capacity increase purpose is clear, the expected capacity increase target I is used exp to determine the capacity increase scheduling interval [I e , I exp and the capacity increase ratio, as well as the gear for increasing the current-carrying capacity for scheduling; Alternatively, instead of using the target transmission capacity in the security verification process, the ampacity boundary I of the wire is calculated by taking the preset maximum wire temperature, the measured wire temperature, the micro-meteorological parameters, the wire current, and the wire sag as fixed boundary conditions. max , thereby determining the capacity increase scheduling range as [I e , I max and the load current increase gear for scheduling, and determining the capacity increase ratio through I max and I e ; where I e is the maximum load current of the line. Step 4: When it is monitored by the digital twin model that the wind power transmission line channel area is affected by extreme weather, determine the operation and maintenance method by comprehensively considering equipment reliability and grid reliability; Step 5: When it is monitored by the digital twin model that the wind power prediction and micro-meteorology meet the capacity increase conditions, the wind power transmission line enters the capacity increase scheduling operation state, and the line load current is increased according to the gear; Step 6: During the scheduling operation of the wind power transmission line, when it is monitored and simulated by the digital twin model that the temperature and sag of the transmission line exceed the limit, lower the load current of the wind power transmission line.

2. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 1 Characterized in that: In step 1, a digital twin model of the wind power transmission line is established by integrating BIM and 3D laser scanning technology, which specifically includes: Step 1.1: Construct a tower structure model through BIM data; Step 1.2: Construct a conductor and channel model through 3D laser scanning; Step 1.3: Integrate the tower structure model with the conductor and channel model; Step 1.4: Superimpose the transmission line status perception data on the basis of the integrated model, and perform data linkage between the line instant status and the model to dynamically evaluate the operation safety of the line and the channel, that is, form a digital twin model of the wind power transmission line to realize line status monitoring, visual display and operation status simulation.

3. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 2 Characterized in that: Step 1.2 is specifically: after the installation of the line equipment and facilities is completed, by carrying a lidar device on a drone, directly collect the 3D laser point cloud of the line corridor, and then obtain the 3D line corridor terrain, landform, structures and the spatial information of the line facilities and equipment to construct a conductor and channel model; The spatial information includes tower height and coordinates, span, defect location, crossing angle, hanging point location, conductor sag.

4. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 2 Characterized in that: In step 1.4, wind power prediction data is also accessed in the digital twin model of the transmission line for the use of the dispatching department; The wind power prediction refers to calculating the output power of the wind farm by physical methods according to the data of numerical weather prediction.

5. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 2 Characterized in that: The realization of line status monitoring in step 1.4 specifically includes: 1) Online monitoring of the sag of the transmission line: The monitoring method includes at least one of laser ranging, Beidou differential positioning, and binocular vision distance measurement methods; Among them, the laser ranging and Beidou differential positioning method installs sensors at the lowest point of the sag of the wire to monitor in real time the parameter of the vertical distance from the lowest point of the sag to the ground; the binocular visual range method installs sensors on the tower to measure the sag of the wire within the visual range based on binocular vision; the data is superimposed on the fusion model to realize the online monitoring of the sag of the transmission line; 2) Micro-meteorological monitoring of the transmission line: The monitoring method is as follows: Install the micro-meteorological monitoring device on the tower and on the wire at the same time. The monitoring device on the tower collects the environmental temperature, humidity, air pressure, wind speed, wind direction, and rainfall parameters of the tower, and the monitoring device on the wire collects the environmental temperature, solar radiation intensity, and wind speed parameters of the wire; the data is superimposed on the fusion model to realize the micro-meteorological monitoring of the transmission line; 3) Comprehensive status monitoring of the transmission line: The monitoring method is as follows: Install the comprehensive status monitoring device on the wire, collect the temperature, current, environmental temperature, solar radiation intensity, and wind speed of the wire, and calculate the load-carrying capacity of the wire. The data is superimposed on the fusion model to realize the comprehensive status monitoring of the transmission line.

6. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 5, characterized in that: In step 1.4, the transmission line status perception data is obtained in the following way to realize line status monitoring: Install the tower body and environmental monitoring device on the tower to achieve full-dimensional three-dimensional monitoring of the tower bolts, insulators, pins, and conductors of the tower body, timely discover the defects of the tower body, and at the same time realize the micro-meteorological monitoring record around the tower, including temperature, humidity, air pressure, wind speed, wind direction, and rainfall status; Install an inclination monitoring sensor on the tower to automatically collect the longitudinal and transverse inclination angles of the tower and monitor the inclination of the tower in real time; Install a night vision card camera monitoring device on the tower to observe the external insulation of the line at night and give an early warning when abnormalities occur; Install a tension sensor on the tower to monitor and perceive the galloping of the line; Install a bolt tightening monitoring sensor on the tower to monitor the bolt tightening force at the key nodes of the tower body; Install a binocular video ranging device on the tower to realize the reproduction of the terrain and landform scene within the visual range, the calculation and early warning of the sag of the wire by reconstructing the three-dimensional point cloud of the line channel; Install a temperature sensor at the key connection points of the strain tower to monitor the connection temperature of the strain clamp in real time and locate the hidden danger of overheating; Install a comprehensive status monitoring device on the wire to collect the temperature, current, environmental temperature, solar radiation intensity, and wind speed of the wire, and calculate the load-carrying capacity of the wire; Install an abnormal status monitoring device on the wire to locate, identify and give an early warning of insulator deterioration, floating discharge of fittings, and pollution, and find the line fault point; Install an intelligent spacer device on the wire to monitor the galloping and ground clearance of the line in real time; Install a sag monitoring device on the wire to monitor in real time the parameter of the vertical distance from the lowest point of the sag to the ground at the key positions with large spans, across rivers, and low sag points.

7. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 1, characterized in that: In step 2, the safety of the transmission line is verified according to the target capacity increase, and the safety of the interval substation equipment on both sides of the transmission line is verified according to the target transmission current. When both verifications are passed, step 3 is entered; The verification of the safety of the transmission line specifically includes: Step A1: Determine the ratio of the capacity exceeding the line transmission capacity through the target transmission capacity and the maximum installed wind power capacity, and determine the sag intersection and span check gears; Step A2: Collect and analyze the wind speed-power data of the wind turbines, and determine the corresponding wind speeds of different types of turbines at different powers according to the relationship between the single-unit capacity and the power curve of the turbines in the wind farm; Step A3: Collect and analyze the typical meteorological data of the wind farm, and combine the historical broadcast data provided by the meteorological bureau and the measured monitoring meteorological data in the wind farm to statistically analyze the average wind speed, ambient temperature, and sunshine intensity of each month in the past 2-3 years in the farm; Step A4: Analyze the conductor temperature-sag check data, calculate the conductor temperature respectively with the current, wind speed, ambient temperature, and sunshine intensity corresponding to each gear of the sag intersection and span check, and conduct the sag intersection and span check; Step A5: Obtain the conclusion of the line safety verification: When conducting the intersection and span check of each gear of the line, if the crossing distances between the conductor and the ground, power lines, trees, and structures all meet the requirements of GB 50545-2010, it means that after positioning and checking the sag according to the operating conditions and environmental conditions of the line, the conductor can at least safely increase the transmission capacity by the ratio of the target transmission capacity exceeding the line transmission capacity, realizing 100% output of the load of all wind turbines and avoiding wind curtailment; if it cannot meet the requirements of GB 50545-2010 due to the influence of trees, the trees can be cut down to meet the requirements. If it cannot meet the requirements of GB 50545-2010 due to the influence of other factors, the target transmission capacity should be reduced and the safety verification should be carried out again.

8. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 7, characterized in that: The verification of the safety of the interval substation equipment on both sides of the transmission line specifically includes: Step B1: Verify the rated current of the circuit breakers on both sides of the interval through the target transmission current; Step B2: Verify the rated current of the disconnectors on both sides of the interval through the target transmission current; Step B3: Verify the protection, measurement, and metering transformation ratios of the current transformers on both sides of the interval through the target transmission current; Step B4: According to the verification results of steps B1 - B3, adjust the circuit breakers, disconnectors, or current transformers that fail the verification, that is, replace or transform the equipment. After the equipment is replaced or transformed, the dispatching department should finally verify the protection setting values of this line to complete the safety verification of the substation equipment.

9. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 1, characterized in that: In step 4, the digital twin model is used to monitor whether the area of the wind power transmission line corridor is affected by extreme weather. Receiving an extreme weather forecast and warning is regarded as being affected. At this time, the operation and maintenance method is determined by comprehensively considering the equipment reliability and grid reliability, providing a decision for equipment management and dispatching operation. At the same time, if it is monitored that the area is affected by cold wave weather, an icing state warning is issued for the wind turbines and transmission lines; If not affected, proceed to step 5.

10. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 9, characterized in that: In step 4, determining the operation and maintenance method by comprehensively considering the equipment reliability and grid reliability, and providing a decision for equipment management and dispatching operation, specifically: When the area of the wind power transmission line corridor is affected by extreme weather, taking the current wind farm, wind power transmission line, and wind power receiving and collecting station as the equipment subset affected by the weather, mainly considering the strongly related station-line equipment, introducing the associated station-line and power source points, removing the weakly related station-line equipment, reconstructing the power grid fault set, realizing the data interaction from equipment reliability analysis to power grid reliability analysis, and based on this, conducting static and dynamic security and stability analysis of the power grid to determine the operation and maintenance method and provide a decision for equipment management and dispatching operation.

11. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 1, characterized in that: In step 5, the module monitors whether the wind power prediction and micro-meteorology meet the capacity increase conditions. If not, the wind power transmission line is scheduled to operate in the normal state; if so, the wind power transmission line enters the capacity increase scheduling operation state, and the line current-carrying capacity is increased in accordance with the gear. Specifically: If it is judged through wind power prediction and micro-meteorology monitoring that the wind speed is higher than the set value but does not exceed the operating conditions of the wind turbines, it means that the wind speed meets the condition for increasing the current-carrying capacity of the wind power transmission line. Then the wind power transmission line enters the capacity increase scheduling operation state. Considering the wind power coincidence rate, the dispatching department respectively increases the first-level section, that is, the current-carrying capacity of the wind power transmission line, according to the transmission line status and unit load of each wind farm. At the same time, in the second-level section, that is, the transmission lines of the wind power receiving and collecting substation, the second-level section current-carrying capacity is dynamically adjusted according to the N-1 principle.

12. The digital twin evaluation method for dynamic capacity increase of wind power transmission lines according to claim 1, characterized in that: In step 6, during the dispatching operation of the wind power transmission line, the operation state of the wind power transmission line is dynamically monitored and simulated through the digital twin model of the transmission line. It is judged whether the temperature and sag of the transmission line exceed the limit. If they exceed the limit, the current-carrying capacity of the wind power transmission line is reduced, and step 5 is returned; if they do not exceed the limit, the current capacity increase operation state is maintained, and step 5 is returned.

13. A digital twin evaluation system for dynamic capacity increase of wind power transmission lines, characterized in that: The system is used to implement the digital twin evaluation method for dynamic capacity increase of wind power transmission lines described in any one of claims 1-12.

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