阅读说明：本技术 一种基于高程数据覆冰预测模型的建立方法 (Method for establishing icing prediction model based on elevation data ) 是由 谭伟 曹双和 王雅竹 李扬松 陈浩 李芳芳 贺瑶 汤旻 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种基于高程数据覆冰预测模型的建立方法,包括以下步骤：S01、进行覆冰相似性分区；S02、利用覆冰基础数据与覆冰影响因子进行回归分析并建模,对于数据不足的重现期,通过与邻近重现期覆冰数据作相关性分析,确定转换系数,进行覆冰数据的补充。以解决现有技术覆冰影响因子复杂和实测覆冰数据缺乏地区获取不同重现期的覆冰厚度非常困难的问题。(The invention discloses a method for establishing an icing prediction model based on elevation data, which comprises the following steps of: s01, carrying out icing similarity partitioning; and S02, carrying out regression analysis and modeling by using the icing basic data and the icing influence factors, and determining a conversion coefficient for the ice coating data supplementation by carrying out correlation analysis on the ice coating data in the adjacent reappearance period in the reappearance period with insufficient data. The method solves the problems that icing influence factors are complex and icing thicknesses in different reappearance periods are difficult to obtain in areas where actual measurement icing data is insufficient in the prior art.)

1. A method for establishing an icing prediction model based on elevation data is characterized by comprising the following steps:

s01, carrying out icing similarity partitioning;

and S02, carrying out regression analysis and modeling by using the icing basic data and the icing influence factors, and determining a conversion coefficient for the ice coating data supplementation by carrying out correlation analysis on the ice coating data in the adjacent reappearance period in the reappearance period with insufficient data.

2. The method for building an icing prediction model based on elevation data of claim 1, wherein the method is characterized in that

The icing influencing factors are: elevation of altitude.

3. The method for building an icing prediction model based on elevation data according to claim 1, wherein the method for partitioning the icing similarity in step S01 comprises:

analyzing the icing similarity before modeling, and analyzing according to the climate characteristic, the terrain characteristic, the icing property and the icing process to obtain an initial partition;

and (4) performing icing similarity analysis during modeling, and correcting the initial partition according to the accuracy of the model result and the difference of the boundaries of adjacent regions to obtain a final partition.

4. The method for building the icing prediction model based on the elevation data according to claim 3, wherein the icing similarity partition method during modeling further follows the following principle: the principle of ice coating property similarity, the principle of terrain similarity, the principle of ice coating process similarity and the principle of ice coating similarity partition and modeling are carried out simultaneously.

5. The method for building the icing prediction model based on the elevation data according to claim 4, wherein the icing property similarity principle is as follows: in an icing similar area, the icing properties are consistent;

the terrain similarity principle is as follows: the whole altitude and elevation are the same, the landform is the same and an obvious regional boundary exists.

6. The method for building the icing prediction model based on the elevation data according to claim 4, wherein the modeling step of the step S02 is as follows:

firstly, screening out icing and elevation data of each subarea as basic data for modeling,

secondly, carrying out regression analysis on the icing basic data through SPSS data statistical software, and primarily fitting an icing height calculation model with the best correlation between icing thickness and elevation;

thirdly, calculating the icing thickness of the boundary area of the adjacent subareas through the initial subarea icing height calculation model, performing difference analysis on the icing thickness of the boundary area, and if the icing thicknesses are consistent or similar, enabling the icing height calculation model of the adjacent subareas to be available; if the difference of the icing thicknesses is obvious, the adjacent partitions are unreasonably divided, the adjacent partitions are required to be adjusted, the icing thickness of the boundary area is calculated by fitting a new icing height calculation model through SPSS software, and the partitioning and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and finally obtaining the icing height calculation model corresponding to each partition by a method of modeling and correcting.

7. The method for building the icing prediction model based on the elevation data according to claim 6, wherein the second step is specifically as follows: the method comprises the steps of selecting linear, logarithmic, reciprocal, quadratic, cubic, composite, power, S, growth, exponential and Logistic functions through SPSS data statistical software to conduct regression fitting analysis on icing basic data, selecting the function with the best fitting goodness and significance test effect as an icing height calculation model, and taking the function with the high fitting goodness as a selection principle when the fitting goodness and the significance test effect are different.

8. The method for building an icing prediction model based on elevation data according to claim 6, wherein the difference analysis in the third step is as follows:

when the thickness of the ice coating at the junction of the adjacent subareas is different between the light ice area and the middle ice area, firstly analyzing the terrain conditions of the terrain at the junction, and if the terrain conditions are different, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are the same, the subareas are adjusted, and the icing thickness is calculated by using the icing height calculation model of the subarea corresponding to the middle ice area until the icing thickness is calculated to be fitted with the light ice area;

when the thickness of the ice coating at the junction of the adjacent subareas is the difference between a light ice area/a middle ice area and a heavy ice area, firstly analyzing the terrain conditions of the junction if the difference between the ice areas is within 10mm, and if the terrain conditions are suddenly changed, not adjusting each subarea, and enabling an ice coating height calculation model to be available; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be re-partitioned, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent;

the thickness of the ice coating at the junction of the adjacent subareas is the difference between the heavy ice area and the heavy ice area, if the difference between the ice areas is within 10mm, the terrain and topography conditions of the junction are firstly analyzed, if the terrain conditions are suddenly changed, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be subjected to partition adjustment, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent.

Technical Field

The invention relates to a method for establishing an icing prediction model based on elevation data, and belongs to the technical field of ice thickness prediction.

Background

In the Guizhou province, in the cloud and precious plateau east slope region where the cold and hot air flows are intersected mutually in winter, the terrain is complex, the climate is variable, ice coating is easily formed under the interaction of the cloud and precious quasi-static front and the complex terrain environment, electric ice coating disaster accidents of different degrees occur in each year in the province, and the province is one of the most serious provinces of national ice coating along with the characteristics of long time, great harm and the like. Icing disasters seriously affect industrial and agricultural production and normal life of people, and Guizhou province is an important channel for 'West electric and east delivery' in western major development, and the transmission lines are various, so that the icing hazard degree is at the top of the whole country. In order to guarantee the normal operation of the power transmission line in winter, the capacity of coping with icing disasters is greatly improved.

The actual measurement icing data in Guizhou area is lack, the icing influence factor is complex, and the accurate and rapid acquisition of the icing thickness of a certain area in different reappearance periods is very difficult. Aiming at the problem, the invention provides a method for rapidly acquiring the icing thicknesses of different reappearance periods of a certain area specially aiming at the areas with complex icing influence factors and insufficient actually-measured icing data.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for establishing the icing prediction model based on the elevation data is provided to overcome the defects of the prior art.

The technical scheme of the invention is as follows: a method for establishing an icing prediction model based on elevation data comprises the following steps:

s01, carrying out icing similarity partitioning;

and S02, carrying out regression analysis and modeling by using the icing basic data and the icing influence factors, and determining a conversion coefficient for the ice coating data supplementation by carrying out correlation analysis on the ice coating data in the adjacent reappearance period in the reappearance period with insufficient data.

Further, the icing influencing factor is: elevation of altitude.

Further, the method for ice coating similarity partition in step S01 includes:

analyzing the icing similarity before modeling, and analyzing according to the climate characteristic, the terrain characteristic, the icing property and the icing process to obtain an initial partition;

and (4) performing icing similarity analysis during modeling, and correcting the initial partition according to the accuracy of the model result and the difference of the boundaries of adjacent regions to obtain a final partition.

Further, the ice coating similarity partitioning method in modeling also follows the following principle: the principle of ice coating property similarity, the principle of terrain similarity, the principle of ice coating process similarity and the principle of ice coating similarity partition and modeling are carried out simultaneously.

Further, the principle of similar icing properties is as follows: in an icing similar area, the icing properties are consistent;

the terrain similarity principle is as follows: the whole altitude and elevation are the same, the landform is the same and an obvious regional boundary exists.

Further, the modeling step of step S02 is as follows:

firstly, screening out icing and elevation data of each subarea as basic data for modeling,

secondly, carrying out regression analysis on the icing basic data through SPSS data statistical software, and primarily fitting an icing height calculation model with the best correlation between icing thickness and elevation;

thirdly, calculating the icing thickness of the boundary area of the adjacent subareas through the initial subarea icing height calculation model, performing difference analysis on the icing thickness of the boundary area, and if the icing thicknesses are consistent or similar, enabling the icing height calculation model of the adjacent subareas to be available; if the difference of the icing thicknesses is obvious, the adjacent partitions are unreasonably divided, the adjacent partitions are required to be adjusted, the icing thickness of the boundary area is calculated by fitting a new icing height calculation model through SPSS software, and the partitioning and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and finally obtaining the icing height calculation model corresponding to each partition by a method of modeling and correcting.

Further, the second step specifically comprises: the method comprises the steps of selecting linear, logarithmic, reciprocal, quadratic, cubic, composite, power, S, growth, exponential and Logistic functions through SPSS data statistical software to conduct regression fitting analysis on icing basic data, selecting the function with the best fitting goodness and significance test effect as an icing height calculation model, and taking the function with the high fitting goodness as a selection principle when the fitting goodness and the significance test effect are different.

Further, the method for differential analysis in the third step is as follows:

when the thickness of the ice coating at the junction of the adjacent subareas is different between the light ice area and the middle ice area, firstly analyzing the terrain conditions of the terrain at the junction, and if the terrain conditions are different, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are the same, the subareas are adjusted, and the icing thickness is calculated by using the icing height calculation model of the subarea corresponding to the middle ice area until the icing thickness is calculated to be fitted with the light ice area;

when the thickness of the ice coating at the junction of the adjacent subareas is the difference between a light ice area/a middle ice area and a heavy ice area, firstly analyzing the terrain conditions of the junction if the difference between the ice areas is within 10mm, and if the terrain conditions are suddenly changed, not adjusting each subarea, and enabling an ice coating height calculation model to be available; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be re-partitioned, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent;

the thickness of the ice coating at the junction of the adjacent subareas is the difference between the heavy ice area and the heavy ice area, if the difference between the ice areas is within 10mm, the terrain and topography conditions of the junction are firstly analyzed, if the terrain conditions are suddenly changed, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be subjected to partition adjustment, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent.

The invention has the beneficial effects that:

according to the method, the icing similarity partition is firstly carried out, so that the icing rule of each partition is consistent, modeling is convenient for the partitions with the same icing property, and for the reappearance period with insufficient data, the conversion coefficient is determined by carrying out correlation analysis on the icing data in the adjacent reappearance period, so that the icing data is supplemented, and therefore the icing influence factor is complex and the icing thickness of a certain area in the area with insufficient actually-measured icing data can be rapidly obtained.

Drawings

FIG. 1 is a comparison inspection diagram of 30-year-one-time ice thickness of the meteorological station restoration and reconstruction and 30-year-one-time ice thickness calculated by a model;

FIG. 2 is a comparison inspection chart of 50-year-one-time ice thickness of the meteorological station restoration and reconstruction and 50-year-one-time ice thickness calculated by a model;

FIG. 3 is a comparison test of the ice thickness of the meteorological station for recovery and reconstruction in 100 years and the ice thickness of the meteorological station for model calculation in 100 years;

FIG. 4 is a flow chart of the ice coating height calculation model modeling of the present invention.

Detailed Description

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, and furthermore, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

According to the method for establishing the icing prediction model based on the elevation data, the problems that icing influence factors are complex and icing thicknesses of different reappearance periods are difficult to obtain in areas where the actually measured icing data is deficient in the prior art are solved, and the method for quickly obtaining the icing thicknesses of different reappearance periods of a certain area in areas where the icing influence factors are complex and the actually measured icing data is deficient is achieved.

In order to solve the problems that icing influence factors are complex and icing thicknesses in different reappearance periods are difficult to obtain in areas where actually measured icing data is deficient, the technical scheme in the embodiment of the application has the following general idea:

according to the method, the icing similarity partition is firstly carried out, so that the icing rule of each partition is consistent, modeling is convenient for the partitions with the same icing property, and for the reappearance period with insufficient data, the conversion coefficient is determined by carrying out correlation analysis on the icing data in the adjacent reappearance period, so that the icing data is supplemented, and therefore the icing influence factor is complex and the icing thickness of a certain area in the area with insufficient actually-measured icing data can be rapidly obtained.

In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the detailed description.

Example 1 was carried out: referring to fig. 4, a method for building an icing prediction model based on elevation data includes the following steps:

s01, carrying out icing similarity partitioning;

and S02, carrying out regression analysis and modeling by using the icing basic data and the icing influence factors, and determining a conversion coefficient for the ice coating data supplementation by carrying out correlation analysis on the ice coating data in the adjacent reappearance period in the reappearance period with insufficient data.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

the icing influence factor is complex, and the icing thickness of a certain area in an area with insufficient actually measured icing data can be quickly acquired.

Example 2, the icing effect factor is: elevation of altitude.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

elevation facilitates quantitative modeling.

Embodiment 3, referring to fig. 4, the method of ice coating similarity partition in step S01 includes:

analyzing the icing similarity before modeling, and analyzing according to the climate characteristic, the terrain characteristic, the icing property and the icing process to obtain an initial partition;

and (4) performing icing similarity analysis during modeling, and correcting the initial partition according to the accuracy of the model result and the difference of the boundaries of adjacent regions to obtain a final partition.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

and gradually correcting the partitions to enable the similarity partitions to be more accurate.

Example 4, the ice coating similarity partitioning method at modeling also follows the following principle: the principle of ice coating property similarity, the principle of terrain similarity, the principle of ice coating process similarity and the principle of ice coating similarity partition and modeling are carried out simultaneously.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

the similarity partition in modeling is more accurate, and the speed of obtaining the final similarity partition is higher.

Example 5, the ice coating properties are similar as follows: in an icing similar area, the icing properties are consistent; the terrain similarity principle is as follows: the whole altitude and elevation are the same, the landform is the same and an obvious regional boundary exists.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

the accuracy of the similarity partition in modeling is further improved, and the speed of obtaining the final similarity partition is higher.

Example 5, referring to fig. 4, the modeling step of step S02 is as follows:

firstly, screening out icing and elevation data of each subarea as basic data for modeling,

secondly, carrying out regression analysis on the icing basic data through SPSS data statistical software, and primarily fitting an icing height calculation model with the best correlation between icing thickness and elevation;

thirdly, calculating the icing thickness of the boundary area of the adjacent subareas through the initial subarea icing height calculation model, performing difference analysis on the icing thickness of the boundary area, and if the icing thicknesses are consistent or similar, enabling the icing height calculation model of the adjacent subareas to be available; if the difference of the icing thicknesses is obvious, the adjacent partitions are unreasonably divided, the adjacent partitions are required to be adjusted, the icing thickness of the boundary area is calculated by fitting a new icing height calculation model through SPSS software, and the partitioning and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and finally obtaining the icing height calculation model corresponding to each partition by a method of modeling and correcting.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

the method comprises the steps of respectively modeling each subarea through icing data and elevation data, calculating the icing thickness of a boundary area of adjacent subareas according to an initial subarea icing height calculation model, and then correcting the model through difference analysis to obtain a final model, so that the accuracy of an icing height calculation model and the accuracy of similarity subareas are improved.

Example 6, the second step was specifically: the method comprises the steps of selecting linear, logarithmic, reciprocal, quadratic, cubic, composite, power, S, growth, exponential and Logistic functions through SPSS data statistical software to conduct regression fitting analysis on icing basic data, selecting the function with the best fitting goodness and significance test effect as an icing height calculation model, and taking the function with the high fitting goodness as a selection principle when the fitting goodness and the significance test effect are different.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

and fitting through a plurality of functions, and selecting the function with the best fitting goodness and significance test effect as an icing height calculation model, so that the model is more accurate.

Example 7, with reference to fig. 4, the method for differential analysis in the third step was:

when the thickness of the ice coating at the junction of the adjacent subareas is different between the light ice area and the middle ice area, firstly analyzing the terrain conditions of the terrain at the junction, and if the terrain conditions are different, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are the same, the subareas are adjusted, and the icing thickness is calculated by using the icing height calculation model of the subarea corresponding to the middle ice area until the icing thickness is calculated to be fitted with the light ice area;

when the thickness of the ice coating at the junction of the adjacent subareas is the difference between a light ice area/a middle ice area and a heavy ice area, firstly analyzing the terrain conditions of the junction if the difference between the ice areas is within 10mm, and if the terrain conditions are suddenly changed, not adjusting each subarea, and enabling an ice coating height calculation model to be available; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be re-partitioned, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent;

the thickness of the ice coating at the junction of the adjacent subareas is the difference between the heavy ice area and the heavy ice area, if the difference between the ice areas is within 10mm, the terrain and topography conditions of the junction are firstly analyzed, if the terrain conditions are suddenly changed, each subarea does not need to be adjusted, and an ice coating height calculation model can be used; if the terrain conditions are not changed, the adjacent subareas are unreasonably divided, the adjacent areas need to be partitioned again, a new icing height calculation model is fitted to calculate the icing thickness of the boundary area, and the subarea and modeling steps are repeated until the icing magnitude of the boundary area is consistent; and if the difference of the ice regions is more than 10mm, the adjacent regions are unreasonably divided, the adjacent regions need to be subjected to partition adjustment, a new ice coating height calculation model is fitted to calculate the ice coating thickness of the boundary region, and the partitioning and modeling steps are repeated until the ice coating magnitude of the boundary region is consistent.

The technical scheme in the embodiment of the application at least has the following technical effects or advantages:

and correcting the similarity partition to enable the similarity partition to be more accurate.

In order to check the accuracy of the ice coating height calculation model obtained by the present invention, the applicant conducted tests from several points,

1. comparison inspection for ice thickness recovery of meteorological station

The weather station ice thickness recovery method includes the steps of firstly, calculating the maximum ice thickness formed in a continuous ice coating process through relevant ice coating weather factors such as temperature, humidity and wind speed by using a new K.J model added into a rime mechanism, screening the maximum ice thickness in the recovery year, and performing Pearson III type frequency analysis and calculation to obtain the recovery ice thickness of the weather station under different frequencies. And calculating theoretical ice thickness of each recurrence period through the obtained recovered ice thickness of the meteorological station in different recurrence periods and an ice coating height calculation model, and performing comparison and inspection.

The method randomly selects the ice thickness of 30a, 50a and 100a which are recovered and rebuilt in 11 weather stations such as Guizhou Chapter, Reishan and the like, and the calculation theoretical ice thickness of the ice coating height calculation model result for comparative analysis, and further verifies the scientificity and reliability of the project modeling method by checking the accuracy of the calculation theoretical ice thickness of the ice coating height calculation model. And (3) comparing the reconstructed ice thickness of 30a, 50a and 100a at once with the theoretical ice thickness of the calculation model result of the ice coating height of 30a, 50a and 100a at once, which is restored by each meteorological station, as shown in figures 1-3.

The ordinate in fig. 1-3 is the ice coating thickness (converted to standard ice thickness in mm) and the abscissa is the elevation (in m) corresponding to the observation field at each meteorological site. Through the comparison and inspection, the theoretically calculated ice thickness of 30a, 50a and 100a meeting calculated by the ice coating height calculation model and the corresponding ice thickness restored and reconstructed by most of weather stations are in the same ice coating magnitude, the difference value of the theoretically calculated ice thickness of the model and the reconstructed ice thickness of Zhaotong weather stations and Guiyang weather stations is only more than one ice coating magnitude, the accuracy of the ice thickness comparison and inspection is 81.8%, and the inspection effect of the overall model is good. Further analysis, comparison and inspection show that the theoretical calculated ice thickness of each station and the weather station restored and reconstructed ice thickness have certain difference, the difference of the Zhaotong weather station and the Guiyang weather station is most obvious, and the model theoretical calculated ice thickness is basically lower than the weather station restored and reconstructed ice thickness (except for Bijie); the reason is that the formation of the ice coating is a comprehensive complex physical process of meteorological science, hydrodynamics, thermodynamics and the like, influence factors are complex and easy to change, the altitude selected in the research is only one of important influence factors, although ice coating similarity partitioning is performed on each province, the interference of the ice coating influence factors except the altitude in the modeling process is greatly reduced, the influence of complex terrain and climate cannot be completely eliminated, particularly, the ice coating thickness is extremely easy to suddenly increase or reduce in micro-terrain microclimate areas (such as cold air channels, windward slopes and the like), and therefore the ice coating thickness calculation model established by the altitude cannot accurately calculate the ice coating thickness of all elevation points in one area.

In conclusion, in the ice coating similarity subarea, the ice coating height calculation models related to the ice thickness and the altitude at different reappearance periods are obtained through regression modeling, and the theoretical ice thickness at different altitudes can be calculated; the reconstructed ice thickness is recovered by selecting a weather station and is compared and checked with the calculated theoretical ice thickness of the ice coating height calculation model, the calculated theoretical ice thickness is different from the actual ice thickness to a certain extent, but is accurate and reliable in ice coating magnitude, and meanwhile, the modeling method of the ice coating height calculation model by the project is scientific and reasonable.

2. Inspection of designed ice region of established power transmission line

Because the relief of the topography along the power transmission line is large, the climate conditions have certain difference, and the influence of the microclimate microtopography is large, the ice region division of the power transmission line needs to be treated differently aiming at different terrains and climate characteristics, and meanwhile, the data and the data of the path region are fully utilized as the division basis; the method comprises the steps of fully utilizing information such as plant types and distribution, topographic features, plant icing traces and the like in a path area, fully considering the mutual relation between water vapor source distribution, climate features, wind speed and direction and the terrain, reasonably analyzing and utilizing regional icing investigation data and ice and snow disaster analysis data, and finally performing ice region division by adopting methods such as comprehensive analysis, classification, analogy and the like. In order to reduce the interference of icing influence factors outside the altitude of the icing height calculation model in the modeling process, the final result of the icing similar area is obtained by modeling and correcting based on external conditions such as climate, terrain, icing characteristics and the like, so that the correlation between the altitude and the ice thickness is increased, and the icing height calculation model with the best fitting effect is obtained. Therefore, in order to verify the practicability of the ice coating height calculation model, the designed ice area of the built power transmission line and the theoretical ice area along the line calculated by the ice coating height calculation model are used for comparison and inspection.

The +/-500 kV stream-wide line direct current transmission line is selected as a detection line, the line passes through Guizhou in a southern power grid region along the line, the topographic relief of the line is large, the climate condition is complex, and the method has certain representativeness. As the recurrence period of the designed ice region of the +/-500 kV stream-wide direct current transmission line is fifty years, the calculated recurrence period of the ice coating height calculation model is also fifty years, and the ice region magnitude for calculating the theoretical ice thickness is determined according to the grading merging standard of the designed ice region in the transmission line ice coating survey regulation (DL/T5509-2015) and is shown in Table 1.

TABLE 1 design ice zone grading merge criteria

Serial number	Design ice thickness B (mm)	Merging design ice zone (mm)
			1	0<B≤5	5
2	5<B≤10	10
			3	10<B≤15	15
4	15<B≤25	20
			5	25<B≤35	30
6	35<B≤45	40
			7	45<B≤55	50
8	55<B≤65	60
			9	65<B≤75	70
10	75<B≤85	80

Calculating theoretical ice thickness of 50-year-first-encounter recurrence periods of corresponding heights of sections along the +/-500 kV stream-wide direct-current transmission line by using an ice coating height calculation model, analyzing the model calculation ice sections of the sections by combining with a design ice section grading merging standard, and comparing and inspecting the design ice sections and the model calculation ice sections of the line, wherein inspection results are shown in a table 2.

TABLE 2 inspection of the designed ice zone of the established transmission line

In the comparison and inspection table of the designed ice area of the power transmission line and the model calculation ice area, the model inspection results are yes, no and basically consistent, and the various inspection results are explained as follows: the 'yes' represents that the designed ice area of the power transmission line is the same as the ice area merged by theoretical ice thickness calculated by the ice coating height calculation model, and represents that the inspection is successful; if not, the designed ice area of the power transmission line is different from the ice area merged by theoretical ice thickness calculated by the ice coating height calculation model, and the inspection fails; the 'basic consistency' represents that the designed ice region of the power transmission line is similar to the ice region merged by calculating the theoretical ice thickness by the ice coating height calculation model, namely the model calculated ice region comprises the designed ice region of the line, usually the terrain involved along the power transmission line is complex, and large relief possibly exists in a certain section, and multiple ice region magnitude levels can be involved, but in order to save cost and ensure the operation safety of the line, the fragmentary ice regions are generally merged, but the model calculates the ice thicknesses with different altitudes, and multiple ice region magnitude level achievements can be generated in the area with large relief, so that the inspection is successful if the ice region calculated by the model comprises the designed ice region of the line and does not exceed one ice region magnitude level. The three types of test results are counted according to partitions, and the statistical results are shown in Table 3.

TABLE 3 statistical results of the tests

Analysis table 3 shows that, from the overall inspection result, the success rate of the ice coating height calculation model on the overall design ice region inspection of the established +/-500 kV stream-wide direct current transmission line reaches 60%, and the model has higher practicability on the whole.

Further analyzing the test result, the difference between the calculated ice region of the ice coating height calculation model in the test failure section and the designed ice region of the power transmission line is basically one ice region magnitude (namely the difference is 5-10 mm), and 97.3% of the calculated ice regions of the model in the failure section are lower than the designed ice region of the power transmission line, which is shown in a statistical table 4. Therefore, although the ice coating height calculation model has poor practicability in a terrain complex section (particularly an area with remarkable micro-terrain microclimate influence), the ice coating height calculation model can roughly preliminarily reflect the basic ice coating condition of the section and still play a certain guiding role in dividing the ice zone of the power transmission line in the terrain complex section.

Table 4 statistical results of the tests

In conclusion, the ice coating height calculation model researched by the project has higher practicability on the whole and has important guiding significance for the design ice area division of the power transmission line. Although the practicability to the terrain complex section (particularly the area with remarkable micro-terrain microclimate influence) is not high, the basic icing condition of the terrain complex section can be roughly reflected preliminarily, and a certain guiding effect can be still played for the ice area division of the power transmission line in the terrain complex section.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.