Early warning analysis method for extreme meteorological windage yaw flashover of power transmission line

Abstract

The invention discloses an early warning analysis method for extreme meteorological windage yaw flashover of a power transmission line. The early warning analysis method comprises the following analysis steps: S1, collecting information and meteorological data of the power transmission line; s2, calculating the maximum wind deflection angle of the line suspension insulator through a rigid body straight rod model; s3, the minimum air gap is calculated according to the maximum wind deflection angle, and the line wind deflection flashover voltage under the corresponding gap condition is obtained; s4, based on the line windage yaw flashover voltage and the line operation voltage, obtaining a line windage yaw flashover probability; s5, evaluating the line windage yaw flashover risk based on the line windage yaw flashover probability, and giving an early warning; the method can accurately reflect the actual influence of a non-stationary wind field and meteorological factors on the power transmission line, gives out risk early warning, and guarantees the safe and stable operation of the power transmission line.

Description

Technical Field

[0001] This invention belongs to the field of wind-induced flashover analysis technology for power transmission lines, specifically relating to a method for early warning analysis of wind-induced flashover in extreme weather conditions for power transmission lines. Background Technology

[0002] In recent years, extreme weather events such as cold waves and strong winds in winter and severe convection in spring have occurred frequently, often accompanied by non-steady wind fields. Non-steady wind fields are characterized by sudden increases in wind speed, causing conductors to oscillate inertially under the influence of pulsating wind pressure. In addition, the conductors are covered with ice by winter rain, which can easily cause large deflections of suspension insulator strings, thereby affecting the wind deflection angle and wind force response of the line, and even inducing flashover accidents, seriously threatening the safe and stable operation of the power grid.

[0003] Due to the lack of accurate wind deflection calculation models and early warning methods, when transmission lines suffer equipment damage under conditions such as abnormal wind deflection and uneven stress on insulator strings, it not only increases the risk of power grid failure but also has a serious impact on regional power supply and socio-economic development.

[0004] Therefore, in order to solve the above problems, it is necessary to develop an early warning and analysis method for extreme weather wind deflection flashover of transmission lines. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an early warning analysis method for extreme weather wind deflection and flashover of transmission lines, which accurately reflects the actual impact of non-steady wind fields and meteorological factors on transmission lines, issues risk warnings, and ensures the safe and stable operation of transmission lines.

[0006] The objective of this invention is achieved as follows: a method for early warning analysis of flashover due to extreme weather winds in power transmission lines, comprising the following analysis steps:

[0007] S1. Collect information on power transmission lines and meteorological data;

[0008] S2. Calculate the maximum wind deflection angle of the suspension insulator string of the line using a rigid straight rod model;

[0009] S3. Calculate the minimum air gap based on the maximum wind deflection angle, and obtain the line wind deflection flashover voltage under the corresponding gap conditions;

[0010] S4. Based on the line wind-induced flashover voltage and the line operating voltage, the line wind-induced flashover probability is obtained.

[0011] S5. Assess the risk of line wind-induced flashover based on the line wind-induced flashover probability and issue an early warning.

[0012] Furthermore, the transmission line information in step S1 includes transmission line structure information and spatial coordinate information, and the meteorological data includes wind speed, wind direction, air pressure, temperature, humidity and precipitation corresponding to the location of the transmission line.

[0013] Furthermore, the formula for calculating the wind deflection angle in step S2 is expressed as follows: In the formula: , These represent the horizontal and vertical loads on the insulator string and its fittings, respectively. , These represent the horizontal and vertical loads on the conductor, respectively.

[0014] Furthermore, the horizontal and vertical loads on the insulator string and its fittings in step S2 are expressed as follows: , In the formula: This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. This represents air density, and its standard value is... , This indicates the wind speed in the vertical direction relative to the reference height. Indicates the coefficient of variation of wind pressure at height. This indicates the total wind-receiving area of ​​the insulator string and its fittings. This indicates the angle between the wind direction and the direction of the conductor or ground wire.

[0015] Further, the horizontal and vertical loads on the conductor in step S2 are expressed as follows: , In the formula: Indicates the number of split wires. This indicates the magnitude of the horizontal wind load per unit length of conductor on the line. , Indicates the horizontal span on both sides of the tower. , These represent the elevation difference angles between the line tower and its adjacent tower. Indicates the horizontal tension of the conductor. Indicates the turning point of the line. These represent the complementary angles between the transmission line and the crossarm, respectively. This represents the weight per unit length of the conductor. , This represents the height difference between adjacent towers; where the horizontal wind load per unit length of conductor is the magnitude of the line. In the formula: This represents the wind pressure non-uniformity coefficient. This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. Indicates the coefficient of variation of wind pressure at height. Indicates the shape factor of the conductor. Indicates the overall outer diameter of the conductor. This indicates the amplification factor of horizontal wind load on the conductor after icing.

[0016] Furthermore, the formula for calculating the minimum air gap in step S3 is expressed as follows: In the formula: This indicates the distance from suspension point A to the center line of the tower. Indicates the length of the insulator string. Indicates the conductor splitting radius. Indicates the wind deflection angle of the insulator string. Indicates the angle between the tower and the crossarm. This indicates the distance from the suspension point C to the center line of the tower.

[0017] Furthermore, in step S3, air density, humidity, and precipitation are used to correct the line wind-induced flashover voltage under standard operating conditions; wherein, the air density correction coefficient is expressed as: , Indicates the air density correction index. Represents relative air density. , , , These are real-time air pressure and temperature, respectively; the humidity correction factor is expressed as: , This indicates the humidity correction index. , Represents relative air density. Indicates absolute humidity. The rainfall correction coefficient was fitted using a Gaussian formula under different rainfall intensities, as follows: The corrected line wind-induced flashover voltage is then expressed as: , and Line wind-induced flashover voltage before and after correction.

[0018] Furthermore, the line wind-induced flashover probability in step S4 is expressed as: In the formula: Indicates the line operating voltage. Indicates the line wind-induced flashover voltage. This represents the standard deviation, taken as 10%. This represents a standard normal distribution.

[0019] Furthermore, in step S5, the line wind-induced flashover risk level includes safe, low risk, medium risk, and high risk; wherein, when the line wind-induced flashover probability is less than 30%, the risk level is safe; when the line wind-induced flashover probability is greater than or equal to 30% and less than 60%, the risk level is low risk; when the line wind-induced flashover probability is greater than or equal to 60% and less than 90%, the risk level is medium risk; and when the line wind-induced flashover probability is greater than or equal to 90%, the risk level is high risk.

[0020] The beneficial effects of this invention, achieved by combining meteorological data to calculate the line wind deflection angle and considering the effects of air density, humidity, and rainfall to correct the flashover voltage, are as follows: the line wind deflection flashover probability is obtained and the line wind deflection flashover risk is assessed. This enables accurate assessment of the safety status of transmission lines under complex meteorological conditions, timely issuance of safety level warnings, significantly improved power grid response efficiency to extreme weather disasters, effective protection of the safe and stable operation of the power grid, and reduction of equipment failures and power outages caused by extreme weather such as wind deflection and flashover, thereby significantly reducing maintenance and repair costs. Attached Figure Description

[0021] Figure 1 This is a flowchart of the present invention.

[0022] Figure 2 This is a schematic diagram of the tower coordinates when the insulator string is suspended in this invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0024] like Figure 1 , Figure 2 As shown, a method for early warning analysis of flashover due to extreme weather winds on transmission lines includes the following analysis steps:

[0025] S1. Collect information on power transmission lines and meteorological data; preferably, the power transmission line information in step S1 includes power transmission line structure information and spatial coordinate information, and the meteorological data includes wind speed, wind direction, air pressure, temperature, humidity and precipitation at the location of the power transmission line.

[0026] S2. Calculate the maximum wind deflection angle of the suspension insulator string of the line using a rigid straight rod model.

[0027] Preferably, the formula for calculating the wind deflection angle in step S2 is expressed as follows: In the formula: , These represent the horizontal and vertical loads on the insulator string and its fittings, respectively. , These represent the horizontal and vertical loads on the conductor, respectively.

[0028] The horizontal and vertical loads of the insulator string and its fittings are expressed as follows: , In the formula: This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. This represents air density, and its standard value is... , This indicates the wind speed in the vertical direction relative to the reference height. Indicates the coefficient of variation of wind pressure at height. This indicates the total wind-receiving area of ​​the insulator string and its fittings. This indicates the angle between the wind direction and the direction of the conductor or ground wire.

[0029] The horizontal and vertical loads on the conductor are expressed as follows: , In the formula: Indicates the number of split wires. This indicates the magnitude of the horizontal wind load per unit length of conductor on the line. , Indicates the horizontal span on both sides of the tower. , These represent the elevation difference angles between the line tower and its adjacent tower. Indicates the horizontal tension of the conductor. Indicates the turning point of the line. These represent the complementary angles between the transmission line and the crossarm, respectively. This represents the weight per unit length of the conductor. , This represents the height difference between adjacent towers; where the horizontal wind load per unit length of conductor is the magnitude of the line. In the formula: This represents the wind pressure non-uniformity coefficient. This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. Indicates the coefficient of variation of wind pressure at height. Indicates the shape factor of the conductor. Indicates the overall outer diameter of the conductor. This indicates the amplification factor of horizontal wind load on the conductor after icing.

[0030] S3. Calculate the minimum air gap based on the maximum wind deflection angle, and obtain the line wind deflection flashover voltage under the corresponding gap conditions.

[0031] Preferably, taking a goblet-shaped tower as an example, such as Figure 2 As shown, the formula for calculating the minimum air gap in step S3 is expressed as follows: In the formula: This represents the distance from suspension point A to the centerline OY of the tower. Indicates the length of the insulator string. Indicates the conductor splitting radius. Indicates the wind deflection angle of the insulator string. Indicates the angle between the tower and the crossarm. This represents the distance from the suspension point C to the center line OY of the tower.

[0032] Preferably, in step S3, air density, humidity, and precipitation are used to correct the line wind-induced flashover voltage under standard operating conditions; wherein, the air density correction coefficient is expressed as: , Indicates the air density correction index. Represents relative air density. , , , These are real-time air pressure and temperature, respectively; the humidity correction factor is expressed as: , This indicates the humidity correction index. , Represents relative air density. Indicates absolute humidity. The rainfall correction coefficient was fitted using a Gaussian formula under different rainfall intensities, as follows: The breakdown voltage of the air gap under different rainfall intensities is shown in Table 1 below, and the coefficients after fitting using the Gaussian formula are shown in Table 2 below; then the corrected line wind-induced flashover voltage is expressed as: , and Line wind-induced flashover voltage before and after correction.

[0033] Table 1. Breakdown voltage of air gaps (kV) under different rainfall intensities

[0034]

[0035] The maximum variation in Table 1 refers to the decrease in flashover voltage when the rainfall intensity is at its maximum (14.4 mm / min) compared to the flashover voltage 1 minute after the rain.

[0036] Table 2 Coefficients fitted using Gaussian formula

[0037]

[0038] S4. Based on the line wind-induced flashover voltage and the line operating voltage, the line wind-induced flashover probability is obtained.

[0039] Preferably, the line wind-induced flashover probability in step S4 is expressed as: In the formula: Indicates the line operating voltage. Indicates the line wind-induced flashover voltage. This represents the standard deviation, taken as 10%. This represents the standard normal distribution, and the formula for the standard normal distribution is: .

[0040] S5. Assess the risk of line wind-induced flashover based on the line wind-induced flashover probability and issue an early warning.

[0041] Preferably, the line wind-induced flashover risk level in step S5 includes safe, low risk, medium risk, and high risk; wherein, when the line wind-induced flashover probability is less than 30%, the risk level is safe; when the line wind-induced flashover probability is greater than or equal to 30% and less than 60%, the risk level is low risk; when the line wind-induced flashover probability is greater than or equal to 60% and less than 90%, the risk level is medium risk; and when the line wind-induced flashover probability is greater than or equal to 90%, the risk level is high risk; as shown in Table 3.

[0042] Table 3. Risk Level Assessment of Line Wind-Driven Flashover

[0043]

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for early warning analysis of flashover caused by extreme weather winds in power transmission lines, characterized in that: The analysis includes the following steps: S1. Collect information on power transmission lines and meteorological data; S2. Calculate the maximum wind deflection angle of the suspension insulator string of the line using a rigid straight rod model; S3. Calculate the minimum air gap based on the maximum wind deflection angle, and obtain the line wind deflection flashover voltage under the corresponding gap conditions; S4. Based on the line wind-induced flashover voltage and the line operating voltage, the line wind-induced flashover probability is obtained. S5. Assess the risk of line wind-induced flashover based on the line wind-induced flashover probability and issue an early warning.

2. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: The transmission line information in step S1 includes transmission line structure information and spatial coordinate information, and the meteorological data includes wind speed, wind direction, air pressure, temperature, humidity and precipitation corresponding to the location of the transmission line.

3. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: The formula for calculating the wind deflection angle in step S2 is expressed as follows: In the formula: , These represent the horizontal and vertical loads on the insulator string and its fittings, respectively. , These represent the horizontal and vertical loads on the conductor, respectively.

4. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 3, characterized in that: The horizontal and vertical loads on the insulator string and its fittings in step S2 are respectively expressed as follows: , In the formula: This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. This represents air density, and its standard value is... , This indicates the wind speed in the vertical direction relative to the reference height. Indicates the coefficient of variation of wind pressure at height. This indicates the total wind-receiving area of ​​the insulator string and its fittings. This indicates the angle between the wind direction and the direction of the conductor or ground wire.

5. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 3, characterized in that: The horizontal and vertical loads on the conductor in step S2 are respectively expressed as follows: , In the formula: Indicates the number of split wires. This indicates the magnitude of the horizontal wind load per unit length of conductor on the line. , Indicates the horizontal span on both sides of the tower. , These represent the elevation difference angles between the line tower and its adjacent tower. Indicates the horizontal tension of the conductor. Indicates the turning point of the line. These represent the complementary angles between the transmission line and the crossarm, respectively. This represents the weight per unit length of the conductor. , This represents the height difference between adjacent towers; where the horizontal wind load per unit length of conductor is the magnitude of the line. In the formula: This represents the wind pressure non-uniformity coefficient. This represents the vertical wind pressure experienced per unit area by the insulator string and its fittings. Indicates the coefficient of variation of wind pressure at height. Indicates the shape factor of the conductor. Indicates the overall outer diameter of the conductor. This indicates the amplification factor of horizontal wind load on the conductor after icing.

6. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: The formula for calculating the minimum air gap in step S3 is expressed as follows: In the formula: This indicates the distance from suspension point A to the center line of the tower. Indicates the length of the insulator string. Indicates the conductor splitting radius. Indicates the wind deflection angle of the insulator string. Indicates the angle between the tower and the crossarm. This indicates the distance from the suspension point C to the center line of the tower.

7. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: In step S3, air density, humidity, and precipitation are used to correct the line wind-induced flashover voltage under standard operating conditions; wherein, the air density correction coefficient is expressed as: , Indicates the air density correction index. Represents relative air density. , , , These are real-time air pressure and temperature, respectively; the humidity correction factor is expressed as: , This indicates the humidity correction index. , Represents relative air density. Indicates absolute humidity. The rainfall correction coefficient was fitted using a Gaussian formula under different rainfall intensities, as follows: The corrected line wind-induced flashover voltage is then expressed as: , and Line wind-induced flashover voltage before and after correction.

8. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: The line wind-induced flashover probability in step S4 is expressed as follows: In the formula: Indicates the line operating voltage. Indicates the line wind-induced flashover voltage. This represents the standard deviation, taken as 10%. This represents a standard normal distribution.

9. The method for early warning analysis of extreme weather wind-induced flashover of transmission lines according to claim 1, characterized in that: In step S5, the line wind-induced flashover risk levels include safe, low risk, medium risk, and high risk. Specifically, when the line wind-induced flashover probability is less than 30%, the risk level is safe; when the line wind-induced flashover probability is greater than or equal to 30% and less than 60%, the risk level is low risk; when the line wind-induced flashover probability is greater than or equal to 60% and less than 90%, the risk level is medium risk; and when the line wind-induced flashover probability is greater than or equal to 90%, the risk level is high risk.

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