High-voltage overhead transmission line typhoon disaster prediction method based on classification decision treeTechnical Field
The invention belongs to the technical field of natural disaster prediction of high-voltage transmission lines, and particularly relates to a typhoon disaster prediction method of a high-voltage overhead transmission line based on a classification decision tree.
Background
The high-voltage overhead transmission line is one of the most important infrastructures in modern society, and is used for remotely transmitting large-capacity electric energy from a power supply side to a load side. The high-voltage overhead transmission line is generally located in the field and is seriously influenced by natural disasters, wherein typhoons can damage the high-voltage overhead transmission line in a large range in a short time, and serious threats are caused to the safe and stable operation of a power grid.
By predicting typhoon disasters of the high-voltage overhead transmission line before typhoons come, the method is beneficial to the operation and maintenance department of the high-voltage overhead transmission line to carry out targeted transmission channel cleaning so as to avoid foreign matter external damage faults caused by strong winds, and can also guide the operation and maintenance department to carry out tower reinforcement in advance so as to avoid tower collapse faults, or specifically prepare emergency materials and rapidly carry out rush repair and recovery after tower collapse faults.
Whether the high-voltage overhead transmission line has typhoon disasters depends on a series of factors such as typhoon strength, typhoon landing positions, wind resistance of high-voltage overhead transmission line towers, geographical positions of the high-voltage overhead transmission line towers, trend of the high-voltage overhead transmission line and the like. In the traditional method, disaster prediction is usually performed by comparing the forecast wind speed and the design wind speed at the pole and tower of the high-voltage overhead transmission line, but the method is limited by the defect that the accuracy of a meteorological numerical forecasting system for wind speed forecast is insufficient, and the accuracy of typhoon disaster prediction is low. Typhoon disasters of high-voltage overhead transmission lines are often difficult to predict accurately, and troubles are caused to the operation and maintenance departments to carry out disaster prevention and reduction work in a targeted manner.
Disclosure of Invention
Aiming at the defect that the traditional typhoon disaster prediction method is low in accuracy, the invention provides the typhoon disaster prediction method for the high-voltage overhead transmission line based on the classification decision tree, and the classification decision tree comprehensively analyzes multiple elements to realize accurate prediction of the typhoon disaster of the high-voltage overhead transmission line, so that the disaster prevention and reduction work can be better guided.
In order to achieve the purpose, the invention adopts the following technical scheme: a high-voltage overhead transmission line typhoon disaster prediction method based on a classification decision tree comprises the following steps:
s1, selecting typhoon disaster influence factors of the high-voltage overhead transmission line;
s2, building a historical typhoon disaster fault point influence factor database of the high-voltage overhead transmission line;
s3, training a typhoon disaster prediction model by adopting a classification decision tree;
and S4, adopting a typhoon disaster prediction model and combining the target high-voltage overhead transmission line and typhoon forecast data to carry out typhoon disaster prediction.
Further, in step S1, the typhoon disaster influence factor includes a forecast wind speed at a position of the high voltage overhead transmission line tower, a design wind speed of the high voltage overhead transmission line tower, a terrain classification, a predicted landing point distance between the high voltage overhead transmission line tower and a typhoon, a voltage grade of the high voltage overhead transmission line, a forecast heading angle between a prevailing wind direction and a line of the high voltage overhead transmission line, a line corner number of the high voltage overhead transmission line, a distance between the high voltage overhead transmission line tower and a coast, an environmental corrosion grade of the high voltage overhead transmission line tower, a commissioning life of the high voltage overhead transmission line tower, an altitude of the high voltage overhead transmission line tower, and a height.
Further, in step S1, the forecasted wind speed at the tower position of the high voltage overhead transmission line is an average wind speed at a height of 10m from the ground surface; the designed wind speed of the high-voltage overhead transmission line tower refers to a wind speed value at a height of 10m from the ground; the landform classification is divided into two types of mountain land and flat land; the expected landing point distance between the tower and the typhoon of the high-voltage overhead transmission line is the linear distance between the position of the tower and the first landing point of the center of the typhoon; the voltage class of the high-voltage overhead transmission line is divided into Alternating Current (AC) 110kV, Alternating Current (AC) 220kV, Alternating Current (AC) 500kV, Alternating Current (AC) 1000kV, Direct Current (DC) 500kV, Direct Current (DC) 800kV and Direct Current (DC) 1100 kV; forecasting an included angle between the main wind direction and the direction of the high-voltage overhead transmission line to be the smaller angle of two complementary intersection angles formed by the main wind direction and the line direction; the number of the rotation angles of the high-voltage overhead transmission line refers to the rotation angles of the line path direction in front of and behind a certain base tower; the distance between the high-voltage overhead transmission line tower and the coast is the closest straight line distance between the position of the tower and the coast line; the corrosion grade of the environment where the high-voltage overhead transmission line tower is located is divided into C1, C2, C3, C4, C5 and CX from low to high; the commissioning age of the high-voltage overhead transmission line refers to the difference between the current year and the commissioning year; the altitude of the high-voltage overhead transmission line tower refers to the altitude of the position where the tower is located; the height of the high-voltage overhead transmission line tower refers to the total height of the tower.
Further, in step S2, the pointer of the typhoon disaster fault point impact factor database establishes a data record for the high-voltage overhead transmission line tower that has a typhoon disaster historically, and the database field includes all typhoon disaster impact factors instep 1, and the name, number, fault type and fault time of the line to which the historical typhoon disaster tower belongs.
Further, the fault types comprise three types of windage yaw flashover, foreign body external damage and body damage.
Furthermore, a historical typhoon disaster fault point influence factor database is built on the basis of historical typhoon disaster investigation of the high-voltage overhead transmission line, 1 data record is set for each base fault tower, the fault tower refers to the tower with the typhoon disaster, and when the typhoon disaster occurs between two base fault towers, the tower closest to the fault occurrence position is used as the fault tower; when the numerical values of the various influence factors are calculated, the actual values are used for replacing forecast values, specifically, the actual monitored wind speed is used for replacing forecast wind speed, the actual landing point of a typhoon center is used for replacing a forecast landing point, and the actual dominant wind direction of the typhoon is used for replacing forecast dominant wind direction.
Further, in step S3, the typhoon disaster prediction model training using the classification decision tree is to train a mathematical model that predicts an output parameter based on an input parameter using the historical typhoon disaster fault record as an input parameter and the typhoon disaster type as an output parameter using the classification decision tree.
Further, in step S3, a classification decision tree is adopted to conduct typhoon disaster prediction model training, historical typhoon disaster data and randomly selected data records of the same number of transmission line towers which do not have faults are utilized to conduct training on three types of typhoon disaster prediction models, the three types of typhoon disaster prediction models are respectively used for predicting wind deflection flashover risks and foreign matter external damage risks (and body damage risks), and three influence factors including terrain classification, voltage grades of the high-voltage overhead transmission line and environmental corrosion grades of the high-voltage overhead transmission line towers are subjected to one-bit effective coding before training is started.
Further, the classification decision tree method selects node sorting based on information gain, selects the influence factor with the largest information gain as a root node, and the information gain calculation formula is as follows:
gain(A)=info(D)-infoA(D) (1)
in the formula: a is an influencing factor; d is a sample set; info (d) is the information entropy of the sample set; infoA(D) The entropy of the information of the sample set under the condition of the known influence factor A;
the information entropy calculation formula of the sample set is as follows:
in the formula: p is a radical ofiThe probability of occurrence in the sample set for the ith class; n is the total amount of samples;
suppose that the impact factor A has m possible values { A }1,A2,……,AmAnd the calculation formula of the information entropy of the sample set under the condition of the known influence factor A is as follows:
in the formula: i DiThe value of | is equal to A as the influence factor AiThe number of samples of (a); | D | is the total number of samples; info (D)i) The value of the influencing factor A is equal to AiThe entropy of the information of the sample of (1);
after the root node is selected, selecting a subsequent leaf node based on the information gain;
the classification decision tree used in the typhoon disaster prediction of the high-voltage overhead transmission line does not exceed 6 layers.
Further, in step S4, the developing of the typhoon disaster prediction by combining the target high voltage overhead transmission line and the typhoon prediction data means calculating each influence factor value of the high voltage overhead transmission line for which the typhoon disaster prediction is required, and performing the typhoon disaster prediction by using the trained typhoon disaster prediction model.
The high-voltage overhead transmission line typhoon disaster prediction method based on the classification decision tree has the beneficial effects that: the typhoon disaster prediction model is established based on a classification decision tree mode, so that the influence of the typhoon disaster on the high-voltage overhead transmission line can be accurately predicted, and the work of disaster prevention and reduction is scientifically guided.
Drawings
Fig. 1 is a flowchart of a typhoon disaster prediction method for a high-voltage overhead transmission line based on a classification decision tree according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a power transmission line transmission channel structure of a high-voltage overhead power transmission line typhoon disaster prediction method based on a classification decision tree according to an embodiment of the present invention (for calculating and forecasting a heading angle between a main wind direction and a line of a high-voltage overhead power transmission line and a rotation angle of the line of the high-voltage overhead power transmission line).
Fig. 3 is a schematic training flow diagram of a typhoon disaster prediction method for a high-voltage overhead transmission line based on a classification decision tree according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of a one-bit effective encoding result of the voltage class of the high-voltage overhead transmission line typhoon disaster prediction method based on the classification decision tree according to the first embodiment of the present invention.
Fig. 5 is a flowchart of a decision tree of the method for predicting a typhoon disaster of a high-voltage overhead transmission line based on a classification decision tree according to the first embodiment of the present invention, in which the decision tree starts to determine a state corresponding to an impact factor value layer by layer from a root node.
Detailed Description
The technical solutions of the embodiments of the present invention will be explained and explained below with reference to the drawings of the embodiments of the present invention, but the embodiments described below are only preferred embodiments of the present invention, and are not all embodiments. Other embodiments obtained by persons skilled in the art without any inventive work based on the embodiments in the embodiment belong to the protection scope of the invention.
Referring to fig. 1 to 5, a method for predicting typhoon disasters of a high-voltage overhead transmission line based on a classification decision tree according to an embodiment of the present invention includes:
s1, selecting typhoon disaster influence factors of the high-voltage overhead transmission line;
s2, building a historical typhoon disaster fault point influence factor database of the high-voltage overhead transmission line;
s3, training a typhoon disaster prediction model by adopting a classification decision tree;
and S4, adopting a typhoon disaster prediction model and combining the target high-voltage overhead transmission line and typhoon forecast data to carry out typhoon disaster prediction.
Further, in step S1, the typhoon disaster influence factor includes a forecast wind speed at a position of the high voltage overhead transmission line tower, a design wind speed of the high voltage overhead transmission line tower, a terrain classification, a predicted landing point distance between the high voltage overhead transmission line tower and a typhoon, a voltage grade of the high voltage overhead transmission line, a forecast heading angle between a prevailing wind direction and a line of the high voltage overhead transmission line, a line corner number of the high voltage overhead transmission line, a distance between the high voltage overhead transmission line tower and a coast, an environmental corrosion grade of the high voltage overhead transmission line tower, a commissioning life of the high voltage overhead transmission line tower, an altitude of the high voltage overhead transmission line tower, and a height.
Further, in step S1, the forecasted wind speed at the tower position of the high voltage overhead transmission line is an average wind speed at a height of 10m from the ground surface; the designed wind speed of the high-voltage overhead transmission line tower refers to a wind speed value at a height of 10m from the ground; the landform classification is divided into two types of mountain land and flat land; the expected landing point distance between the tower and the typhoon of the high-voltage overhead transmission line refers to the linear distance between the position of the tower and the first landing point of the center of the typhoon. The voltage class of the high-voltage overhead transmission line is divided into Alternating Current (AC) 110kV, Alternating Current (AC) 220kV, Alternating Current (AC) 500kV, Alternating Current (AC) 1000kV, Direct Current (DC) 500kV, Direct Current (DC) 800kV and Direct Current (DC) 1100 kV; forecasting an included angle between the main wind direction and the direction of the high-voltage overhead transmission line to be the smaller angle of two complementary intersection angles formed by the main wind direction and the line direction; the number of the rotation angles of the high-voltage overhead transmission line refers to the rotation angles of the line path direction in front of and behind a certain base tower; the distance between the high-voltage overhead transmission line tower and the coast is the closest straight line distance between the position of the tower and the coast line; the corrosion grade of the environment where the high-voltage overhead transmission line tower is located is divided into C1, C2, C3, C4, C5 and CX from low to high; the commissioning age of the high-voltage overhead transmission line refers to the difference between the current year and the commissioning year; the altitude of the high-voltage overhead transmission line tower refers to the altitude of the position where the tower is located; the height of the high-voltage overhead transmission line tower refers to the total height of the tower.
As shown in fig. 2, in which θ1And theta2For the angle between the main wind direction and the line trend, the main wind direction and the line trend form two complementary crossing angles, and the angle value with smaller degree is taken. In the figure theta3Is a wireThe number of road turning angles refers to the turning angles of the lines in the front and back directions of a certain base tower.
Further, in step S2, the pointer of the typhoon disaster fault point impact factor database establishes a data record for the high-voltage overhead transmission line tower that has a typhoon disaster historically, and the database field includes all typhoon disaster impact factors instep 1, and the name, number, fault type and fault time of the line to which the historical typhoon disaster tower belongs.
Further, the fault types comprise three types of windage yaw flashover, foreign body external damage and body damage.
Furthermore, a historical typhoon disaster fault point influence factor database is built on the basis of historical typhoon disaster investigation of the high-voltage overhead transmission line, 1 data record is set for each base fault tower, the fault tower refers to the tower with the typhoon disaster, and when the typhoon disaster occurs between two base fault towers, the tower closest to the fault occurrence position is used as the fault tower; when the numerical values of the various influence factors are calculated, the actual values are used for replacing forecast values, specifically, the actual monitored wind speed is used for replacing forecast wind speed, the actual landing point of a typhoon center is used for replacing a forecast landing point, and the actual dominant wind direction of the typhoon is used for replacing forecast dominant wind direction.
Further, in step S3, the typhoon disaster prediction model training using the classification decision tree is to train a mathematical model that predicts an output parameter based on an input parameter using the historical typhoon disaster fault record as an input parameter and the typhoon disaster type as an output parameter using the classification decision tree. The classification decision tree is a machine learning algorithm, and particularly relates to a classifier comprising a plurality of decision trees.
Further, in step S3, a classification decision tree is used to train a typhoon disaster prediction model, and historical typhoon disaster data and randomly selected data records of the same number of transmission line towers that have not failed are used to train three types of typhoon disaster prediction models, which are respectively used to predict the windage yaw flashover risk (typhoon disaster prediction model 1), the foreign object external damage risk (typhoon disaster prediction model 2) and the body damage risk (typhoon disaster prediction model 3) of the high-voltage overhead transmission line. Before training, three influence factors of terrain classification, voltage grade of the high-voltage overhead transmission line and corrosion grade of the environment where the high-voltage overhead transmission line tower is located are subjected to one-bit effective coding. A schematic diagram of the one-bit effective encoding result of the voltage class of the high-voltage overhead transmission line is shown in figure 4,
further, the classification decision tree method selects node sorting based on information gain, selects the influence factor with the largest information gain as a root node, and the information gain calculation formula is as follows:
gain(A)=info(D)-infoA(D) (1)
in the formula: a is an influencing factor; d is a sample set; info (d) is the information entropy of the sample set; infoA(D) The entropy of the information of the sample set under the condition of the known influence factor A;
the information entropy calculation formula of the sample set is as follows:
in the formula: p is a radical ofiThe probability of occurrence in the sample set for the ith class; n is the total amount of samples;
suppose that the impact factor A has m possible values { A }1,A2,……,AmAnd the calculation formula of the information entropy of the sample set under the condition of the known influence factor A is as follows:
in the formula: i DiThe value of | is equal to A as the influence factor AiThe number of samples of (a); | D | is the total number of samples; info (D)i) The value of the influencing factor A is equal to AiThe entropy of the information of the sample of (1);
after the root node is selected, selecting a subsequent leaf node based on the information gain;
the classification decision tree used in the typhoon disaster prediction of the high-voltage overhead transmission line does not exceed 6 layers.
Further, in step S4, the developing of the typhoon disaster prediction by combining the target high voltage overhead transmission line and the typhoon prediction data means calculating each influence factor value of the high voltage overhead transmission line for which the typhoon disaster prediction is required, and performing the typhoon disaster prediction by using the trained typhoon disaster prediction model.
Specifically, when a typhoon comes, the predicted longitude and latitude of a landing point and the wind speed when the typhoon lands can be obtained by using typhoon path forecast data issued by a meteorological department, and in addition, the forecasted wind speed values and the main wind directions of different high-voltage overhead transmission line towers can be obtained through a numerical weather forecasting system. Based on the forecast parameters, the values of the various influence factors listed in S1 can be calculated, and then the typhoon disaster situation of the high-voltage overhead transmission line can be forecasted by using the three typhoon disaster forecasting models trained in S3.
Specifically, as shown in fig. 5, a decision tree in the typhoon disaster prediction model starts to judge the states corresponding to the impact factor values layer by layer from a root node, the states include yes and no, different states enter different next-level nodes until the process runs to the last-level node, and a final result is obtained, that is, whether three risks, namely wind deflection flashover, foreign object external damage and body damage, exist.
The method for predicting the typhoon disaster of the high-voltage overhead transmission line based on the classification decision tree has the beneficial effects that: the typhoon disaster prediction model is established based on a classification decision tree mode, so that the influence of the typhoon disaster on the high-voltage overhead transmission line can be accurately predicted, and the work of disaster prevention and reduction is scientifically guided.
While the invention has been described with reference to specific embodiments thereof, it will be understood by those skilled in the art that the invention is not limited thereto but is intended to cover various modifications and changes, including but not limited to the details shown in the drawings and described in the foregoing detailed description. Any modification which does not depart from the functional and structural principles of the invention is intended to be included within the scope of the following claims.