CN-120995531-B - Visual calculation method for shielding failure tripping rate of transmission line under complex terrain

CN120995531BCN 120995531 BCN120995531 BCN 120995531BCN-120995531-B

Abstract

The invention relates to the technical field of power transmission line risk assessment, in particular to a shielding failure tripping rate visual calculation method of a power transmission line under complex terrain. The technical scheme includes that a transmission line under complex terrain serving as a main body object of study is determined, a transmission line corridor is split, three-dimensional data of the complex terrain is obtained by utilizing a spatial analysis function of a GIS (geographic information system) and a three-dimensional GIM (graphic information model), the lightning-resistant level of an insulator is calculated and used as the minimum surrounding lightning current of an EGM (enhanced gas metal) based on the obtained terrain profile data, then the lightning-wire distance circle radius, the wire distance circle radius and the earth distance radius are calculated through a distance-hitting formula of an electric geometric model, and the electric geometric model under the profile is established. The method comprehensively considers the influence of complex terrains on the shielding failure of the power transmission line, provides scientific and effective support for the lightning protection of the power transmission line through accurate calculation and visual analysis, and has important significance in guaranteeing the safe and stable operation of the power grid.

Inventors

WANG CHAOQUN
WANG HAIBO
Wu Chenxian
XIANG NIANWEN
Lv Zengwei
CHEN ZHIWEI
WANG SHULAI
WANG WEIQI
LI SEN
DENG SHI

Assignees

合肥综合性国家科学中心能源研究院(安徽省能源实验室)

Dates

Publication Date: 20260508
Application Date: 20250811

Claims (8)

1. A visual calculation method for the shielding failure trip rate of a transmission line under complex terrain is characterized by comprising the following steps: S1, determining a transmission line under a complex terrain as a main body object of study, splitting a transmission line corridor, and acquiring three-dimensional data of the complex terrain by utilizing a space analysis function of a GIS and a three-dimensional GIM model; S2, calculating the lightning-proof level of the insulator based on the obtained topographic profile data and taking the lightning-proof level as the minimum surrounding lightning current of the EGM, calculating the radius of a lightning wire pitch circle, the radius of a lead pitch circle and the radius of a ground pitch by using a pitch formula of an electrical geometric model, establishing an electrical geometric model under the profile, and calculating the lightning-proof level of the insulator by using the formula And as a minimum lightning current for EGM Level of lightning endurance The calculation formula of (2) is as follows: , Wherein: 50% of the negative polarity impact flashover voltage of the insulator is measured in kV; The unit is kV for the highest operation voltage of the system; the lightning channel wave impedance is shown as omega; the impedance of the lead wave is shown as omega; S3, calculating the lengths of the exposed arcs of the lightning conductor and the lead wire under the minimum shielding failure lightning current by utilizing a program, and taking the mutual shielding effect between the exposed arcs into consideration to obtain and store the projected lengths of the exposed arcs of the lead wire when the lightning leading incident angle is vertically downward; S4, calculating different elevation angles Lower wire exposure arc oblique projection length Determining probability distribution of lightning lead incident angles, and determining maximum lightning current by judging whether the horizontal oblique projection length of the exposed arc of the lead is 0; s5, converting the horizontal oblique projection length of the exposed arc of the wire into an effective exposed arc projection length, calculating the times of line shielding failure and flashover, and further obtaining the shielding failure tripping rate of the section and the shielding failure tripping rate of the infinitesimal; And S6, carrying out sectional calculation processing on each span of the power transmission line, reducing the shielding failure tripping rate of each half of the spans at two sides of the tower to the tower, and evaluating the shielding failure tripping risk of the corridor of the power transmission line through the shielding failure tripping rate of the tower.
2. The visual calculation method of the shielding failure tripping rate of the power transmission line under the complex terrain according to claim 1, wherein in the step S1, the whole power transmission line corridor with the complex terrain is split according to a fixed interval delta L, and the extracted data comprise the ground height, the relative center line distance and the complex terrain elevation of the ground lead of the whole power transmission line corridor with the complex terrain.
3. The visual calculation method for shielding failure tripping rate of power transmission line under complex terrain according to claim 1, wherein in step S2, the radius of lightning rod striking distance circle is calculated by the striking distance formula of an electrical geometric model respectively Radius of wire pitch circle Ground strike distance radius The specific calculation formula is as follows: ; , , Wherein: The unit is m for the radius of the lightning stroke distance circle of the lightning wire; the unit is m, which is the radius of the wire stroke distance circle; The unit is m, which is the radius of the ground strike distance; the unit is kA for the amplitude of the lightning current; The unit is kV for the instantaneous value of the working voltage on the lead; The height of the wire to ground is given in m.
4. The visual calculation method for shielding failure tripping rate of power transmission line under complex terrain according to claim 1, wherein in step S3, a Matlab program is used for calculating to obtain a section At minimum lightning current The calculated result is stored in a matrix form for judging the maximum shielding failure lightning current when the lightning conductor completely shields the lead 。
5. The visual calculation method for the shielding failure trip rate of the transmission line under the complex terrain according to claim 1, wherein in the step S4, Ranging from To the point of At each calculation interval Calculating the distribution probability of different lightning incident angles by using the formula, wherein the formula is specifically as follows: , Wherein: The lightning incident angle is given in rad; for probability distribution of lightning incidence angle, the lightning current increment is =0.1kA。
6. The visual calculation method of shielding failure tripping rate of power transmission line under complex terrain as claimed in claim 1, wherein in step S5, all exposed arc horizontal oblique projection lengths of the wires are calculated by a formula Conversion to effective exposed arc projected length The conversion formula is: , in the formula, The effective projection length of the exposure arc is expressed as m; the unit is m for the horizontal oblique projection length of the exposure arc; The lightning incident angle is given in rad; the unit is kA for the amplitude of the lightning current; number of line shield failures and resulting flashovers after consideration of different lightning incident angles Expressed as: , Wherein: The unit is the number of times of flashovers, namely times per 100km 2 ∙ a; The unit is secondary/km 2 ∙ a for ground flash density; the unit is kA for maximum shielding failure lightning current; the unit is kA for minimum shielding failure lightning current; the effective projection length of the exposure arc is expressed as m; The lightning incident angle is given in rad; the unit is kA for the amplitude of the lightning current; probability distribution for lightning incidence angle; As a function of the probability density of the lightning current, 。
7. The visual calculation method of shielding failure trip rate of transmission line under complex terrain as set forth in claim 6, wherein in step S5, to simplify the calculation, the method comprises the steps of The integral calculation is converted into differential summation, and the specific calculation formula is as follows: , in the formula, The unit is the number of times of flashovers, namely times per 100km 2 ∙ a; The unit is secondary/km 2 ∙ a for ground flash density; the unit is kA for maximum shielding failure lightning current; the unit is kA for minimum shielding failure lightning current; the effective projection length of the exposure arc is expressed as m; The lightning incident angle is given in rad; the unit is kA for the amplitude of the lightning current; probability distribution for lightning incidence angle; Is expressed as lightning current probability Calculated to obtain Matrix substitution calculation to obtain section Number of winding shots to flash over By the formula The section can be calculated And multiplies the winding trip rate of the profile by the subdivision pitch Approximately the infinitesimal The winding trip rate of (2) ; Wherein: the unit is secondary/100 km 2 ∙ a for the winding trip rate; The unit is the number of times of flashovers, namely times per 100km 2 ∙ a; For trip probability after flashover, no reclosing lines are provided Line provided with automatic reclosing 。
8. The visual calculation method of the shielding failure trip rate of the transmission line under the complex terrain according to claim 7, wherein in the step S6, all the infinitesimal elements are obtained The winding trip rate of (2) And then, carrying out sectional calculation processing on each span of the power transmission line, and reducing the shielding failure tripping rate of each half of the spans at two sides of a certain tower to the tower.

Description

Visual calculation method for shielding failure tripping rate of transmission line under complex terrain Technical Field The invention relates to the technical field of power transmission line risk assessment, in particular to a shielding failure tripping rate visual calculation method of a power transmission line under complex terrain. Background Lightning disasters are one of ten serious disasters listed as relevant organizations of united nations, and form a great threat to safe and stable operation of a power system. With the continuous expansion of the construction scale of the power grid in China, the coverage area of the overhead power transmission line is continuously extended, the line corridor is gradually dense, and the probability of lightning stroke of the power transmission line is obviously increased. A large number of operation practices show that for high-pole towers and high-voltage-class power transmission lines, lightning trip accidents mainly occur in the form of shielding failure, and particularly when the power transmission lines pass through complex terrains, the power transmission lines are limited by the complex terrains, so that the difficulty of shielding failure performance evaluation is greatly improved. Transmission line corridors are often subjected to a variety of complex terrain environments, including curved, undulating hills, valleys, hills, and the like. The diversity of the topography and geology parameters leads the complexity of the lightning protection work of the power transmission line to be obviously increased, for example, the lightning protection work spans the long-span lines of valleys and rivers, and the risk of the lightning striking the lead from the side to cause the shielding failure trip to be greatly increased. In the prior art, when a conventional Electric Geometric Model (EGM) calculates the shielding failure tripping rate of a power transmission line corridor, only a simple ground inclination angle is adopted to approximately represent a complex terrain, the actual influence of the complex terrain on the shielding failure risk of the power transmission line cannot be accurately reflected by the simplified processing mode, so that a larger deviation exists between a calculation result and the actual situation, and an effective lightning stroke protection measure is difficult to formulate according to the calculation result, so that the risk of safe operation of the power transmission line is increased. Patent documents (CN 119674887A) and (transmission line lightning strike risk assessment system and method and storage medium (CN 119990740A) are used for researching the shielding failure risk of the transmission line under the complex topography and providing a corresponding calculation model according to the characteristic information such as lightning activity data, topography and the like, but on the aspect of processing the complex topography, the ground inclination angle is still adopted to approximate the complex topography, the influence on the transmission line caused by the irregular mountain fluctuation in the actual complex topography area cannot be accurately considered, and the shielding failure tripping rate of a transmission line corridor under the complex topography is difficult to calculate and analyze in a targeted manner. Therefore, in order to realize the fine and accurate evaluation of the shielding failure tripping risk of the transmission line with the complex terrain, a calculation method capable of fully combining the actual characteristics of the complex terrain is needed. Disclosure of Invention The invention aims to provide a visual calculation method for the shielding failure trip rate of a power transmission line under complex terrains, aiming at solving the problem that corresponding lightning protection measures are not adopted under the conditions of irregular mountain fluctuation under complex terrains and different shielding effects of different mountain terrains on the power transmission line in the background technology. The technical scheme of the invention is that the visual calculation method for the shielding failure trip rate of the transmission line under the complex terrain comprises the following steps: S1, determining a transmission line under a complex terrain as a main body object of study, splitting a transmission line corridor, and acquiring three-dimensional data of the complex terrain by utilizing a space analysis function of a GIS and a three-dimensional GIM model; S2, calculating the lightning resistance level of the insulator based on the obtained topographic profile data and taking the lightning resistance level as the minimum surrounding lightning current of the EGM, calculating the lightning conductor pitch circle radius, the lead pitch circle radius and the earth pitch radius through a pitch formula of the electrical geometric model, and establishing the electrical geometric model under the pr