CN104573192B - Online monitoring method for equivalent icing thickness of overhead line strain tower - Google Patents

Abstract

The invention discloses an online monitoring method for the equivalent ice-covered thickness of a tension tower of an overhead line. The method includes the following steps: (1) extracting the online monitoring guide/ground wire historical pull data to obtain the guide/ground wire historical pull force in the ice-free period; (2) obtaining the guide/ground wire historical pull force data in the ice-free period; /Ground wire historical load data to obtain the maximum load; (3) According to the maximum load and the basic information of the tower provided by the grid company, the maximum equivalent conductor/ground wire length is obtained; (4) Extract the online monitoring conductor/ground wire real-time tension data, Calculate the equivalent ice thickness of the conductor/ground wire; (5) According to the real-time meteorological data, select the equivalent ice thickness to judge the amount of ice on the overhead line. The invention has the advantages of simple calculation, high accuracy and reliability.

Description

An online monitoring method for the equivalent ice thickness of the tension tower of the overhead line

technical field

The invention relates to the field of on-line monitoring of transmission lines in the field of electric power, in particular to an on-line monitoring method for the equivalent ice thickness of tension towers of overhead lines.

Background technique

With the development of social economy, the stable, safe and reliable supply of electric power has become an increasingly important issue. Although icing is a common natural phenomenon, ice disasters seriously threaten the safe operation of power grids. In terms of power equipment, ice disasters can cause insulators to flash, hardware damage, poles and towers to collapse, and wires to break, which directly lead to power outages in line areas; However, the paralysis of large-scale power grids caused the suspension of industrial and agricultural production and the stagnation of various service industries, which directly led to heavy economic losses and the people's lives could not be carried on normally. In order to ensure the safe operation of the power grid, it is necessary to monitor the icing situation of the transmission line and judge whether to take corresponding measures to avoid accidents such as disconnection and inversion.

At present, almost all online monitoring of icing on transmission lines adopts weighing method. The so-called weighing method is to replace the ball head hanging ring of the insulator with the tension sensor, use the angle and tension sensors to measure the inclination angle, wind angle and comprehensive load of the hanging insulator string respectively, and use the micro meteorological sensor group (including temperature, relative humidity, wind speed, Wind direction, rainfall and other sensors) measure wind speed, etc., and then substitute into the equivalent ice thickness calculation model to calculate the real-time wire equivalent ice thickness. According to the existing patent "on-line monitoring method for equivalent icing thickness of overhead lines", combined with the actual engineering application, the calculation of the equivalent thickness of icing of linear towers applied to the online monitoring system for icing of overhead lines in China Southern Power Grid is proposed Model. However, at present, there are still few studies on the calculation of the ice coating thickness of the strain tower conductor based on the weighing method, and even fewer applications are applied to the ice monitoring system. As a result, it is impossible to calculate the ice coating thickness of the strain tower conductor, and the power grid company is still unable to accurately and Effectively grasp the icing condition of the strain tower line, and then compare it with the design specification for early warning. The insufficient calculation of the ice thickness of the tension tower of the existing transmission line is mainly manifested in: 1. The theoretical calculation model involves too many parameters and formulas, and a large amount of ice data needs to be collected as the basic data, which limits the model to a certain extent 2. Some models take wind load into account, but this value cannot be accurately calculated, and the wind speed sensor often freezes when ice is covered, and the obtained data is invalid; 3. The ice thickness calculated by the theoretical model of some models is different from the ice thickness measured on the spot Large, resulting in inaccurate model calculation results, and most of the models have no experience in applying to the actual icing online monitoring system, and their calculation accuracy needs to be verified.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide an online monitoring method for the equivalent ice thickness of the tension tower of an overhead line with simple calculation, high accuracy and reliability.

The purpose of the present invention is achieved through the following technical solutions: an online monitoring method for the equivalent ice thickness of an overhead line tension tower, comprising the following steps:

(1) Extract the historical tension data and historical meteorological data of the online monitoring guide/ground wire of the tension tower, remove the historical tension of the tension tower guide/ground wire in the ice-covered period according to the historical meteorological data, and obtain the tensile tower guide in the ice-free period /Historical tension data of the ground wire;

(2) Obtain the historical load data of the conductor/ground wire according to the historical tension data of the strain tower guide/ground wire in the ice-free period; and perform frequency analysis on the obtained strain tower guide/ground wire historical load data to obtain the maximum load;

(3) Calculate the maximum equivalent conductor/ground wire length according to the maximum load obtained in step (2) and the tower foundation parameters provided by the grid company;

(4) Extract the real-time tension data of the online monitoring conductor/ground wire of the strain tower, obtain the real-time load data of the strain tower conductor/ground wire, and substitute the maximum load, the maximum equivalent conductor/ground wire length and the real-time load data of the conductor/ground wire into the Into the equivalent ice thickness model of the tension tower, calculate the equivalent ice thickness of the tension tower guide/ground wire;

(5) According to the real-time meteorological data monitored online, the calculated equivalent ice thickness is selected to judge the amount of ice on the overhead line.

Preferably, the guide/ground historical load G in the step ( ₂ ) is:

G ₀ =F;

Among them, F is the historical tension value of the guide/ground wire.

Further, when the insulator string type is I string, then the strain tower online monitoring conductor/ground wire historical tension value is the conductor/ground wire historical tension value F;

When the insulator string type is a double I string, and one of them is equipped with a tension sensor, the tension tower online monitoring conductor/ground wire historical tension value multiplied by 2 is the conductor/ground wire historical tension value F;

When the string type of insulators is a double I string, and each string is equipped with a tension sensor, the historical tension value of the conductor/ground wire monitored online by the strain tower is the historical tension value F of the conductor/ground wire.

Preferably, the maximum equivalent guide/ground length 1 _m in the step (3) is:

l _m =G _m /(q ₀ n);

Among them, G _m is the maximum load obtained in step (2); q ₀ is the self-weight per unit length of the conductor/ground wire, and n is the split number of the conductor/ground wire.

Preferably, the guide/ground wire real-time load data G in the step (4) is:

G = F';

Among them, F' is the real-time pulling force of the guide/ground wire.

Further, in the step (4), the equivalent ice thickness h _m of the strain tower is calculated as follows:

①When G≤G _m , h _m =0;

②When G≥G _m , the actual wire length S is:

The icing load w per unit length of wire is:

Add the following correction factor w1 as _:

The equivalent ice thickness h _m is:

Where G _m is the maximum load obtained in step (2); D is the diameter of the conductor/ground wire, l _m is the maximum equivalent conductor/ground wire length obtained in step (3), ρ is the standard ice density, n is the number of conductor/ground splits.

Furthermore, when the insulator string type is I string, the real-time tension value of the conductor/ground wire monitored online is the real-time tension value F' of the conductor/ground wire;

When the insulator string type is a double I string, and one of the strings is equipped with a tension sensor, the real-time tension value of the online monitoring conductor/ground wire is multiplied by 2 to be the real-time tension value F' of the conductor/ground wire;

When the insulator string type is a double I string, and each string is equipped with a tension sensor, the real-time tension value of the conductor/ground wire monitored online is the real-time tension value of the conductor/ground wire F′.

Preferably, the meteorological data in the step (1) includes temperature and relative humidity data, and in the step (1), the period in which the ambient temperature is less than 1 degree Celsius and the relative humidity is greater than 80% is judged as the ice-covered period.

Preferably, the method for obtaining the maximum load in the step (2) is: carry out a normal distribution simulation on the frequency of the obtained conductor/ground wire historical load data, and use the maximum value obtained by the normal distribution simulation as the maximum load, wherein The maximum value in the normal distribution simulation is one of the values with a probability of 95% to 99.9%.

Preferably, the basic information of the tower in the step (3) includes the self-weight per unit length of the conductor/ground wire, the number of splits of the conductor/ground wire, the diameter of the conductor/ground wire and the type of insulator string.

Compared with the prior art, the present invention has the following advantages and effects:

(1) The inventive method utilizes the historical load data frequency of the conductor/ground wire in the ice-free period to analyze the maximum load by analyzing the historical monitoring data of the strain tower, then obtains the maximum equivalent conductor/ground wire length according to the maximum load, and finally The maximum load, the maximum equivalent conductor/ground wire length, and the real-time load of the conductor/ground wire are substituted into the equivalent ice thickness model to calculate the equivalent ice thickness, and the equivalent ice thickness is selected according to the current meteorological data to estimate the overhead For the amount of ice in the line, the present invention starts from the mechanical principle and considers the change data of the historical length of the conductor/ground wire, which has the advantages of high accuracy and reliability, so it can provide an effective basis for the decision-making of the monitoring system; And it also has the advantages of simple calculation and strong generalization.

(2) In the process of calculating the equivalent ice thickness by the method of the present invention, the amount of tower information required is small, and the power grid company only needs to provide the self-weight per unit length of the wire/ground wire, the insulator string type, the split number of the conductor/ground wire, and the number of conductor/ground wires. The wire diameter is enough for the basic information of the towers. Since these information are easy to find from the manuals and drawings, avoid using information such as the span and design wire length that are difficult to find accurately by the grassroots units. The required tower information is easy to find and provide. .

Description of drawings

Fig. 1 is a schematic flowchart of an online monitoring method for the equivalent ice thickness of an overhead line tension tower in an embodiment.

detailed description

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

This embodiment discloses an online monitoring method for the equivalent ice-covered thickness of an overhead line tension tower, as shown in Figure 1, the specific steps of the method are as follows:

(1) Extract the online monitoring conductor/ground wire historical tension data and historical temperature and relative humidity data meteorological data of the power grid that needs to be monitored in 2011, judge the period when the ambient temperature is less than 1 degree Celsius and the relative humidity is greater than 80% as the ice-covered period, and exclude The historical pull data of the guide/ground wire in the ice-covered period, and the historical pull data of the guide/ground wire in the ice-free period;

(2) Obtain the historical load data of the guide/ground wire according to the historical tension of the guide/ground wire in the ice-free period; and carry out frequency analysis to the obtained guide/ground wire historical load data to obtain the maximum load G _m ;

In this embodiment, the historical load G of the guide/ground wire is _:

G ₀ =F;

Among them, F is the historical tension value of the guide/ground wire. In this embodiment, because the insulator string type is a double I string, and each string is equipped with a tension sensor, the historical tension value F of the conductor/ground wire is equal to the historical tension value of the on-line monitoring conductor/ground wire obtained in step (1).

In this embodiment, the maximum load is obtained in the following manner _: the historical load data G0 obtained above is subjected to frequency analysis, and the normal distribution simulation is performed according to the frequency, and the maximum value obtained through the normal distribution simulation is respectively used as the maximum load G _m ;

(3) according to the maximum load obtained in the step (2) and the tower basic information provided by the grid company, calculate the maximum equivalent conduction/ground wire length 1 _m ;

Wherein the present embodiment maximum equivalent lead/ground wire length l _m is:

l _m =G _m /(q ₀ n);

Among them, q ₀ is the self-weight per unit length of the conductor/ground wire, and n is the split number of the conductor/ground wire;

(4) Extract the real-time tension data of the online monitoring conductor/ground wire from December 11, 2012 to December 21, 2012, calculate the real-time load data G of the conductor/ground wire according to these data, and calculate the maximum load G _m , the maximum equivalent The conductor/ground wire length l _m and the conductor/ground wire real-time comprehensive load data G are substituted into the equivalent ice thickness model to calculate the conductor/ground wire equivalent ice thickness h _m ;

Wherein the guide/ground wire real-time load data G in the present embodiment is:

G = F';

Among them, F' is the real-time tension value of the guide/ground wire. In this embodiment, since the insulator string type is a double I string, and each string is equipped with a tension sensor, the real-time tension value F of the conductor/ground wire is equal to the real-time tension value of the online monitoring conductor/ground wire.

In this embodiment, the conservative equivalent ice thickness _hm is calculated as follows:

①When G≤G _m , h _m =0;

②When G≥G _m , the actual wire length S is:

The icing load w per unit length of wire is:

Add the following correction factor w1 as _:

The equivalent ice thickness h _m is:

Among them, G _m is the maximum load obtained in step (2); D is the diameter of the conductor/ground wire, l _m is the maximum equivalent conductor/ground wire length obtained in step (3), and n is the conductor/ground wire split ρ is the standard ice density, ρ=900kg/m ³ in this embodiment.

(5) According to the real-time meteorological data of online monitoring, the equivalent ice thickness h _m is selected to judge the amount of ice on the overhead line, so as to decide whether to take corresponding deicing measures.

In step (2) of this embodiment, the maximum value can also be roughly estimated as the maximum load G _m by manually observing the frequency diagram.

In this embodiment, when the string type of insulators used is other string types, for example:

When the insulator string type is I string, the historical tension value of the online monitoring conductor/ground wire is the historical tension value F of the conductor/ground wire; the real-time tension value of the online monitoring conductor/ground wire is the real-time tension value F′ of the conductor/ground wire;

When the insulator string type is a double I string, and one of them is equipped with a tension sensor, the online monitoring conductor/ground wire historical tension value multiplied by 2 is the conductor/ground wire historical tension value F, and the online monitoring conductor/ground wire real-time tension value Multiply by 2 for the real-time tension value F' of the guide/ground wire.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (2)

1. an online monitoring method of the equivalent ice-covered thickness of an overhead line strain tower, is characterized in that, comprises the following steps: (1) Extract the online monitoring conductor/ground wire historical tension data and historical meteorological data, remove the conductor/ground wire historical tension in the ice-covered period according to the historical meteorological data, and obtain the conductor/ground wire historical tension data in the ice-free period; Meteorological data include temperature and relative humidity data, and the period when the ambient temperature is less than 1 degree Celsius and the relative humidity is greater than 80% is judged as the ice-covered period; (2) Obtain the historical load data of the conductor/ground wire according to the historical tension data of the conductor/ground wire in the ice-free period; and conduct frequency analysis on the obtained historical load data of the conductor/ground wire to obtain the maximum load; the method for obtaining the maximum load is : Carry out a normal distribution simulation on the frequency of the acquired historical load data of conductors/ground wires, and use the maximum values obtained by the normal distribution simulation as the maximum load respectively, wherein the maximum value in the normal distribution simulation has a probability of 95% to one of the values of 99.9%; The historical load G0 of the conductor/ground wire is _: G ₀ ＝F; when the insulator string type is I string, then the online monitoring conductor/ground wire historical tension value is the conductor/ground wire historical tension value F; When the insulator string type is a double I string, and one of them is equipped with a tension sensor, the online monitoring conductor/ground wire historical tension value multiplied by 2 is the conductor/ground wire historical tension value F; When the string type of insulators is a double I string, and each string is equipped with a tension sensor, then the historical tension value of the conductor/ground wire monitored online is the historical tension value F of the conductor/ground wire; Among them, F is the historical tension value of the conductor/ground wire; when the insulator string type is I string, the real-time tension value of the conductor/ground wire monitored online is the real-time tension value of the conductor/ground wire F′; When the insulator string type is a double I string, and one of the strings is equipped with a tension sensor, the real-time tension value of the online monitoring conductor/ground wire is multiplied by 2 to be the real-time tension value F' of the conductor/ground wire; When the insulator string type is a double I string, and each string is equipped with a tension sensor, the real-time tension value of the conductor/ground wire monitored online is the real-time tension value of the conductor/ground wire F′; (3) According to the maximum load obtained in step (2) and the basic information of the tower provided by the grid company, calculate the maximum equivalent conductor/ground wire length: l _m =G _m /(q ₀ n); Among them, G _m is the maximum load obtained in step ( ₂ ); q0 is the self-weight per unit length of the conductor/ground wire, and n is the split number of the conductor/ground wire; (4) Extract the real-time tension data of the online monitoring conductor/ground wire, calculate the real-time load data of the conductor/ground wire according to these data, and substitute the maximum load, the maximum equivalent conductor/ground wire length and the real-time load data of the conductor/ground wire into the equivalent value In the ice thickness model, the equivalent ice thickness of the conductor/ground wire is calculated; the real-time load data G of the conductor/ground wire is: G = F'; Where F′ is the real-time tension of the conductor/ground wire; the equivalent ice thickness h _m of the conductor/ground wire is calculated as follows: ①When G≤G _m , h _m =0; ②When G≥G _m , the actual wire length S is: <mrow><mi>S</mi><mo>=</mo><mn>400</mn><mo>+</mo><mfrac><mrow><msup><msub><mi>q</mi><mn>0</mn></msub><mn>2</mn></msup><mo>&amp;times;</mo><msup><mn>400</mn><mn>3</mn></msup></mrow><mrow><mn>24</mn><mo>&amp;times;</mo><msup><mrow><mo>(</mo><msub><mi>l</mi><mi>m</mi></msub><mo>&amp;times;</mo><msub><mi>q</mi><mn>0</mn></msub><mo>)</mo></mrow><mn>2</mn></msup></mrow></mfrac><mo>;</mo></mrow> The icing load w per unit length of wire is: <mrow><mi>w</mi><mo>=</mo><mfrac><mi>G</mi><mi>n</mi></mfrac><mo>&amp;times;</mo><mfrac><msqrt><mrow><mn>24</mn><mo>&amp;times;</mo><mi>S</mi><mo>-</mo><mn>400</mn></mrow></msqrt><mrow><mn>400</mn><mo>&amp;times;</mo><mn>20</mn></mrow></mfrac><mo>;</mo></mrow> Add the following correction factor w1 as _: <mrow><msub><mi>w</mi><mn>1</mn></msub><mo>=</mo><mfrac><mi>w</mi><mn>2</mn></mfrac><mo>&amp;times;</mo><mrow><mo>(</mo><mfrac><mrow><msub><mi>l</mi><mi>m</mi></msub><mo>&amp;times;</mo><msub><mi>q</mi><mn>0</mn></msub><mo>&amp;times;</mo><mi>n</mi></mrow><msup><mi>F</mi><mo>&amp;prime;</mo></msup></mfrac><mo>+</mo><mfrac><mi>w</mi><msub><mi>q</mi><mn>0</mn></msub></mfrac><mo>)</mo></mrow><mo>;</mo></mrow> The equivalent ice thickness h _m is: <mrow><msub><mi>h</mi><mi>m</mi></msub><mo>=</mo><msqrt><mrow><mfrac><mrow><mo>(</mo><msub><mi>w</mi><mn>1</mn></msub><mo>-</mo><msub><mi>q</mi><mn>0</mn></msub><mo>)</mo></mrow><mrow><mi>&amp;rho;</mi><mo>&amp;times;</mo><mi>&amp;pi;</mi></mrow></mfrac><mo>+</mo><mfrac><msup><mi>D</mi><mn>2</mn></msup><mn>4</mn></mfrac></mrow></msqrt><mo>-</mo><mfrac><mi>D</mi><mn>2</mn></mfrac></mrow> Among them, G _m is the maximum load obtained in step (2); D is the diameter of the conductor/ground wire, l _m is the maximum equivalent conductor/ground wire length obtained in step (3), and n is the conductor/ground wire split ρ is the standard ice density; (5) According to the real-time meteorological data monitored online, the equivalent ice thickness is selected to judge the amount of ice on overhead lines. 2. the on-line monitoring method of the equivalent icing thickness of overhead line strain tower according to claim 1, is characterized in that, described step (3) pole tower basic information comprises guide/ground wire unit length self-weight, guide/ground wire Number of splits, conductor/ground diameter, and insulator string type.