A method for selecting the installation point of lightning arresters for transmission lines based on the cumulative lightning trip rate curve

Abstract

The present invention discloses a method for selecting a point for installing a lightning arrester for a power transmission line based on a cumulative lightning trip rate curve, comprising the following steps: calculating the shielding trip rate, the counter-attack trip rate and the horizontal span weighted coefficient of the base tower of the entire power transmission line, multiplying the horizontal span weighted coefficient with the shielding trip rate and the counter-attack trip rate to obtain the lightning trip rate of the entire line, comparing the lightning trip rate of the entire line with the control value of the lightning trip rate of the voltage level line, and when it is necessary to carry out lightning protection transformation, calculating the weighted shielding trip rate and the weighted counter-attack trip rate to obtain a cumulative curve of the lightning trip rate, finding a control point in the cumulative curve of the lightning trip rate, and all points on the right side of the control point are the base towers of the entire line to which the line lightning arrester is to be installed. The present invention effectively solves the installation point of the lightning arrester for the power transmission line, improves the scientificity, rationality and efficiency of the selection of the installation point of the line lightning arrester, and improves the quality and efficiency of the lightning protection transformation of the power transmission line.

Description

Technical Field

[0001] The invention belongs to the technical field of power transmission and transformation equipment operation and maintenance and disaster prevention and mitigation, and specifically relates to a method for selecting points for lightning arrester installation of a power transmission line based on a cumulative lightning strike tripping rate curve. Background Art

[0002] Strengthening line insulation and reducing ground wire protection angle can generally only be adopted during the line construction stage, and there are many restrictions in the implementation process; tower head side needles, anti-winding lightning rods, controllable discharge lightning rods, lightning arresters, parallel gaps all have poor lightning protection effects, small protection ranges, or other negative effects, and are currently restricted from use or gradually removed. After years of operational verification, reducing the grounding resistance of towers and installing line lightning arresters have become the most practical and reliable lightning protection measures in the line operation stage. The phase separation and counter-tripping rates of towers equipped with line lightning arresters have been reduced to 0.

[0003] The grounding resistance of the tower has corresponding standards according to different soil resistivity. If it exceeds the threshold, it will be modified. The modification principle is clear, but it is more difficult to determine the installation strategy of the line lightning arrester. Which towers and phases to install, what is the installation order, and the scale of the final modification are all pain points that the power grid operation unit is very concerned about but has no effective methods. At present, based on operating experience, towers with high ground lightning density, unfavorable terrain (located on the top of the mountain) or towers that have experienced lightning strikes and tripping are generally selected for modification. From the statistical results, the effect is not good; or further based on the lightning protection calculation software to obtain the lightning strike tripping rate of the tower, but it is impossible to directly obtain the installation point, installation scale and priority of the line lightning arrester. There is no clear modification target, which is not conducive to the effective implementation of the lightning protection modification of the transmission line. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for selecting points for the installation of lightning arresters for power transmission lines based on a cumulative lightning trip rate curve, which aims to solve the problem of the method for selecting points for the installation of lightning arresters for power transmission lines and improve the quality and efficiency of lightning protection work for power transmission lines.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for selecting a point for installing a lightning arrester for a power transmission line based on a cumulative lightning trip rate curve, comprising the following steps:

[0006] Step S1: using the regulation method to calculate the lightning resistance level and counter-attack tripping rate of each phase of the base tower of the entire transmission line; using the electrical geometry model algorithm to calculate the shielding failure probability and shielding failure tripping rate of each phase of the base tower of the entire transmission line, and obtain the shielding failure tripping rate and counter-attack tripping rate of the base tower of the entire line;

[0007] Step S2: Calculate the horizontal span weighted coefficient of the base towers of the entire transmission line, multiply the horizontal span weighted coefficient by the shielding failure tripping rate and the counter-attack tripping rate to obtain the weighted shielding failure tripping rate and the weighted counter-attack tripping rate of the base towers of the entire line;

[0008] Step S3: summing the weighted shielding failure tripping rate and the weighted back-strike tripping rate to obtain the lightning stroke tripping rate of the entire line;

[0009] Step S4: Compare the lightning trip rate of the entire line with the control value of the lightning trip rate of the voltage level line. When the lightning trip rate of the entire line is less than or equal to the control value of the lightning trip rate of the voltage level line, there is no need to carry out lightning protection transformation. Otherwise, carry out lightning protection transformation, that is, enter step S5;

[0010] Step S5: arranging the weighted shielding failure tripping rate and weighted back-strike tripping rate of all the line-based towers in ascending order;

[0011] Step S6: Calculate the cumulative value of the weighted lightning trip rate of the line phase by phase from small to large, and obtain the cumulative curve of the lightning trip rate by using the exponential fitting method;

[0012] Step S7: Find the control point in the cumulative curve of lightning tripping rate, and use all points to the right of the control point as all the line-based towers where line arresters are to be installed.

[0013] Further, the counter-attack lightning resistance level indicates:

[0014] (1);

[0015] In the formula, Indicates the lightning resistance level of the base tower; Indicates the coupling coefficient between the conductor and the ground wire; It indicates the diversion coefficient of the base tower; Indicates the impact grounding resistance of the base tower; Indicates the height of the cross arm above the ground; Indicates the base tower height; Indicates the base tower inductance; Indicates the average height of the ground line; Indicates the average height of the conductor; Indicates the geometric coupling coefficient between the conductor and the ground wire; U 50% Indicates the positive polarity 50% impulse discharge voltage of the insulator string.

[0016] Furthermore, the back-tripping rate indicates:

[0017] (2);

[0018] In the formula, Indicates the back-tripping rate; Indicates the annual number of lightning strikes per 100km of the line; Indicates arc building rate; It indicates the stroke rate; It indicates the probability of lightning current exceeding the lightning withstand level I1 when lightning strikes the base tower.

[0019] Furthermore, the shielding failure trip rate is expressed as:

[0020] (3);

[0021] In the formula, Indicates the circuit breaker trip rate; Indicates the density of ground-to-ground flashes; represents the grand mean projection.

[0022] Furthermore, the shielding failure trip rate includes r iA 、r iB 、r iC ; r iA represents the tripping rate of phase A of the ith tower; r iB represents the tripping rate of phase B of the ith tower; r iC It represents the tripping rate of C phase winding failure of the ith tower;

[0023] Among them, the counter-tripping rate includes f iA 、f iB 、f iC ;f iA f represents the tripping rate of phase A of the i-th tower; iB f represents the tripping rate of phase B of the i-th tower; iC It represents the tripping rate of phase C of the i-th tower; i∈1,2,3...N; N represents the total number of towers in the entire line.

[0024] Furthermore, the specific process of obtaining the weighted shielding failure tripping rate and weighted counter-attack tripping rate of the whole line tower is as follows:

[0025] For a single-circuit line, when the total number of base towers on the entire line is N, the corresponding 6N weighted lightning trip rate values ​​are expressed as follows:

[0026] (4);

[0027] (5);

[0028] (6);

[0029] (7);

[0030] (8);

[0031] (9);

[0032] (10);

[0033] In the formula, Represents the horizontal span weighting coefficient; represents the horizontal span of the i-th tower; It represents the weighted shielding failure tripping rate of phase A of the ith tower; represents the weighted shielding failure tripping rate of phase B of the ith tower; represents the weighted shielding failure tripping rate of phase C of the ith tower; represents the weighted back-tripping rate of phase A of the ith tower; represents the weighted back-tripping rate of phase B of the ith tower; It represents the weighted back-tripping rate of phase C of the ith tower.

[0034] Furthermore, the lightning trip rate of the entire line is expressed as:

[0035] (11);

[0036] In the formula, n represents the lightning trip rate of the entire line, It represents the weighted lightning tripping rate of the ith tower.

[0037] Compared with the existing technology, the present invention has the following beneficial effects: (1) The present invention can effectively solve the problem of unreasonable installation points (base towers of the entire line) and transformation sequence of lightning arresters for transmission lines, improve the scientificity, rationality and efficiency of the selection of installation points for lightning arresters for lines, and improve the quality and efficiency of lightning protection transformation for transmission lines. (2) The method of the present invention is applicable to the lightning protection transformation of high-voltage transmission lines, and changes the decision-making of lightning arrester installation for lightning protection transformation lines from the original experience and qualitative analysis to quantitative comprehensive evaluation, scientifically, reasonably and efficiently determine the installation points (base towers of the entire line) and the installation sequence of lightning arresters for lines, and improve the quality and efficiency of lightning protection transformation work. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flow chart of the present invention.

[0039] Figure 2 This is the weighted lightning tripping rate distribution diagram of the base towers of the entire line of the present invention.

[0040] Figure 3 This is a curve diagram of the cumulative lightning tripping rate of the line of the present invention.

[0041] Figure 4 The invention calculates the shielding failure probability diagram of each phase of the base tower of the entire transmission line. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below with reference to implementation cases and accompanying drawings.

[0043] like Figure 1 As shown, the method for selecting the installation point of the transmission line arrester based on the cumulative lightning trip rate curve includes the following steps:

[0044] Step S1: Use the procedure method to calculate the lightning strike resistance level and counter-strike tripping rate of each phase of the transmission line tower; use the electrical geometry model algorithm to calculate the shielding failure probability and shielding failure tripping rate of each phase of the transmission line tower, and obtain the shielding failure tripping rate r of the transmission line tower. iA 、r iB 、r iC and the counter-tripping rate f iA 、f iB 、f iC ;

[0045] Step S2: Calculate the horizontal span weighting coefficient k of the transmission line towers i , the horizontal span weighting coefficient k i Multiply it by the shielding failure tripping rate and the counter-attack tripping rate to get the weighted shielding failure tripping rate of the entire line tower. , , and weighted back-tripping rate , , ;

[0046] Step S3: summing the weighted shielding failure tripping rate and the weighted back-strike tripping rate to obtain the lightning stroke tripping rate n of the entire line;

[0047] Step S4: Compare the lightning trip rate n of the entire line with the voltage level line lightning trip rate control value N S For comparison, when n≤N S , no need to carry out lightning protection transformation, when n>N S , lightning protection transformation needs to be carried out, that is, entering step S5;

[0048] Step S5: The weighted shielding failure tripping rate of all the line towers , , and weighted back-tripping rate , , Sort in ascending order;

[0049] Step S6: Calculate the cumulative value n of the line weighted lightning trip rate phase by phase from small to large acc , the cumulative curve of lightning tripping rate is obtained by using exponential fitting method;

[0050] Step S7: Find the control point S(X,N) in the lightning trip rate accumulation curve S ); All points to the right of point X are all the base towers of the entire line that need to be equipped with line arresters. The final lightning trip rate after the transformation will meet the standard control value requirements;

[0051] Among them, N S It indicates the control value of the lightning tripping rate of a certain voltage level line; X indicates the horizontal coordinate corresponding to the point on the lightning tripping rate curve.

[0052] Among them, the anti-lightning resistance level indicates:

[0053] (1);

[0054] In the formula, It indicates the lightning resistance level of the base tower, in kA; Indicates the coupling coefficient between the conductor and the ground wire; It indicates the diversion coefficient of the base tower; It indicates the impact grounding resistance of the base tower, in Ω; Indicates the height of the cross arm from the ground, in m; Indicates the base tower height, in m; Indicates the base tower inductance, unit: μH; Indicates the average height of the ground line, in meters; Indicates the average height of the conductor, in m; Indicates the geometric coupling coefficient between the conductor and the ground wire; U 50% It indicates the positive polarity 50% impulse discharge voltage of the insulator string, in kV.

[0055] Among them, the counter-tripping rate is expressed as:

[0056] (2);

[0057] In the formula, Indicates the counter-tripping rate, times / (100km·a); Indicates the annual number of lightning strikes per 100km of the line, times / 100km; Indicates arc building rate; It indicates the stroke rate; It indicates the probability of lightning current exceeding the lightning withstand level I1 when lightning strikes the base tower.

[0058] Among them, the probability of each phase of the transmission line tower is calculated, such as Figure 4 As shown in the figure B Indicates the height of the lightning conductor B, in meters; h D Indicates the height of the conductor D, in meters; represents the protection angle (positive in the figure); r s Indicates the striking distance between the conductor and the ground wire; Indicates ground strike distance; represents the incident angle of the lightning current (negative in the figure), and the strike distance corresponding to the lightning current I is ; I represents lightning current, unit is kA; F represents the intersection of the exposed arc of the conductor and the shielded arc of the ground wire; x1 represents the horizontal coordinate of point F; y1 represents the vertical coordinate of point F; G represents the intersection of the exposed arc of the conductor and the shielded arc of the ground; x2 represents the horizontal coordinate of point G; y2 represents the vertical coordinate of point G; L1 and L2 represent two incident leader lines; C1 represents the shielded arc of the lightning conductor; C2 represents the exposed arc; C3 represents the area where the lightning current hits the ground.

[0059] Among them, the shielding failure trip rate is expressed as:

[0060] (3);

[0061] In the formula, Indicates the circuit breaker tripping rate, times / (100km·a); Indicates the density of ground-to-ground lightning, times / (km 2 ·Year); Represents the total average projection, unit: m.

[0062] Among them, the regulation method is used to calculate the lightning resistance level and counter-strike tripping rate of each phase of the transmission line base tower; the electrical geometry model algorithm is used to calculate the shielding failure probability and shielding failure tripping rate of each phase of the transmission line base tower, and the shielding failure tripping rate r of the whole line base tower is obtained. iA 、r iB 、r iC and the counter-tripping rate f iA 、f iB 、f iC , as shown in Table 1:

[0063] Table 1: Shielding failure trip rate and counter-attack trip rate

[0064] ;

[0065] Table 1, r iA represents the tripping rate of phase A of the ith tower; r iB represents the tripping rate of phase B of the ith tower; r iC represents the tripping rate of phase C of the ith tower; f iA f represents the tripping rate of phase A of the i-th tower; iB f represents the tripping rate of phase B of the i-th tower; iC It represents the tripping rate of phase C of the i-th tower; i∈1,2,3...N; N represents the total number of towers along the entire line.

[0066] Among them, the weighted shielding failure tripping rate of the whole line tower is obtained , , and weighted back-tripping rate , , The specific process is:

[0067] For a single-circuit line, if the total number of base towers along the entire line is N, then there are 6N weighted lightning trip rate values ​​corresponding to it;

[0068] (4);

[0069] (5);

[0070] (6);

[0071] (7);

[0072] (8);

[0073] (9);

[0074] (10);

[0075] In the formula, Represents the horizontal span weighting coefficient; represents the horizontal span of the i-th tower; It represents the weighted shielding failure tripping rate of phase A of the ith tower; represents the weighted shielding failure tripping rate of phase B of the ith tower; represents the weighted shielding failure tripping rate of phase C of the ith tower; represents the weighted back-tripping rate of phase A of the ith tower; represents the weighted back-tripping rate of phase B of the ith tower; It represents the weighted back-tripping rate of phase C of the ith tower.

[0076] Among them, the lightning trip rate of the entire line is obtained express;

[0077] (11);

[0078] In the formula, It represents the weighted lightning tripping rate of the ith tower.

[0079] like Figure 3 As shown, the lightning trip rate of the entire line is The control value of lightning trip rate of voltage level line N S The specific process of comparison is as follows:

[0080] when ≤N S , there is no need to carry out lightning protection transformation on the base towers of the entire line, and the work is completed; when >N S, then it is necessary to carry out lightning protection transformation; the control values ​​of lightning tripping rate of typical high-voltage transmission lines are shown in Table 2:

[0081] Table 2 Control values ​​of lightning trip rate of typical high voltage transmission lines

[0082] .

[0083] Among them, Figure 2 As mentioned above, the weighted lightning tripping rate of the entire line tower and each phase , , , , , Sort in ascending order.

[0084] Among them, the cumulative value of the weighted lightning trip rate of the line is calculated phase by phase from small to large. acc , the exponential fitting method is used to obtain the cumulative curve of lightning trip rate; since the weighted lightning trip rate of the entire line gradually increases, the slope of the cumulative curve of lightning trip rate will continue to increase, such as Figure 3 described.

[0085] The invention obtains the lightning tripping rate of the base towers and each phase of the whole line considering the span factor by introducing the weighted coefficient of the horizontal span of the base towers of the whole line, which is convenient for direct sorting. , , and weighted back-tripping rate , , The cumulative sum from small to large and the exponential fitting method are used to obtain the cumulative curve of lightning trip rate, and the installation points (towers) of all line arresters are directly determined. This is different from the traditional method of selecting installation points from high to low according to the lightning trip rate, calculating the lightning trip rate of the entire line, and then comparing it with the voltage level line lightning trip rate control value N. S Compared with the method of repeatedly comparing and determining whether to continue to perform more transformation steps, the efficiency is significantly improved.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve, characterized in that: The steps include: Step S1: using the regulation method to calculate the lightning resistance level and counter-attack tripping rate of each phase of the base tower of the entire transmission line; using the electrical geometry model algorithm to calculate the shielding failure probability and shielding failure tripping rate of each phase of the base tower of the entire transmission line, and obtain the shielding failure tripping rate and counter-attack tripping rate of the base tower of the entire line; Step S2: Calculate the horizontal span weighted coefficient of the base towers of the entire transmission line, multiply the horizontal span weighted coefficient by the shielding failure tripping rate and the counter-attack tripping rate to obtain the weighted shielding failure tripping rate and the weighted counter-attack tripping rate of the base towers of the entire line; Step S3: summing the weighted shielding failure tripping rate and the weighted back-strike tripping rate to obtain the lightning stroke tripping rate of the entire line; Step S4: Compare the lightning trip rate of the entire line with the control value of the lightning trip rate of the voltage level line. When the lightning trip rate of the entire line is less than or equal to the control value of the lightning trip rate of the voltage level line, there is no need to carry out lightning protection transformation. Otherwise, carry out lightning protection transformation, that is, enter step S5; Step S5: arranging the weighted shielding failure tripping rate and weighted back-strike tripping rate of all the line-based towers in ascending order; Step S6: Calculate the cumulative value of the weighted lightning trip rate of the line phase by phase from small to large, and obtain the cumulative curve of the lightning trip rate by using the exponential fitting method; Step S7: Find the control point in the cumulative curve of lightning tripping rate, and use all points to the right of the control point as all the line-based towers where line arresters are to be installed.

2. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 1 is characterized in that: The level of lightning resistance against counterattack indicates: （1）； In the formula, Indicates the lightning resistance level of the base tower; Indicates the coupling coefficient between the conductor and the ground wire; It indicates the diversion coefficient of the base tower; Indicates the impact grounding resistance of the base tower; Indicates the height of the cross arm above the ground; Indicates the base tower height; Indicates the base tower inductance; Indicates the average height of the ground line; Indicates the average height of the conductor; It represents the geometric coupling coefficient between the conductor and the ground wire; U 50% Indicates the positive polarity 50% impulse discharge voltage of the insulator string.

3. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 2, characterized in that: The back-tripping rate indicates: （2）； In the formula, Indicates the back-tripping rate; Indicates the annual number of lightning strikes per 100km of the line; Indicates arc building rate; It indicates the stroke rate; It indicates the probability of lightning current exceeding the lightning withstand level I1 when lightning strikes the base tower.

4. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 3 is characterized in that: The shielding trip rate is expressed as: （3）； In the formula, Indicates the circuit breaker trip rate; Indicates the density of ground-to-ground flashes; represents the grand mean projection.

5. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 4 is characterized in that: The shielding failure trip rate includes r iA 、r iB 、r iC ; r iA represents the tripping rate of phase A of the ith tower; r iB represents the tripping rate of phase B of the ith tower; r iC It represents the tripping rate of C phase winding failure of the ith tower; Among them, the counter-tripping rate includes f iA 、f iB 、f iC ;f iA f represents the tripping rate of phase A of the i-th tower; iB f represents the tripping rate of phase B of the i-th tower; iC It represents the tripping rate of phase C of the i-th tower; i∈1,2,3...N; N represents the total number of towers in the entire line.

6. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 5 is characterized in that: The specific process of obtaining the weighted shielding failure tripping rate and weighted counter-attack tripping rate of the whole line tower is as follows: For a single-circuit line, when the total number of base towers on the entire line is N, the corresponding 6N weighted lightning trip rate values ​​are expressed as follows: （4）； （5）； （6）； （7）； （8）； （9）； （10）； In the formula, Represents the horizontal span weighting coefficient; represents the horizontal span of the i-th tower; It represents the weighted shielding failure tripping rate of phase A of the ith tower; represents the weighted shielding failure tripping rate of phase B of the ith tower; represents the weighted shielding failure tripping rate of phase C of the ith tower; represents the weighted back-tripping rate of phase A of the ith tower; represents the weighted back-tripping rate of phase B of the ith tower; It represents the weighted back-tripping rate of phase C of the ith tower.

7. The method for selecting a transmission line arrester installation point based on a cumulative lightning trip rate curve according to claim 6 is characterized in that: The lightning trip rate of the entire line is expressed as: （11）； In the formula, n represents the lightning trip rate of the entire line, It represents the weighted lightning tripping rate of the ith tower.

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