CN102680834A - Method and device for evaluating induction lightning protection range of low-voltage distribution line arrester - Google Patents

Abstract

The invention discloses a risk assessment method for the protection range of lightning arresters for low-voltage distribution lines. Firstly, relevant parameters of low-voltage distribution lines are collected, and then the collected parameters are substituted into specific formulas to calculate the maximum value of lightning arresters that can prevent the lines from being subjected to induction lightning. Longer installation distance, if the arrester is installed within the farthest installation distance, it can protect the low-voltage distribution line, so it provides a reference for the configuration scheme of the arrester for the low-voltage distribution line. The data collected by this evaluation method is easy to obtain, and the whole process does not involve complex calculations. The invention also discloses a device for evaluating the protection range of the lightning arrester for low-voltage distribution lines corresponding to the above evaluation method. The evaluation method and the evaluation device can be used in combination to realize the purpose of evaluating the protection range.

Description

Low-voltage distributing line lightning arrester induction thunder protection domain appraisal procedure and device

Technical field

The present invention relates to distribution line shocking preventing technology field, particularly relate to a kind of low-voltage distributing line lightning arrester induction thunder protection domain methods of risk assessment and device.

Background technology

Lightning protection measures to low-voltage distributing line mainly contains: lightning arrester, protection gap, reinforced insulation are installed, are set up lightning conducter etc.Because the restriction of cost and feasibility factor, lightning protection does not have good lightning protection effect to reinforced insulation to low-voltage distributing line with setting up lightning conducter.Can release lightning current and in time turn-off power frequency continued flow of lightning arrester is the effective means that reduces lightning outage rate, thereby improves the reliability of system.See that from China's more than ten years leakage conductor ruuning situation leakage conductor reduces the line upkeep workload to reducing tripping rate with lightning strike and accident rate, has good effect.At present, a large amount of lightning arresters that use in the low-voltage distributing line are in order to avoid controller switching equipment is damaged under lightning surge.

It is significant to improving the lightning arrester work efficiency to greatest extent to form rational low-voltage distribution Allocation of Lightning Arrester scheme.Leakage conductor is installed can play good effect to the lightning protection of 10kV distribution line completely, but receives the restriction of factors such as cost.In addition, lightning arrester has influenced the power supply reliability of system in case damage or puncture need to have a power failure and could change.Therefore, form rational Allocation of Lightning Arrester scheme to the lightning protection of 10kV distribution line with to ensure power supply reliability significant.

Low-voltage distributing line insulator chain tolerance lightning impulse voltage level is between 100 ~ 300kV, and circuit direct lightning strike lightning withstand level has only several kilo-amperes.During the thunderbolt the earth, can reach more than the 500kV at the induced overvoltage that produces on the lead, considerably beyond insulator chain lightning impulse voltage tolerance value.The investigation data show: distribution line damage to crops caused by thunder accident accounts for 70 ~ 80% of whole electric system damage to crops caused by thunder accident, causes for responding to thunder 75% or more wherein approximately, and about 25% causes for direct lightning strike.Pertinent literature is through setting up the electric geometric model of distribution line, and the ratio that calculates induction thunder trip-out rate and direct lightning strike trip-out rate is 5:1.Therefore, in distribution line, reduce the tripping operation accident that causes because of the induction thunder and will reduce the distribution line tripping rate with lightning strike to a great extent.

The most important factor of the lightning induced voltage that in the 10kV distribution line, forms of thunderbolt the earth is because the electric charge that pilot stage is assembled rapid release after discharge takes place produces.After discharge takes place, provide the leakage path of enough gathering electric charge that lightning induced voltage is reduced.Therefore, as long as low-voltage distributing line lightning arrester packing density is suitable, the line influence tripping rate with lightning strike will reduce greatly.

Summary of the invention

Based on above-mentioned situation, the present invention proposes a kind of low-voltage distributing line lightning arrester induction thunder protection domain appraisal procedure and device, through analyzing the protection domain of lightning arrester induction thunder, for the allocation plan of low-voltage distributing line lightning arrester provides reference.

A kind of low-voltage distributing line lightning arrester induction thunder protection domain appraisal procedure comprises step:

Gather the related data of low-voltage distributing line: circuit average height h, amplitude of lightning current I, lightning arrester operation voltage U _m, insulator chain impulse flashover voltage U _50%

Respond to thunder protection domain x according to the computes lightning arrester:

$x<0.67\sqrt{[{\left(\frac{U_{50\%}}{U_m}\right)}^2-1]}{h}^{0.4}{I}^{0.74}.$

A kind of low-voltage distributing line lightning arrester induction thunder protection domain apparatus for evaluating comprises:

Data acquisition module, the related data that is used to gather low-voltage distributing line: circuit average height h, amplitude of lightning current I, lightning arrester operation voltage U _m, insulator chain impulse flashover voltage U _50%

The protection domain determination module is used for according to computes lightning arrester induction thunder protection domain x:

$x<0.67\sqrt{[{\left(\frac{U_{50\%}}{U_m}\right)}^2-1]}{h}^{0.4}{I}^{0.74}.$

Low-voltage distributing line lightning arrester induction thunder protection domain methods of risk assessment of the present invention; Gather the correlation parameter of low-voltage distributing line earlier; With the specific formula of gathering of parameter substitution, calculating can avoid circuit to be responded to the mounting distance farthest of the lightning arrester of thunder again, and lightning arrester is installed in this farthest in the mounting distance; Can play a protective role to low-voltage distributing line, therefore reference is provided for the Allocation of Lightning Arrester scheme of low-voltage distributing line.The data of the required collection of this appraisal procedure are easy to obtain, and whole process does not relate to complex calculations.Low-voltage distributing line lightning arrester induction thunder protection domain apparatus for evaluating of the present invention is the device corresponding with above-mentioned appraisal procedure, and appraisal procedure is used in combination with apparatus for evaluating, can realize the purpose of protection domain assessment.

Description of drawings

Fig. 1 is a leakage conductor operating point synoptic diagram;

Fig. 2 is low-voltage distributing line lightning arrester induction thunder protection domain appraisal procedure schematic flow sheet of the present invention;

Fig. 3 is low-voltage distributing line lightning arrester induction thunder protection domain apparatus for evaluating structural representation of the present invention.

Embodiment

Low-voltage distributing line lightning arrester of the present invention induction thunder protection domain appraisal procedure and device through specific computing method, obtain the protection domain of lightning arrester, thereby the data support are provided for the installation of lightning arrester.Be example with the 10kV distribution line below, and combine the present invention of accompanying drawing illustrated in detail.

The leakage path of lightning current in time is provided near the lead the lightning strike spot,, prevents that the tripping operation of insulator chain flashover has vital role reducing lightning induced voltage.Shown in Figure 1 is lightning arrester operating point synoptic diagram, and O is a lightning strike spot among the figure, O ₁For the shaft tower coordinate points and apart from the lightning strike spot horizontal range the most nearby, and distance is S, O ₂Be lightning arrester mounting points, O ₁With O ₂Between distance be x, suppose that x is the upper limit of protection domain, the value of then the obtaining x scope that promptly is protected.At O ₁Point voltage surpasses before the line insulator string impulse withstand voltage, O ₂The action of some lightning arrester in time provides the leakage path of assembling electric charge, therefore, and O ₂Point need meet the following conditions:

1) O ₂Point induced overvoltage value is greater than the lightning arrester operation voltage;

2) at O ₂Put the lightning induced voltage value greater than before the lightning arrester operation voltage, O ₁Point lightning induced voltage value is less than insulator chain impulse flashover voltage tolerance value U _50%

Suppose lightning current Get 10kV distribution line insulator chain lightning impulse tolerance value U _50%=200kV, lightning arrester lightning impulse residual voltage is 50kV, then O ₁Point lightning induced voltage size is:

$U_{o_{1}g}=\frac{9.62\mathrm{gIt}}{S}\&le;\frac{9.62\mathrm{hIt}}{0.67h^{0.6}{I}^{0.74}}<U_{50\%}---\left(1\right)$

O ₂Point lightning induced voltage size is:

$U_{o_{2}g}=\frac{9.62\mathrm{Ith}}{\sqrt{S^2+x^2}}=\frac{9.62\mathrm{Ith}}{\sqrt{{\left(0.67h^{0.6}{I}^{0.74}\right)}^2+x^2}}\&GreaterEqual;U_m---\left(2\right)$

Simultaneous formula (1), (2)

$x<0.67\sqrt{[{\left(\frac{U_{50\%}}{U_m}\right)}^2-1]}{h}^{0.4}{I}^{0.74}---\left(3\right)$

Can know x and I by formula (3) ^0.74Be directly proportional, promptly work as

The time, satisfy condition 1), 2), therefore, lightning arrester induction thunder protection domain does

Based on above-mentioned theory, the appraisal procedure of low-voltage distributing line lightning arrester induction thunder protection domain of the present invention, as shown in Figure 2, comprise step:

Step S1, the related data of gathering low-voltage distributing line: circuit average height h, amplitude of lightning current I, lightning arrester operation voltage U _m, insulator chain impulse flashover voltage U _50%

Step S2, calculate lightning arrester induction thunder protection domain x according to formula (3):

The apparatus for evaluating of low-voltage distributing line lightning arrester induction thunder protection domain of the present invention is the device corresponding with above-mentioned appraisal procedure, and is as shown in Figure 3, comprising:

Data acquisition module, the related data that is used to gather low-voltage distributing line: circuit average height h, amplitude of lightning current I, lightning arrester operation voltage U _m, insulator chain impulse flashover voltage U _50%

The protection domain determination module is used for according to computes lightning arrester induction thunder protection domain x:

$x<0.67\sqrt{[{\left(\frac{U_{50\%}}{U_m}\right)}^2-1]}{h}^{0.4}{I}^{0.74}.$

Can know that by above description and Fig. 3 data acquisition module links to each other with the protection domain determination module, has constituted this apparatus for evaluating.This apparatus for evaluating is used in combination with above-mentioned appraisal procedure, can realizes the object of the invention.

The above embodiment has only expressed several kinds of embodiments of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to claim of the present invention.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the present invention's design, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with accompanying claims.

Claims (2)

1. A low-voltage power distribution line surge arrester induction lightning protection range evaluation method, is characterized in that, comprises the steps: Collect relevant data of low-voltage distribution lines: average line height h, lightning current amplitude I, surge arrester operating voltage U _m , insulator string impact flashover voltage U _50% ; Calculate the lightning protection range x of the arrester according to the following formula: $\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0.67</span>}\sqrt{<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 50</span>}<span\; class="notranslate">\; \%</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; 0.4</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; 0.74</span>}}<span\; class="notranslate">\; .</span>$ 2. A low-voltage distribution line lightning arrester induction lightning protection range evaluation device, characterized in that it includes: The data acquisition module is used to collect relevant data of low-voltage power distribution lines: average line height h, lightning current amplitude I, arrester operating voltage U _m , insulator string impact flashover voltage U _50% ; The protection range determination module is used to calculate the lightning protection range x of the lightning arrester according to the following formula: $\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0.67</span>}\sqrt{<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 50</span>}<span\; class="notranslate">\; \%</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; 0.4</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; 0.74</span>}}<span\; class="notranslate">\; .</span>$

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