CN103675511B - Method for evaluating double-track elevated section electrified railway lightning trip-out rate in AT mode - Google Patents

Abstract

The invention discloses a method for measuring an electrified railway double-track elevated section contact network lightning trip-out rate in an AT mode. The method comprises the steps of (1) obtaining electrified railway line parameters, (2) determining the influence areas of different lightning types of a contact network and calculating the coordinates of single side lightning type dividing points, (3) calculating a double-track induction lightning trip-out rate, (4) calculating a double-track shielding failure trip-out rate, and (5) determining a double-track total trip-out rate. The method is convenient to calculate, and a problem of the difficult calculation of the electrified railway lightning trip-out rate in the AT mode is solved.

Description

The method of overhead section of electric railway tripping rate with lightning strike of multiple line under evaluation and test AT modes

Technical field

The present invention relates to electric railway multiple line elevated bridge section contact net tripping rate with lightning strike under a kind of measurement AT power supply modes Method, it is more particularly to a kind of electric railway multiple line elevated bridge section under AT power supply modes is calculated based on electric geometry method to connect The method of net-fault indirect lightning strike, back flash-over rate, it is adaptable to electric railway lightning Protection Design and Lightning Transformation under AT power supply modes, Belong to railway system's overvoltage field.

Background technology

Tractive power supply system lightning stroke trip has had a strong impact on the safe and stable operation of China's electric railway.To ensure train Reliability of operation, accurately calculates the tripping rate with lightning strike of contact net supply line, assesses its impact to traction power supply reliability, Often it needs to be determined that the tripping rate with lightning strike of contact net.At present, electrification railway contact net thunderbolt type is divided into sense under AT power supply modes Should be struck by lightning (thunderbolt the earth), two kinds of shielding (thunderbolt positive feeder, carrier cable, contact line), conventional data deficiencies are to AT power supply modes The method that lower both tripping rate with lightning strike of electric railway carry out accurate calculating, is that electric railway is entered under China's AT power supply modes Targetedly lightning Protection Design brings very big difficulty to row with Lightning Transformation.

The content of the invention

It is an object of the invention to provide electric railway multiple line elevated bridge section contact net under a kind of measurement AT power supply modes The method of tripping rate with lightning strike, can calculate electric railway multiple line elevated bridge section contact net under AT power supply modes every using the method Hundred kilometers of year indirect lightning strike and back flash-over rate.

The present invention realizes that the know-why of above-mentioned purpose is using electricity under conventional electrical geometric model analysis AT power supply modes Indirect lightning strike, the shielding situation of gasification Double-Track Railway elevated bridge section contact net, its principle is as shown in Figure 1.Multiple line contacts barrier Section is in symmetrical structure, it is assumed that left side is uplink, and right side is downlink, and O is zero, is held with up, downlink respectively Power rope, positive feeder position are the center of circle, and carrier cable is hit away from r with lightning leader_c, lightning leader hit away from r to positive feeder_gFor radius work Camber line, then the earth is hit away from r with lightning leader_eMake the straight line parallel to the earth, A, B, C, A ', B ' points, wherein H are intersected at respectively It is overpass to ground level, h_gBe positive feeder to overhead bridge floor height, h_cBe carrier cable to overhead bridge floor height, a arrives for carrier cable The distance of post inboard, b is distance of the positive feeder to post inboard, and c is multiple line up and down line centre distance.Thunder and lightning falls in A Ground is hit when point left side and A ' right sides, induced overvoltage is now produced on contact net high-voltage conducting wires, that is, indirect lightning strike occurs；Thunder When electricity falls in the middle of A, B and 2 points of A ', B ', the positive feeder of contact net is hit at 2 points, when falling in the middle of B, B ', hit contact at 2 points Net carrier cable, this all will produce shielding overvoltage on contact net, that is, shielding will occur.

Under normal circumstances contact net up-downgoing structure is identical, in order to simplify calculating, it can be assumed that A points left side and A ' right side Indirect lightning strike siding-to-siding block length it is essentially equal, shielding interval AB and A ' B ', BC and CB ' it is equal respectively, now indirect lightning strike correspondence Siding-to-siding block length be (- ∞, x_a) interval 2 times, the corresponding siding-to-siding block length of shielding is (x_a, x_c) 2 times.Therefore, uplink Indirect lightning strike, back flash-over rate are respectively equal to the overhead induced lightening of the indirect lightning strike of downgoing line, back flash-over rate, i.e. multiple line Hit, back flash-over rate be respectively unilateral circuit (upstream or downstream) indirect lightning strike, 2 times of back flash-over rate.

The technical solution adopted for the present invention to solve the technical problems is mainly included the following steps that：

The first step, obtains electric railway line parameter circuit value, including overpass, to ground level, carrier cable, positive feeder are to overhead Bridge floor height, the distance of carrier cable, positive feeder to post inboard, multiple line up and down line centre distance, the 50% of insulator chain Impulse sparkover voltage, positive feeder radius, Thunderstorm Day, lightning strike density, insulator chain average running voltage gradient, pillar ground connection electricity Resistance, pillar equivalent inductance, lightning current wave head time, corona correction coefficient, inductance in parallel value of the adjacent positive feeder in pillar both sides etc..

Second step, determines the influence area of the different thunderbolt types of contact net, calculates unilateral separation A, C coordinate.

Coordinate system as shown in Figure 1 is set up, the corresponding coordinate of A points is (x_a, y_a), the corresponding coordinate of C points is (x_c, y_c), A ' corresponding coordinate is (x_a′, y_a′).Now indirect lightning strike is corresponding interval for (- ∞, x_a) and (x_a′,+∞), shielding correspondence Interval be (x_a, x_a′)。

According to the geometrical relationship of each point, the coordinate of unilateral separation A, C is calculated, each point coordinates is determined by following formula：

In formula：H is overpass to ground level (unit：M), h_gBe positive feeder to overhead bridge floor height (unit：M), h_cTo hold Power rope is to overhead bridge floor height (unit：M), a is distance (unit of the carrier cable to post inboard：M), b is positive feeder to pillar Distance (the unit of inner side：M), c is multiple line up and down line centre distance (unit：M), r_cFor lightning leader carrier cable is hit away from (unit：M), r_gPositive feeder is hit away from (unit for lightning leader：M), r_eThe earth is hit away from (unit for lightning leader：m).

r_c、r_gCan be calculated using following empirical equation：

Or

In formula：I is amplitude of lightning current (unit：KA), H is overpass to ground level, h_cIt is high to overhead bridge floor for carrier cable Degree, h_gBe positive feeder to overhead bridge floor height.

a₀、b₀、c₀Value can be carried out according to field experimentation or mimic buss experimental result, it is also possible to reference to power system Experience takes values below：

a₀=10, b₀=0.65；Or a₀=0.67, b₀=0.74, c₀=0.6；Or a₀=1.57, b₀=0.69, c₀= 0.45。

r_eCan be calculated as follows：

r_e=k₂r_c

Wherein k₂For striking distance factor, computing formula is as follows：

k₂=1.066+ (h_c+H)/216.45

In formula：H is overpass to ground level, h_cBe carrier cable to overhead bridge floor height.

Or k₂=22/ (h+H), or k₂=1.94- (h+H)/26,

Or k₂=1.08- (h+H)/59, or k₂=1.05- (h+H)/87.

In formula：H is overpass to ground level, and h is pillar to overhead bridge floor height (unit：m).

To simplify calculating, r can be also made_c=r_g=r_e。

3rd step, calculates multiple line indirect lightning strike trip-out rate.

First, unilateral indirect lightning strike interval (- ∞, x are calculated according to following formula_a) effective projected length：

Wherein：

In formula：H be overpass to ground level, I is amplitude of lightning current, h_gBe positive feeder to overhead bridge floor height, h_cFor load Rope is to overhead bridge floor height, k₀For the geometrical coupling ratio between positive feeder and carrier cable, U_50%For insulator chain 50% impacts Discharge voltage (unit：kV).

k₀Can be calculated as follows：

In formula：D ' is the distance (unit between carrier cable and positive feeder mirror image：M), d is the distance between carrier cable and positive feeder (unit：M), r is positive feeder radius (unit：m).

Then, unilateral indirect lightning strike trip-out rate is calculated according to the following formula：

Then multiple line indirect lightning strike trip-out rate is：

Wherein：Υ=0.023T_d ^0.3For lightning strike density (unit：Secondary/km²My god), T_dFor Thunderstorm Day (unit：My god/year), f (I) it is probability of lightning current density, η is to build lonely rate.

F (I) may be used to lower empirical equation and be calculated：

Or

Or

Or

Or

Or

The calculating of η can be carried out as the following formula：

η=(4.5E^0.75-14)×10^-2

In formula：E is insulator chain average running voltage gradient (unit：kV/m).

Calculate the lower limit of integral I in multiple line indirect lightning strike trip-out rate formula_eDetermine as the following formula：

Wherein：

In formula：β be pillar diverting coefficient, R_iFor pillar earth resistance (unit：Ω), k is between positive feeder and carrier cable The coefficient of coup, L_tPillar equivalent inductance (unit：μ H), τ_fFor lightning current wave head time (unit：μs).

Wherein k=k₁k₀, k₁For corona correction coefficient, contact net desirable 1.15.

In formula：L_gFor the inductance in parallel value (unit of the adjacent positive feeder in pillar both sides：μH).

Upper limit of integral I_maxAccording to the significance level or the specific requirement value of industry of circuit, it is also possible to be by distribution probability Amplitude of lightning current when 90% or 99% is estimated.

4th step, calculates according to the following formula multiple line back flash-over rate：

In formula：For unilateral back flash-over rate.

Lower limit of integral

Upper limit of integral I_maxValue is ibid.

5th step, total tripping rate with lightning strike of multiple line contact net is indirect lightning strike and back flash-over rate sum, i.e., according to the following formula Calculate the total trip-out rate of multiple line：

N=n_gy+n_c

The solution have the advantages that and adopt electric geometry method, it is proposed that electric railway under a kind of AT power supply modes is answered The indirect lightning strike of line elevated bridge section contact net, back flash-over rate computational methods, solve electric railway thunder under AT power supply modes Hit the problem of trip-out rate dyscalculia.

Description of the drawings

The present invention is further illustrated with reference to the accompanying drawings and examples.

Fig. 1 is multiple line elevated bridge section contact net electric geometry method schematic diagram

Specific embodiment

Below by example, with reference to accompanying drawing 1, technical scheme is further described.

The first step, obtains line parameter circuit value.Certain Double-Track Railway elevated bridge section circuit, overpass is to ground level 10m, positive feeder pair Overhead bridge floor height 8m, to overhead bridge floor height 7.8m, away from post inboard 3m, positive feeder is away from post inboard for carrier cable for carrier cable 0.8m, centre distance 6m of multiple line up and down line, positive feeder radius 6.25mm, insulator U50% discharge voltage 270kV, thunder The μ s of electric current wave head time 2.6, Thunderstorm Day 40 days, insulator chain average running voltage gradient 20.36kV, pillar earth resistance 10 Ω, the μ H of pillar equivalent inductance 6.72, the μ H of inductance in parallel value 36.85 of the adjacent positive feeder in pillar both sides, corona correction coefficient 1.15.

Calculate seasonAnd a₀=10, b₀=0.65；Choosing probability of lightning current density is

Second step, calculates indirect lightning strike, back flash-over rate upper limit of integral and lower limit.

Indirect lightning strike lower limit of integral I is calculated using above-mentioned formula_eFor：

I_e=39kA

I_maxAmplitude of lightning current when by distribution probability being 99% is estimated：

I_max=176kA

Calculate shielding range of integration I_c、I_maxFor：

I_c=4kA, I_max=176kA

3rd step, calculates multiple line indirect lightning strike trip-out rate.

Using A, C coordinate formula in indirect lightning strike lightning current bound interval range I_e～I_maxIt is interior to calculate A, C coordinate point Cloth, it is determined that unilateral indirect lightning strike valid interval, recycles following formula to calculate multiple line indirect lightning strike trip-out rate：

Result of calculation is n_gy=0.8981 time/100km.

4th step, calculates multiple line back flash-over rate.

Using A, C coordinate formula in shielding lightning current bound interval range I_c～I_maxIt is interior to calculate the distribution of A, C coordinate, really The shielding of order side affects interval, recycles following formula to calculate multiple line back flash-over rate：

Result of calculation is n_g=8.8468 times/100km.

5th step, using following formula total trip-out rate is calculated：

N=n_gy+n_c

Result of calculation is n=9.7449 time/100km.

Claims (2)

1. under a kind of measurement AT power supply modes electric railway multiple line elevated bridge section contact net tripping rate with lightning strike method, its feature It is that it is comprised the following steps：

The first step, obtains electric railway line parameter circuit value, including overpass, to ground level, carrier cable, positive feeder are to overhead bridge floor Highly, carrier cable, positive feeder to post inboard distance, multiple line up and down line centre distance, insulator chain 50% impact Discharge voltage, positive feeder radius, Thunderstorm Day, lightning strike density, insulator chain average running voltage gradient, pillar earth resistance, Post equivalent inductance, lightning current wave head time, corona correction coefficient, the inductance in parallel value of the adjacent positive feeder in pillar both sides；

Second step, calculates the coordinate of unilateral separation A, C, and computing formula is as follows：

$\left\{\begin{array}{c}{x}_a=-\sqrt{{r_g}^2-{\[r_e-(h_g+H)\]}^2}-(a+b)\\ y_a=r_e\end{array}\right.$

$\left\{\begin{array}{c}{x}_c=\frac{c}{2}\\ y_c=\sqrt{{r_c}^2-\frac{c^2}{4}}+h_c+H\end{array}\right.$

In formula：H is overpass to ground level, unit：m；h_gBe positive feeder to overhead bridge floor height, unit：m；h_cFor carrier cable pair Overhead bridge floor height, unit：m；A be carrier cable to post inboard distance, unit：m；B be positive feeder to post inboard away from From unit：m；C be multiple line up and down line centre distance, unit：m；r_cCarrier cable is hit away from unit for lightning leader：m；r_g Positive feeder is hit away from unit for lightning leader：m；r_eThe earth is hit away from unit for lightning leader：m；

3rd step, the impact for dividing different thunderbolt types is interval, and the corresponding siding-to-siding block length of indirect lightning strike is (- ∞, x_a) interval 2 Times, the corresponding siding-to-siding block length of shielding is (x_a, x_c) 2 times；

4th step, calculates according to the following formula multiple line indirect lightning strike trip-out rate：

Wherein：Υ=0.023T_d ^0.3For lightning strike density, unit：Secondary/km²My god；T_dFor Thunderstorm Day, unit：My god/year, f (I) is Probability of lightning current density, to build lonely rate, Δ L is the interval effective projected length of indirect lightning strike to η；

η computing formula are as follows：

η=(4.5E^0.75-14)×10^-2

In formula：E be insulator chain average running voltage gradient, unit：kV/m；

Probability of lightning current density f (I) computing formula is as follows：

$f\left(I\right)=0.026\×{10}^{-\frac{I}{88}}$

Δ L computing formula are as follows：

$\mathrm{\&Delta;}L=\left\{\begin{array}{cc}{x}_a-x_e,& x_e<x_a\\ 0,& x_e\&GreaterEqual;x_a\end{array}\right.$

Wherein：

$x_e=-\frac{I\&CenterDot;25(h_c+H)(1-k_0\frac{h_g+H}{h_c+H})}{U_{50\%}}$

In formula：H be overpass to ground level, I is amplitude of lightning current, unit：KA, h_gBe positive feeder to overhead bridge floor height, h_cFor Carrier cable is to overhead bridge floor height, k₀For the geometrical coupling ratio between positive feeder and carrier cable, U_50%For the 50% of insulator chain Impulse sparkover voltage, unit：kV；

k₀It is calculated as follows：

$k_0=\frac{\ln \frac{d^{\&prime;}}{d}}{\ln \frac{2(h_g+H)}{r}}$

In formula：D ' is the distance between carrier cable and positive feeder mirror image, unit：m；D is the distance between carrier cable and positive feeder, single Position：m；R be positive feeder radius, unit：m；

Calculate the lower limit of integral I in indirect lightning strike trip-out rate formula_eDetermine as the following formula：

$I_e=\frac{U_{50\%}\left|x_{ag}\right|}{25(h_c+H)(1-k_0\frac{h_g+H}{h_c+H})}$

Wherein：

$x_{ag}=\sqrt{{\left(10{I_g}^{0.65}\right)}^2-{\&lsqb;10{I_g}^{0.65}-(h_g+H)\&rsqb;}^2}-(a+b)$

$I_g=\frac{U_{50\%}}{(1-k){\mathrm{\&beta;R}}_i+(\frac{h_g+H}{h_c+H}-k)\mathrm{\&beta;}\frac{L_t}{{\mathrm{\&tau;}}_f}+(1-\frac{h_g+H}{h_c+H}{k}_0)\frac{h_c+H}{{\mathrm{\&tau;}}_f}}$

In formula：β be pillar diverting coefficient, R_iFor pillar earth resistance, unit：Ω；K is the coupling between positive feeder and carrier cable Coefficient, L_tFor pillar equivalent inductance, unit：μH；τ_fFor lightning current wave head time, unit：μs；

Wherein k=k₁k₀, k₁For corona correction coefficient, contact net takes 1.15；

$\mathrm{\&beta;}=1/(1+\frac{L_t}{L_g}+\frac{R_i{\mathrm{\&tau;}}_f}{2L_g})$

In formula：L_gFor the inductance in parallel value of the adjacent positive feeder in pillar both sides, unit：μH；

Upper limit of integral I_maxAccording to the significance level or the specific requirement value of industry of circuit, or by distribution probability be 90% or Amplitude of lightning current when 99% is estimated；

5th step, calculates according to the following formula multiple line back flash-over rate：

Lower limit of integral in formula

Upper limit of integral I_maxValue is ibid；

6th step, calculates according to the following formula the total tripping rate with lightning strike of contact net multiple line：

N=n_gy+n_c

In formula：n_gyFor multiple line indirect lightning strike trip-out rate, n_cFor multiple line back flash-over rate.

2. a kind of method according to claim 1, wherein hitting away from r in unilateral separation A, C coordinate computing formula_c、r_gWith Following empirical equation is calculated：

$r_c=r_g=a_0{I}^{b_0}$

Or

In formula：I is amplitude of lightning current, unit：kA；H is overpass to ground level, h_cBe carrier cable to overhead bridge floor height, h_gFor Positive feeder is to overhead bridge floor height；

a₀、b₀、c₀Value is carried out according to field experimentation or mimic buss experimental result, or with reference to power system experience take it is following Numerical value：

a₀=10, b₀=0.65；Or a₀=0.67, b₀=0.74, c₀=0.6；Or a₀=1.57, b₀=0.69, c₀=0.45；

r_eIt is calculated as follows：

r_e=k₂r_c

Wherein k₂For striking distance factor, computing formula is as follows：

k₂=1.066+ (h_c+H)/216.45

In formula：H is overpass to ground level, h_cBe carrier cable to overhead bridge floor height；

Or k₂=22/ (h+H), or k₂=1.94- (h+H)/26,

Or k₂=1.08- (h+H)/59, or k₂=1.05- (h+H)/87；

In formula：H is overpass to ground level, and h is pillar to overhead bridge floor height, unit：m；

Or to simplify calculating, make r_c=r_g=r_e。