CN103344810A - Method for calculating electric shock effects of vehicle on human body under high-voltage alternating current transmission line - Google Patents

Abstract

The invention relates to a method for calculating electric shock effects of a vehicle on a human body under a high-voltage alternating current transmission line, wherein the electric shock effects comprise a transient state electric shock effect and a steady state electric shock effect. The method for calculating the electric shock effects comprises the following steps: step 1, a model of the human body and a model of the vehicle are established, calculating parameters of the human body and the vehicle are set, and the induced voltage of the human body and the induced voltage of the vehicle under the transmission line are calculated according to a finite element method; step 2, the difference value delta U between the surface induced voltage of the vehicle and the surface induced voltage of the human body under the transmission line is calculated; step 3, the transient state electric shock effect of the vehicle on the human body is calculated; step 4, the steady state electric shock effect of the vehicle on the human body is calculated. Compared with the prior art, the method for calculating the electric shock effects of the vehicle on the human body under the high-voltage alternating current transmission line has the advantages of being simple in modeling and accurate in calculation result, and reducing cost.

Description

Vehicle is to the computing method of human body electric shock effect under the high-voltage AC transmission circuit

Technical field

The present invention relates to a kind of human induction current's computing method, especially relate to vehicle under a kind of high-voltage AC transmission circuit to the computing method of human body electric shock effect.

Background technology

Transmission line of electricity is in construction and in service, it is a series of induced electricity problems that the resident complains more, when the higher regional activity of electric field intensity, some people can produce horripilation or skin irritatin sense, even in some cases can be because generation discharge and electric shock between human body and other objects cause tangible shouting pain, the people who stands for the level land can cause worry.These phenomenons have caused public's impression of shocking by electricity, and it is frightened that the public is produced extra high voltage network, have hindered that transmission line of electricity is completed on time and normal operation.For this reason, be necessary to study the electric shock effect problem that high voltage transmission line produces, in order to solution can be provided, take adequate measures, alleviate the contradiction between current transmission line construction and the resident complaint, for State Grid's construction contributes.

Summary of the invention

Purpose of the present invention be exactly provide in order to overcome the defective that above-mentioned prior art exists that a kind of modeling is simple, result of calculation is accurate, under the cost-effective high-voltage AC transmission circuit vehicle to the computing method of human body electric shock effect.

Purpose of the present invention can be achieved through the following technical solutions:

Vehicle is to the computing method of human body electric shock effect under a kind of high-voltage AC transmission circuit, and described electric shock effect comprises transient state electric shock effect and stable state electric shock effect, and described computing method specifically may further comprise the steps:

1) sets up human body and auto model, set the calculating parameter of human body and vehicle, calculate human body and the induced voltage of vehicle under transmission line of electricity by finite element method;

2) vehicle is followed the difference DELTA U of human body surface induced voltage under the computing electric power line;

3) calculate vehicle to the transient state electric shock effect of human body:

A1) calculate transient state shock current i:

i′＝I ₀e ^-i/T

In the formula, discharge time constant value T=C ' ₀(R ' ₀+ R _He), maximum current amplitude

R _HeThe expression human body resistance, R ' ₀And C ' ₀Resistance and the ground capacitance of representing vehicle respectively, t are the time;

A2) calculate vehicle to the transient state discharge energy W ' of human body:

$W^{\′}={\∫}_0^t{i}^2{R}_{\mathrm{he}}\mathrm{dt}\≈{\∫}_0^{\∞}{i}^2{R}_{\mathrm{he}}\mathrm{dt};$

4) calculate vehicle to the stable state electric shock effect of human body:

B1) calculate stable state shock current i:

i＝I _sc＝jw(U ₁C ₁₀+U ₂C ₂₀+U ₃C ₃₀)

In the formula, I _ScBe short-circuit current, U ₁, U ₂, U ₃Be respectively the three-phase voltage of transmission line of electricity, C ₁₀, C ₂₀, C ₃₀Be the electric capacity of vehicle to three phase line, w is frequency of operation;

B2) calculate vehicle to the steady-state discharge energy W of human body:

$W=\frac{1}{2}{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^{\&prime;}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">U</figure-callout>}}^2.$

The calculating parameter of described human body and vehicle comprises resistivity and the specific inductive capacity of the specific inductive capacity of human body and conductivity, vehicle.

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

1, modeling simple, tally with the actual situation;

2, the result is accurate, and simulation calculation result and measured result deviation are little;

3, save cost.

Description of drawings

Fig. 1 (a) is the equivalent electrical circuit during the object insulation against ground under the transmission line of electricity;

Fig. 1 (b) is the equivalent electrical circuit during object ground connection under the transmission line of electricity;

Fig. 2 (a) is the equivalent electrical circuit under the open circuit discharging condition;

Fig. 2 (b) is for connecting the equivalent electrical circuit under the impedance Z discharging condition;

Fig. 3 is human body transient state electric shock equivalent circuit;

Fig. 4 is common-tower double-return road tower synoptic diagram;

Fig. 5 is human body simplified model synoptic diagram;

Fig. 6 (a) is middle-size and small-size vehicle simplified model synoptic diagram;

Fig. 6 (b) is big bus car simplified model synoptic diagram;

Fig. 6 (c) is agricultural vehicle simplified model synoptic diagram;

Fig. 7 is that dissimilar vehicles is schemed people's transient state electric shock;

Fig. 8 is that dissimilar vehicles is schemed people's stable state electric shock.

Embodiment

The present invention is described in detail below in conjunction with the drawings and specific embodiments.Present embodiment is that prerequisite is implemented with the technical solution of the present invention, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

The present invention touches the vehicle of depositing under the electric field for the people, proposed a kind of for the computing method of vehicle under the high-voltage AC transmission circuit to human body electric shock effect, pointing out will be through transient state with two process of stable state when human body is shocked by electricity, and proposed to calculate the method for human body transient state shock current, stable state shock current, transient state electric shock energy and stable state electric shock energy in these two processes, draw the power frequency electric field public expose to the open air (5kV/m) servant touch vehicle have shocked by electricity may.

Under ultra-high-tension power transmission line or near the high-tension apparatus, when the people contacts the object of insulation against ground in the electric field, may produce the electric current of tingle, i.e. electric shock.When the people who wears insulated shoes contacts grounding body or touches the object with different induced potentials, also this situation can take place.This electric shock that is produced by electrostatic induction can be divided into two classes, and a class is the transient state electric shock, and a class is the stable state electric shock.Transient state electric shock refers to that the people contacts the moment of the object that is subjected to electrostatic induction, and originally the electric charge of putting aside on sensing object discharges by human body, that is the electric shock that is caused by transient current.After stable state electric shock referred to that the people contacts sensing object, because the capacitive coupling of sensing object and high-voltage charged body, the electric shock that the lasting power current of human body causes was flow through in generation.

One, finite element method calculates the induced voltage principle

Electric charge in the AC power line produces alternating electric field around power transmission line and in the human body under the power transmission line, electric field is divided into coulomb electric field and induction field again, for power frequency electromagnetic field, the enclosed pasture electric field is much larger than induction field, induction field can be ignored, so the Maxwell equation of the power frequency electric field that power transmission line produces is:

$\&dtri;\&CenterDot;(J+\&PartialD;D/\&PartialD;t)=0---\left(1\right)$

$\&dtri;\&times;E=0---\left(2\right)$

J＝σE (3)

In the formula, J is current density, and D is electric displacement vector, and E is electric field intensity, and σ is conductivity,

Be current potential,

Be Hamiltonian operator.For the isotropy homogeneous medium

D＝εE ₀ (5)

Formula (3)～(5) substitution formula (1) is got power frequency alternating electric field governing equation:

The plural form of formula (6) is:

In the formula, ε is specific inductive capacity; W is frequency of operation, the Hz of unit.

With

The interfacial boundary condition of expression different medium is:

In the formula, Be interphase both sides current potential, ε ₁, ε ₂Be the specific inductive capacity of interphase both sides, J _1n, J _2nBe the surface current density of interphase both sides, ρ _sBe surface charge density.

Two, vehicle is to the electric shock effect analysis of human body

Be located at the object M that is placed with a conduction under the three phase line, three-phase voltage is respectively U ₁, U ₂, U ₃, suppose two kinds of extreme cases: object M is insulation fully over the ground, shown in Fig. 1 (a); Object M is connected with ground by a lead, shown in Fig. 1 (b).

The current potential of object M with the static equation of electric charge relation is:

Q＝U ₀C ₀+(U ₀-U ₁)C ₁₀+(U ₀-U ₂)C ₂₀+(U ₀-U ₃)C ₃₀ (11)

In the situation of Fig. 1 (a), because of this object insulation against ground, so Q=0, then its open-circuit voltage U ₀For

${\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">U</figure-callout>}}_0=\frac{U_1{\mathrm{<figure-callout\; id="10"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{10}+U_2{\mathrm{<figure-callout\; id="20"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{20}+U_3{C}_{30}}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_0+{\mathrm{<figure-callout\; id="10"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{10}+{\mathrm{<figure-callout\; id="20"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{20}+C_{30}}---\left(12\right)$

Because object is near ground and away from lead, C in the reality ₀＞＞C ₁₀+ C ₂₀+ C ₃₀So,

${\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">U</figure-callout>}}_0=\frac{U_1{\mathrm{<figure-callout\; id="10"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{10}+U_2{\mathrm{<figure-callout\; id="20"\; label="C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">C</figure-callout>}}_{20}+U_3{C}_{30}}{C_0}---\left(13\right)$

Under the situation of Fig. 1 (b), because object is zero potential, i.e. U ₀=0, so induced charge is

Q＝U ₁C ₁₀+U ₂C ₂₀+U ₃C ₃₀ (14)

Under sinusoidal situation, charge Q is relevant with charging current I, therefore flows through the short-circuit current I of ground wire _ScFor

I _sc＝jwQ＝jw(U ₁C ₁₀+U ₂C ₂₀+U ₃C ₃₀) (15)

Can obtain open-circuit voltage U by (13) and (15) formula ₀Use short-circuit current I _ScWith object ground capacitance C ₀The relational expression of expressing is

${\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">U</figure-callout>}}_0=\frac{I_{\mathrm{sc}}}{\mathrm{jw}{C}_0}---\left(16\right)$

Object M and the earth can be regarded as has open-circuit voltage U ₀With short-circuit current I _ScThe two ends of power supply, the internal impedance of this power supply such as Fig. 2 (a) are depicted as

$Z_i=\frac{1}{\mathrm{jw}{C}_0}---\left(17\right)$

If there is an impedance Z to connect this power supply, the current i of this impedance of then flowing through and in the voltage U at impedance two ends _p, shown in Fig. 2 (b), can directly obtain

$i=\frac{U_0}{Z+\frac{1}{\mathrm{<figure-callout\; id="0"\; label="jw\; C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">jw</figure-callout>}{C}_{}{}_0}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="I\; sc"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{sc}}}{1+\mathrm{jw}{C}_{0}Z}---\left(18\right)$

$U_p=U_0\frac{Z}{Z+\frac{1}{\mathrm{<figure-callout\; id="0"\; label="jw\; C"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">jw</figure-callout>}{C}_{}{}_0}}={\mathrm{<figure-callout\; id="1"\; label="I\; sc\; Z"\; filenames="HDA00003403563500011.png,HDA00003403563500012.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{sc}}\frac{Z}{}\frac{}{1+\mathrm{jw}{C}_{0}Z}---\left(19\right)$

Work as wC as can be seen from (8) formula ₀Z＜＜1 o'clock, the as many as I of the current i of the Z that flows through _Sc

Among the present invention when object M be vehicle under the line, then its when people's ground connection since human body with hundreds of to the resistance in several ten thousand Europe with hundreds of megaohm C ₀Capacitive reactance is compared and can be ignored, and therefore, electric current in fact still is I _ScThe I here _ScBe the stable state shock current by human body.During online time contact vehicle of people, transient state electric shock equivalent circuit is illustrated in fig. 3 shown below.

R among Fig. 3 _HeThe expression human body resistance, R ' ₀And C ' ₀Resistance and the ground capacitance of representing vehicle respectively, Δ U are the difference that vehicle is followed the human body surface induced voltage under the line.

Under people's osculatory during vehicle, human body with can take place with the transient state electric shock before vehicle contacts fully, this is owing to the inductive voltage value of vehicle under the line is higher, as people near vehicle but when not contacting fully as yet, little clearance therebetween punctures and the flashing discharge, under the AC field effect of transmission line of electricity, as long as also there is little gap, charging and the discharge again that causes are therefrom carried out continuously, so the transient state shock current is normally acyclic, its variation can represent with an exponential function, namely

i＝I ₀e ^-i/T (20)

In the formula, discharge time constant value T=C ' ₀(R ' ₀+ R _He), maximum current amplitude

Vehicle can pass through formula to the transient state discharge energy of human body

Try to achieve, the steady-state discharge energy can by formula Try to achieve.

Three, application example

Be example to go into to stand in to contact under the 500kV same tower double back transmission line compact car, big bus car, agricultural vehicle, analyze vehicle to the electric shock effect of human body.Fig. 4 has provided the lead wire and earth wire locus of 500kV same tower double back transmission line, two leads of shaft tower the top are lightning conducter, because the lead of the shaft tower left and right sides is symmetrically distributed, only provide the locus of left side lead wire and earth wire among Fig. 4, the position of right side lead wire and earth wire is symmetry with it.The 500kV lead adopts the LGJK-400/35 type, spontaneous fission spacing 40cm, and diameter of wire 26.82mm, phase division number are 6.

Induced voltage calculates under 1 line

This patent calculates human body with the inductive voltage value of vehicle according to finite element method, sets up human body with the computation model of vehicle by ANSYS software.

1) manikin is set up

The human body electric parameter that is positioned under the high-voltage AC transmission circuit mainly contains conductivity and specific inductive capacity, the conductivity difference of Different Organs, and the conductivity of human body Different Organs under power frequency is as shown in table 1.

The conductivity of table 1 human body Different Organs

According to the study, the relation of living tissue relative dielectric constant and frequency is bigger in the human body, under the 50Hz electric field environment in the human body living tissue relative dielectric constant variation range be about 105～2 * 106 (brain and lung are about 106, and fat is about 105, and blood is about 2 * 106).Present embodiment during the human body internal electric intensity, is not considered the difference of conductivity between the human body Different Organs under computing electric power line, and the supposition human body is made of uniform dielectric, and its relative dielectric constant ε is 106, and the conductivity is 0.1S/m.

The each several part of human body simplified model is of a size of: the top of head is the circle hat of radius 10cm, and the bottom of head is long 20cm, the rectangle of high 10cm; Neck is long 12cm, the rectangle of high 6cm; Waist is long 40cm, the rectangle of high 60cm; Shank is long 30cm, the rectangle of high 90cm; People's overall height is 176cm.The human body simplified model is seen Fig. 5.

2) dissimilar auto models are set up

The electric parameter that is positioned at compact car under the high-voltage AC transmission circuit mainly contains the resistivity of body shell steel material and the specific inductive capacity of tire, the vehicle body steel plate belongs to alloy material, its resistivity is bigger than normal than common metal, the resistivity of present embodiment vehicle body steel material is taken as 10-7 Ω m, vehicle tyre belongs to elastomeric material, and its relative dielectric constant can be taken as 2.5.

The popular new Passat of the middle-size and small-size car dimension reference of Fig. 6 (a), long 4.769m wherein, high 1.472m, wide 1.82m, the high 0.57m of car the latter half, the high 0.581m of the first half, diameter of tyres are 0.642m.The logical ZK6122H9 type of big bus dimension reference space among Fig. 6 (b), wherein long is 12m, height is 3.83m, wide 2.55m, tire radius is 0.666m, and the automobile left border is 3.334m apart from left tire central horizontal distance, and right side boundary is 2.666m apart from right tire central horizontal distance.Agricultural vehicle dimension reference Kubo field M954 type among Fig. 6 (c).Long 4.05m wherein, high 2.7m, wide 2.12m, back wheel diameter 1.8m, preceding wheel diameter 0.8m.Simplified model is seen Fig. 6.

3) simulation calculation

The power frequency electric field that the high-voltage AC transmission circuit produces, its characteristics are that the electric field of space every bit is the elliptical field of a rotation, but become electric field perpendicular to ground in the ground elliptical field, the vertical component of electric field intensity is uniform basically near ground, horizontal component is to ignore, when transmission line of electricity during apart from the big 15m of floor level, this simplification is also suitable substantially for the vehicle of large-sized object even the such size of motorbus.Present embodiment substitutes the approximate uniform electric field that transmission line of electricity produces with an infinitely great cylindrical capacitor model.

Approximate uniform field among the present invention under the 500kV same tower double back transmission line is taken power frequency electric field public exposure limit 5kV/m by force.

Cell type selects two-dimentional 8 node quadrilateral units: PLANE121 in the ANSYS software, can guarantee analysis precision; The relative dielectric constant of air is 1.

By on-the-spot test obtain human body surface 5kV/m not the induced voltage in the distortion electric field be about 0.9kV.The inductive voltage value that in like manner can draw dissimilar vehicles is as shown in table 2 below

The inductive voltage value of the dissimilar vehicles of table 2 (field intensity that do not distort 5kV/m)

According to above inductive voltage value, thus can draw the induced voltage difference DELTA U of human body and dissimilar vehicles, as shown in table 3 below.

The induced voltage difference DELTA U of table 3 human body and dissimilar vehicles (field intensity that do not distort 5kV/m)

Vehicle is to the electric shock calculation of effect of human body under 2 lines

If human body resistance R _He=4 * 10 ⁴Ω, ground capacitance C _He=400pF: the ground capacitance of dissimilar vehicles is as shown in table 4 below.

The ground capacitance of the dissimilar vehicles of table 4

The resistance of vehicle changes between 70～550 Ω, can ignore with respect to the resistance value of human body, so can draw dissimilar vehicles to electric shock effect such as Fig. 7, shown in Figure 8 of human body according to above data.

The people lacks transient state electric shock time of also not contacting fully before the vehicle very much as shown in Figure 7, the general time through 0.5ms just carries out the transition to the stable state electric shock stage, namely this moment, the people contacted fully with vehicle, and as shown in Figure 8, the electric current that continues at this moment to flow through human body is the industrial frequency AC electric current.Therefore, when human body went to touch vehicle, along with near the dwindling of distance, electric current became that number increases but the less pulse of amplitude becomes the metastability exchange electric current at last from very short heavy current pulse of duration.Following table 5 is dissimilar vehicle to the electric shock value of human body relatively.

The dissimilar vehicle of table 5 compares (field intensity that do not distort 5kV/m) to human body electric shock value

According to document " International Commission on Non-Ionizing Radiation Protection.Guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic fields ", when pickup current surpasses 0.2mA, when discharge energy surpasses 0.5mJ, the people just has tactility, therefore, when the people is under the not distortion field intensity of 5kV/m the contact vehicle, have shocked by electricity may.

Claims (2)

1. vehicle is characterized in that the computing method of human body electric shock effect under the high-voltage AC transmission circuit, and described electric shock effect comprises transient state electric shock effect and stable state electric shock effect, and described computing method specifically may further comprise the steps:

1) sets up human body and auto model, set the calculating parameter of human body and vehicle, calculate human body and the induced voltage of vehicle under transmission line of electricity by finite element method;

2) vehicle is followed the difference DELTA U of human body surface induced voltage under the computing electric power line;

3) calculate vehicle to the transient state electric shock effect of human body:

A1) calculate transient state shock current i:

i′＝I ₀e ^-i/T

In the formula, discharge time constant value T=C ' ₀(R ' ₀+ R _He), maximum current amplitude R _HeThe expression human body resistance, R ' ₀And C ' ₀Resistance and the ground capacitance of representing vehicle respectively, t are the time;

A2) calculate vehicle to the transient state discharge energy W ' of human body:

$W^{\&prime;}={\&Integral;}_0^t{i}^2{R}_{\mathrm{he}}\mathrm{dt}\&ap;{\&Integral;}_0^{\&infin;}{i}^2{R}_{\mathrm{he}}\mathrm{dt};$

4) calculate vehicle to the stable state electric shock effect of human body:

B1) calculate stable state shock current i:

i＝I _sc＝jw(U ₁C ₁₀+U ₂C ₂₀+U ₃C ₃₀)

In the formula, I _ScBe short-circuit current, U ₁, U ₂, U ₃Be respectively the three-phase voltage of transmission line of electricity, C ₁₀, C ₂₀, C ₃₀Be the electric capacity of vehicle to three phase line, w is frequency of operation;

B2) calculate vehicle to the steady-state discharge energy W of human body:

$W=\frac{1}{2}{C}_0^{\&prime;}\mathrm{\&Delta;}{U}^2.$

Under a kind of high-voltage AC transmission circuit according to claim 1 vehicle to the computing method of human body electric shock effect, it is characterized in that the calculating parameter of described human body and vehicle comprises resistivity and the specific inductive capacity of the specific inductive capacity of human body and conductivity, vehicle.

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