CN102315642B - Environmental impact assessment method of power grid planning scheme - Google Patents

Abstract

The invention discloses an assessment method of a power grid planning scheme. A powder frequency electric field takes a vertical component of the strength of the electric field with 1.5m away from the ground as an assessment value; a powder frequency magnetic field takes vertical components and horizontal components of the strengths of the magnetic fields on the ground and with a certain distance away from the ground as assessment values; the effective value of a new added line utilizes the utilization ratio of a land resource to evaluate the power grid planning scheme; finally the degree of coordination between each planning line and an urban landscape is predicted for various landscape real pictures in a planning range by utilizing a graph overlay method. According to the assessment method of the power grid planning scheme in the invention, the environmental impact assessment on a power grid plan can be carried out by utilizing the technical indexes above, the influences of a plurality of planning schemes to be selected on ecological environment quality, environment sensitivity points, human body health and the like during implementation can be comprehensively compared, the disadvantages of the power grid planning scheme are identified, a recommended scheme is determined, countermeasures and measures for preventing or reducing the environmental influences are obtained, and the coordination of the power grid plan and the requirements of nature and society is guaranteed.

Description

A kind of method for evaluating environmental effect of Electric Power Network Planning scheme

Technical field

The present invention relates to a kind of method for evaluating environmental effect of Electric Power Network Planning scheme.

Background technology

In the world, a large-scale market-oriented reform is being carried out in electric power system, whether the economy of electric power transmission network is reasonable, and whether fail safe meets the demands, and whether transmission capacity, grid structure reach the most excellent vital interests that all are related to different main market players.Along with China's interconnected network scale enlarges day by day, that " separates the factory and network; surf the Net at a competitive price " and reform progressively gos deep into, the uncertain factor of operation of power networks increases, the Transmission Expansion Planning in Electric work of China also is faced with great challenge, Transmission Expansion Planning in Electric not only will be considered the coordination of economy and reliability, also at electric network security, load adaptability, aspects such as operational flexibility face higher requirement, while is along with the raising of entire society's environmental consciousness, especially along with the raising of electric pressure, people are to transmission line electromagnetic environment along the line, acoustic environment, the ecological balance is more and more paid close attention to, therefore to consider more that environmental problem that Transmission Expansion Planning in Electric brings is to the influence of social production life, how is quantitative each programme of analysis to the satisfaction degree of every requirement? which more can satisfy the demand of electrical network and society in a plurality of mutual competitive schemes? this just need carry out the integrated decision-making analysis to programme by means of the multiattribute comprehensive evaluation theory, and therefore the Transmission Expansion Planning in Electric scheme is carried out Comprehensive Appraisal Study important practical sense.

Along with development of electric power industry, the high voltage power transmission of China, extra high voltage network construction scale constantly enlarge, and each big electrical network of the whole nation is key rack with the 500kV circuit all basically, based on the 220kV circuit, and form the interconnected power system that is mutually related.This is favourable to distributing rationally of nationwide electric power resource, but meanwhile intensive day by day electrical network has also caused people's extensive concern, especially China is populous, load is concentrated, high pressure even extra high voltage network inevitably will enter densely inhabited district, whether project of transmitting and converting electricity can produce adverse effect to health and daily life to the electromagnetic interference that influence and the ultra-high-tension power transmission line of natural, ecologicals such as water source, soil causes, cause that people pay close attention to greatly.Therefore need carry out comprehensive and careful assessment to the influence of environment to project of transmitting and converting electricity in the Electric Power Network Planning stage.

The Fifth Plenary Session of the Sixteenth Central Committee of party proposes, and accelerate to build a resource-conserving and environment-friendly society, and power network development is had higher requirement.The further proposition of State Grid Corporation of China and Southern Power Grid Company will be built " amphitypy " electrical network of " resource-conserving, environmentally friendly ".For a long time; power network development is followed the objective technology of electric power system and economic law; formed with fail safe, reliability and economy is the appraisement system of core; " amphitypy " electrical network then need be on the basis of satisfying conventional fail safe, reliability and economy; strict execution environment influences evaluation system, strengthens the ecological protection to natural resourcess such as water source, soil, forests, takes to reduce the measure of ecological pollution and electromagnetic pollution; satisfy economizing on resources, with the requirement of environment harmonious development.

" the Environmental Impact Assessment Law of the PRC " implemented on September 1st, 2003, and the power planning environmental impact assessment of China is also progressively launching, and estimates emphasis and mainly comprises: electromagnetic radiation environment (comprising: power frequency electric field, power frequency magnetic field, radio interference); The sensitive area acoustic environment; The sensitive area biological environment.Carry out the environmental impact assessment work of Electric Power Network Planning, comprehensively more a plurality of programmes to be selected in implementation process to the influence of eco-environmental quality, environment sensitive point, health etc., the deficiency that identification Electric Power Network Planning scheme exists, and definite suggested design and draw prevention or the countermeasure and the measure that alleviate environmental impact, guarantee that Electric Power Network Planning and nature, social requirement are harmonious.

Summary of the invention

For remedying the deficiencies in the prior art, the invention provides a kind of method for evaluating environmental effect of Electric Power Network Planning scheme.

For achieving the above object, the present invention adopts following technical scheme:

A kind of method for evaluating environmental effect of Electric Power Network Planning scheme, the evaluation procedure of this method is as follows:

1) in transmission line, the size of power frequency electric field that transmission line produces is returned several relevant with phase conductor radical factor with electric pressure, lead distance to the ground, arrangements of conductors mode, circuit, the method of simulation analogy and the method that theoretical calculating combines are adopted in the evaluation of power frequency electric field, according to actual measurement and the just power frequency electric field influence of measurable circuit yet to be built of theoretical result calculated to the close working line of condition;

2) vertical component of the magnetic field intensity of power frequency magnetic field that transmission line produces employing ground surface place and liftoff certain distance and horizontal component are as evaluation amount;

3) adopt land resources utilization efficient to weigh the effective value of newly-increased circuit in the Electric Power Network Planning scheme, its computing formula is:

In: n is the number in newly-increased circuit corridor;

4) last, various types of view outdoor scene photos in the planned range are carried out stochastical sampling, choose representational view as the sample material of estimating, to the sample material of choosing, adopt folded figure method to predict the coordination degree of respectively planning circuit and urban look.

Simulation class ratio method is as follows in the described step 1): the ground subpoint with span centre drift sag maximum wire center is the test initial point, along carrying out perpendicular to line direction, the measuring point spacing is 5m, end at order survey 50m place to the subpoint of phase conductor ground, limit, measures the electric field strength vertical component at liftoff 1.5m place.

Theoretical calculation method is as follows in the described step 1): the electric Field Calculation under the transmission line adopts equivalent charge method, it mainly contains two parts and forms, the one, the equivalent electric charge on the unit of account length lead, the 2nd, calculate the electric field by these charge generation, simplified condition in the calculating is: the power frequency alternating electric field is quasi-static electric field, the electric field that power transmission line produces is the parallel plane field, and extra high voltage network often adopts bundle conductor, and the equivalent redius of bundle conductor is:

$r_{\mathrm{eq}}=R\·\sqrt[n]{\frac{\mathrm{nr}}{R}}$

In the formula: the radius of every lead of r-;

The radical of n-bundle conductor;

The geometric radius of R-bundle conductor;

In order to calculate the equivalent electric charge on the lead in the multiple conductor line, list following matrix equation:

$\left[\begin{array}{c}{U}_1\\ {\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">U</figure-callout>}}_2\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ U_n\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{\&lambda;}}_{11}& {\mathrm{\&lambda;}}_{12}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{1n}\\ {\mathrm{\&lambda;}}_{21}& {\mathrm{\&lambda;}}_{22}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{2n}\\ \&CenterDot;& & & \\ \&CenterDot;& & & \\ \&CenterDot;& & & \\ {\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">n</figure-callout>}1}& {\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">n</figure-callout>}2}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{\mathrm{nn}}\end{array}\right]\left[\begin{array}{c}{Q}_1\\ {\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ Q_n\end{array}\right]$

In the formula: the one-column matrix of [U]-each lead voltage to earth;

The n rank square formation that the some potential coefficient of [λ]-each lead is formed, n is the lead number;

The one-column matrix of equivalent electric charge on [Q]-each lead;

After the quantity of electric charge of unit length was obtained, electric field strength was calculated with Gauss theorem, and the electric field strength of any point calculates according to principle of stacking in the space, at (x, electric field strength horizontal component E y) _xWith vertical component E _yCan be expressed as:

$E_x=\frac{1}{{2\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{x-x_i}{L_i^2}-\frac{x-x_i}{{\left(L_i^{\&prime;}\right)}^2})$

$E_y=\frac{1}{{2\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{y-y_i}{L_i^2}-\frac{y-y_i}{{\left(L_i^{\&prime;}\right)}^2})$

In the formula: x _i, y _iThe coordinate of-lead i, (i=1,2 ... m); M-lead radical; L _i, L ' _i-lead i and be mirrored to the distance of calculation level.

Described step 2) vertical component of the magnetic field intensity at power frequency magnetic field employing ground surface place and liftoff 1.5m place and horizontal component are as evaluation amount in, and the magnetic field intensity at space A point place when flowing through electric current I in the lead is:

$H=\frac{I}{2\mathrm{\&pi;}\sqrt{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}}$

In the formula: the current value among the I-lead i;

The h-A point is apart from the vertical height of lead;

The L-A point is apart from the horizontal range of lead.

Beneficial effect: the present invention utilizes the coordination degree of power frequency electric field, power frequency magnetic field, land resources utilization efficient and urban look, carry out the environmental impact assessment work of Electric Power Network Planning, according to above technical indicator comprehensively more a plurality of programmes to be selected in implementation process to the influence of eco-environmental quality, environment sensitive point, health etc., the deficiency that identification Electric Power Network Planning scheme exists, and definite suggested design and draw prevention or the countermeasure and the measure that alleviate environmental impact, guarantee that Electric Power Network Planning and nature, social requirement are harmonious.

Description of drawings

Fig. 1 is for calculating the schematic diagram of the coefficient of potential;

Fig. 2 is garver-6 system original net shelf structure schematic diagram;

Fig. 3 is the grid structure schematic diagram of the feasible programme 1 of garver-6 system;

Fig. 4 is the grid structure schematic diagram of the feasible programme 2 of garver-6 system;

Fig. 5 is the grid structure schematic diagram of the feasible programme 3 of garver-6 system;

Fig. 6 is the grid structure schematic diagram of the feasible programme 4 of garver-6 system;

Fig. 7 is the grid structure schematic diagram of the feasible programme 5 of garver-6 system;

Fig. 8 is the electric field strength that the 50m each point is respectively extended at 1.5 places to both sides apart from ground under the 200kV circuit;

Fig. 9 is the electric field strength that the 50m each point is respectively extended at 1.5 places to both sides apart from ground under the 500kV circuit;

Figure 10 be under the various arrangements of conductors modes during 0.45kA apart from the magnetic field distribution of ground 1.5m place each point.

Embodiment

The invention will be further described below in conjunction with drawings and Examples:

This paper chooses four of power frequency electric field, power frequency magnetic field, land resources utilization efficient and urban look degrees of coordination as the environmental evaluation index according to the Transmission Expansion Planning in Electric circuit to the actual conditions of environmental impact and the complexity of obtaining data.

(1) power frequency electric field

The power frequency electric field of three-phase alternating current transmission line is the coefficient result of three-phase conducting wire electric charge, and the time dependent track of space electric field strength vector is an ellipse.For electric field, the earth can be similar to regards conductor as, perpendicular to the ground substantially in the electric field strength direction of ground surface.Near the square 1.5m, the horizontal component of electric field strength is very little on the ground, the component approximately equal of the maximum of electric field strength and vertical ground.So in environmental impact assessment, adopt the vertical component of liftoff 1.5m place electric field strength as evaluation amount usually.

" 500kV superhigh pressure transmission and transformation engineering electromagnetic radiation environment influences the assessment technique standard " that national environmental protection is promulgated (HJ/T24-1998) recommended temporarily with 4kV/m as residential block power frequency electric field evaluation criterion.

The size of power frequency magnetic field that transmission line produces is returned multiple factors such as number, phase conductor radical with electric pressure, lead distance to the ground, arrangements of conductors mode, circuit relevant, generally can adopt method and the theoretical method that combines of calculating of simulation analogy to the evaluation of power frequency electric field.

A) the simulation analogy is measured

Other that adopts similar project construction scale, electric pressure, stringing pattern, arrangements of conductors moved the actual measurement that transmission line carries out power frequency electric field, is used for this project is built up the prediction of back electromagnetic environment quantitative effect.Method of measurement is: the ground subpoint with the vertical maximum wire center of span centre drift fox is the test initial point, along carrying out perpendicular to line direction, the measuring point spacing is 5m, and end at order survey 50m place to the subpoint of phase conductor ground, limit, measures the electric field strength vertical component at liftoff 1.5m place.

B) theoretical calculating

Electric Field Calculation under the transmission line generally adopts equivalent charge method, and it mainly contains two parts forms, and the one, the equivalent electric charge on the unit of account length lead, the 2nd, calculate the electric field by these charge generation, the simplified condition in the calculating is:

1. because the frequency of power frequency electric field is lower, visual power frequency alternating electric field is quasi-static electric field.

2. looking power transmission line is the straight lead parallel to the ground of endless, and getting the maximum sag minimum point of transmission pressure is the terrain clearance of lead, so the electric field of its generation is the parallel plane field.

3. extra high voltage network often adopts bundle conductor, and the equivalent redius of bundle conductor is:

$r_{\mathrm{eq}}=R\&CenterDot;\sqrt[n]{\frac{\mathrm{nr}}{R}}---\left(1\right)$

In the formula: the radius of every lead of r-;

The radical of n-bundle conductor;

The geometric radius of R-bundle conductor.

In order to calculate the equivalent electric charge on the lead in the multiple conductor line, can list following matrix equation:

$\left[\begin{array}{c}{U}_1\\ {\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">U</figure-callout>}}_2\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ U_n\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{\&lambda;}}_{11}& {\mathrm{\&lambda;}}_{12}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{1n}\\ {\mathrm{\&lambda;}}_{21}& {\mathrm{\&lambda;}}_{22}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{2n}\\ \&CenterDot;& & & \\ \&CenterDot;& & & \\ \&CenterDot;& & & \\ {\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">n</figure-callout>}1}& {\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">n</figure-callout>}2}& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&lambda;}}_{\mathrm{nn}}\end{array}\right]\left[\begin{array}{c}{Q}_1\\ {\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ Q_n\end{array}\right]---\left(2\right)$

In the formula: the one-column matrix of [U]-each lead voltage to earth;

The n rank square formation (n is the lead number) that the some potential coefficient of [λ]-each lead is formed;

The one-column matrix of equivalent electric charge on [Q]-each lead.

According to image theory, wherein the calculating of the coefficient of potential can be written as:

${\mathrm{\&lambda;}}_{\mathrm{ii}}=\frac{1}{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_0}\ln \frac{{2h}_i}{r_i}---\left(3\right)$

${\mathrm{\&lambda;}}_{\mathrm{ij}}=\frac{1}{{2\mathrm{\&pi;\&epsiv;}}_0}\ln \frac{D_{\mathrm{ij}}^{\&prime;}}{D_{\mathrm{ij}}}---\left(4\right)$

Each variable implication as shown in Figure 1 in the formula.

After the quantity of electric charge of unit length was obtained, electric field strength can be calculated with Gauss theorem, and the electric field strength of any point can calculate according to principle of stacking in the space, at (x, electric field strength horizontal component E y) _xWith vertical component E _yCan be expressed as:

$E_x=\frac{1}{{2\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{x-x_i}{L_i^2}-\frac{x-x_i}{{\left(L_i^{\&prime;}\right)}^2})---\left(5\right)$

$E_y=\frac{1}{{2\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{y-y_i}{L_i^2}-\frac{y-y_i}{{\left(L_i^{\&prime;}\right)}^2})---\left(6\right)$

In the formula: x _i, y _iThe coordinate of-lead i (i=1,2 ... m);

M-lead radical;

L _i, L ' _i-lead i and be mirrored to the distance of calculation level

According to actual measurement and the just power frequency electric field influence of measurable circuit yet to be built of theoretical result calculated to the close working line of condition.

(2) power frequency magnetic field

The power frequency magnetic field of three-phase alternating current transmission line is the coefficient result of three-phase conducting wire electric current, and magnetic flux density vector time dependent track in space also is an ellipse.Under the power frequency condition, the magnetic field of circuit only has electric current to produce, and can directly use Ampere circuit law and calculate the magnetic field that every current in wire produces respectively, again with the result of calculation stack, draws lead magnetic field intensity on every side.

At present, most countries does not propose the power frequency magnetic field standard as yet.China's state environment protecting standard " 500kV superhigh pressure transmission and transformation engineering electromagnetic radiation environment influences the assessment technique standard " is recommended temporarily the evaluation criterion as magnetic flux density with the power frequency limit value 0.1mT of international anti-radiation protection association (ICNIRP) about to the radiation of the public's whole day time.

Identical with the power frequency electric field evaluation method, power frequency magnetic field also normally adopts simulation analogy measurement and theoretical Calculation Method to predict the size of circuit power frequency magnetic field yet to be built.

The magnetic field intensity of transmission line is only relevant with size of current, and and independent from voltage, so the selection of analogy circuit need be considered the current strength factor of circuit.

Current in wire all can theory calculate in the magnetic field intensity of the every some generation in space.In environmental impact assessment, adopt the vertical component of magnetic field intensity at ground surface place and liftoff 1.5m place and horizontal component as evaluation amount usually, the magnetic field intensity at space A point place when flowing through electric current I in the lead is:

$H=\frac{I}{2\mathrm{\&pi;}\sqrt{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000071436050000012.png,HDA0000071436050000013.png"\; state="\{\{state\}\}">h</figure-callout>}}^2+L^2}}---\left(7\right)$

In the formula: the current value among the I-lead i

The h-A point is apart from the vertical height of lead

The L-A point is apart from the horizontal range of lead

(3) land resources utilization efficient

The Transmission Expansion Planning in Electric engineering can take farmland along the line, forest land and residential building, obviously the scheme that resource occupation is more few is more superior, the transmission line that takies same area simultaneously carries that electric weight is more big to illustrate that then the utilization of this circuit is more abundant, therefore adopt land resources utilization efficient to weigh the effective value of the newly-increased circuit of programme, its computing formula is:

In the formula: n is the number in newly-increased circuit corridor.

Can find out also that from this formula for identical circuit width of corridor, the common-tower double-return circuit can be carried the transmission line capability of single back line twice, therefore, single back line adopts to have environmental benefit preferably with many loop lines of tower road relatively.

(4) urban look degrees of coordination

The urban look degrees of coordination is mainly reflected in the visual impact aspect, and visual impact comprises subjective feeling factors such as vision U.S. and psychological comfort.It is that various types of view outdoor scene photos in the planned range are carried out stochastical sampling that landscape impact is estimated adoptable main method, choose representational view at last as the sample material of estimating, to the sample material of choosing, adopt folded figure method to predict the coordination degree of respectively planning circuit and urban look.Because subjective judgement is depended in this evaluation to a great extent, therefore can adopt Specialist Research method (Delphi) method, this is a kind of method of investigation and study of sending a letter, consulting on to the expert, invite a plurality of experts to estimate according to evaluation objective and evaluation object, with the investigation result statistical disposition, draw evaluation conclusion then.

Embodiment:

This paper adopts the garver-6 system to come, and its original net shelf structure as shown in Figure 2.The grid structure of 5 feasible programmes of this system is respectively shown in Fig. 3～7.

The in-site measurement data of power frequency electric field, power frequency magnetic field are collected relatively difficulty in the environmental index, so only suppose that canonical parameter carries out theory and calculates.The size of power frequency electric field is relevant with voltage swing, and the canonical parameter that adopts is as shown in table 1.

Table 1 Theory of Electromagnetic Field computational scheme parameter

Electric pressure (kV)	Wire type	Solid conductor radius (mm)	Wire diameter (diameter) (mm)
				220	2*LGJ-400/35	26.82	400
500	4*LGJ-400/35	26.82	450

Different arrangements of conductors modes varies in size with the electromagnetic field that different distance to the ground produces, the arrangements of conductors mode is got respectively vertically, level, equilateral triangle, four kinds of arrangement modes of del are carried out calculation check, distance to the ground is according to DL/T5092-1999, verification is carried out in " 110～500kV aerial power transmission line designing technique rules " middle residential block minimum safe distance over the ground, this distance refers to the sag minimum point distance to the ground of transmission pressure, and its value is as shown in table 2:

Table 2 residential block lead is to the ground minimum safe distance

Electric pressure (kV)	110	220	330	500
					Distance to the ground	7.0	7.5	8.5	14

Write the matlab program, carry out emulation according to aforementioned theoretical calculation method, wherein calculating voltage is got 1.05 times rated voltage, obtains the vertical component of liftoff 1.5m place electric field strength under 220kV and the 500kV line respectively, as Fig. 8 and shown in Figure 9,

" 500kV superhigh pressure transmission and transformation engineering electromagnetic radiation environment influences the assessment technique standard " that national environmental protection is promulgated (HJ/T24-1998) recommended temporarily with 4kV/m as residential block power frequency electric field evaluation criterion; as can be seen from the figure; when distance circuit central point 10m place; electric field strength value under the various situations all meets the demands; but comparatively speaking; the electric field ratio vertical arrangement of the lead of equilateral triangle arrangement and del spread pattern and horizontal electric field strength are low, therefore recommend the arrangements of conductors mode of these two kinds of patterns.All to compose according to the comment value be 1 to each scheme electric field strength in this example, is fine.

Therefore the size of field strength values and current related is got the roll off the production line maximum of road trend of each scheme and is tested, and wire type, arrangement mode, distance to the ground are identical with electric field strength calculating.Each scheme lowest high-current value is respectively: 0.43kA, 0.45kA, 0.42kA, 0.43kA, 0.34kA, maximum current 0.45kA is carried out theory calculate, can get the composite value of horizontal component and vertical component under four kinds of arrangements of conductors modes, as seen from Figure 10,0.45kA following each point magnitude of field intensity is much smaller than limit value 0.1mT, therefore, each scheme magnetic field intensity comment value is fine, and assignment is 1.

According to DL/T5092-1999, " 110～500kV aerial power transmission line designing technique rules ", the distance between power transmission line roadside lead and the building, under max calculation windage yaw situation, should be less than the listed numerical value of table 3.

Minimum range between table 3 limit lead and the building

Suppose that distance is 5m between two phase conductors, then the width in circuit corridor is at least 20m under the 220kV, according to the bar number in each programme circuit corridor of ga rver-6 system, sets circuit width of corridor shown in the table 4.

Circuit width of corridor in each programme of table 4garver-6 system

The number of lines	1	2	3	4	5
						Width of corridor (m)	20	25	30	35	40

According to the conveying quantity of each bar circuit, carry out the calculating of land resources utilization efficient according to formula (8), calculate each scheme efficiency value successively and be: 10.1667,8.1071,7.8321,8.6071,9.8571.

The urban look degrees of coordination gives comment for well for respectively each scheme at this, and [good, fine], [poor, in], [in, good], in, the comment value is followed successively by 0.75,0.9, and 0.45,0.6,0.5.

It is as shown in table 5 to calculate each evaluation index value more than the foundation.

Each programme desired value of table 5garver-6 example

Claims (3)

1. the method for evaluating environmental effect of an Electric Power Network Planning scheme is characterized in that, the evaluation procedure of this method is as follows:

1) in transmission line, the size of power frequency electric field that transmission line produces is returned several relevant with phase conductor radical factor with electric pressure, lead distance to the ground, arrangements of conductors mode, circuit, the method of simulation analogy and the method that theoretical calculating combines are adopted in the evaluation of power frequency electric field, according to actual measurement and the just power frequency electric field influence of measurable circuit yet to be built of theoretical result calculated to the close working line of condition;

Described theoretical calculation method is as follows: the electric Field Calculation under the transmission line adopts equivalent charge method, it mainly contains two parts and forms, the one, the equivalent electric charge on the unit of account length lead, the 2nd, calculate the electric field by these charge generation, simplified condition in the calculating is: the power frequency alternating electric field is quasi-static electric field, the electric field that power transmission line produces is the parallel plane field, and extra high voltage network often adopts bundle conductor, and the equivalent redius of bundle conductor is:

$r_{\mathrm{eq}}=R\&CenterDot;n\sqrt{\frac{\mathrm{nr}}{R}}$

In the formula: the radius of r-every lead;

The radical of n-bundle conductor;

The geometric radius of R-bundle conductor;

In order to calculate the equivalent electric charge on the lead in the multiple conductor line, list following matrix equation:

In the formula: the one-column matrix of [U]-each lead voltage to earth;

The n rank square formation that the some potential coefficient of [λ]-each lead is formed, n is the lead number;

The one-column matrix of equivalent electric charge on [Q]-each lead;

After the quantity of electric charge of unit length was obtained, electric field strength was calculated with Gauss theorem, and the electric field strength of any point calculates according to principle of stacking in the space, at (x, electric field strength horizontal component E y) _xWith vertical component E _yCan be expressed as:

$E_x=\frac{1}{2{\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{x-x_i}{L_i^2}-\frac{x-x_i}{{\left(L_i^{\&prime;}\right)}^2})$

$E_y=\frac{1}{2{\mathrm{\&pi;\&epsiv;}}_0}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{Q}_i(\frac{y-y_i}{L_i^2}-\frac{y-y_i}{{\left(L_i^{\&prime;}\right)}^2})$

In the formula: x _i, y _iThe coordinate of-lead i, (i=1,2 ... m); M-lead radical; L _i, L' _i-lead i and be mirrored to the distance of calculation level;

2) vertical component of the magnetic field intensity of power frequency magnetic field that transmission line produces employing ground surface place and liftoff certain distance and horizontal component are as evaluation amount;

3) adopt land resources utilization efficient to weigh the effective value of newly-increased circuit in the Electric Power Network Planning scheme, its computing formula is:

In: n is the number in newly-increased circuit corridor;

4) last, various types of view outdoor scene photos in the planned range are carried out stochastical sampling, choose representational view as the sample material of estimating, to the sample material of choosing, adopt folded figure method to predict the coordination degree of respectively planning circuit and urban look.

2. the method for evaluating environmental effect of a kind of Electric Power Network Planning scheme as claimed in claim 1, it is characterized in that, simulation class ratio method is as follows in the described step 1): the ground subpoint with span centre drift sag maximum wire center is the test initial point, along carrying out perpendicular to line direction, the measuring point spacing is 5m, end at order survey 50m place to the subpoint of phase conductor ground, limit, measures the electric field strength vertical component at liftoff 1.5m place.

3. the method for evaluating environmental effect of a kind of Electric Power Network Planning scheme as claimed in claim 1, it is characterized in that, described step 2) vertical component of the magnetic field intensity at power frequency magnetic field employing ground surface place and liftoff 1.5m place and horizontal component are as evaluation amount in, and the magnetic field intensity at space A point place when flowing through electric current I in the lead is:

$H=\frac{I}{2\mathrm{\&pi;}\sqrt{h^2+L^2}}$

In the formula: the current value among I-lead i;

H-A point is apart from the vertical height of lead;

L-A point is apart from the horizontal range of lead.

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