CN102608462B - Method for measuring radio interference of electric transmission line - Google Patents

Abstract

The invention provides a method for measuring the radio interference of an electric transmission line. The corona and current coefficients of the electric transmission line in heavy rain are acquired, the pulsed currents of each phase of conducting wire are obtained through certain modulus transformation, and the fields, i.e. the radio interference, generated by the currents are calculated. With the adoption of the method for measuring the radio interference of the electric transmission line, the calculation on the basic electrical parameters and the radio interference of various different voltage levels, different conducting wire arrangement manners and different circuit numbers can be realized, and the referable data for circuit design are provided.

Description

Transmission line of electricity radio interference measuring method

Technical field

The present invention relates to a kind of ultra-high-tension power transmission line radio interference calculating method, realize the radio interference of various different electric pressures, different conductor arrangement mode, different circuit number and calculate, to line design provide can reference data.

Background technology

Construction along with large capacity scale power plant, and the number of high pressure, ultra high-tension transmission line and transformer station is increasing, environmental problem becomes and becomes increasingly conspicuous, and is mainly manifested in the utilization in soil, the Communication Jamming that corona brings, and audible noise, power frequency electromagnetic field are on the ecological aspects such as impact.Due to features such as UHV transmission voltage are high, split conductor is many, must cause the rising of conductive line surfaces electric field intensity and transmission facility surrounding space electric field intensity, and whether corona phenomenon and highfield effect that UHV transmission line and transformer station occur can bring harm to human body and ecologic environment, it is the problem that people are concerned about very much always.

Therefore; in most cases; determining etc. of the selection in transmission line wire cross section, wire distance to the ground; except guaranteeing line security operation; also must meet environmental protection requirement, determine that the electromagnetic environment parameter such as circuit below radio interference become one of key issue of Transmission Line Design, the while is due to the continuous expansion of electrical network scale; extra-high voltage, multi-circuit lines on the same tower, alternating current-direct current are with the appearance of the complicated circuits such as corridor circuit, and the design effort of transmission line of electricity is difficulty day by day.

For transmission line of alternation current radio interference level, can obtain by calculating or surveying at present.But because China's power network development speed is very fast, circuit is not surveyed one by one, simultaneously in the process of actual measurement, the impact of the factor such as weather, survey instrument all can exert an influence to the accuracy of measurement result, therefore the radio interference of existing transmission line of electricity is carried out to theory and calculate, meaning is very great.Especially along with UHV transmission line, with the many back transmission lines of tower and alternating current-direct current with the appearance of the complicated circuits such as corridor, more need transmission line of electricity electromagnetic environment to calculate, obtain data comparatively accurately, to the design of circuit, provide foundation.

Summary of the invention

In order to address the above problem, the invention provides a kind of method that transmission line of electricity radio interference is calculated, realize the basic electric parameter of various different electric pressures, different conductor arrangement mode, different circuit number and radio interference and calculate, to line design provide can reference data.

Transmission line of electricity radio interference measuring method, to the i loop j phase conductor Injection Current of transmission line of electricity, i=1 ..., n, n is the loop sum in transmission line of electricity, j=A, B, C, specified coordinate central point, decanting point is { x with respect to the coordinate of coordinate central point _j, y _j, h _j, observation station with respect to the coordinate of coordinate central point be h}, is characterized in that for x, y, and the method comprises the following steps:

(1) calculate the mould current density matrix that electric current is propagated from decanting point to observation station [i _0m] be the mould current matrix of transmission line of electricity, propagation constant λ _mfor the eigenwert of matrix [B], matrix [B]=[Y] [Z], the admittance matrix that [Y] is transmission line of electricity, the impedance matrix that [Z] is transmission line of electricity;

(2) calculate current density matrix [i (x)]=[N] i that electric current is propagated from decanting point to observation station _m(x)], [N] is the proper vector of matrix [B];

(3) calculate the radio interference of electric current from decanting point to observation station $E_j(x,y)=60\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{i}_{\mathrm{kj}}\left(x\right)[\frac{(h_j-h)}{{(h_j-h)}^2+{(y-y_j)}^2}+\frac{(h_j+h+2p)}{{(h_j+h+2p)}^2+{(y-y_j)}^2}],$ P is magnetic penetration depth, i _kj(x) ∈ i (x);

(4) calculate electric current in the radio interference of i loop j phase conductor $R{I}_j\left(y\right)=20{\log }_{10}\sqrt{2{\∫}_{x_j}^{\∞}{\left|E_j(x,y)\right|}^2\mathrm{dx}};$

Mould current matrix [the i of the transmission line of electricity in described step (1) _0m] determine in the following manner:

Obtain corona current matrix of coefficients [Γ]=[Γ that transmission line of electricity is raining greatly _ij] ^t, wherein, the corona current coefficient value Γ that the i loop j phase conductor of transmission line of electricity is raining greatly _ij=70-(585/E _max)+35lgd-10lgn _d, E _maxfor phase conductor surface maximum field intensity, d is the sub-conductor diameter in phase conductor, n _dfor the sub-conductor quantity in phase conductor, subscript ^trepresent transposition;

Mould current matrix [the i of computing electric power line _0m]=[N] ^-1[i ₀], wherein, the corona current density matrix [i that each phase conductor produces in each loop ₀]=[C] [Γ]/2 π ε ₀, the capacitance matrix that [C] is transmission line of electricity, ε ₀for the specific inductive capacity of air, π is circular constant, [N] ^-1inverse matrix for the proper vector [N] of matrix [B].

Further, also comprise the radio interference step of calculating i loop: if the radio interference of a certain phase in i loop is all than the large 3dB of other two-phase, the radio interference in i loop equivalence is the radio interference of this phase, otherwise total radio interference in i loop $\mathrm{RI}\left(y\right)=\frac{R{I}_{j1}\left(y\right)+R{I}_{j2}\left(y\right)}{2}+1.5,$ RI _j0(y), RI _j2(y) be that two in the three-phase conducting wire in i loop compared large radio interference.

Further, the total radio interference step that also comprises computing electric power line: the radio interference of the homophase in each loop of transmission line of electricity is cumulative, if the radio interference accumulated value of a certain phase is all than the large 3dB of radio interference accumulated value of other two-phase, total radio interference equivalence of transmission line of electricity is the radio interference accumulated value of this phase, otherwise total radio interference of transmission line of electricity $R\left(y\right)=\frac{R_1\left(y\right)+R_2\left(y\right)}{2}+1.5,$ R ₁(y), R ₂(y) be that two in the three-phase conducting wire in i loop compared large radio interference.

Technique effect of the present invention is embodied in:

The present invention is based on test circuit or corona cage and measure the corona current coefficient under heavy rain condition, by certain modal transformation, obtain the pulse current of each phase conductor, then what calculate that these electric currents produce is radio interference.The present invention can realize the basic electric parameter of various different electric pressures, different conductor arrangement mode, different circuit number and radio interference is calculated, to line design provide can reference data.

Accompanying drawing explanation

Fig. 1 is transmission line structure figure;

Fig. 2 is the inventive method process flow diagram;

Fig. 3 is that radio interference and the observation station three-dimensional position that corona current infinitesimal produces is related to schematic diagram.

Embodiment

Fig. 1 provides a typical double circuit transmission line line structure.Each transmission line of electricity once in about shaft tower, each back transmission line is comprised of three-phase conducting wire, and each is linked together by gold utensil by many roots wire, and sub-conductor is generally steel-cored aluminium strand.

Fig. 2 provides the inventive method process flow diagram, is specifically calculated as follows:

1. because heavy rain condition is the most stable and can reproduce, so general excitation function is all to obtain in the corona cage of heavy rain condition, the corona current coefficients by using formula (1) under heavy rain condition is calculated.

Γ _ij＝70-(585/E _max)+35lgd-10lgn _d (1)

In formula, Γ _ijfor transmission line of electricity i returns j phase conductor at the corona current matrix of coefficients raining greatly, dB; E _maxfor phase conductor surface maximum field intensity, kV/cm; D is sub-conductor diameter, cm; n _dfor wire division number is the sub-conductor quantity in phase conductor, subscript ^trepresent transposition.

Calculate each at the corona current coefficient value raining greatly, obtain excitation function matrix:

[Γ]＝[Γ ₁₁ Γ ₁₂ Γ ₁₃ ... ... ... Γ _n1 Γ _n2 Γ _n3] ^T (2)

In formula, n is that transmission line of electricity returns number.

2. by excitation function, can be obtained the corona pulse current matrix [i of phase conductor ₀], the current density matrix that corona produces in each phase conductor, its off-diagonal element has reflected the coupling between phase conductor:

[i ₀]＝[C][Γ]/2πε ₀ (3)

In formula, [i ₀] be corona pulse current matrix, A; [C] is the capacitance matrix of transmission line of electricity, F; ε ₀for the specific inductive capacity of air, F/m; π is circular constant.

By transmission line of electricity admittance matrix and impedance matrix, calculated:

[B]＝[Y][Z] (4)

In formula, [Y] is transmission line of electricity admittance matrix; [Z] is transmission line of electricity impedance matrix.

The self-admittance self-impedance that [Y] and [Z] comprised the every phase of transmission line of electricity and not the transimpedance transadmittance between homophase, self-admittance self-impedance can be asked by the position relationship between wire and the earth, and transimpedance transadmittance can be tried to achieve by the position relationship between wire.

Ask for proper vector [N] and the inverse matrix [N] thereof of [B] matrix ^-1and eigenvalue λ _m, [N] and [N] ^-1can be used as MODAL TRANSFORMATION OF A matrix, λ _mfor propagation constant.

By modular transformation, obtain mould current matrix and be:

[i _0m]＝[N] ^-1[i ₀] (5)

[i in formula _0m] be mould current matrix.

Fig. 3 provides radio interference and the observation station three-dimensional position relation that a corona current infinitesimal produces.

First choose coordinate central point, coordinate central point can arrange arbitrarily in theory, for convenience of calculation, coordinate coordinate central point is arranged at shaft tower along in transmission line of electricity direction, and the j phase conductor calculating is like this { 0, y for neutral point coordinate _j, h _j, the coordinate of observation station is { x, y, h}.

Electric current injects after wire, by decanting point, to both sides, is propagated, and the current density matrix that calculating electric current is propagated from decanting point to observation station is:

$\left[i_m\left(x\right)\right]=\frac{1}{2}\exp ({\mathrm{\λ}}_m\·x)\left[i_{0m}\right]---\left(6\right)$

In formula, [i _m(x)] be the current density matrix apart from decanting point x place.

Again mould being propagated to the current density matrix that electric current inverse transformation obtains each phase current is:

[i(x)]＝[N][i _m(x)] (7)

In formula, [i (x)] is each phase conductor corona at the current density matrix producing apart from observation station x place, and its off-diagonal element has reflected the coupling between phase conductor;

When j phase conductor produces corona, the electric field component of the electromagnetic field of its generation is calculated as follows:

$E_j(x,y)=60\underset{j^{,}=1}{\overset{n}{\mathrm{\Σ}}}{i}_{j^{,}j}\left(x\right)[\frac{(h_j-h)}{{(h_j-h)}^2+{(y-y_j)}^2}+\frac{(h_j+h+2p)}{{(h_j+h+2p)}^2+{(y-y_j)}^2}]---\left(8\right)$

In formula, E _j(x, y) is the radio interference that j phase conductor produces; P is magnetic penetration depth, i _{j ' j}(x) be the group member in matrix [i (x)], refer to that the relative j phase conductor coupling of j ' corona is in the current density producing apart from observation station x place.

The radio interference E being produced at horizontal coordinate y place by all source current infinitesimals of a phase conductor _j(y) can be by following formula integration:

$E_j\left(y\right)=\sqrt{2{\∫}_0^{\∞}{\left|E_j(x,y)\right|}^2\mathrm{dx}}---\left(9\right)$

Be converted to decibel value:

RI _j(y)＝20log ₁₀(E _j(y)) (10)

In formula, RI _j(y) for turning to the radio interference field intensity of decibel.

3. the result of calculating according to formula (10) is for only to consider the result of a phase conductor corona, if will calculate the total radio interference of three-phase conducting wire, can adopt to be followingly practically applicable to 4 divisions with the synthetic way in the formula of lower wire.

If have the radio interference field intensity value of a phase at least than the large 3dB of all the other every phases, radio interference field intensity value is this field intensity value, otherwise calculates according to the following formula:

$\mathrm{RI}\left(y\right)=\frac{R{I}_{j1}\left(y\right)+R{I}_{j2}\left(y\right)}{2}+1.5---\left(11\right)$

In formula, RI (x, y) is radio interference field intensity, dB; Ri _j1(y), RI _j2(y) for two comparing large radio interference field intensity, dB in three-phase conducting wire.

If calculate total radio interference of multi-circuit lines on the same tower, first that the homophase radio interference in each loop is cumulative, if the radio interference accumulated value of a certain phase is all than the large 3dB of radio interference accumulated value of other two-phase, total radio interference equivalence of transmission line of electricity is the radio interference accumulated value of this phase, otherwise total radio interference of transmission line of electricity $R\left(y\right)=\frac{R_1\left(y\right)+R_2\left(y\right)}{2}+1.5,$ R ₁(y), R ₂(y) be that two in the three-phase conducting wire in i loop compared large radio interference.

Claims (3)

1. transmission line of electricity radio interference measuring method, to the i loop j phase conductor Injection Current of transmission line of electricity, i=1 ..., n, n is the loop sum in transmission line of electricity, j=A, B, C phase, specified coordinate central point, decanting point is { x with respect to the coordinate of coordinate central point _j, y _j, h _j, observation station with respect to the coordinate of coordinate central point be h}, is characterized in that for x, y, and the method comprises the following steps:

(1) calculate the mould current density matrix that electric current is propagated from decanting point to observation station [i _0m] be the mould current matrix of transmission line of electricity, propagation constant λ _mfor the eigenwert of matrix [B], matrix [B]=[Y] [Z], the admittance matrix that [Y] is transmission line of electricity, the impedance matrix that [Z] is transmission line of electricity;

(2) calculate current density matrix [i (x)]=[N] [i that electric current is propagated from decanting point to observation station _m(x)], [N] is the proper vector of matrix [B];

(3) calculate the radio interference of electric current from decanting point to observation station $E_j(x,y)=60\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{i}_{\mathrm{kj}}\left(x\right)[\frac{(h_j-h)}{{(h_j-h)}^2+{(y-y_j)}^2}+\frac{(h_j+h+2p)}{{(h_j+h+2p)}^2+{(y-y_j)}^2}],$ P is magnetic penetration depth, i _kj(x) ∈ i (x);

(4) calculate electric current in the radio interference of i loop j phase conductor $R{I}_j\left(y\right)=20{\log }_{10}\sqrt{2{\∫}_{x_j}^{\∞}{\left|E_j(x,y)\right|}^2\mathrm{dx}};$

Mould current matrix [the i of the transmission line of electricity in described step (1) _0m] determine in the following manner:

Obtain corona current matrix of coefficients [Γ]=[Γ that transmission line of electricity is raining greatly _ij] ^t, wherein, the corona current coefficient value Γ that the i loop j phase conductor of transmission line of electricity is raining greatly _ij=70-(585/E _max)+35lgd-10lgn _d, E _maxbe j phase conductor surface, i loop maximum field intensity, d is the sub-conductor diameter in the j phase conductor of i loop, n _dbe the sub-conductor quantity in the j phase conductor of i loop, subscript ^trepresent transposition;

Mould current matrix [the i of computing electric power line _0m]=[N] ^-1[i ₀], wherein, the corona current density matrix [i that each phase conductor produces in each loop ₀]=[C] [Γ]/2 π ε ₀, the capacitance matrix that [C] is transmission line of electricity, ε ₀for the specific inductive capacity of air, π is circular constant, [N] ^-1inverse matrix for the proper vector [N] of matrix [B].

2. transmission line of electricity radio interference measuring method according to claim 1, it is characterized in that, also comprise the radio interference step of calculating i loop: if the radio interference of a certain phase in i loop is all than the large 3dB of other two-phase, the radio interference in i loop equivalence is the radio interference of this phase, otherwise total radio interference in i loop

rI _j1(y), RI _j2(y) be that two in the three-phase conducting wire in i loop compared large radio interference.

3. transmission line of electricity radio interference measuring method according to claim 1, it is characterized in that, the total radio interference step that also comprises computing electric power line: the radio interference of the homophase in each loop of transmission line of electricity is cumulative, if the radio interference accumulated value of a certain phase is all than the large 3dB of radio interference accumulated value of other two-phase, total radio interference equivalence of transmission line of electricity is the radio interference accumulated value of this phase, otherwise total radio interference of transmission line of electricity

r ₁(y), R ₂(y) be that two in the three-phase conducting wire in i loop compared large radio interference.

Images