CN101459334A - Electrical power system failure information obtaining method - Google Patents

Abstract

The invention relates to a method for obtaining failure information of a power system, which uses space electromagnetic field induction to obtain the failure information of an overhead line, wherein failure voltage traveling wave and failure transient state and steady voltage information are obtained through measuring an electric field on the lower portion of the overhead line, failure current traveling wave and failure transient state and steady current information are obtained through measuring a magnetic field, and the failure voltage traveling wave, the transient state and the steady information of the overhead line are obtained through inducing space electric field by using a capacitive electric field sensor. For a small current grounding system, failure direction is calculated through using components of the transient state failure information which is obtained through using the electromagnetic field induction in a characteristic frequency band, and the failure distance is calculated through the failure voltage and the current traveling wave information which are obtained by the electromagnetic field induction for output circuits and distribution lines. The method for obtaining failure information of a power system has the advantages that the failure traveling wave information, the transient state and steady failure voltage and current information are easily obtained, the safety is greatly increased, and the cost is reduced and the like.

Description

Electrical power system failure information obtaining method

Technical field

The present invention relates to the acquisition methods of a kind of electric power system transmission of electricity and distribution overhead transmission line fault message.

The invention particularly relates to a kind of external electromagnetic field that utilizes and respond to fault traveling wave information, fault transient information and the fault stable state information obtained.

Background technology

China's intermediate distribution system extensively adopts neutral non-effective grounding (earth-free or through grounding through arc) operational mode, is called small current neutral grounding system.Be applied to the single phase ground fault checkout gear of small current neutral grounding system, mostly realize by detection system zero-sequence current and residual voltage.The method of the extraction zero-sequence current that generally adopts in the electric power system at present is to install zero sequence current mutual inductor (TA) in the system of cable outlet, installs threephase current transformer (TA) in the overhead outlet system, again by the synthetic zero sequence current signal of three-phase TA.Residual voltage then is to obtain by the voltage transformer (TV) that install at bus or circuit place.Though these method and apparatus can obtain low current grounding voltage, current information, but cost an arm and a leg, bulky, need to have a power failure and install, particularly in the fault section location, if zero sequence TV, TA are installed or three-phase TA obtains residual voltage, current signal at each test point along the line, not only invest huge but also bring potential safety hazard to system, be unfavorable for that large tracts of land promotes.

Utilize induction voltage transformer (TV), current transformer (TA) to obtain the method for line voltage distribution, current traveling wave information respectively, obtain to use widely at transmission line and distribution line.Though can progress of disease high frequency travelling wave signal as the optical fiber TV of future thrust and optical fiber TA, its sample frequency when digitlization is lower, can not satisfy the requirement of travelling wave ranging.Therefore, research acquisition methods new, easy-to-install travelling wave signal is very crucial for travelling wave ranging technology development in future.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of overhead transmission line that is applicable to different structure is provided, is easy to realize, the electrical power system failure information obtaining method based on the external electromagnetic field induction easy for installation, with low cost.

The technical scheme that technical solution problem of the present invention is taked is: electric-field sensor and magnetic field sensor are installed below overhead transmission line, according to the external electromagnetic field principle of induction, electric field and magnetic field by the induction different directions obtain fault traveling wave, transient state and stable state false voltage, current information.

Utilize electric-field sensor induction line below vertical ground direction electric field, obtain capable wave voltage, transient voltage and steady state voltage information that fault produces based on zero mould,

Utilize electric-field sensor induction line lower horizontal direction electric field, obtain the capable wave voltage based on the line mould, transient voltage and steady state voltage information that fault produces,

Utilize magnetic field sensor induction line lower horizontal direction magnetic field, obtain travelling wave current, transient current and steady-state current information that fault produces based on zero mould,

Utilize vertical ground direction magnetic field, magnetic field sensor induction line below, obtain the travelling wave current based on the line mould, transient current and steady-state current information that fault produces.

1. the method for determining to be parallel to the optimal detection point of three-phase line below, ground zero mode voltage is:

$\left[\begin{array}{ccc}{T}_a& T_b& T_c\end{array}\right]=\left[\begin{array}{ccc}{L}_a& L_b& L_c\end{array}\right]{\left[\begin{array}{c}{\mathrm{\λ}}_{11}{\mathrm{\λ}}_{12}{\mathrm{\λ}}_{13}\\ {\mathrm{\λ}}_{21}{\mathrm{\λ}}_{22}{\mathrm{\λ}}_{23}\\ {\mathrm{\λ}}_{31}{\mathrm{\λ}}_{32}{\mathrm{\λ}}_{33}\end{array}\right]}^{-1}$

Wherein: $L_k=\frac{1}{2{\mathrm{\π\ϵ}}_0}[\frac{y-Y_k}{{(x-X_k)}^2+{(y-Y_k)}^2}-\frac{y+Y_k}{{(x-X_k)}^2+{(y+Y_k)}^2}],$ K=a, b, c, three-phase conducting wire coordinate (X _k, Y _k), the test point coordinate (x, y), ε ₀Be the dielectric constant of air, λ is the self-potential coefficient and the mutual coefficient of potential matrix of each lead.

With the parameter substitutions such as lead coordinate of actual track, T solves an equation _a=T _b=T _cGet the optimal detection point P of zero mode voltage _E(x, y).

2. at the optimal detection point place of zero mode voltage, vertical ground direction electric field and the zero proportional relation of mode voltage can obtain zero mode voltage row ripple, transient state and stable state zero mode voltage signal by the electric field of responding to zero mode voltage optimal detection point place vertical ground direction; Near under circuit in certain zone of the optimal detection point of offset from zero mode voltage, though contain the pressure-wire mold component in the vertical ground direction electric field fault component, but, obtain the capable wave voltage of low current grounding, transient state and steady state voltage information based on zero mold component by the vertical ground direction electric field of responding to each point place in this zone still based on zero mold component.

3. the method for determining to be parallel to the optimal detection point of three-phase line below, ground zero mould electric current is:

$S_k=\frac{{\mathrm{\μ}}_0}{2\mathrm{\π}}\frac{Y_k-y}{{(X_k-x)}^2+{(Y_k-y)}^2},$ K=a, b, c; μ ₀Be the magnetic permeability of air, with the lead coordinate (X of actual track _k, Y _k) substitution S _k, S solves an equation _a=S _b=S _cGet the optimal detection point P of zero mould electric current _B(x, y).

4. in the horizontal direction magnetic field, optimal detection point place and the zero proportional relation of mould electric current of zero mould electric current, the horizontal direction magnetic field at the optimal detection point place by responding to zero mould electric current can obtain zero mould current traveling wave, transient state and stable state zero mould current signal; Near under circuit in certain zone of the optimal detection point of offset from zero mould electric current, contain electric current line mold component in the fault component of horizontal direction magnetic field, but, obtain low current grounding current traveling wave, transient state and steady-state current information based on zero mold component by the horizontal direction magnetic field of responding to each point in this zone still based on zero mold component.

5. the implementation procedure of utilizing this method to obtain the line mold component is:

In the time of under test point is positioned at circuit, horizontal direction electric field and the proportional relation of line mode voltage can be obtained fault wire mode voltage row ripple, transient state and steady state voltage line mold component by sensation level direction electric field.Hour, horizontal direction electric field fault component is based on the line mold component under test point departs from circuit, can obtain the capable ripple of false voltage, transient state and steady state voltage information based on the line mold component by sensation level direction electric field.

In the time of under test point is positioned at circuit, vertical ground direction magnetic field and the proportional relation of line mould electric current can be obtained fault wire mould current traveling wave, transient state and steady-state current line mold component by induction vertical ground direction magnetic field; Hour, vertical ground direction magnetic field, test point place fault component is based on the line mold component under test point departs from circuit, can obtain the capable ripple of fault current, transient state and steady-state current information based on the line mold component by induction vertical ground direction magnetic field.

6. the electric-field sensor that this method adopted is a condenser type, and magnetic field sensor then adopts single coil.The condenser type electric-field sensor is made up of metal electrode and pre-amplification circuit, utilizes the electrode of sheet metal as transducer, utilizes charge amplifier as pre-amplification circuit, the output voltage U of charge amplifying circuit _oWith pass be perpendicular to the electric field E of pole plate:

$U_o=-\frac{{\mathrm{\ϵ}}_{0}A}{C_f}E.$

In the formula: A is the pole plate area; C _fBe the charge amplifying circuit feedback capacity.

7. fault transient voltage, the transient current information of utilizing electric-field sensor and magnetic field sensor to obtain based on zero mould realize low-current ground fault line selection (faulty line selection) and section location; Utilization is obtained based on the fault traveling wave voltage of zero mold component, travelling wave current information and is realized the low current grounding range finding; Fault traveling wave voltage, travelling wave current information that utilization is obtained based on the line mould realize short circuit and low current grounding range finding.

8. calculate fault direction according to the following equation, realize failure line selection and section location:

${\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0=\frac{1}{T}{\&Integral;}_0^T{U}_B\left(t\right)\widehat{U_E}\left(t\right)\mathrm{dt}=\frac{1}{\mathrm{\&pi;T}}{\&Integral;}_0^T{U}_B\left(t\right){\&Integral;}_{-\&infin;}^{\&infin;}\frac{U_E\left(\mathrm{\&tau;}\right)}{t-\mathrm{\&tau;}}\mathrm{d\&tau;dt}$

In the formula: U _B(t) be the output voltage of magnetic field sensor, reflection is based on the low current grounding transient current information of zero mold component; U _E(t) be the output voltage of electric-field sensor, reflection is based on the low current grounding transient voltage information of zero mold component.

If Q ₀＜0, then fault is positioned at the test point downstream; If Q ₀〉=0 fault is positioned at test point upstream or other outlet.

Compared with prior art the invention has the beneficial effects as follows: utilize the external electromagnetic field induction to obtain the method for overhead transmission line fault message, not only can effectively obtain fault traveling wave information, fault transient and stable state information, can also take into account cost and practicality, apparatus structure is simple, volume is little, and there are bigger electrical safety distance in induction installation and high-tension line, need not have a power failure during installation and maintenance, improve fail safe, reduced cost.

Description of drawings

Fig. 1 is three-phase conducting wire and electromagnetic field measurements point coordinate system schematic diagram;

Fig. 2 is 5 meters vertical ground direction electric fields under the circuit and T ₀u ₀The transient emulation waveform;

Fig. 3 is horizontal direction magnetic field, 5 meters and S under the circuit ₀i ₀The transient emulation waveform;

Fig. 4 is the capable ripple simulation waveform of horizontal direction electric field that is positioned at bus end test point place;

Fig. 5 is the vertical ground direction magnetic field row ripple simulation waveform that is positioned at bus end test point place;

Fig. 6 is a condenser type electric-field sensor schematic diagram;

Fig. 7 is the magnetic field sensor schematic diagram;

Fig. 8 is a contactless fault section location schematic diagram;

Fig. 9 uses schematic diagram for magnetic field sensor in failure line selection;

Figure 10 realizes electric line fault localization schematic diagram for utilizing electromagnetic field inducing to obtain fault traveling wave information.

Wherein: Ey is a vertical electric field intensity; C _fBe integrating circuit electric capacity; Bx is the horizontal direction magnetic field intensity; S and R are respectively two measuring junctions.

Embodiment

Below in conjunction with accompanying drawing this method is described further.

Electrical power system failure information obtaining method of the present invention can be applied in the overhead transmission line of different electric pressure different structures.Can be used for realizing low-current ground fault line selection and section location and electric line travelling wave ranging, below narration respectively:

1. the implementation procedure based on the failure information obtaining method of zero mold component is:

(1) the false voltage information getting method implementation procedure based on zero mold component is:

Utilize equivalent charge method to calculate electric field strength, establish three-phase conducting wire endless and parallel to the ground, ground potential is 0, and at certain in a flash, the current potential of A, B, C three-phase line is u _a, u _b, u _c, its unit length equivalence electric charge is τ _a, τ _b, τ _c, then:

$\left[\begin{array}{c}{\mathrm{\&tau;}}_a\\ {\mathrm{\&tau;}}_b\\ {\mathrm{\&tau;}}_c\end{array}\right]={\left[\begin{array}{c}{\mathrm{\&lambda;}}_{11}{\mathrm{\&lambda;}}_{12}{\mathrm{\&lambda;}}_{13}\\ {\mathrm{\&lambda;}}_{21}{\mathrm{\&lambda;}}_{22}{\mathrm{\&lambda;}}_{23}\\ {\mathrm{\&lambda;}}_{31}{\mathrm{\&lambda;}}_{32}{\mathrm{\&lambda;}}_{33}\end{array}\right]}^{-1}\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]---\left(1\right)$

In the formula: $\mathrm{\&lambda;}=\left[\begin{array}{c}{\mathrm{\&lambda;}}_{11}{\mathrm{\&lambda;}}_{12}{\mathrm{\&lambda;}}_{13}\\ {\mathrm{\&lambda;}}_{21}{\mathrm{\&lambda;}}_{22}{\mathrm{\&lambda;}}_{23}\\ {\mathrm{\&lambda;}}_{31}{\mathrm{\&lambda;}}_{32}{\mathrm{\&lambda;}}_{33}\end{array}\right]$ For the self-potential coefficient and the mutual coefficient of potential matrix of each lead, can try to achieve by image method.

Set up rectangular coordinate system in the plane vertical with three-phase conducting wire, as shown in Figure 1, establishing the lead coordinate is (X _k, Y _k), k=a, b, c; Test point P coordinate be (x, y), three-phase conducting wire in the vertical ground direction electric field strength that the P point produces is:

$E_y=\left[\begin{array}{ccc}{L}_a& L_b& L_c\end{array}\right]\left[\begin{array}{c}{\mathrm{\&tau;}}_a\\ {\mathrm{\&tau;}}_b\\ {\mathrm{\&tau;}}_c\end{array}\right]---\left(2\right)$

In the formula: $L_k=\frac{1}{2{\mathrm{\&pi;\&epsiv;}}_0}[\frac{y-Y_k}{{(x-X_k)}^2+{(y-Y_k)}^2}-\frac{y+Y_k}{{(x-X_k)}^2+{(y+Y_k)}^2}],$ K=a, b, c; ε ₀Dielectric constant for air.(1) formula substitution (2) formula is got vertical ground direction electric field and three-phase voltage closes and is:

$E_y=\left[\begin{array}{ccc}{L}_a& L_b& L_c\end{array}\right]\left[\begin{array}{c}{\mathrm{\&tau;}}_a\\ {\mathrm{\&tau;}}_b\\ {\mathrm{\&tau;}}_c\end{array}\right]=\left[\begin{array}{ccc}{T}_a& T_b& T_c\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]---\left(3\right)$

In the formula: [T _aT _bT _c]=[L _aL _bL _c] [λ] ^-1(4)

According to the Karrenbauer conversion, (3) formula is transformed to the mold component system, transformation matrix is:

$\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]=\left[\begin{array}{ccc}1& 1& 1\\ 1& -2& 1\\ 1& 1& -2\end{array}\right]\left[\begin{array}{c}{u}_0\\ u_1\\ {\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">u</figure-callout>}}_2\end{array}\right]$

The pass of vertical ground direction electric field and voltage-mode component is:

E _y＝T ₀u ₀+T ₁u ₁+T ₂u ₂

In the formula: T ₀=T _a+ T _b+ T _cT ₁=T _a-2T _b+ T _cT ₂=T _a+ T _b-2T _c

According to the actual track structural parameters, with parameter substitutions such as lead coordinates, T solves an equation ₁=T ₂=0, i.e. T _a=T _b=T _c, the optimal detection point P of zero mode voltage _E(x, y), this some E of place _y=T ₀u ₀=3T _au ₀, i.e. the optimal detection point place vertical ground direction electric field of zero mode voltage and the zero proportional relation of mode voltage, the vertical ground direction electric field of measuring this some place can obtain zero mode voltage row ripple, transient state and stable state zero mode voltage signal.

Near under the three-phase overhead transmission line in certain zone of the optimal detection point of offset from zero mode voltage, the each point place $E_y=T_0{\mathrm{<figure-callout\; id="0"\; label="u"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">u</figure-callout>}}_0+T_1{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="A200810135881E00171.png,A200810135881E00175.png"\; state="\{\{state\}\}">u</figure-callout>}}_1+T_2{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">u</figure-callout>}}_2=T_0{u}_0(1+\frac{T_1{u}_1}{T_0{\mathrm{<figure-callout\; id="0"\; label="u"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">u</figure-callout>}}_0}+\frac{T_2{u}_2}{T_0{u}_0}),$ T ₁, T ₂Non-vanishing, but T ₁, T ₂With respect to T ₀Very little, and u ₁, u ₂With respect to u ₀Less, therefore under circuit near in certain zone of optimal detection point of offset from zero mode voltage, though vertical ground direction electric field fault component contains the pressure-wire mold component, take as the leading factor with the zero mold component of false voltage, can be expressed as E _Fy≈ T ₀u ₀, therefore can obtain voltage traveling wave, transient state and steady state voltage information by responding to each test point place vertical ground direction electric field in this zone based on zero mold component, realize that further failure line selection and section locate and the power transmission and distribution travelling wave ranging.

In typical 10KV overhead transmission line, three-phase conducting wire becomes " equilateral triangle " to arrange, and the base is height 10m overhead, three-phase conducting wire is spacing 1m in twos, conductor radius 0.0033m, height 9.715m place overhead under the optimal detection point of zero mode voltage under this structure is positioned at circuit, this some E of place _y=T ₀u ₀=3T _au ₀Height 5m place overhead under circuit, $\left|\frac{T_1}{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}\right|=0.22,$ $\left|\frac{T_2}{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}\right|=0.11,$ T ₁, T ₂With respect to T ₀Very little, this some E of place _Fy≈ T ₀u ₀

Become " word " to arrange at three-phase line, lead is height 10m overhead, wire pitch 0.5m, and under the conductor radius 0.0033m structure, the optimal detection point of zero mode voltage is positioned under the circuit overhead height 7.8m place, this some E of place _y=T ₀u ₀=3T _au ₀Height 5m place overhead under circuit, $\left|\frac{T_1}{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}\right|=0.08,$ $\left|\frac{T_2}{{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">T</figure-callout>}}_0}\right|=0.04,$ T ₁, T ₂With respect to T ₀Very little, this some E of place _Fy≈ T ₀u ₀

Under three-phase line " word " arrangement architecture, 5 meters vertical ground direction electric fields and T under the circuit ₀u ₀Curve as shown in Figure 2.Therefrom as seen, the two error is very little, can satisfy the engineering demands of applications fully.

(2) the fault current information getting method implementation procedure based on zero mold component is:

Adopt the analytical method identical, be parallel to the three-phase line below on ground, with horizontal magnetic field B in the three-phase conducting wire vertical plane with electric field _xWith the three-phase current pass be:

$B_x=\left[\begin{array}{ccc}{S}_a& S_b& S_c\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

In the formula: $S_k=\frac{{\mathrm{\&mu;}}_0}{2\mathrm{\&pi;}}\frac{Y_k-y}{{(X_k-x)}^2+{(Y_k-y)}^2},$ K=a, b, c; μ ₀Magnetic permeability for air.

According to the Karrenbauer conversion, system is become the mold component system, horizontal magnetic field and current-mode divide magnitude relation to be:

B _x＝S ₀i ₀+S ₁i ₁+S ₂i ₂

In the formula: S ₀=S _a+ S _b+ S _cS ₁=S _a-2S _b+ S _cS ₂=S _a+ S _b-2S _c

According to the actual track structural parameters, with the substitution of three-phase conducting wire coordinate parameters, S solves an equation ₁=S ₂=0, i.e. S _a=S _b=S _cGet the optimal detection point P of zero mould electric current _B(x, y), this some B of place _x=S ₀i ₀=3S _ai ₀, i.e. the horizontal direction magnetic field, optimal detection point place of zero mould electric current and the zero proportional relation of mould electric current, the horizontal magnetic field of responding to this some place can obtain zero mould current traveling wave, transient state and stable state zero mould current signal.Under the three-phase line that becomes " equilateral triangle " to arrange, overhead highly $y=\frac{{X_a}^2+{Y_a}^2-Y_a{Y}_b}{Y_a-Y_b}$ The place is the optimal detection point of zero mould electric current.

Near under the three-phase overhead transmission line in certain zone of the optimal detection point of offset from zero mould electric current, the each point place $B_x=S_0{\mathrm{<figure-callout\; id="0"\; label="i"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">i</figure-callout>}}_0+S_1{\mathrm{<figure-callout\; id="1"\; label="i"\; filenames="A200810135881E00171.png,A200810135881E00175.png"\; state="\{\{state\}\}">i</figure-callout>}}_1+S_2{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">i</figure-callout>}}_2=S_0{i}_0(1+\frac{S_1{i}_1}{S_0{\mathrm{<figure-callout\; id="0"\; label="i"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">i</figure-callout>}}_0}+\frac{S_2{i}_2}{S_0{i}_0}),$ S ₁, S ₂Non-vanishing, but S ₁, S ₂With respect to S ₀Very little, but horizontal direction magnetic field fault component approximate representation is B _x≈ S ₀i ₀, therefore can obtain the capable ripple of fault current, transient state and steady-state current information by responding to horizontal direction magnetic field in this zone based on zero mold component, utilize the fault message that obtains to realize that further failure line selection and section locate and the power transmission and distribution travelling wave ranging.

Become " equilateral triangle " to arrange at three-phase line, base height 10m, three-phase line be in twos under the spacing 1m structure, and the optimal detection point of zero mould electric current is positioned under the circuit overhead height 9.711m place, this some B of place _x=S ₀i ₀=3S _ai ₀Height 5m place overhead under circuit, $\left|\frac{S_1}{{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">S</figure-callout>}}_0}\right|=0.097,$ $\left|\frac{S_2}{{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">S</figure-callout>}}_0}\right|=0.049,$ S ₁, S ₂With respect to S ₀Very little, B _x≈ S ₀i ₀

Become " word " to arrange at three-phase line, under the wire pitch 0.5m structure, there is not the optimal detection point of zero mould electric current in lead height 10m under the circuit, height 5m place overhead under circuit, $\left|\frac{S_1}{{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">S</figure-callout>}}_0}\right|=0.0066,$ $\left|\frac{S_2}{{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">S</figure-callout>}}_0}\right|=0.0033,$ S ₁, S ₂With respect to S ₀Very little, B _x≈ S ₀i ₀Above-mentioned " word " arranged under the overhead transmission line structure, overhead height horizontal direction magnetic field, 5 meters and S under the circuit ₀i ₀Waveform as shown in Figure 3.Therefrom as seen, the two error is very little, can satisfy the engineering demands of applications fully.

2. the implementation procedure based on the failure information obtaining method of line mold component is:

(1) based on the implementation procedure of the false voltage information getting method of line mold component:

In the system shown in the accompanying drawing 1, three-phase conducting wire is expressed as in the horizontal direction electric field strength that the P point produces:

$E_x=\left[\begin{array}{ccc}{Q}_a& Q_b& Q_c\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]$

In the formula: [Q _aQ _bQ _c]=[H _aH _bH _c] [λ] ^-1 $H_k=\frac{1}{2{\mathrm{\&pi;\&epsiv;}}_0}\left[\frac{x-X_k}{{(x-X_k)}^2+{(y-Y_k)}^2}\frac{x-X_k}{{(x-X_k)}^2+{(y+Y_k)}^2}\right]$

According to the Karrenbauer conversion, system is become the mold component system, horizontal component of electric field is expressed as:

E _x＝Q ₀u ₀+Q ₁u ₁+Q ₂u ₂

In the formula: Q ₀=Q _a+ Q _b+ Q _cQ ₁=Q _a-2Q _b+ Q _cQ ₂=Q _a+ Q _b-2Q _c

When being abscissa x=0 under test point is positioned at circuit,, can get Q with the substitution of line construction parameter ₀=Q ₁=0, i.e. E _x=Q ₂u ₂, promptly (x=0) horizontal direction electric field reflects false voltage line mold component under the circuit, the horizontal direction electric field can obtain fault wire mode voltage row ripple, transient state and stable state line mode voltage signal under the induction line.Under test point departs from circuit hour (test point coordinate x ≠ 0), $E_x=Q_2{u}_2(1+\frac{Q_0{u}_0}{Q_2{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">u</figure-callout>}}_2}+\frac{Q_1{u}_1}{Q_2{u}_2}),$ Q ₀, Q ₁Be not equal to zero still with respect to Q ₂Very little, but test point place horizontal direction electric field fault component approximate representation is E _x≈ Q ₂u ₂, can obtain the capable ripple of false voltage, transient state and steady state voltage information based on the line mold component by detection level direction electric field.

Be positioned at the detected capable ripple simulation waveform of horizontal direction electric field that produces by two-phase short-circuit fault of the test point at bus place as shown in Figure 4.

(2) based on the implementation procedure of the fault current information getting method of line mold component:

In the system shown in the accompanying drawing 1, three-phase conducting wire is expressed as at the vertical ground direction magnetic flux density that the P point produces:

$B_y=\left[\begin{array}{ccc}{W}_a& W_b& W_c\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

In the formula: $W_k=\frac{{\mathrm{\&mu;}}_0}{2\mathrm{\&pi;}}\frac{X_k-x}{{(X_k-x)}^2+{(Y_k-y)}^2}$

According to the Karrenbauer conversion, system is become the mold component system, vertical ground direction magnetic field is expressed as:

B _y＝W ₀i ₀+W ₁i ₁+W ₂i ₂

In the formula: W ₀=W _a+ W _b+ W _cW ₁=W _a-2W _b+ W _cW ₂=W _a+ W _b-2W _c

When being coordinate x=0 place under test point is positioned at circuit, with line construction parameter and test point coordinate x=0 substitution W _k, can get W ₀=W ₁=0, B _y=W ₂i ₂=3W _ai ₂, promptly (x=0) vertical ground direction magnetic field and fault current line mold component are proportional under the circuit, can obtain fault wire mould current traveling wave, transient state and steady-state current signal by induction vertical ground direction magnetic field.When departing under the circuit hour W ₀, W ₁It is non-vanishing, $B_y=W_2{i}_2(1+\frac{W_0{i}_0}{W_2{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">i</figure-callout>}}_2}+\frac{W_1{i}_1}{W_2{i}_2}),$ But W ₀, W ₁With respect to W ₂Very little, but vertical ground direction magnetic field, test point place fault component approximate representation is B _y≈ W ₂i ₂, can obtain the capable ripple of fault current, transient state and steady-state current information based on the line mold component by induction vertical ground direction magnetic field.

Be positioned at the detected vertical ground direction magnetic field row ripple simulation waveform that produces by two-phase short-circuit fault of the test point at bus place as shown in Figure 5.

3, the measurement of electromagnetic field signal

(1) utilize the electric field of condenser type electric-field sensor induction different directions to obtain the capable ripple of false voltage, transient state and steady state voltage information.

The condenser type electric-field sensor is made up of metal electrode and pre-amplification circuit, as shown in Figure 6.Two sheet metals are as the electrode of electric-field sensor, owing to cause that perpendicular to the variation of pole plate direction electric field the quantity of electric charge of pole plate upper and lower surface produces corresponding the variation, therefore can realize electric field measurement by the quantity of electric charge on measuring pad surface.The frequency characteristic of electric-field sensor, impedance matching and antijamming capability depend primarily on pre-amplification circuit, be subjected to the influence of electrode capacitance, stube cable distributed capacitance and pre-amplification circuit input capacitance etc. for solving output voltage, adopt charge amplifying circuit as pre-amplification circuit.

The output voltage U of charge amplifying circuit _oWith pole plate electric charge q, be perpendicular to the pass of the electric field E of pole plate:

$U_o=-\frac{q}{C_f}=-\frac{{\mathrm{\&epsiv;}}_{0}A}{C_f}E$

In the formula: A is the pole plate area; C _fBe the charge amplifying circuit feedback capacity.

(2) utilize the different directions magnetic field at single-point place, single coil induction line below to obtain the capable ripple of fault current, transient state and steady-state current information.

Magnetic field sensor is made up of hollow (or permeability magnetic material kernel) coil of column type and corresponding signal processing circuit, as shown in Figure 7.Cause that when passing the changes of magnetic field of coil the electromotive force of inducting on the coil changes, thereby utilize this feature to realize the measurement in magnetic field is obtained the capable ripple of fault current, transient state and steady-state current information.

4. play the component of interference effect in the transient state fault message based on zero mold component that filtering is obtained and component in the keeping characteristics frequency range utilizes the component calculating fault direction of fault transient information in characteristic spectra, implementation procedure is:

According to the requirement of protection speed, get fault after a set time section as the Temporal Data time window, choose that zero all circuits of lay wire network all become the low-frequency range of capacitive as characteristic spectra after the fault.To carrying out filtering based on the electric-field sensor of zero mold component, the output signal of magnetic field sensor, keeping characteristics frequency range component is according to formula $Q_{}$ ${}_0=\frac{1}{T}{\&Integral;}_0^T{U}_B\left(t\right)\widehat{U_E}\left(t\right)\mathrm{dt}=\frac{1}{\mathrm{\&pi;T}}{\&Integral;}_0^T{U}_B\left(t\right){\&Integral;}_{-\&infin;}^{\&infin;}\frac{U_E\left(\mathrm{\&tau;}\right)}{t-\mathrm{\&tau;}}\mathrm{d\&tau;dt}$ Calculate fault direction, further realize low-current ground fault line selection and section location.

In the formula: U _B(t) be the output voltage of magnetic field sensor, reflection is based on the low current grounding transient current information of zero mold component; U _E(t) be the output voltage of electric-field sensor, reflection is based on the low current grounding transient voltage information of zero mold component.

5. utilize the fault traveling wave information calculations fault distance that obtains, realize travelling wave ranging low current grounding based on zero mold component; The fault traveling wave information based on the line mold component that utilization is obtained realizes the travelling wave ranging to short circuit and low current grounding.Implementation procedure is:

If the fault initial row wave-wave head that the travelling wave ranging device is noted by emf sensor arrives the time of circuit two ends test point and is respectively T _SAnd T _R, the distance between two ends test point S, the R is L, then fault point and test point distance can be calculated by following formula:

$X_S=\frac{(T_S-T_R)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2},$ ? $X_R=\frac{(T_R-T_S)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}$

In the formula: v is a wave velocity.

Embodiment 1:

1, utilization realizes low current grounding section location based on the transient state fault message of zero mold component

Utilize the present invention to realize that low current grounding section location can be the fault detector of single-minded function, also can replace fault detector as core processing unit, be referred to as accident indicator with FTU.Typical fault automatic location system is made up of three parts: be distributed in the accident indicator at each test point place of circuit, communication network (as GPRS etc.), the fault automatic location system main website.Accident indicator is gathered false voltage, the current information of electric field, magnetic field sensor output.After breaking down, utilize the component of fault message in characteristic spectra to calculate fault direction, accident indicator by communication system with fault information reporting fault automatic location main website.The fault automatic location main website determines fault section and sends alarm signal that realize fault automatic location, the specific implementation step is as follows after receiving the fault message that each accident indicator reports:

Accident indicator:

1) according to the line construction parameter of reality, determine electric field, magnetic field detection point position,

Because accident indicator is installed on the shaft tower, be positioned under the circuit, ignore the error that measurement point departs from horizontal direction, according to the actual track structural parameters T that solves an equation _a=T _b=T _c, determine the optimal detection point P of the zero mode voltage under this line construction _E(x, y),

Become at three-phase conducting wire under " positive triangle " structure arranged, the substitution of actual track structural parameters $y=\frac{{X_a}^2+{Y_a}^2-Y_a{Y}_b}{Y_a-Y_b},$ Determine the optimal detection point P of zero mould electric current _B(x, y),

2) electric field, magnetic field sensor are installed, are obtained low current grounding transient voltage, current information based on zero mold component,

3) determine the characteristic spectra scope according to the main resonatnt frequency of transient signal,

4) electric field, magnetic field sensor output signal filtering are obtained the component in characteristic spectra,

5) basis $Q_{}$ ${}_0=\frac{1}{T}{\&Integral;}_0^T{U}_B\left(t\right)\widehat{U_E}\left(t\right)\mathrm{dt}=\frac{1}{\mathrm{\&pi;T}}{\&Integral;}_0^T{U}_B\left(t\right){\&Integral;}_{-\&infin;}^{\&infin;}\frac{U_E\left(\mathrm{\&tau;}\right)}{t-\mathrm{\&tau;}}\mathrm{d\&tau;dt}$ Calculate fault direction, accident indicator by communication network with the automatic positioning master station of fault information reporting.Contactless fault section location schematic diagram as shown in Figure 8.

The fault automatic location main website:

Determine fault section according to different test point fault messages on the faulty line.The fault point is positioned at a side fault detect node Q ₀＜0 and opposite side fault detect node Q ₀Between 0 two test points.After earth fault takes place, if all detection node Q ₀0, then the fault point is positioned at faulty line and exports on first test point section; If all detection node Q on certain bar circuit ₀＜0, then the fault point is positioned on last test point of this circuit and the line end section.

Embodiment 2:

2, utilization realizes low-current ground fault line selection based on the transient state fault message of zero mold component

Fault line selection device is installed in the transformer station, utilizes the voltage transformer (TV) that is installed in the bus place can obtain the residual voltage signal, does not need additionally to install electric-field sensor.For cable outlet, can obtain zero sequence current signal by zero sequence TA, for the overhead outlet that can not obtain zero-sequence current, can install magnetic field sensor on the wall near the overhead outlet wall bushing, as shown in Figure 9; Performing step is as follows:

1) according to the line construction parameter of reality, determine magnetic field detection point position,

2) magnetic field sensor is installed on the wall and is inserted low-current ground fault line selection device can not obtaining near the overhead outlet wall bushing of zero-sequence current, obtain fault transient state current information based on zero mold component,

3) residual voltage is inserted low-current ground fault line selection device, obtains the fault transient information of voltage,

4) determine the characteristic spectra scope according to the main resonatnt frequency of transient signal,

5) the transient state fault-signal is carried out filtering and obtains the characteristic spectra component,

6) basis $Q_{}$ ${}_0=\frac{1}{T}{\&Integral;}_0^T{U}_B\left(t\right){\hat{u}}_0\left(t\right)\mathrm{dt}$ (install magnetic field sensor circuit) or ${\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="A200810135881E00172.png,A200810135881E00173.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0=\frac{1}{T}{\&Integral;}_0^T{i}_0\left(t\right){\hat{u}}_0\left(t\right)\mathrm{dt}$ (the zero sequence current mutual inductor circuit is installed) calculates fault direction,

7) relatively each bar outlet fault direction is determined faulty line,

The Q of faulty line ₀Be the negative circuit Q that perfects ₀For just.Utilize this method to determine faulty line, determining to provide route selection result and alarm signal with different forms behind the faulty line.And can as required fault data or analysis result be uploaded higher level main website or distant place system.

Embodiment 3:

3, utilize capable ripple information to realize the low current grounding travelling wave ranging, utilize capable ripple information to realize short circuit and low current grounding travelling wave ranging based on the line mold component based on zero mold component

1) install near under the circuit two ends electric-field sensor and (or) magnetic field sensor detect space electric field and (or) magnetic field obtain based on the false voltage of zero mold component or line mold component with (or) the current traveling wave signal, as shown in Figure 10,

2) the fault traveling wave information obtained by emf sensor of circuit two ends range unit record and with data remote to the PC of control centre work station,

3) utilize time based on the fault initial row ripple arrival circuit two ends test point of zero mold component of record, according to $X_S=\frac{(T_S-T_R)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}$ With $X_R=\frac{(T_R-T_S)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}$ Calculate fault distance or under area of computer aided, analyze the row wave datum by operating personnel and determine fault distance, realize that low current grounding finds range,

4) utilize time based on the fault initial row ripple arrival circuit two ends test point of line mold component of record, according to $X_S=\frac{(T_S-T_R)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}$ With $X_R=\frac{(T_R-T_S)v+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200810135881E00173.png,A200810135881E00175.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}$ Calculate fault distance or under area of computer aided, analyzes the row wave datum by operating personnel and determine fault distance, realize that short circuit and low current grounding find range.

Claims (9)

1, electrical power system failure information obtaining method, utilize the external electromagnetic field induction to obtain fault message, it is characterized in that: electric-field sensor and magnetic field sensor are installed below overhead transmission line, by the electric field and the magnetic field of induction different directions, obtain the fault message of capable ripple, transient state and the stable state difference components of the voltage and current of fault generation.

2, electrical power system failure information obtaining method according to claim 1 is characterized in that:

A utilizes electric-field sensor induction line below vertical ground direction electric field, obtains capable wave voltage, transient voltage and steady state voltage information based on zero mould that fault produces;

B utilizes electric-field sensor induction line lower horizontal direction electric field, obtains the capable wave voltage based on the line mould, transient voltage and steady state voltage information that fault produces;

C utilizes magnetic field sensor induction line lower horizontal direction magnetic field, obtains travelling wave current, transient current and steady-state current information based on zero mould that fault produces;

D utilizes vertical ground direction magnetic field, magnetic field sensor induction line below, obtains the travelling wave current based on the line mould, transient current and steady-state current information that fault produces.

3, electrical power system failure information obtaining method according to claim 2 is characterized in that:

A determines that the method that is parallel to three-phase line below, ground zero mode voltage optimal detection point is:

$\left[\begin{array}{ccc}{T}_a& T_b& T_c\end{array}\right]=\left[\begin{array}{ccc}{L}_a& L_b& L_c\end{array}\right]{\left[\begin{array}{c}{\mathrm{\&lambda;}}_{11}{\mathrm{\&lambda;}}_{12}{\mathrm{\&lambda;}}_{13}\\ {\mathrm{\&lambda;}}_{21}{\mathrm{\&lambda;}}_{22}{\mathrm{\&lambda;}}_{23}\\ {\mathrm{\&lambda;}}_{31}{\mathrm{\&lambda;}}_{32}{\mathrm{\&lambda;}}_{33}\end{array}\right]}^{-1}$

Wherein: $L_k=\frac{1}{2{\mathrm{\&pi;\&epsiv;}}_0}[\frac{y-Y_k}{{(x-X_k)}^2+{(y-Y_k)}^2}-\frac{y+Y_k}{{(x-X_k)}^2+{(y+Y_k)}^2}],$ K=a, b, c, (X _k, Y _k) be the three-phase conducting wire coordinate, (x y) is the test point coordinate, ε ₀Be the dielectric constant of air, λ is the self-potential coefficient and the mutual coefficient of potential matrix of each lead;

With the parameter substitutions such as coordinate of actual track, T solves an equation _a=T _b=T _cGet the optimal detection point P of zero mode voltage _E(x, y);

B determines that the method that is parallel to three-phase line below, ground zero mould electric current optimal detection point is:

$S_k=\frac{{\mathrm{\&mu;}}_0}{2\mathrm{\&pi;}}\frac{Y_k-y}{{(X_k-x)}^2+{(Y_k-y)}^2},$ K=a, b, c; μ ₀Be the magnetic permeability of air, with the lead coordinate (X of actual track _k, Y _k) substitution S _k, S solves an equation _a=S _b=S _cGet the optimal detection point P of zero mould electric current _B(x, y).

4, according to claim 2 or 3 described electrical power system failure information obtaining methods, it is characterized in that:

A is at the optimal detection point place vertical ground direction electric field and the zero proportional relation of mode voltage of zero mode voltage, obtain capable ripple, transient state and the steady-state component of zero mode voltage signal by the electric field of responding to zero mode voltage optimal detection point place vertical ground direction, below circuit in certain zone of offset from zero mode voltage optimal detection point, still based on zero mold component, obtain capable ripple, transient state and steady-state component in the vertical ground direction electric field based on the voltage signal of zero mold component by the vertical ground direction electric field of responding to each point place in this zone;

B is in the horizontal direction magnetic field, optimal detection point place and the zero proportional relation of mould electric current of zero mould electric current, obtain capable ripple, transient state and the steady-state component of zero mould current signal by the horizontal direction magnetic field of responding to zero mould electric current optimal detection point place, below circuit in certain zone of offset from zero mould electric current optimal detection point, still based on zero mold component, obtain capable ripple, transient state and steady-state component in the horizontal direction magnetic field based on the current signal of zero mold component by the horizontal direction magnetic field of responding to each point in this zone.

5, electrical power system failure information obtaining method according to claim 2 is characterized in that:

Horizontal direction electric field under a circuit and the proportional relation of line mode voltage, can obtain capable ripple, transient state and the steady-state component of line mode voltage signal by sensation level direction electric field, the horizontal direction electric field is still based on the line mold component in certain zone under departing from circuit, obtains capable ripple, transient state and steady-state component based on the voltage signal of line mold component by sensation level direction electric field;

Vertical ground direction magnetic field under the b circuit and the proportional relation of line mould electric current, can obtain capable ripple, transient state and the steady-state component of line mould current signal by induction vertical ground direction magnetic field, depart from the certain zone under the circuit vertical ground direction magnetic field still based on the line mold component, obtain capable ripple, transient state and steady-state component based on the current signal of line mold component by induction vertical ground direction magnetic field.

6, electrical power system failure information obtaining method according to claim 1 and 2 is characterized in that: electric-field sensor adopts condenser type, and magnetic field sensor adopts single coil.

7, electrical power system failure information obtaining method according to claim 6 is characterized in that:

The condenser type electric-field sensor is made up of metal electrode and pre-amplification circuit, utilizes the electrode of sheet metal as transducer, utilizes charge amplifier as pre-amplification circuit, the output voltage U of charge amplifying circuit _oWith pass be perpendicular to the electric field E of pole plate: $U_o=-\frac{{\mathrm{\&epsiv;}}_{0}A}{C_f}E,$

In the formula: A is the pole plate area; C _fBe the charge amplifying circuit feedback capacity.

8, electrical power system failure information obtaining method according to claim 1 and 2 is characterized in that:

Fault transient voltage, transient current information that a utilizes electric-field sensor and magnetic field sensor to obtain based on zero mould realize low-current ground fault line selection (faulty line selection) and section location;

Fault traveling wave voltage, travelling wave current information that b utilizes electric-field sensor and magnetic field sensor to obtain based on zero mould realize the low current grounding range finding;

Fault traveling wave voltage, travelling wave current information that c utilizes electric-field sensor and magnetic field sensor to obtain based on the line mould realize short circuit and low current grounding range finding.

9, electrical power system failure information obtaining method according to claim 8 is characterized in that: low-current ground fault line selection and section localization method be,

Utilize following formula to calculate fault direction:

$Q_0=\frac{1}{T}{\&Integral;}_0^T{U}_B\left(t\right)\widehat{U_E}\mathrm{dt}=\frac{1}{\mathrm{\&pi;T}}{\&Integral;}_0^T{U}_B\left(t\right){\&Integral;}_{-\&infin;}^{\&infin;}\frac{U_E\left(\mathrm{\&tau;}\right)}{t-\mathrm{\&tau;}}\mathrm{d\&tau;dt}$

In the formula: U _B(t) be the output voltage of magnetic field sensor, reflection is based on the low current grounding transient current information of zero mold component; U _E(t) be the output voltage of electric-field sensor, reflection is based on the low current grounding transient voltage information of zero mold component;

If Q ₀＜0, then fault is positioned at the test point downstream; If Q ₀〉=0 fault is positioned at test point upstream or other outlet.

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