CN104035002A - Fault phase selection method using traveling wave inherent frequency and atom decomposition energy entropy - Google Patents

Abstract

The invention relates to a fault phase selection method for a power transmission line, in particular to a fault phase selection method using traveling wave inherent frequency and atom decomposition energy entropy. The method comprises the following steps of: processing three-phase current by using an atom decomposition algorithm, determining the frequency value and energy entropy information of a dominant frequency component in a current signal according to atoms generated by iteration, and judging fault types under the situations of multi-phase fault and multi-phase grounding fault by combining the dominant component frequency value and the energy entropy characteristic of the three-phase current; specific to a single-phase fault, searching for a fault phase according to a beta modulus obtained by decoupling under different reference phases. The method is accurate and effective, and fault types can be rapidly distinguished.

Description

A kind of Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy

Technical field

The invention belongs to electricity field, especially relate to a kind of Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy.

Background technology

At present, after fault, identification of defective type is significant to safeguarding that power system safety and stability uses rapidly and accurately, at present the fault phase-selecting method based on power frequency characteristic quantity is difficult to take into account phase selection speed and two aspects of phase selection stability, and Fault Phase Selection rule based on transient state travelling wave mould value is subject to external interference and lost efficacy.Accuracy is higher simultaneously to adopt the phase-selecting method of traveling wave inherent frequency to have faster phase selection speed, but accurately identify traveling wave inherent frequency composition, still has problems.

Summary of the invention

Above-mentioned technical matters of the present invention is mainly solved by following technical proposals:

A Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy, is characterized in that, comprises the following steps:

Step 1, the A collecting according to transmission line malfunction wave recording device, B, C three-phase fault electric current, based on the decoupling zero of Clarke transformation matrix, obtain 0 modulus and 6 line modulus, I _{α A}, I _{α B}, I _{α C}, I _{β A}, I _{β B}, I _{β C}; And A, B, C three-phase fault electric current are carried out to filtering, and then adopting the filtered three-phase current of Atomic Decomposition algorithm process, the frequency values that obtains three leading atoms in phase current is f _a, f _b, f _cand corresponding energy entropy is E _a, E _b, E _c;

Step 2, then according to 0 modulus and 6 line modulus, judgement is earth fault or ungrounded fault, that is:

Judged result: calculate 0 modulus energy, during value when its energy value is greater than normal operation, failure judgement type is earth fault; Otherwise be ungrounded fault, then carry out the operation of following selection step, continuing under judgement ground fault condition is the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault; Or under ungrounded failure condition, be the concrete fault phase of heterogeneous earth fault;

Step 3, carry out the judgement of following selection step:

If earth fault, needs to judge under ground fault condition to be the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault, specifically:

The frequency values of leading atom in judgement A1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determine that fault type is heterogeneous fault, what satisfy condition is separate separate for fault, and described threshold range is arranged on 0.8-1;

The energy value of three electric current modulus under judgement A2, calculating β modulus, what in three β modulus, the modulus of energy entropy minimum was corresponding is fault phase;

If ungrounded fault, needs to judge the concrete fault phase of the heterogeneous earth fault of ungrounded failure condition, specifically:

The frequency values of leading atom in judgement B1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determine that fault type is heterogeneous fault, satisfy condition separate for fault separate; Described threshold range is arranged on 0.8-1.

In above-mentioned a kind of Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy, in described step 1, adopt the concrete grammar of the filtered current signal of Atomic Decomposition Algorithm Analysis to be: current signal is decomposed into a plurality of atoms, the atom obtaining is arranged (scope of Atomic Decomposition energy entropy is 0-1) according to its Atomic Decomposition energy entropy, the atomic order that energy entropy is large is forward, leading atom is exactly the atom of energy entropy maximum, decompose first atom obtaining, in A phase current, the energy entropy of leading atom is E _a, its frequency values is f _a, in B phase current, the energy entropy of leading atom is E _b, its frequency values is f _b, in C phase current, the energy entropy of leading atom is E _c, its frequency values is f _c.

Therefore, tool of the present invention has the following advantages: 1, traveling wave inherent frequency composition is the characteristic quantity of a kind of stable existence in fault phase electric current, leading position during heterogeneous fault in fault phase electric current is especially remarkable, and the fault phase-selecting method based on traveling wave inherent frequency has that stability is high, the feature of phase selection speed; 2, Atomic Decomposition algorithm has very strong time-frequency resolution capability, the feature of the present invention's leading composition in atom decomposition identification fault phase electric current, and effect accurately and reliably, can be effective to the identification of natural frequency composition.

Embodiment

Below by embodiment, technical scheme of the present invention is described in further detail.

Embodiment:

One, paper theoretical method of the present invention once,

(1). mainly comprise the following steps:

Step 1, the A collecting according to transmission line malfunction wave recording device, B, C three-phase fault electric current, based on the decoupling zero of Clarke transformation matrix, obtain 0 modulus and 6 line modulus, I _{α A}, I _{α B}, I _{α C}, I _{β A}, I _{β B}, I _{β C}; And A, B, C three-phase fault electric current are carried out to filtering (in the present embodiment, adopt the FIR shock response Hi-pass filter of common Jia Kaise window, the cutoff frequency that wave filter is set is 200Hz, filtering power frequency component), then adopt the filtered three-phase current of Atomic Decomposition algorithm process, the frequency values that obtains three leading atoms in phase current is f _a, f _b, f _cand corresponding energy entropy is E _a, E _b, E _c;

Step 2, then according to 0 modulus and 6 line modulus, judgement is earth fault or ungrounded fault, that is:

Judged result: calculate 0 modulus energy, failure judgement type is earth fault when the value of its energy value during much larger than normal operation; Otherwise be ungrounded fault, then carry out the operation of following selection step, continuing under judgement ground fault condition is the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault; Or under ungrounded failure condition, be the concrete fault phase of heterogeneous earth fault;

Step 3, carry out the judgement of following selection step:

If earth fault, needs to judge under ground fault condition to be the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault, specifically:

The frequency values of leading atom in judgement A1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determines that fault type is heterogeneous fault, what satisfy condition is separate separate for fault, and threshold value setting is 0.8;

The energy value of three electric current modulus under judgement A2, calculating β modulus, what in three β modulus, the modulus of energy entropy minimum was corresponding is fault phase;

If ungrounded fault, needs to judge the concrete fault phase of the heterogeneous earth fault of ungrounded failure condition, specifically:

The frequency values of leading atom in judgement B1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determine that fault type is heterogeneous fault, satisfy condition separate for fault separate; Threshold value setting is 0.8.

(2). the operation steps of step 3, concrete situation performance is as described below:

When there is two phase ground, line to line fault or three-phase shortcircuit, traveling wave inherent frequency stable components is present in each fault phase electric current, substantially there is not natural frequency composition in healthy phases electric current, after filtering is processed, natural frequency composition in fault phase accounts for significant proportion in whole signal, adopts Atomic Decomposition algorithm to be easy to identification.

When there is singlephase earth fault, the energy of the natural frequency composition in fault phase and healthy phases is all very weak, now, according to failure boundary condition, knows, the β mould electric current that the fault phase of take obtains after benchmark decoupling zero is zero, thus Judging fault phase.

When there is three-phase fault, because fault is symmetric fault, in three-phase current, all there is stable natural frequency composition, now f _a=f _b=f _c, E _a, E _b, E _call be greater than setting threshold 0.8.

When fault type is AC phase-to phase fault or AC earth fault, between natural frequency existence and A, C two-phase, now meet f _a=f _c, E _a, E _call be greater than setting threshold 0.8.

When fault type is BC phase-to phase fault or BC earth fault, between natural frequency existence and B, C two-phase, now meet f _b=f _c, E _b, E _call be greater than setting threshold 0.8.

When fault type is AB phase-to phase fault or AB earth fault, between natural frequency existence and A, B two-phase, now meet f _a=f _b, E _b, E _call be greater than setting threshold 0.8.

When there is A phase earth fault, the couple current of the travelling wave current being produced mutually by fault phase A in B, C two-phase is identical, has I _b=I _c, the A of take is benchmark phase mutually, adopts the modulus obtaining after Clarke decoupling zero to be: I ₀=I _a+ 2I _b, and

$\left\{\begin{array}{c}{I}_{\mathrm{\βA}}=0\\ I_{\mathrm{\βB}}=I_B-I_A\\ I_{\mathrm{\βC}}=I_A-I_A\end{array}\right.$

Except I _{β A}outside other five line modulus will can not be all 0 with reference to zero mould composition, only take the A I after benchmark decoupling zero mutually _{β A}=0.B phase and C phase earth fault are all similar therewith.

(3). in step 1, adopt the concrete grammar of the filtered current signal of Atomic Decomposition Algorithm Analysis to be: current signal is decomposed into a plurality of atoms, the atom obtaining is arranged according to its Atomic Decomposition energy entropy, the atomic order that energy entropy is large is forward, leading atom is exactly the atom of energy entropy maximum, decompose first atom obtaining, in A phase current, the energy entropy of leading atom is E _a, its frequency values is f _a, in B phase current, the energy entropy of leading atom is E _b, its frequency values is f _b, in C phase current, the energy entropy of leading atom is E _c, its frequency values is f _c; The concrete operations of this Atomic Decomposition algorithm are as follows:

1, build the former word bank of Gabor, the expression formula of atom is as follows:

$g_{\mathrm{\γ}}\left(t\right)=\frac{K_{\mathrm{\γ}}}{\sqrt{s}}g\left(\frac{t-\mathrm{\τ}}{s}\right)\cos (\mathrm{\ξ}+\mathrm{\φ})$

Wherein, for Gauss function, constant K _γfor the normalized factor of atom, γ=(s, τ, ξ, φ), title γ is g _γ(t) index, s is scale parameter, has determined the span of Gabor atom in time domain; τ is displacement parameter, represents that atom is in the center of temporal envelope; ξ is frequency parameter, represents that atom is in the center of frequency domain envelope; φ is phase parameter, has determined the initial phase angle of envelope atom signals.

2, Gabor atomic expression is done to Fourier transform

3, Gabor atom being done to time-frequency distributions is expressed as

$W{g}_{\mathrm{\γ}}(t,\mathrm{\ω})=2H\left(\frac{t-\mathrm{\τ}}{s}\right)\·F\left[(\mathrm{\ω}-\mathrm{\ξ})\right]$

Wherein, H (t)=e ^{-2 π t2}, $F\left(\mathrm{\ω}\right)=e^{-\frac{1}{2\mathrm{\π}}{\mathrm{\ω}}^2}.$

4, Gabor atom is done to discretize and processed, the discrete signal that is N for a length, γ becomes γ=(2 after discretize is processed ^j, p2 ^j, ^kπ 2 ^1-j, φ), j wherein, p, k ∈ Z, φ ∈ R, the atomic expression after discretize is:

g _γ(n)=g _j(n-p2 ^j)cos(nkπ2 ^1-j+φ)，(n=0,1,…,N-1)

Wherein, $g_j\left(n\right)\left\{\begin{array}{c}\mathrm{\δ}\left(j\right)j=0\\ K_{\mathrm{\γ}}g\left(n{2}^{-j}\right)j\∈[1,L)\\ \frac{1}{\sqrt{N}}j\∈L,L=\mathrm{lo}{g}_{2}N,j\∈[0,L],p\∈[0,{N2}^{-j}]\end{array}\right.$ k∈[0,2 ^j]。L=log ₂N，j∈[0,L]，p∈[0,N2 ^-j]，k∈[0,2 ^j]

5, adopt MP algorithm in former word bank, to seek and signal X _m, X _nthe atom of optimum matching:

If D is over-complete dictionary of atoms, X _m, X _nfor original travelling wave signal, g _γfor the atom in D, algorithm search process is exactly to find the atom g mating the most with original travelling wave signal in each iterative process _{γ m}(atom of the m time iteration), has the atom of maximum inner product with current residue signal.

$|<f,g_{\mathrm{\&gamma;m}}>|=\underset{\mathrm{\&gamma;}\&Element;\mathrm{\&Gamma;}}{\sup }|<X_m/X_n,g_{\mathrm{\&gamma;}}>|$

After each iteration, the optimum matching atom of acquisition is extracted away and forms new residue signal from residue signal.Initial residue signal is made as the expression formula of residue signal is

$R_f^m=R_f^{m-1}-(R_f^{m-1},g_{\mathrm{\&gamma;m}})g_{\mathrm{\&gamma;m}}$

Obviously with g _{γ m}quadrature, so have

${\left|\right|R_f^{m-1}\left|\right|}^2={|<R_f^{m-1},g_{\mathrm{\&gamma;m}}>|}^2+{\left|\right|R_f^m\left|\right|}^2$

Owing to calculating quantitative limitation, in the scope that must allow in error, give up residue signal and obtain the atom of near optimal.Through after N iteration, giving up residue signal by original signal X _m, X _nwith the linear combination of N atom, come approximate representation to be:

$X_m/X_n\&ap;\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}<R_f^{m-1},g_{\mathrm{\&gamma;}}m>g_{\mathrm{\&gamma;m}}$

Because along with constantly carrying out of decomposing, the energy of remaining residue signal die down gradually, this has just guaranteed MP convergence, and carrys out termination of iterations process by artificial setting iterations or error end condition.The iterations that this patent adopts is set to 5 times.

6, according to atom decomposition analytic signal result, find the atom of the inner product value maximum that signal is corresponding, obtain frequency values and the corresponding Atomic Decomposition energy entropy of this atom.

Two, be below the emulation experiment that adopts method of the present invention to carry out.

For the validity and reliability of checking the inventive method, adopt the example method to carry out following emulation experiment:

Realistic model as shown in subordinate list 1, the long 500km of simulated line, 10 ° of power supply phase angle differences, electric pressure 500kv, frequency 50Hz.R ₁=0.01273 Ω/km, X ₁=0.2932 Ω/km, C ₁=0.0127 μ F/km; R ₀=0.3864 Ω/km, X ₀=1.2957 Ω/km, C ₀=0.07751 μ F/km, sample frequency is 100kHz, sampling number 2000 points.

Simulation result in table 1 different faults situation

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various modifications or supplement or adopt similar mode to substitute described specific embodiment, but can't depart from spirit of the present invention or surmount the defined scope of appended claims.

Claims (2)

1. a Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy, is characterized in that, comprises the following steps:

Step 1, the A collecting according to transmission line malfunction wave recording device, B, C three-phase fault electric current, based on the decoupling zero of Clarke transformation matrix, obtain 0 modulus and 6 line modulus, I _{α A}, I _{α B}, I _{α C}, I _{β A}, I _{β B}, I _{β C}; And A, B, C three-phase fault electric current are carried out to filtering, and then adopting the filtered three-phase current of Atomic Decomposition algorithm process, the frequency values that obtains three leading atoms in phase current is f _a, f _b, f _cand corresponding energy entropy is E _a, E _b, E _c;

Step 2, then according to 0 modulus and 6 line modulus, judgement is earth fault or ungrounded fault, that is:

Judged result: calculate 0 modulus energy, during value when its energy value is greater than normal operation, failure judgement type is earth fault; Otherwise be ungrounded fault, then carry out the operation of following selection step, continuing under judgement ground fault condition is the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault; Or under ungrounded failure condition, be the concrete fault phase of heterogeneous earth fault;

Step 3, carry out the judgement of following selection step:

If earth fault, needs to judge under ground fault condition to be the concrete fault phase of heterogeneous earth fault or the concrete fault phase of singlephase earth fault, specifically:

The frequency values of leading atom in judgement A1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determine that fault type is heterogeneous fault, what satisfy condition is separate separate for fault, and described threshold range is arranged on 0.8-1;

The energy value of three electric current modulus under judgement A2, calculating β modulus, what in three β modulus, the modulus of energy entropy minimum was corresponding is fault phase;

If ungrounded fault, needs to judge the concrete fault phase of the heterogeneous earth fault of ungrounded failure condition, specifically:

The frequency values of leading atom in judgement B1, comparison three-phase current, in there is two-phase or three-phase current, the frequency values of leading atom equates, and each nuclear energy entropy all meets setting threshold, determine that fault type is heterogeneous fault, satisfy condition separate for fault separate; Described threshold range is arranged on 0.8-1.

2. a kind of Fault Phase Selection method of utilizing traveling wave inherent frequency and Atomic Decomposition Energy-Entropy according to claim 1, it is characterized in that, in described step 1, adopt the concrete grammar of the filtered current signal of Atomic Decomposition Algorithm Analysis to be: current signal is decomposed into a plurality of atoms, the atom obtaining is arranged according to its Atomic Decomposition energy entropy, the atomic order that energy entropy is large is forward, leading atom is exactly the atom of energy entropy maximum, decompose first atom obtaining, in A phase current, the energy entropy of leading atom is E _a, its frequency values is f _a, in B phase current, the energy entropy of leading atom is E _b, its frequency values is f _b, in C phase current, the energy entropy of leading atom is E _c, its frequency values is f _c.