CN101509949B - Double-end asynchronous and parameter self-adapting fault distance measuring time-domain method for direct current transmission line - Google Patents

Abstract

The invention discloses a time-domain failure distance measuring method with two asynchronous ends of a direct-current power line and self-adaptive parameters, which comprises the following steps of: setting up an asynchronous time-domain failure observation equation of the direct-current line, which includes quantities of fault distance, distributed resistances of the line, transmission wave velocity, wave impedance, asynchronous time difference of data at the two ends and the like to be observed; taking the time of initial failure traveling waves which arrive at the two ends of the line respectively as reference time of data at each end; introducing a traveling wave characteristic equation; and eliminating the quantities to be observed of asynchronous time difference in the time-domain failure observing equation, thus obtaining a novel time-domain failure distance measuring method of the direct-current line so as to realize self-adaption of the line parameter self-adapting without synchronizing with a clock. The time-domain failure distance measuring method has higher transition resistance durability and can effectively improve the accuracy and reliability of failure distance measurement at the two ends of the direct-current line.

Description

The fault distance measuring time-domain method of direct current transmission line double-end asynchronous and parameter self-adapting

Technical field

The present invention relates to the method for electric system direct current transmission line fault range finding, particularly a kind ofly need not synchronous clock and parameter adaptive direct current transmission line double-end fault distance measuring time-domain method in conjunction with the row wave property.

Background technology

The fed distance of DC transmission system is long, the probability height of line failure, and the accurate range finding of line fault is significant for the reliability of minimizing interruption maintenance time, raising DC transmission system.At present, what the direct current transmission line fault range finding was adopted is the both-end traveling wave method, promptly realizes fault localization by the accurate moment at detection failure initial line mode voltage row ripple arrival circuit two ends.But under the situation of high resistance earthing fault, the more weak situation of transient state travelling wave may appear, especially on the over distance DC power transmission line, be subjected to the influence of row wave dispersion and decay even more serious, the both-end traveling wave method often occurs than mistake because of row ripple arrival circuit two ends accurately obtain than difficulty constantly.

The accuracy that row wave-wave speed detects and the clock synchronization of two end datas also have considerable influence to the both-end travelling wave ranging.For definite method of row wave-wave speed, can revise row wave-wave speed by the historical failure data, but these class methods can not satisfy the requirement that real time environment changes, the slight change of velocity of wave all can bring than mistake.The both-end traveling wave method two ends data synchronization that places one's entire reliance upon, though the precision of synchronous clock (GPS) can reach the requirement of both-end travelling wave ranging at present,, if both-end distance measuring can be broken away from the dependence to synchronous clock, then not only can reduce cost, more can improve the reliability of Two-terminal Fault Location.

Summary of the invention

The objective of the invention is to solve the range error that circuit parameter uncertainty and both-end data asynchronism are brought in the direct current transmission line fault ranging process, the accuracy and the reliability of raising DC line fault range finding under metallic earthing and high resistance earthing fault situation, provide a kind of in conjunction with the fault traveling wave characteristic, dependence can be broken away from, and the direct current transmission line fault distance-finding method of double-end asynchronous and parameter self-adapting can be realized synchronous clock.

For reaching above-mentioned purpose, the present invention adopts following technical scheme: a kind of fault distance measuring time-domain method of direct current transmission line double-end asynchronous and parameter self-adapting, be characterized in, and comprise the steps:

The first step is with sample frequency f _sGather utmost point I, utmost point II DC line two ends M, the voltage of N, current instantaneous value u _MI, i _NI, u _MII, i _MII, u _NI, u _NII, i _NII, i _NII, convert line mode voltage, the line mould electric current u at M, N two ends to _m, i _m, u _n, i _n:

$\left\{\begin{array}{c}{u}_m=\sqrt{2}(u_{\mathrm{mI}}-u_{\mathrm{mII}})\\ i_m=\sqrt{2}(i_{\mathrm{mI}}-i_{\mathrm{mII}})\\ u_n=\sqrt{2}(u_{\mathrm{nI}}-u_{\mathrm{nII}})\\ i_n=\sqrt{2}(i_{\mathrm{nI}}-i_{\mathrm{nII}})\end{array}\right.$

Second step, window scope [t during specified data _Star, t _Stop], the line mode voltage travelling wave signal u when decomposing data in the window with multi-scale wavelet _mAnd u _nCarry out layering, and calculate the frequency content E of each layer _K, in frequency domain scope 4～30kHz, choose E _KPeaked frequency domain (experimental results show that the frequency range of 4～30kHz can avoid the influence of direct current and low frequency component on the one hand as the centre frequency of wave filter, can reduce the influence of line parameter circuit value frequency dependent characteristic on the other hand), to described line mode voltage, line mould current traveling wave signal u _m, i _m, u _n, i _nFilter, obtain band signal best in the fault analysis signal;

Wherein, t _StartAnd t _StopThe initial sum of window stops constantly when being respectively data,

t _stop＝t _start+3l/v _min+t _rdn

In the formula: l is the distance of DC line two ends M, N, v _MinFor the line mould of DC line is propagated the minimum value of velocity of wave, v _Min=0.97～0.99c, c are the light velocity; t _RdnFor calculating redundancy time, t _Rdn=p Δ t _Cal, p is a fault time domain observation equation number, the p＞actual number for the treatment of observed quantity, Δ t _CalBe interval computing time, Δ t _Cal＞to the voltage of utmost point I or utmost point II DC line two ends M, N, current instantaneous value sampling time interval 10 times;

$E_K=\frac{1}{t_{\mathrm{stop}}-t_{\mathrm{start}}}\sqrt{{\∫}_{t=t_{\mathrm{start}}}^{t_{\mathrm{stop}}}{S}_K^2\left(t\right)\mathrm{dt}}$

In the formula: s _K(t) be described line mode voltage travelling wave signal u _mAnd u _nThe HFS of K layer signal after wavelet decomposition; The frequency band of described K layer correspondence is: f _s/ 2 ^K+1～f _s/ 2 ^K, centre frequency is 3f _s/ 2 ^K+1, bandwidth is f _s/ 2 ^K+1

In the 3rd step, set up fault time domain observation equation:

$f_{\mathrm{Location}}(d,r,v{,Z}_C,t_{\mathrm{\Δ}},t)=\frac{1}{2}{(1+\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\Δ}}+\frac{d}{v})-i_m(t-t_{\mathrm{\Δ}}+\frac{d}{v})(Z_C+\frac{\mathrm{rd}}{4})]$

$+\frac{1}{2}{(1-\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\Δ}}-\frac{d}{v})-i_m(t-t_{\mathrm{\Δ}}-\frac{d}{v})(Z_C-\frac{\mathrm{rd}}{4})]$

$-{\left(\frac{\mathrm{rd}}{4Z_C}\right)}^2{u}_m(t-t_{\mathrm{\Δ}})-\frac{\mathrm{rd}}{4}(1+\frac{\mathrm{rd}}{4Z_C})(1-\frac{\mathrm{rd}}{4Z_C})i_m(t-t_{\mathrm{\Δ}})---\left(1\right)$

$-\frac{1}{2}{(1+\frac{r(l-d)}{4Z_C})}^2[u_n(t+\frac{l-d}{v})-i_n(t+\frac{l-d}{v})(Z_C+\frac{r(l-d)}{4})]$

$-\frac{1}{2}{(1-\frac{r(l-d)}{4Z_C})}^2[u_n(t-\frac{l-d}{v})-i_n(t-\frac{l-d}{v})(Z_C-\frac{r(l-d)}{4})]$

$+{\left(\frac{r(l-d)}{4Z_C}\right)}^2{u}_n\left(t\right)+\frac{r(l-d)}{4}(1+\frac{r(l-d)}{4Z_C})(1-\frac{r(l-d)}{4Z_C})i_n\left(t\right)=0$

Wherein, l is that distance, the d of DC line two ends M, N are distance, the t of trouble spot apart from DC line M end _ΔFor DC line M, asynchronous mistiming of N two ends, r are that the line mould distributed resistance of DC line, the line mould that v is DC line are propagated velocity of wave, Z _CLine modular character impedance for DC line;

Wherein, t _Δ=t _M0-t _N0

In the formula, t _M0For the reference of the M end data clock of DC line constantly, t _N0Be the reference moment of DC line N end data clock;

Set up row wave property equation:

d＝(v _twΔt _f+l)/2

Δt _f＝T _fm-T _fm＝t _fm-t _fn+t _Δ

In the formula, v _TwBe the capable wave-wave speed of described line mode voltage, Δ t _fBe the capable ripple arrival DC line M of described line mode voltage, the mistiming at N two ends, T _FmAnd T _FnBe respectively fault initial line mode voltage row ripple and arrive the moment that DC line M holds and N holds; t _FmAnd t _FnBe respectively fault initial line mode voltage row ripple and arrive the moment at DC line M, N two ends with respect to each self-reference moment t _M0, t _N0Time;

The 4th step is to described line mode voltage travelling wave signal u _mAnd u _nAsk for modulus maximum constantly, it is arrived moment of DC line M end and N end as fault initial line mode voltage row ripple, and be made as the reference moment t of M, N two ends data clock the moment that fault initial line mode voltage row ripple arrives DC line M, N two ends respectively _M0, t _N0, t then _Fm=t _Fn=0, t _Δ=Δ t _f, promptly M, asynchronous mistiming of N two ends equal the mistiming that fault initial line mode voltage row ripple arrives the circuit two ends, according to row wave property equation, then:

t _Δ＝Δt _f＝(2d-l)/k _vv (2)

Wherein, k _vRatio for travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave;

In the 5th step,, get respectively and calculate t=t constantly formula (2) substitution formula (1) ₁, t ₂, t ₃..., t _P, foundation comprises the described actual asynchronous fault Optimization of Time Domain of the both-end equation for the treatment of observed quantity:

$F(d,r,v,Z_C)=\min \left[\underset{k=1}{\overset{P}{\mathrm{\Σ}}}\right|f_{\mathrm{Location}}(d,r,v,Z_C,\frac{2d-l}{k_{v}v},t_k)\left|\right]---\left(3\right)$

Formula (3) is carried out global optimizing find the solution, can realize the fault time domain range finding of direct current transmission line double-end asynchronous and parameter self-adapting;

Wherein, calculate t constantly ₁, t ₂..., t _k..., t _pFor:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1=t_{\mathrm{start}}+2l/v_{\min }\\ t_p=t_{\mathrm{stop}}-l/{\mathrm{<figure-callout\; id="2"\; label="v\; min\; t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\min }& \\ t_{}{}_2={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+(t_p-t_1)/p\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ t_k={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+(k-1)(t_p-t_1)/p\end{array}\right.$

In the formula, 1＜k＜p, k are natural number.

More specifically, the collection utmost point I in the described first step, utmost point II DC line two ends M, the voltage of N, current instantaneous value are meant with the fault traveling wave wave recording device that is installed in DC line M, N two ends and gather DC line two ends M, the voltage of N, current instantaneous value.

Sample frequency f in the described first step _sBe 1MHz or 500kHz, this is a preferred version.

Wave filter in described second step is meant the Butterworth digital band-pass filter.

Described in described second step and the 5th step actual treat observed quantity be meant the trouble spot apart from the line modular character impedance of the line mould propagation velocity of wave of the line mould distributed resistance of the distance of DC line M end, DC line, DC line and DC line totally four treat observed quantity.

Described the 4th the step in to described line mode voltage travelling wave signal u _mAnd u _nAsk for modulus maximum constantly, be meant and adopt wavelet analysis detection signal singular point theory described line mode voltage travelling wave signal u _mAnd u _nAsk for modulus maximum constantly.

In described the 5th step formula (3) being carried out global optimizing finds the solution and is meant that utilizing particle swarm optimization algorithm that formula (3) is carried out global optimizing finds the solution.

The ratio k of travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave in described the 4th step _vDefinite method be: (1) adopts LINE CONSTANTS program, according to the actual track parameter: the solid conductor internal diameter of transmission line of electricity, solid conductor external diameter, direct current resistance, horizontal range, suspension height, sag minimum altitude, split conductor number, heading spacing and lead angle, the line mould that calculates DC line is propagated the relation curve of velocity of wave and analysis frequency; (2), obtain described the 4th step employing wavelet analysis detection signal singular point theory to described line mode voltage travelling wave signal u according to described relation curve _mAnd u _nAsk for the line mould of analysis frequency range pairing DC line in curve that modulus maximum constantly adopted and propagate velocity of wave And the E that chooses in described second step _KThe line mould of the DC line of peaked frequency domain correspondence is propagated velocity of wave v '; (3) can get as calculated

Because

And the value of v ' has certain scope, therefore the k that calculates _vCertain scope is also arranged; This value is surveyed used frequency range and the required frequency range of time-domain analysis, then k as long as determined capable wave-wave head for a certain transmission line of electricity _vThe span of value not for some reason the barrier situation change and change, be a scope of determining, k _vOptional value in its span all can reach and reduce row wave-wave speed v _TwThe purpose of the influence that brings with the difference of propagating velocity of wave v.

The present invention with respect to the major advantage and the beneficial effect of prior art is: the fault distance measuring time-domain method of direct current transmission line double-end asynchronous and parameter self-adapting of the present invention, can be in conjunction with the row wave property, realization need not the asynchronous and adaptive direct current transmission line fault range finding of line parameter circuit value of both-end of synchronous clock, have higher transition resistance tolerance, can improve the accuracy and the reliability of DC line Two-terminal Fault Location effectively.

Description of drawings

Fig. 1 is the structural representation that comprises the DC transmission system of utmost point I, utmost point II DC line; Wherein, utmost point I circuit is the transmission line of electricity that breaks down, and utmost point II circuit is the circuit of normal transmission of electricity;

Fig. 2 be utilize among embodiment one and the embodiment two LINE CONSTANTS program right ± 500kV and ± 800kV DC line model calculates the line mould velocity of wave of gained and the relation curve of frequency.

Embodiment

The present invention is described in further detail below in conjunction with embodiment and accompanying drawing, but embodiments of the present invention are not limited thereto.

Embodiment one

This example employing ± 500kV DC transmission system model, its transmission line of electricity total length is 936km, and wherein utmost point I circuit is the transmission line of electricity that breaks down, and utmost point II circuit is the transmission line of electricity of normal transmission of electricity, and the transmission line of electricity two ends are made as M end and N end respectively.The transmission line of electricity two ends adopt the fault traveling wave wave recording device to gather the voltage and current of M end and N end, and the data sampling frequency is 1MHz.

The first step converts the voltage and current instantaneous value that utmost point I, utmost point II DC line M hold and N holds that collects to M, the line mode voltage at N two ends, electric current:

$\left\{\begin{array}{c}{u}_m=\sqrt{2}(u_{\mathrm{mI}}-u_{\mathrm{mII}})\\ i_m=\sqrt{2}(i_{\mathrm{mI}}-i_{\mathrm{mII}})\\ u_n=\sqrt{2}(u_{\mathrm{nI}}-u_{\mathrm{nII}})\\ i_n=\sqrt{2}(i_{\mathrm{nI}}-i_{\mathrm{nII}})\end{array}\right.$

Second step, window scope [t during specified data _Star, t _Stop], begin to calculate t from fault moment _StartGet 0, v _MinDetermine according to 97% of the light velocity, get 2.91 * 10 ⁵Km/s, p gets 100, computing time interval of delta t _CalGet 0.03ms, greater than 10 times of the sampling interval of data, so calculate redundancy time t _Rdn=p Δ t _Cal=3ms, t _Stop=t _Start+ 3l/v _Min+ t _Rdn=12.65ms; Utilize multi-scale wavelet to decompose, during to data in the window signal carry out layering, sample frequency is 1MHz, 4～30KHz frequency range correspondence be the frequency domain scope of the 7th layer to the 5th layer high-frequency signal, this frequency range can be avoided the influence of direct current and low frequency component on the one hand, can reduce the influence of line parameter circuit value frequency dependent characteristic on the other hand, utilize formula

$E_K=\frac{1}{t_{\mathrm{stop}}-t_{\mathrm{start}}}\sqrt{{\&Integral;}_{t=t_{\mathrm{start}}}^{t_{\mathrm{stop}}}{S}_K^2\left(t\right)\mathrm{dt}}$

The frequency content E of evaluation between from the 7th layer to the 5th layer _K(if sample frequency is 500kHz, the frequency range of 4～30KHz correspondence is the frequency domain scope of the 6th layer to the 4th layer high-frequency signal, the frequency content between needing this moment to estimate from the 6th layer to the 4th layer.) choose E _KPeaked frequency domain, i.e. f _s/ 2 ^K+1～f _s/ 2 ^K, as the logical frequency of band of Butterworth digital band-pass filter, to described line mode voltage, line mould current traveling wave signal u _m, i _m, u _n, i _nFilter, obtain band signal best in the fault analysis signal;

In the 3rd step, set up fault time domain observation equation:

$f_{\mathrm{Location}}(d,r,v{,Z}_C,t_{\mathrm{\&Delta;}},t)=\frac{1}{2}{(1+\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})(Z_C+\frac{\mathrm{rd}}{4})]$

$+\frac{1}{2}{(1-\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})(Z_C-\frac{\mathrm{rd}}{4})]$

$-{\left(\frac{\mathrm{rd}}{4Z_C}\right)}^2{u}_m(t-t_{\mathrm{\&Delta;}})-\frac{\mathrm{rd}}{4}(1+\frac{\mathrm{rd}}{4Z_C})(1-\frac{\mathrm{rd}}{4Z_C})i_m(t-t_{\mathrm{\&Delta;}})---\left(1\right)$

$-\frac{1}{2}{(1+\frac{r(l-d)}{4Z_C})}^2[u_n(t+\frac{l-d}{v})-i_n(t+\frac{l-d}{v})(Z_C+\frac{r(l-d)}{4})]$

$-\frac{1}{2}{(1-\frac{r(l-d)}{4Z_C})}^2[u_n(t-\frac{l-d}{v})-i_n(t-\frac{l-d}{v})(Z_C-\frac{r(l-d)}{4})]$

$+{\left(\frac{r(l-d)}{4Z_C}\right)}^2{u}_n\left(t\right)+\frac{r(l-d)}{4}(1+\frac{r(l-d)}{4Z_C})(1-\frac{r(l-d)}{4Z_C})i_n\left(t\right)=0$

Wherein, l is that distance, the d of DC line two ends M, N are distance, the t of trouble spot apart from DC line M end _ΔFor DC line M, asynchronous mistiming of N two ends, r are that the line mould distributed resistance of DC line, the line mould that v is DC line are propagated velocity of wave, Z _CLine modular character impedance for DC line;

Wherein, t _Δ=t _M0-t _N0

In the formula, t _M0For the reference of the M end data clock of DC line constantly, t _N0Be the reference moment of DC line N end data clock;

Set up row wave property equation:

d＝(v _twΔt _f+l)/2

Δt _f＝T _fm-T _fn＝t _fm-t _fn+t _Δ

In the formula, v _TwBe the capable wave-wave speed of described line mode voltage, Δ t _fBe the capable ripple arrival DC line M of described line mode voltage, the mistiming at N two ends, T _FmAnd T _FnBe respectively fault initial line mode voltage row ripple and arrive the moment that DC line M holds and N holds; t _FmAnd t _FnBe respectively fault initial line mode voltage row ripple and arrive the moment at DC line M, N two ends with respect to each self-reference moment t _M0, t _N0Time;

In the 4th step, adopt wavelet analysis detection signal singular point theory to above-mentioned line mode voltage travelling wave signal u _mAnd u _nAnalyze, ask for described line mode voltage travelling wave signal u _mAnd u _nModulus maximum constantly and is made as the moment that fault initial line mode voltage row ripple arrives DC line M, N two ends respectively reference the moment t of M, N two ends data clock _M0, t _N0, t then _Fm=t _Fn=0, t _Δ=Δ t _f, promptly M, asynchronous mistiming of N two ends equal the mistiming that fault initial line mode voltage row ripple arrives the circuit two ends, according to row wave property equation, then:

t _Δ＝Δt _f＝(2d-l)/k _vv (2)

Wherein, k _vRatio for travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave, according to the actual track parameter: the solid conductor internal diameter of transmission line of electricity, the solid conductor external diameter, direct current resistance, horizontal range, suspension height, the sag minimum altitude, the split conductor number, heading spacing and lead angle, the relation curve that utilizes LINECONSTANTS program computational scheme line mould to propagate velocity of wave and analysis frequency is determined, as shown in Figure 2 ± the 500kV curve is described relation curve, in time-domain analysis, the 5th layer to the 7th layer HFS of the corresponding wavelet decomposition of the frequency range of bandpass filter, sample frequency for 1MHz, the centre frequency scope is 5k to 20kHz, and corresponding velocity of wave scope is 2.963～2.966km/s; Above-mentioned employing wavelet analysis detection signal singular point theory is to described line mode voltage travelling wave signal u _mAnd u _nAsk for the analysis frequency range that modulus maximum is adopted constantly, centre frequency is about 250～500kHz, and corresponding row wave-wave speed is about 2.977km/s, so for this circuit, k _vSpan be: 1.004～1.0047, get 1.004 herein.

In the 5th step,, get a plurality of calculating t=t constantly with formula (2) substitution formula (1) ₁, t ₂, t ₃..., t _P, foundation comprises fault distance, distributed resistance, propagation velocity of wave and characteristic impedance totally 4 the asynchronous fault Optimization of Time Domain of both-end equations for the treatment of observed quantity:

$F(d,r,v,Z_C)=\min \left[\underset{k=1}{\overset{P}{\mathrm{\&Sigma;}}}\right|f_{\mathrm{Location}}(d,r,v,Z_C,\frac{2d-l}{k_{v}v},t_k)\left|\right]---\left(3\right)$

Formula (3) is carried out global optimizing find the solution, can realize that line parameter circuit value is adaptive and need not the synchronous DC power transmission line time domain fault localization of GPS;

Wherein, calculate t constantly ₁, t ₂..., t _k..., t _p:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1=t_{\mathrm{start}}+2l/v_{\min }=6.4\mathrm{ms}\\ t_{100}=t_{\mathrm{stop}}-l/v_{\min }=9.4\mathrm{<figure-callout\; id="2"\; label="ms\; t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">ms</figure-callout>}& \\ t_{}{}_2={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+(t_p-t_1)/p=6.43\mathrm{<figure-callout\; id="3"\; label="ms\; t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">ms</figure-callout>}& \\ t_{}{}_3={\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+(t_p-t_1)/p=6.46\mathrm{ms}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\end{array}\right.$

To optimizing equation (3), adopt PSO algorithm (particle swarm optimization algorithm) to find the solution.

At the transmission line of electricity diverse location metallic earthing fault and high resistance earthing fault are set respectively, the range finding of various faults the results are shown in table 1, as seen, adopts method disclosed by the invention to carry out fault localization, and error is little, accuracy rate is high.

Table 1

10

9.923

2.9726

-3.0820

-0.077

10.118

2.9749

-3.0783

0.118

100	100.332	2.9700	-2.4759	0.332	100.640	2.9705	-2.434	0.640
									200	199.520	2.9724	-1.8065	-0.480	200.404	2.9724	-1.8001	0.404
300	300.189	2.9730	-1.1289	0.189	300.251	2.9722	-1.1288	0.251
									400	399.886	2.9728	-0.4583	-0.114	400.267	2.9714	-0.4559	0.267
536	535.951	2.9711	0.4574	-0.049	535.884	2.9717	0.4569	-0.116
									636	635.770	2.9725	1.1288	-0.230	635.808	2.9728	1.1289	-0.192
736	736.460	2.9726	1.8062	0.460	735.654	2.9717	1.8014	-0.346
									836	835.803	2.9724	2.4748	-0.197	835.769	2.9718	2.4751	-0.231
926	926.255	2.9723	3.0836	0.255	925.385	2.9713	3.0787	-0.615
									936	935.880	2.9759	3.1445	-0.120	935.223	2.9709	3.1453	-0.777

Embodiment two

This example employing ± 800kV DC transmission system model, its transmission line of electricity total length is 1438km, and wherein utmost point I circuit is the transmission line of electricity that breaks down, and utmost point II circuit is the transmission line of electricity of normal transmission of electricity, and the circuit two ends are made as M end and N end respectively.The circuit two ends adopt the fault traveling wave wave recording device to gather the voltage and current of M end and N end, and the data sampling frequency is 1MHz.

The first step converts the voltage and current instantaneous value that utmost point I, utmost point II DC line M hold and N holds that collects to M, the line mode voltage at N two ends, electric current:

$\left\{\begin{array}{c}{u}_m=\sqrt{2}(u_{\mathrm{mI}}-u_{\mathrm{mII}})\\ i_m=\sqrt{2}(i_{\mathrm{mI}}-i_{\mathrm{mII}})\\ u_n=\sqrt{2}(u_{\mathrm{nI}}-u_{\mathrm{nII}})\\ i_n=\sqrt{2}(i_{\mathrm{nI}}-i_{\mathrm{nII}})\end{array}\right.$

Second step, window scope [t during specified data _Star, t _Stop], begin to calculate t from fault moment _StartGet 0, v _MinDetermine according to 97% of the light velocity, get 2.91 * 10 ⁵Km/s, p gets 100, Δ t _CalGet 0.03ms, greater than 10 times of the sampling interval of data, so calculate redundancy time t _Rdn=p Δ t _Cal=3ms, t _Stop=t _Start+ 3l/v _Min+ t _Rdn=17.82ms; Utilize multi-scale wavelet to decompose, during to data in the window signal carry out layering, sample frequency is 1MHz, the frequency range of 4～30KHz correspondence is the frequency domain scope of the 7th layer to the 5th layer high-frequency signal, this frequency range can be avoided the influence of direct current and low frequency component on the one hand, can reduce the influence of line parameter circuit value frequency dependent characteristic on the other hand, utilize formula

$E_K=\frac{1}{t_{\mathrm{stop}}-t_{\mathrm{start}}}\sqrt{{\&Integral;}_{t=t_{\mathrm{start}}}^{t_{\mathrm{stop}}}{S}_K^2\left(t\right)\mathrm{dt}}$

The frequency content E of evaluation between from the 7th layer to the 5th layer _K(if sample frequency is 500kHz, the frequency range of 4～30KHz correspondence is the frequency domain scope of the 6th layer to the 4th layer high-frequency signal, the frequency content between needing this moment to estimate from the 6th layer to the 4th layer.) choose E _KPeaked frequency domain, i.e. f _s/ 2 ^K+1～f _s/ 2 ^K, as the logical frequency of band of Butterworth digital band-pass filter, to described line mode voltage, line mould current traveling wave signal u _m, i _m, u _n, i _nFilter, obtain band signal best in the fault analysis signal;

In the 3rd step, set up fault time domain observation equation:

$f_{\mathrm{Location}}(d,r,v{,Z}_C,t_{\mathrm{\&Delta;}},t)=\frac{1}{2}{(1+\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})(Z_C+\frac{\mathrm{rd}}{4})]$

$+\frac{1}{2}{(1-\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})(Z_C-\frac{\mathrm{rd}}{4})]$

$-{\left(\frac{\mathrm{rd}}{4Z_C}\right)}^2{u}_m(t-t_{\mathrm{\&Delta;}})-\frac{\mathrm{rd}}{4}(1+\frac{\mathrm{rd}}{4Z_C})(1-\frac{\mathrm{rd}}{4Z_C})i_m(t-t_{\mathrm{\&Delta;}})---\left(1\right)$

$-\frac{1}{2}{(1+\frac{r(l-d)}{4Z_C})}^2[u_n(t+\frac{l-d}{v})-i_n(t+\frac{l-d}{v})(Z_C+\frac{r(l-d)}{4})]$

$-\frac{1}{2}{(1-\frac{r(l-d)}{4Z_C})}^2[u_n(t-\frac{l-d}{v})-i_n(t-\frac{l-d}{v})(Z_C-\frac{r(l-d)}{4})]$

$+{\left(\frac{r(l-d)}{4Z_C}\right)}^2{u}_n\left(t\right)+\frac{r(l-d)}{4}(1+\frac{r(l-d)}{4Z_C})(1-\frac{r(l-d)}{4Z_C})i_n\left(t\right)=0$

Wherein, l is that distance, the d of DC line two ends M, N are distance, the t of trouble spot apart from DC line M end _ΔFor DC line M, asynchronous mistiming of N two ends, r are that the line mould distributed resistance of DC line, the line mould that v is DC line are propagated velocity of wave, Z _CLine modular character impedance for DC line;

Wherein, t _Δ=t _M0-t _N0

In the formula, t _M0For the reference of the M end data clock of DC line constantly, t _N0Be the reference moment of DC line N end data clock;

Set up row wave property equation:

d＝(v _twΔt _f+l)/2

Δt _f＝T _fm-T _fn＝t _fm-t _fn+t _Δ

In the formula, v _TwBe the capable wave-wave speed of described line mode voltage, Δ t _fBe the capable ripple arrival DC line M of described line mode voltage, the mistiming at N two ends, T _FmAnd T _FnBe respectively fault initial line mode voltage row ripple and arrive the moment that DC line M holds and N holds; t _FmAnd t _FnBe respectively fault initial line mode voltage row ripple and arrive the moment at DC line M, N two ends with respect to each self-reference moment t _M0, t _N0Time;

In the 4th step, adopt wavelet analysis detection signal singular point theory to above-mentioned line mode voltage travelling wave signal u _mAnd u _nAnalyze, ask for described line mode voltage travelling wave signal u _mAnd u _nModulus maximum constantly and is made as the moment that fault initial line mode voltage row ripple arrives DC line M, N two ends respectively reference the moment t of M, N two ends data clock _M0, t _N0, then be t _Fm=t _Fn=0, t _Δ=Δ t _f, M, asynchronous mistiming of N two ends equal the mistiming that fault initial line mode voltage row ripple arrives the circuit two ends, according to row wave property equation, then:

t _Δ＝Δt _f＝(2d-l)/k _vv (2)

Wherein, k _vRatio for travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave, according to the actual track parameter: the solid conductor internal diameter of transmission line of electricity, the solid conductor external diameter, direct current resistance, horizontal range, suspension height, the sag minimum altitude, the split conductor number, heading spacing and lead angle, the relation curve that utilizes LINECONSTANTS program computational scheme line mould to propagate velocity of wave and frequency is determined, as shown in Figure 2 ± the 800kV curve is described relation curve, in time-domain analysis, the 5th layer to the 7th layer HFS of the corresponding wavelet decomposition of the frequency range of bandpass filter, sample frequency for 1MHz, the centre frequency scope is 5k to 20kHz, and corresponding velocity of wave scope is 2.958～2.961km/s; Above-mentioned employing wavelet analysis detection signal singular point theory is to described line mode voltage travelling wave signal u _mAnd u _nAsk for the analysis frequency range that modulus maximum is adopted constantly, centre frequency is about 250～500kHz, and corresponding row wave-wave speed is about 2.966km/s, so for this circuit, k _vSpan be: 1.0017～1.0027, get 1.002 herein.

In the 5th step,, get a plurality of calculating t=t constantly with formula (2) substitution formula (1) ₁, t ₂, t ₃..., t _P, foundation comprises fault distance, distributed resistance, propagation velocity of wave and characteristic impedance totally 4 the asynchronous fault Optimization of Time Domain of both-end equations for the treatment of observed quantity:

$F(d,r,v,Z_C)=\min \left[\underset{k=1}{\overset{P}{\mathrm{\&Sigma;}}}\right|f_{\mathrm{Location}}(d,r,v,Z_C,\frac{2d-l}{k_{v}v},t_k)\left|\right]---\left(3\right)$

Formula (3) is carried out global optimizing find the solution, can realize that line parameter circuit value is adaptive and need not the synchronous DC power transmission line time domain fault localization of GPS;

Wherein, calculate t constantly ₁, t ₂..., t _k..., t _p:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1=t_{\mathrm{start}}+2l/v_{\min }=9.9\mathrm{ms}\\ t_{100}=t_{\mathrm{stop}}-l/v_{\min }=12.9\mathrm{<figure-callout\; id="2"\; label="ms\; t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">ms</figure-callout>}& \\ t_{}{}_2={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+(t_p-t_1)/p=9.93\mathrm{<figure-callout\; id="3"\; label="ms\; t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">ms</figure-callout>}& \\ t_{}{}_3={\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSB00000195182200012.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+(t_p-t_1)/p=9.96\mathrm{ms}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\end{array}\right.$

To optimizing equation (3), adopt PSO algorithm (particle swarm optimization algorithm) to find the solution.

At the circuit diverse location metallic earthing fault and high resistance earthing fault are set respectively, the range finding of various faults the results are shown in table 2, as seen, adopts method disclosed by the invention to carry out fault localization, and error is little, accuracy rate is high.

Table 2

The foregoing description is a preferred implementation of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under spirit of the present invention and the principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (3)

1. the fault distance measuring time-domain method of a direct current transmission line double-end asynchronous and parameter self-adapting is characterized in that, comprises the steps:

The first step is with sample frequency f _sGather utmost point I, utmost point II DC line two ends M, the voltage of N, current instantaneous value u _MI, i _MI, u _MII, i _MII, u _NI, i _NI, u _NII, i _NII, convert line mode voltage, the line mould electric current u at M, N two ends to _m, i _m, u _n, i _n:

$\left\{\begin{array}{c}{u}_m=\sqrt{2}(u_{\mathrm{mI}}-u_{\mathrm{mII}})\\ i_m=\sqrt{2}(i_{\mathrm{mI}}-i_{\mathrm{mII}})\\ u_n=\sqrt{2}(u_{\mathrm{nI}}-u_{\mathrm{nII}})\\ i_n=\sqrt{2}(i_{\mathrm{nI}}-i_{\mathrm{nII}})\end{array}\right.$

Second step, window scope [t during specified data _Star, t _Stop], the line mode voltage travelling wave signal u when decomposing data in the window with multi-scale wavelet _mAnd u _nCarry out layering, and calculate the frequency content E of each layer _K, in frequency domain scope 4～30kHz, choose E _KPeaked frequency domain is as the centre frequency of wave filter, to described line mode voltage, line mould current traveling wave signal u _m, i _m, u _n, i _nFilter, obtain band signal best in the fault analysis signal; Described wave filter is meant the Butterworth digital band-pass filter;

Wherein, t _StartAnd t _StopThe initial sum of window stops constantly when being respectively data,

t _stop＝t _start+3l/v _min+t _rdn

In the formula: l is the distance of DC line two ends M, N, v _MinFor the line mould of DC line is propagated the minimum value of velocity of wave, v _Min=0.97～0.99c, c are the light velocity; t _RdnFor calculating redundancy time, t _Rdn=p Δ t _Cal, p is a fault time domain observation equation number, the p＞actual number for the treatment of observed quantity, Δ t _CalBe interval computing time, Δ t _Cal＞at interval 10 times of the voltage of utmost point I or utmost point II DC line two ends M, N, current instantaneous value acquisition time; Described actual treat observed quantity be meant propagate velocity of wave and DC line apart from the line mould of the line mould distributed resistance of the distance of DC line M end, DC line, DC line in the trouble spot the impedance of line modular character totally four treat observed quantity;

$E_K=\frac{1}{t_{\mathrm{stop}}-t_{\mathrm{start}}}\sqrt{{\&Integral;}_{t=t_{\mathrm{start}}}^{t_{\mathrm{stop}}}{S}_K^2\left(t\right)\mathrm{dt}}$

In the formula: s _K(t) be described line mode voltage travelling wave signal u _mAnd u _nThe HFS of K layer signal after wavelet decomposition; The frequency band of described K layer correspondence is: f _s/ 2 ^K+1～f _s/ 2 ^K, centre frequency is 3f _s/ 2 ^K+1, bandwidth is f _s/ 2 ^K+1

In the 3rd step, set up fault time domain observation equation:

$f_{\mathrm{Location}}(d,r,v{,Z}_C,t_{\mathrm{\&Delta;}},t)=\frac{1}{2}{(1+\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}+\frac{d}{v})(Z_C+\frac{\mathrm{rd}}{4})]$

$+\frac{1}{2}{(1-\frac{\mathrm{rd}}{4Z_C})}^2[u_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})-i_m(t-t_{\mathrm{\&Delta;}}-\frac{d}{v})(Z_C-\frac{\mathrm{rd}}{4})]$

$-{\left(\frac{\mathrm{rd}}{4Z_C}\right)}^2{u}_m(t-t_{\mathrm{\&Delta;}})-\frac{\mathrm{rd}}{4}(1+\frac{\mathrm{rd}}{4Z_C})(1-\frac{\mathrm{rd}}{4Z_C})i_m(t-t_{\mathrm{\&Delta;}})---\left(1\right)$

$-\frac{1}{2}{(1+\frac{r(l-d)}{4Z_C})}^2[u_n(t+\frac{l-d}{v})-i_n(t+\frac{l-d}{v})(Z_C+\frac{r(l-d)}{4})]$

$-\frac{1}{2}{(1-\frac{r(l-d)}{4Z_C})}^2[u_n(t-\frac{l-d}{v})-i_n(t-\frac{l-d}{v})(Z_C-\frac{r(l-d)}{4})]$

$+{\left(\frac{r(l-d)}{4Z_C}\right)}^2{u}_n\left(t\right)+\frac{r(l-d)}{4}(1+\frac{r(l-d)}{4Z_C})(1-\frac{r(l-d)}{4Z_C})i_n\left(t\right)=0$

Wherein, l is that distance, the d of DC line two ends M, N are distance, the t of trouble spot apart from DC line M end _ΔFor DC line M, asynchronous mistiming of N two ends, r are that the line mould distributed resistance of DC line, the line mould that v is DC line are propagated velocity of wave, Z _CLine modular character impedance for DC line;

Wherein, t _Δ=t _M0-t _N0

In the formula, t _M0For the reference of the M end data clock of DC line constantly, t _N0Be the reference moment of DC line N end data clock;

Set up row wave property equation:

d＝(v _twΔt _f+l)/2

Δt _f＝T _fm-T _fn＝t _fm-t _fn+t _Δ

In the formula, v _TwBe the capable wave-wave speed of described line mode voltage, Δ t _fBe the capable ripple arrival DC line M of described line mode voltage, the mistiming at N two ends, T _FmAnd T _FnBe respectively fault initial line mode voltage row ripple and arrive the moment that DC line M holds and N holds; t _FmAnd t _FnBe respectively fault initial line mode voltage row ripple and arrive the moment at DC line M, N two ends with respect to each self-reference moment t _M0, t _N0Time;

In the 4th step, adopt wavelet analysis detection signal singular point theory to described line mode voltage travelling wave signal u _mAnd u _nAsk for modulus maximum constantly, it is arrived moment of DC line M end and N end as fault initial line mode voltage row ripple, and be made as the reference moment t of M, N two ends data clock the moment that fault initial line mode voltage row ripple arrives DC line M, N two ends respectively _M0, t _N0, t then _Fm=t _Fn=0, t _Δ=Δ t _f, promptly M, asynchronous mistiming of N two ends equal the mistiming that fault initial line mode voltage row ripple arrives the circuit two ends, according to row wave property equation, then:

t _Δ＝Δt _f＝(2d-l)/k _vv (2)

Wherein, k _vRatio for travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave;

The ratio k of described travelling wave analysis line mould velocity of wave and time-domain analysis line mould velocity of wave _vDefinite method be: (1) adopts LINE CONSTANTS program, according to the actual track parameter: the solid conductor internal diameter of transmission line of electricity, solid conductor external diameter, direct current resistance, horizontal range, suspension height, sag minimum altitude, split conductor number, heading spacing and lead angle, the line mould that calculates DC line is propagated the relation curve of velocity of wave and analysis frequency; (2), obtain described the 4th step employing wavelet analysis detection signal singular point theory to described line mode voltage travelling wave signal u according to described relation curve _mAnd u _nAsk for the line mould of analysis frequency range pairing DC line in curve that modulus maximum constantly adopted and propagate velocity of wave

And the E that chooses in described second step _KThe line mould of the DC line of peaked frequency domain correspondence is propagated velocity of wave v '; (3) can get as calculated

In the 5th step,, get respectively and calculate t=t constantly formula (2) substitution formula (1) ₁, t ₂, t ₃..., t _P, foundation comprises the described actual asynchronous fault Optimization of Time Domain of the both-end equation for the treatment of observed quantity:

$F(d,r,v,Z_C)=\min \left[\underset{k=1}{\overset{P}{\mathrm{\&Sigma;}}}\right|f_{\mathrm{Location}}(d,r,v,Z_C,\frac{2d-l}{k_{v}v},t_k)\left|\right]---\left(3\right)$

Utilize particle swarm optimization algorithm that formula (3) is carried out global optimizing and find the solution, can realize the fault time domain range finding of direct current transmission line double-end asynchronous and parameter self-adapting; Described actual treat observed quantity be meant propagate velocity of wave and DC line apart from the line mould of the line mould distributed resistance of the distance of DC line M end, DC line, DC line in the trouble spot the impedance of line modular character totally four treat observed quantity;

Wherein, calculate t constantly ₁, t ₂..., t _k..., t _pFor:

$\left\{\begin{array}{c}{t}_1=t_{\mathrm{start}}+2l/v_{\min }\\ t_p=t_{\mathrm{stop}}-l/v_{\min }\\ t_2=t_1+(t_p-t_1)/p\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ t_k=t_1+(k-1)(t_p-t_1)/p\end{array}\right.$

In the formula, 1＜k＜p, k are natural number.

2. according to the fault distance measuring time-domain method of the described direct current transmission line double-end asynchronous and parameter self-adapting of claim 1, it is characterized in that the collection utmost point I in the described first step, utmost point II DC line two ends M, the voltage of N, current instantaneous value are meant with the fault traveling wave wave recording device that is installed in DC line M, N two ends gathers DC line two ends M, the voltage of N, current instantaneous value.

3. according to the fault distance measuring time-domain method of the described direct current transmission line double-end asynchronous and parameter self-adapting of claim 1, it is characterized in that the sample frequency f in the described first step _sBe 1MHz or 500kHz.

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