CN101299538A - Cable-aerial mixed line fault travelling wave ranging method - Google Patents

Abstract

The invention relates to a cable-overhead joint line failure travelling wave range count method, particularly performing the effective fusion based on the failure range count method of the fundamental frequency and the travelling wave aiming at the particularity and the complexity of the cable joint line, belonging to the technical field of the power system relay protection. The invention judges the failure generating places firstly based on the cable-overhead junction derivated through the electric quantity at the two ends of the system attached with the negative sequence net after the failure, then performs the correct range count by the range count method of the single end; on the basis of considering the line zero modulus component couple, through comparing the performance of the current travelling wave line zero modulus component, the performance of each reflected wave is judged, to find out the fault point reflected wave, and then perform the correct range count.

Description

A kind of cable-aerial mixed line fault travelling wave ranging method

Technical field

The present invention relates to a kind of cable-aerial mixed line fault travelling wave ranging method, particularly, will carry out effective fusion based on the fault distance-finding method of power frequency amount and row ripple at the particularity and the complexity of power cable wire mixed line.Belong to the relay protection of power system technical field.

Background technology

The fault location of transmission line is the medium-term and long-term difficult problem that exists of power system operation, and the line walking time can be shortened greatly in the fault localization location accurately, accelerates to restore electricity, and the safety and the economical operation of electric power system had very important significance.Theory and practice proves that all traveling wave method [can be good at realizing that range accuracy also can meet the demands on single overhead transmission line or cable line.

Along with developing rapidly of electric power system, the extensive use of power cable makes the cable-aerial mixed power transmission line increasing.For example: mountain, small ocean, Shanghai 110kV cable-aerial mixed line, 10kV railway self-closing perforation cable-aerial circuit and electric railway 27.5kV cable-aerial mixed line.Than the fault localization of cable, overhead transmission line, cable-aerial mixed power transmission line fault localization can face a following new difficult problem: the ripple of 1. going can reflect in the junction of cable and overhead transmission line, has increased the identification difficulty of reflected wave; 2. the propagation velocity of ripple in cable and overhead transmission line of going is obviously inconsistent, is difficult to direct range finding; 3. particularly reflected wave is after propagating through long cable line for capable ripple, and the wave head amplitude attenuation is bigger, is vulnerable to the influence of interference signal, thereby influences certainty of measurement.Therefore usually traveling wave method also can't directly be used in the fault localization with joint line.

Relevant cable-aerial mixed power transmission line fault localization has also caused numerous scholars' concern gradually." the cable overhead line hybrid line fault distance-finding method summary " that people such as Yu Yuze, Qin Jian and Li Gongxin deliver be the fault localization at 220kV cable-aerial circuit propose simultaneously to fault mutually with non-fault injected pulse electric current mutually, by fault relatively mutually and non-fault mutually travelling wave signal judge that earlier tie point and position of failure point go the method for precision ranging again, but the pulse emitter with and the difficult in actual applications realization of synchronism." research of the self-closing perforation circuit of 10kV railway fault distance-finding method " that Cai Yumei delivers is carried out the pinpoint method of section at the method that the fault localization problem of the self-closing perforation cable-aerial of 10kV railway circuit has proposed a kind of relatively current traveling wave line zero mold component polarity, but does not consider that the influence of coupling takes place in the fault point line zero mold component.

Summary of the invention

The objective of the invention is to particularity and complexity at the cable joint line, to carry out effective fusion based on the fault distance-finding method of power frequency amount and row ripple, the big or small failure judgement generation section of the distributed current that utilizes the cable-aerial tie point place that derives by system's two ends electric parameters under the additional negative sequence network after the fault is provided, re-use the cable-aerial mixed line fault travelling wave ranging method that the single-ended traveling wave range unit carries out accurate fault localization, elder generation's simulation result has confirmed the correctness and the validity of this distance-finding method, and the range finding result accurately, reliably.

The technical scheme of cable-aerial mixed line fault travelling wave ranging method of the present invention is as follows: add under negative sequence network and the negative-sequence current by joint line system two ends electrical data after gathering fault earlier, big or small failure judgement generation section with the distributed current at cable-aerial tie point place, location, utilize the character of the accurate discriminant line of single-ended traveling wave fault location mode zero each reflected wave of mold component again, accurately measure joint line system failure distance at last, concrete steps are as follows:

1). extract the three-phase voltage and the electric current phasor of fault front and back M end,

Be three-phase voltage before the fault and electric current phasor,

Be three-phase voltage after the fault and electric current phasor, thereby obtain electric current and voltage sudden change amount

With

Obtain the preface component of sudden change amount again according to symmetrical component method

With

2). set up the additional negative sequence network of joint line after the fault, the electric parameters of utilizing the M of system, N end to measure is derived from two ends, draws the distributed current at cable-aerial tie point place

Size;

3). when $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is an overhead wire I section; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is built on stilts I section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is a cut cable; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is that position of failure point is built on stilts II section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is built on stilts II section;

4). on the basis of fault section location, utilize Karrenbauer conversion battle array, extract line zero mold component of measuring junction electric current, and utilize Cubic B-spline Wavelet to detect singular point as the phase-model transformation matrix;

5). on the basis of having considered line zero mold component coupling, utilize line zero mold component polarity relatively to carry out reflected wave wave head property determination:, then to show it is fault point reflection ripple if line mould and zero second wave head of mould are same polarities; Otherwise be represented as opposite end bus reflected wave, then seek again line mould and zero mould for the second time with its initial row ripple wave head of same polarity all separately, thereby this wave head is then found out the fault point reflected wave for the fault point reflected wave, utilizes comparatively stable line mold component to carry out accurate fault localization at last.

Operation principle: when cable-aerial mixed line breaks down, earlier by adding the big or small failure judgement generation section of the distributed current of the cable-aerial tie point of deriving from the system two ends under the negative sequence network after the fault, utilize the character of the accurate discriminant line of single-ended traveling wave fault location method zero each reflected wave of mold component again, thereby accurately carry out fault localization.

1. the three-phase voltage and the electric current phasor of M end before and after the extraction fault,

Be three-phase voltage before the fault and electric current phasor,

Be three-phase voltage after the fault and electric current phasor, thereby obtain electric current and voltage sudden change amount With Obtain the preface component of sudden change amount again according to symmetrical component method

With

2. set up the additional negative sequence network of joint line after the fault, the electric parameters of utilizing the M of system, N end to measure is derived from two ends, draws the distributed current at cable-aerial tie point place

Size.

3. work as $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is an overhead wire I section; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is built on stilts I section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is a cut cable; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is that position of failure point is built on stilts II section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}\right|,$ Position of failure point is built on stilts II section.

4. on the basis of fault section location, utilize Karrenbauer conversion battle array as the phase-model transformation matrix, extract line zero mold component of measuring junction electric current, and utilize Cubic B-spline Wavelet to detect singular point, Cubic B-spline Wavelet is to realize with the filter of structure.

5. on the basis of having considered line zero mold component coupling, utilize line zero mold component polarity relatively to carry out reflected wave wave head property determination:, then to show it is fault point reflection ripple if line mould and zero second wave head of mould are same polarities; Otherwise be represented as opposite end bus reflected wave, then seek again line mould and zero mould for the second time with its initial row ripple wave head of same polarity all separately, thereby this wave head is then found out the fault point reflected wave for the fault point reflected wave, utilizes comparatively stable line mold component to carry out accurate fault localization at last.

The present invention compared with prior art has following advantage:

1. combine the advantage of power frequency amount and traveling wave fault location method, overcome the influence of transition resistance, fault initial phase angle and position of failure point.

2. be not subjected to the influence of joint line structure and electric parameter distribution characteristics.

3. adopt to travelling wave signal wavelet transformation under different scale remedied transmission line especially cable line according to the influence of characteristic frequently.

4. analyze current traveling wave line, zero mold component coupling phenomenon, accurately differentiated reflection polarity.

5. this inventive principle is simple and reliable, the accuracy height.

Use and to increase along with cable-aerial mixed line, after cable-aerial mixed line broke down, the line walking time can be shortened greatly in the fault localization location accurately, accelerated to restore electricity, and the safety and the economical operation of electric power system had very important significance.

Description of drawings

Fig. 1 is a Type B joint line structure of the present invention.

Fig. 2 is a malfunction negative phase-sequence equivalent network.

Fig. 3 is the Bergeron equivalent circuit.

Fig. 4 is the zero line ripple grid chart among the present invention.

Embodiment

Embodiment 1: the present invention's Type B joint line shown in Figure 1 type is an example as analysis and simulation object, and the specific implementation step is as follows:

One. based on the fault section location of distributed constant

As a simple double ended system, when breaking down in any point of circuit, utilization symmetrical component method and linear superposition theorem generally can be decomposed into fault network before the fault additional positive and negative, zero-sequence network behind the proper network and fault.

For the three-phase symmetrical fault, there are not negative phase-sequence and zero-sequence network; For asymmetric non-earth fault, there is not zero-sequence network; For in the electrical network generation single phase ground fault of neutral-point solid ground, when single-phase earthing weak point fault takes place, will very big negative phase-sequence and zero-sequence current appear, so negative phase-sequence and zero-sequence network can be introduced the criterion of finding range, and when other earth faults, zero-sequence current flows back to bus through the earth, because the not intellectual of the resistivity of the earth, so utilize the reliability of negative-sequence current higher.Because 80% above fault causes by single-phase earthing, so only consider joint line range finding problem in the text at single phase ground fault.In sum, in the present invention, introduce the section location that negative-sequence current and negative sequence network carry out joint line.

On the basis of fault section location, utilize Karrenbauer conversion battle array as the phase-model transformation matrix, extract line zero mold component of measuring junction electric current, and utilize Cubic B-spline Wavelet to detect singular point, Cubic B-spline Wavelet is to realize with the filter of structure.The coefficient of filter is as shown in table 1.

Table 1: cubic B-spline wavelet filtering coefficient

Suppose single phase ground fault on the Type B joint line, there are 5 kinds of possibilities its position: the tie point place and the built on stilts II section of built on stilts I section, built on stilts I section and cable connection point, cut cable, cable and built on stilts II section.Fault generation section is accurately located and will be created conditions for next step utilizes the precision ranging of row ripple.Be located at J _ClThe place from the distributed current negative sequence component that M end recursion obtains is The distributed current negative sequence component that obtains from N end recursion is

At J _ClThe place from the distributed current negative sequence component that M end recursion obtains is

The distributed current negative sequence component that obtains from N end recursion is The distributed current negative sequence component that fault occurrence positions and tie point place recursion obtain corresponding as shown in table 2.

Table 2: be the correspondence table of fault occurrence positions and electric current negative sequence component

Can obtain negative phase-sequence equivalent network such as Fig. 2 by the negative phase-sequence equivalent network recursion of malfunction.Wherein: Z _M2, Z _N2System's negative sequence impedance for the system two ends; Z _L12, Z _L22, Z _L32Be respectively the circuit negative sequence impedance of the unit length of built on stilts I section, cable, built on stilts II section; Y _L12, Y _L22, Y _L32Be respectively the circuit negative phase-sequence distribution admittance of the unit length of built on stilts I section, cable, built on stilts II section; L1, L2, L3 are respectively the length of built on stilts I section, cable, built on stilts II section; J _Lc, J _ClTie point for built on stilts I section and cable, cable and built on stilts II section.

M is an example with circuit top, establishes

Be three-phase voltage before the fault and current vector,

Be three-phase voltage after the fault and current vector, the voltage and current sudden change amount that can obtain the M end thus is:

$d{\stackrel{\&CenterDot;}{U}}_{\mathrm{MABC}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{MABC}}^{\&prime;}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{MABC}}---\left(1\right)$

$d{\stackrel{\&CenterDot;}{I}}_{\mathrm{MABC}}={\stackrel{\&CenterDot;}{I}}_{\mathrm{MABC}}^{\&prime;}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{MABC}}---\left(2\right)$

Then according to symmetrical component method with three-phase sudden change amount

With

Be varied to

With

$\left[\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{m0}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{m1}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">m</figure-callout>}2}\end{array}\right]=\frac{1}{3}\left[\begin{array}{ccc}1& 1& 1\\ 1& a& a^2\\ 1& a^2& a\end{array}\right]\left[\begin{array}{c}d{\stackrel{\&CenterDot;}{U}}_{\mathrm{mA}}\\ d{\stackrel{\&CenterDot;}{U}}_{\mathrm{mB}}\\ d{\stackrel{\&CenterDot;}{U}}_{\mathrm{mC}}\end{array}\right]---\left(3\right)$

$\left[\begin{array}{c}\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{m0}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{m1}\\ \mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">m</figure-callout>}2}\end{array}\right]=\frac{1}{3}\left[\begin{array}{ccc}1& 1& 1\\ 1& a& a^2\\ 1& a^2& a\end{array}\right]\left[\begin{array}{c}d{\stackrel{\&CenterDot;}{I}}_{\mathrm{mA}}\\ d{\stackrel{\&CenterDot;}{I}}_{\mathrm{mB}}\\ d{\stackrel{\&CenterDot;}{I}}_{\mathrm{mC}}\end{array}\right]---\left(4\right)$

Taking into account under the situation of distributed capacitance, according to derivation:

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}=(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{M2}-L1\&times;{\mathrm{<figure-callout\; id="12"\; label="Y\; L"\; filenames="A20081005826700132.png"\; state="\{\{state\}\}">Y</figure-callout>}}_L/2\&times;\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{M2})\frac{W_1+L1\&times;{\mathrm{<figure-callout\; id="12"\; label="Z\; L"\; filenames="A20081005826700132.png"\; state="\{\{state\}\}">Z</figure-callout>}}_L+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+W_2}{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+W_2}---\left(5\right)$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="lc"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">lc</figure-callout>}2}^{\&prime;}=(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{N2}-L3\&times;Y_{L32}/2\&times;\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{N2})\frac{W_1+L1\&times;{\mathrm{<figure-callout\; id="12"\; label="Z\; L"\; filenames="A20081005826700132.png"\; state="\{\{state\}\}">Z</figure-callout>}}_L+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+W_2}{L1\&times;{\mathrm{<figure-callout\; id="12"\; label="Z\; L"\; filenames="A20081005826700132.png"\; state="\{\{state\}\}">Z</figure-callout>}}_L+W_1}---\left(6\right)$

Wherein: W ₁Be Z _L12The left side resistance value, W ₂Be Z _L22The right side resistance value;

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}=(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{M2}-L1\&times;{\mathrm{<figure-callout\; id="12"\; label="Y\; L"\; filenames="A20081005826700132.png"\; state="\{\{state\}\}">Y</figure-callout>}}_L/2\&times;\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{M2})\frac{W_3+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+L3\&times;Z_{L32}+W_4}{L3\&times;Z_{L32}+W_4}---\left(7\right)$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="2"\; label="cl"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">cl</figure-callout>}2}^{\&prime;}=(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{N2}-L3\&times;Y_{L32}/2\&times;\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{N2})\frac{W_3+\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+L3\&times;Z_{L32}+W_4}{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A20081005826700133.png"\; state="\{\{state\}\}">L</figure-callout>}2\&times;Z_{L22}+W_3}---\left(8\right)$

Wherein: W ₃Be Z _L22The left side resistance value, W ₄Be Z _L32The right side resistance value.

The section that can failure judgement takes place according to the size of the distributed current at the tie point place that derives, though this invention needs to gather the two ends electric parameters, but do not require the both-end data sync, be not subjected to the influence of circuit two ends system impedance and transition resistance, not having pseudo-root problem, is kind of a practical and accurate method that is applicable to cable-aerial mixed line fault section location.

Two. based on the one-end fault precision ranging of current traveling wave

At first line zero mold component coupling phenomenon is analyzed:

When asymmetric earth fault took place transmission line, though traveling-wave component on the line can be full decoupled by phase-model transformation, the place was then not necessarily full decoupled in the fault point.Each modulus of row ripple need be analyzed the coupling phenomenon of line wave component when discussing transmission line generation single-phase earthing in the mutual transmission at place, fault point.

According to the Bergeron equivalent circuit of the modulus form at fault point place, as shown in Figure 3.

(a) when the line mold component arrived the place, fault point, its refraction coefficient was (6R+Z ₀)/(2 (Z ₀+ 2Z ₁+ 6R)), the refraction coefficient that is coupled to zero mold component is-Z ₁/ (Z ₀+ 2Z ₁+ 6R); Reflection coefficient is-2Z ₁/ (Z ₀+ 2Z ₁+ 6R).The reflection coefficient that is coupled to zero mold component also is-2Z ₁/ (Z ₀+ 2Z ₁+ 6R).As can be seen, refracted component is opposite with refraction coupled component polarity, and the ratio of value is: Z ₁: (6R+Z ₀); Reflecting component is identical with reflection coupled component polarity, and value equates.

(b) when zero line wave component arrived the fault point, its refraction coefficient was (6R+2Z ₁)/(2 (Z ₀+ 2Z ₁+ 6R)), the refraction coefficient that is coupled to the line mold component is-Z ₀/ (2 (Z ₀+ 2Z ₁+ 6R)); Reflection coefficient is-Z ₀/ (Z ₀+ 2Z ₁+ 6R), the reflection coefficient that is coupled to the line mold component is-Z ₀/ (Z ₀+ 2Z ₁+ 6R).And as can be seen, refracted component is opposite with refraction coupled component polarity, and the ratio of value is (6R+2Z ₁): Z ₀Reflecting component is identical with reflection coupled component polarity, and value equates.

Z wherein ₀, Z ₁Be line zero mould and line mould 1 mould wave impedance, R is that fault is passed through in StarNet's conversion equivalent circuit pure resistance over the ground mutually.

When single phase ground fault takes place, as shown in Figure 4, after arriving bus M, zero mould initial row ripple reflects.When this reflected wave component arrived fault point f, because coupling phenomenon, its part reflected after being converted into the line mold component; Another part still is that zero mold component reflects, and refraction row ripple is followed same rule.And the catadioptric situation behind the reflected wave of the line mold component arrival fault point f is similar equally.Also promptly for the line mold component of incomplete decoupling zero on the circuit, the fault point reflected wave is made up of two components: first component is zero mode coupling component, second component is originally intrinsic line mould reflecting component, and two traveling-wave components are all advanced to bus M with line mould velocity of wave.And two parts reflected wave will successively arrive bus M.When the fault point reflected wave generation catadioptric second time, can produce the modulus coupling phenomenon again.If line, zero mould velocity of wave are known, can analyze the character of the several wave heads of capable wavefront that produce in different fault points.

With the uniline is example, and establishing total track length is L, and fault distance is l _f, line mould velocity of wave is v ₁, zero mould velocity of wave is v ₀It is t that fault takes place constantly ₀, the moment that fault initial row ripple arrives measurement point is t ₁, the moment that the line mold component of fault point reflected wave arrives measurement point is t ₂, the moment that the zero mode coupling component of fault point reflected wave (or opposite end bus transmitted wave) arrives measurement point is t ₃, the moment that opposite end bus reflected wave is transmitted to measurement point is t ₄The moment of the line mold component arrival measurement point of reflected wave (or opposite end bus reflected wave second time) is t for the second time in the fault point ₅Because line mould velocity of wave is greater than zero mould velocity of wave, so the line mold component of fault point reflected wave must be gone zero mode coupling component arrival measurement point prior to the fault point reflected wave; And the line mold component of opposite end bus transmitted wave also must arrive measurement point prior to the zero mode coupling component of opposite end bus transmitted wave.

Because the zero mode coupling component of fault point reflected wave just can produce after the fault point is gone back in the initial row wave reflection, therefore the time of zero mode coupling component arrival measurement point must be later than the time that fault initial row ripple arrives measurement point.Again since line mould velocity of wave greater than zero mould velocity of wave, so the line mold component of fault point reflected wave must be prior to the zero mode coupling component arrival measurement point of fault point reflected wave; And the line mold component of opposite end bus transmitted wave also must arrive measurement point prior to the zero mode coupling component of opposite end bus transmitted wave.For the line mold component of fault point secondary reflection ripple, then carry out following discussion.

Zero mode coupling component for the fault point reflected wave has following equation to set up:

$\frac{2l_f}{v_0}+\frac{l_f}{v_1}=t_3-t_0---\left(9\right)$

Line mold component for fault point secondary reflection ripple has following equation to set up:

$\frac{5l_f}{v_1}=t_5-t_0---\left(10\right)$

By equation 9,10 as can be known:

$t_3-t_5=\left(\frac{2v_1-4v_0}{v_0{v}_1}\right)l_f---\left(11\right)$

As can be known t must be arranged according to the correlation on line mould velocity of wave and the zero mould velocity of wave value ₃Less than t ₅Be the line mold component arrival measurement point of the zero mode coupling component of fault point reflected wave prior to fault point secondary reflection ripple.In like manner the zero mode coupling component of opposite end bus transmitted wave must arrive measurement point prior to the line mold component of the opposite end bus transmitted wave second time as can be known.

According to analysis, it is as shown in table 3 that different faults is put the character of pairing preceding four wave heads in one section circuit.

Table 3: be four wave head property lists of the capable wavefront of different faults position failure

Fault coverage	First wave head	Second wave head	The 3rd wave head	The 4th wave head
					0＜l f＜v 0L/(v 0+v 1)	The initial row ripple	The fault point reflected wave	The coupled wave of fault point reflected wave	Fault point secondary reflection ripple or opposite end bus reflected wave
v 0L/(v 0+v 1)＜l f＜L /2	The initial row ripple	The fault point reflected wave	Opposite end bus reflected wave	The coupled wave of fault point reflected wave
					L /2＜l f＜v 1L/(v 0+v 1)	The initial row ripple	Opposite end bus reflected wave	The fault point reflected wave	The coupled wave of opposite end bus transmitted wave
v 1L/(v 0+v 1)＜l f＜L	The initial row ripple	Opposite end bus reflected wave	The coupled wave of opposite end bus transmitted wave	Opposite end bus secondary reflection ripple or fault point reflected wave
					l f＝v 0L/(v 0+v 1)	The initial row ripple	The fault point reflected wave	Opposite end bus reflected wave (or coupled wave)	Fault point secondary reflection ripple
l f＝v 1L/(v 0+v 1)	The initial row ripple	Opposite end bus reflected wave	Fault point reflected wave (or coupled wave)	Opposite end bus secondary reflection ripple
					l f＝L /2	The initial row ripple	Fault point reflected wave or opposite end bus reflected wave	Fault point reflected wave or opposite end bus reflected wave coupled wave	Fault point reflected wave or opposite end bus secondary reflection ripple

On the basis that online then zero mold component coupling phenomenon is analyzed, utilize single-ended method to carry out precision ranging, the basic scheme of this invention is: on the basis of having judged fault section, if line mould and zero second wave head of mould are same polarities, then show it is fault point reflection ripple; Otherwise be represented as opposite end bus reflected wave, then seek again line mould and zero mould for the second time with its initial row ripple wave head of same polarity all separately, this wave head then is the fault point reflected wave, can utilize formula (12) to carry out accurate fault localization with its modulus maximum corresponding sampling points number:

X _L＝v×Δt/2 (12)

Wherein, it is poor to once two-way time between the fault point at measuring junction that Δ t is electric current (voltage) row wave-wave head, and v is the velocity of wave of a certain modulus of capable ripple.

Three. result of calculation and analysis

The cable mixed model that utilizes electromagnetic transient simulation software to build carries out emulation at different faults point and different transition resistance, and the range finding result who draws is as shown in table 4.

Table 4: range finding is table as a result

The result shows that this method has higher accuracy and validity at the range finding of joint line.

Claims (2)

1, a kind of cable-aerial mixed line fault travelling wave ranging method, add under negative sequence network and the negative-sequence current by joint line system two ends electrical data after it is characterized in that gathering earlier fault, big or small failure judgement generation section with the distributed current at cable-aerial tie point place, location, utilize the character of the accurate discriminant line of single-ended traveling wave fault location mode zero each reflected wave of mold component again, accurately measure joint line system failure distance at last.

2, cable-aerial mixed line fault travelling wave ranging method according to claim 1 is characterized in that its concrete steps are as follows:

1). extract the three-phase voltage and the electric current phasor of fault front and back M end,

Be three-phase voltage before the fault and electric current phasor,

Be three-phase voltage after the fault and electric current phasor, thereby obtain electric current and voltage sudden change amount

With

Obtain the preface component of sudden change amount again according to symmetrical component method

With

2). set up the additional negative sequence network of joint line after the fault, the electric parameters of utilizing the M of system, N end to measure is derived from two ends, draws the distributed current at cable-aerial tie point place

Size;

3). when $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}^{\&prime;}\right|,$ Position of failure point is an overhead wire I section; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}^{\&prime;}\right|,$ Position of failure point is built on stilts I section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}^{\&prime;}\right|,$ Position of failure point is a cut cable; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}\right|=\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}^{\&prime;}\right|,$ Position of failure point is that position of failure point is built on stilts II section and cable connection point; When $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}\right|<\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{lc}2}^{\&prime;}\right|$ And $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}\right|>\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{cl}2}^{\&prime;}\right|,$ Position of failure point is built on stilts II section;

4). on the basis of fault section location, utilize Karrenbauer conversion battle array, extract line zero mold component of measuring junction electric current, and utilize Cubic B-spline Wavelet to detect singular point as the phase-model transformation matrix;

5). on the basis of having considered line zero mold component coupling, utilize line zero mold component polarity relatively to carry out reflected wave wave head property determination:, then to show it is fault point reflection ripple if line mould and zero second wave head of mould are same polarities; Otherwise be represented as opposite end bus reflected wave, then seek again line mould and zero mould for the second time with its initial row ripple wave head of same polarity all separately, thereby this wave head is then found out the fault point reflected wave for the fault point reflected wave, utilizes comparatively stable line mold component to carry out accurate fault localization at last.

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