CN102520318B - Fault recognition method for electric transmission line - Google Patents

Abstract

The invention belongs to Relay Protection Technology in Power System fields, disclose a kind of fault recognition method for electric transmission line. It include: to measure transmission line of electricity side m, n transforming plant protecting installation place respectively to refer to the positive sequence voltage fundamental frequency phasor of phase, forward-order current fundamental frequency phasor as input quantity. Using distribution parameter long-line equation, by m/n transforming plant protecting installation place with reference to the positive sequence voltage fundamental frequency phasor of phase, the electric current phasor of forward-order current fundamental frequency phasor calculation route midpoint t

It calculates

With

Wherein k is tuning coefficient. Judgement

With

Size relation, if

It sets up, then judges to be broken down inside protection transmission line of electricity; If

It sets up, then judges that protected circuit is normal. The method of the present invention can reliably detect whether protected circuit breaks down, and meet selectivity, reliability, sensitivity and the quick-action of relay protection, be suitable for ultra-high/extra-high voltage transmission line of alternation current.

Description

A kind of fault recognition method for electric transmission line

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of fault recognition method for electric transmission line.

Background technology

Transmission line malfunction identification based on Wide-area Measurement Information is the core component based on Wide-area Measurement Information electric network protection.The wide area backup protection algorithm > > that the < < that the people such as Wang Hua, Zhang Zhe and Yin Xianggen deliver distributes based on false voltage adopts lumped parameter modeling; utilize the voltage failure component of the measured value estimation opposite side of circuit one side voltage, current failure component, with the ratio formation protection criterion of estimated value and measured value.The method, because adopting lumped parameter modeling, is subject to the impact of line distribution capacitance in principle; The method because of with system impedance relating to parameters, in principle, be subject to the impact of system operation mode.Yet, from current China Power Grids, PMU situation is installed, have the transmission line of electricity electric pressure between the transformer station that installs PMU high, on transmission line of electricity, the transmitting procedure of voltage, electric current has obvious wave process, and distributed capacitance can not be ignored the impact of line fault identification.Modern power network ruuning situation is complicated, and system operation mode also can not be ignored the impact of line fault identification.Therefore,, based on Wide-area Measurement Information platform, study a kind of reliably method of accurate identification circuit fault and there is very strong engineering significance.

Summary of the invention

The object of the invention is to overcome the deficiency of prior art existence and propose a kind of fault recognition method for electric transmission line whether breaking down for detection of protected transmission line of electricity.

The object of the invention is to realize by following approach:

, its main points are, comprise the steps:

(1) transmission line of electricity based between m transformer station and n transformer station, provides a kind of computer based line protection;

First, described protector measuring circuit is in the positive sequence voltage fundamental frequency phasor of m transforming plant protecting installation place

with forward-order current fundamental frequency phasor

Measuring circuit is in the positive sequence voltage fundamental frequency phasor of n transforming plant protecting installation place

with forward-order current fundamental frequency phasor

Wherein, φ is with reference to phase, φ=A phase or B phase or C phase;

(2) computer based line protection is according to the positive sequence voltage fundamental frequency phasor of measured m transforming plant protecting installation place

with forward-order current fundamental frequency phasor

calculate the electric current phasor at transmission line of electricity mid point t place between m transformer station and n transformer station

${\stackrel{\&CenterDot;}{I}}_{\mathrm{mt\&phi;}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&phi;}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&phi;}1}}{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)$

Wherein, γ ₁for transmission line of electricity positive sequence propagation coefficient:

r1, L1, G1, C1 are respectively positive sequence resistance, inductance, the electricity of unit length circuit and lead and capacitance;

Z _c1for transmission line of electricity positive sequence wave impedance:

L _mnfor transmission line length between m transformer station and n transformer station;

T is the mid point of transmission line of electricity between m transformer station and n transformer station;

(3) computer based line protection is according to the positive sequence voltage fundamental frequency phasor of measured n transforming plant protecting installation place

with forward-order current fundamental frequency phasor

calculate the electric current phasor at transmission line of electricity mid point t place between m transformer station and n transformer station

${\stackrel{\&CenterDot;}{I}}_{\mathrm{nt\&phi;}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{n\&phi;}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{n\&phi;}1}}{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)$

(4) calculate

with

(5) judgement whether set up, if set up, judge that between m transformer station and n transformer station, transmission line of electricity breaks down; Otherwise, if meet

judge that between m transformer station and n transformer station, transmission line of electricity is normal.Wherein, k is tuning coefficient, and during long distance transmission line, k value is 0.5; During short distance transmission line of electricity, k span is (0.25,0.5).

Feature of the present invention and technological achievement are: the method physical model adopts distributed parameter model, can accurately describe the physical characteristics of ultra-high/extra-high voltage transmission line of electricity, are not subject to the impact of distributed capacitance, are applicable to ultra-high/extra-high voltage transmission line of electricity; The method only need be used transmission line parameter and participate in calculating, and is not subject to the impact of system operation mode in principle; In the method principle, eliminated the impact of transition resistance and load current; Whether break down the method energy reliable detection transmission line of electricity inside.

Accompanying drawing explanation

Fig. 1 is application supertension line transmission system schematic diagram of the present invention.

Apart from m side 50km place, there is B when 300 Ω earth fault in Fig. 2,

with

change curve;

Fig. 3 is that BC occurs apart from m side 200km place is alternate when 0 Ω short circuit,

with

change curve;

Fig. 4 is that CA occurs apart from m side 200km place is alternate after 0 Ω short circuit again during earth fault,

with change curve;

Fig. 5 is that ABC occurs apart from m side 150km place is alternate after 0 Ω short circuit again during earth fault,

with

change curve;

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that, following explanation is only exemplary, rather than in order to limit the scope of the invention and to apply.

With reference to accompanying drawing 1, supertension line transmission system is typical both end power supplying system, adopts computer based line protection as the application circuit protective device of collection measurement, computational analysis and fault detect required in the method for the invention.Two side bus are respectively m power supply (m transformer station) and n power supply (n transformer station), and transmission line length is 300km.Circuit m, n both sides equivalent source phase angle difference are δ=50 °, and circuit m, n both sides power supply amplitude are respectively the per unit value of 1.05 times and the per unit value of 1 times.Line parameter circuit value adopts Beijing-Tianjin-Tangshan 500kV transmission line parameter:

The positive order parameter of circuit: R1=0.02083W/km, L1=0.8948mH/km, C1=0.0129mF/km, G1=0s/km

Line zero order parameter: R0=0.1148W/km, L0=2.2886mH/km, C0=0.00523mF/km, G0=0s/km

M system positive sequence system equivalent impedance: Zm1=4.2643+j85.1453W

M system zero sequence system equivalent impedance: Zm0=0.6+j29.0911W

N system positive sequence system equivalent impedance: Zn1=7.9956+j59.6474W

N system zero sequence system equivalent impedance: Zn0=2.0+j7.4697W

In the present embodiment, the fundamental frequency electric parameters of m side transformer station and n side transformer station is measured by the synchronous phasor measurement unit that is arranged on this two transformer station respectively, and measurement data sends line protective devices to through optic fibre data channel.

It is with reference to phase mutually that the present embodiment is chosen A, choose tuning coefficient k=0.5, the transmission line of electricity of take illustrates that apart from the computation process of the m side 50km B of place the 160th sampling number certificate after 300 Ω earth faults front the 120th sampled points and fault occur occur as example the concrete steps of the inventive method embodiment are as follows:

First computing electric power line parameter:

Positive sequence wave impedance: ${\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c=\sqrt{\frac{{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+\mathrm{j\&omega;}{L}_1}{{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">G</figure-callout>}}_1+\mathrm{j\&omega;}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}}=263.55-j9.7511\mathrm{\&Omega;}$

Positive sequence propagation coefficient: ${\mathrm{\&gamma;}}_1=\sqrt{({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+\mathrm{j\&omega;}{L}_1)({\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">G</figure-callout>}}_1+\mathrm{j\&omega;}{C}_1)}=0.00003951+j0.001068$

One, adopt the computation process of front the 120th the sampling number certificate of fault to illustrate that the concrete steps of the inventive method embodiment are as follows:

1) measuring circuit is in the A phase positive sequence voltage fundamental frequency phasor of m transforming plant protecting installation place

with A phase forward-order current fundamental frequency phasor

measuring circuit is in the A phase positive sequence voltage fundamental frequency phasor of n transforming plant protecting installation place

with A phase forward-order current fundamental frequency phasor as input quantity:

${\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}=181.28-j235.86\mathrm{kV};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}=0.51068-j0.57207\mathrm{kA};$

${\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}=122.51-j262.05\mathrm{kV};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}=-0.20454-j0.7571\mathrm{kA};$

2) calculate

with

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-{\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)/{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c=0.36195-j0.67404\mathrm{kA};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-{\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)/{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c=-0.36123+j0.67302\mathrm{kA};$

3) calculate

with

$|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}|=0.0012521\mathrm{kA};$

$0.5|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}|=0.17886\mathrm{kA};$

4) judgement

with

magnitude relationship:

$|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}|=0.0012521\mathrm{kA}<0.5|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}|=017886\mathrm{kA},$

Protected circuit reliably to be detected exactly normal for this sampling instant the inventive method.

Two, after employing fault, the concrete steps of computation process explanation the inventive method embodiment of the 160th sampling number certificate are as follows:

1) measuring circuit is in the A phase positive sequence voltage fundamental frequency phasor of m transforming plant protecting installation place

with A phase forward-order current fundamental frequency phasor

measuring circuit is in the A phase positive sequence voltage fundamental frequency phasor of n transforming plant protecting installation place

with A phase forward-order current fundamental frequency phasor

as input quantity:

${\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}=163.1-j242.73\mathrm{kV};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}=0.60376-j0.79021\mathrm{kA};$

${\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}=106.73-j267.87\mathrm{kV};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}=-0.16346+j0.66067\mathrm{kA};$

2) calculate

with

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-{\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)/{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c=0.44928-j0.87836\mathrm{kA};$

${\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-{\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)/{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c=-0.32402-j0.58706\mathrm{kA};$

3) calculate with

$|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}|=0.31709\mathrm{kA};$

$0.5|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}|=0.22938\mathrm{kA};$

4) judgement

with

magnitude relationship:

$|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}|=0.31709\mathrm{kA}>0.5|{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}+{\stackrel{\&CenterDot;}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}|=0.22938\mathrm{kA},$

This sampling instant the inventive method reliably detects exactly protected circuit and breaks down.

Apart from m side 50km place, there is B when 300 Ω earth fault in Fig. 2,

with change curve.Fig. 3 is that BC occurs apart from m side 200km place is alternate when 0 Ω short circuit,

with change curve.Fig. 4 is that CA occurs apart from m side 200km place is alternate after 0 Ω short circuit again during earth fault,

with

change curve.Fig. 5 is that ABC occurs apart from m side 150km place is alternate after 0 Ω short circuit again during earth fault,

with

change curve.From Fig. 2, Fig. 3, Fig. 4 and Fig. 5, when protected circuit normally moves, application the inventive method can reliably judge protected circuit non-fault; When protected circuit breaks down after generation, application the inventive method can be identified accurately and reliably protected circuit and break down.

Order $I_d=|{\stackrel{.}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mtA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mtA</figure-callout>}1}+{\stackrel{.}{I}}_{\mathrm{<figure-callout\; id="1"\; label="ntA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">ntA</figure-callout>}1}|,I_z=0.5|{\stackrel{.}{I}}_{\mathrm{<figure-callout\; id="1"\; label="mA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">mA</figure-callout>}1}+{\stackrel{.}{I}}_{\mathrm{<figure-callout\; id="1"\; label="nA"\; filenames="HDA0000128616960000013.png,HDA0000128616960000021.png"\; state="\{\{state\}\}">nA</figure-callout>}1}|.$ When table 1 has provided m, equivalent source phase angle difference δ=50, n both sides °, while there is dissimilar fault apart from m side diverse location, a situation arises for the inventive method identification protected circuit fault.

When table 1, apart from m side diverse location, dissimilar fault occurs, a situation arises for the inventive method identification protected circuit fault

(m, equivalent source phase angle difference δ=50 °, n both sides)

As shown in Table 1, in the time of m, equivalent source phase angle difference δ=50, n both sides °,, in transmission line of electricity heavy load situation, while there is dissimilar fault apart from m side diverse location, all meet criterion therefore, the inventive method effectively recognizes protected circuit and breaks down.

When table 2 has provided m, equivalent source phase angle difference δ=50, n both sides °, in transmission line of electricity heavy load situation, apart from m side diverse location, C occurs when the different transition resistance ground short circuit, the inventive method is identified protected circuit fault, and a situation arises.Apart from m side diverse location, there is C the inventive method when the different transition resistance ground short circuit and identify protected circuit fault a situation arises in table 2:

(m, equivalent source phase angle difference δ=50 °, n both sides)

As shown in Table 2, in the time of m, equivalent source phase angle difference δ=50, n both sides °, in transmission line of electricity heavy load situation, apart from m side diverse location, there is C when the different transition resistance earth fault, all meet criterion therefore, application the inventive method energy reliable detection breaks down to protected circuit, and testing result accurately and reliably.

Whether from the above, the inventive method is not subject to the impact of the factors such as transition resistance, fault type, abort situation and load current, can break down reliable detection protected circuit inside, has very strong practical value.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited to this; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the variation that can expect easily or replacement, within all should being encompassed in protection scope of the present invention.

It is same as the prior art that the present invention does not state part.

Claims (1)

1. a fault recognition method for electric transmission line, is characterized in that, comprises the following steps:

Transmission line of electricity based between m transformer station and n transformer station, provides a kind of computer based line protection;

(1) first, described protector measuring transmission line of electricity is in the positive sequence voltage fundamental frequency phasor of m transforming plant protecting installation place

with forward-order current fundamental frequency phasor

measure transmission line of electricity in the positive sequence voltage fundamental frequency phasor of n transforming plant protecting installation place

with forward-order current fundamental frequency phasor

wherein, transmission line of electricity is between m transformer station and n transformer station; φ is with reference to phase, φ=A phase or B phase or C phase,

(2) computer based line protection is according to the positive sequence voltage fundamental frequency phasor of measured m transforming plant protecting installation place

with forward-order current fundamental frequency phasor

calculate the electric current phasor at transmission line of electricity mid point t place between m transformer station and n transformer station

${\stackrel{\&CenterDot;}{I}}_{\mathrm{mt\&phi;}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&phi;}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&phi;}1}}{Z_{c1}}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)$

Wherein, γ ₁for transmission line of electricity positive sequence propagation coefficient:

r ₁, L ₁, G ₁, C ₁the positive sequence resistance, inductance, the electricity that are respectively unit length circuit are led and capacitance; Z _c1for transmission line of electricity positive sequence wave impedance:

l _mnfor transmission line length between m transformer station and n transformer station;

T is the mid point of transmission line of electricity between m transformer station and n transformer station,

(3) computer based line protection is according to the positive sequence voltage fundamental frequency phasor of measured n transforming plant protecting installation place

with forward-order current fundamental frequency phasor

calculate the electric current phasor at transmission line of electricity mid point t place between m transformer station and n transformer station

${\stackrel{\&CenterDot;}{I}}_{\mathrm{nt\&phi;}1}={\stackrel{\&CenterDot;}{I}}_{\mathrm{n\&phi;}1}\cosh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)-\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{n\&phi;}1}}{Z_{c1}}\sinh \left(\frac{{\mathrm{\&gamma;}}_1{l}_{\mathrm{mn}}}{2}\right)$

(4) calculate

with

(5) computer based line protection is according to the result of calculation judgement of step (4)

whether set up, if set up, judge that between m transformer station and n transformer station, transmission line of electricity breaks down; Otherwise, if meet

judge that between m transformer station and n transformer station, transmission line of electricity is normal, wherein, k is tuning coefficient, and during long distance transmission line, k value is 0.5; During short distance transmission line of electricity, k span is (0.25,0.5).

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