CN104319750A - Line phase-to-phase short-circuit fault relay protection method based on fault location factor - Google Patents

Abstract

The invention discloses a line phase-to-phase short-circuit fault relay protection method based on a fault location factor. The method includes the steps that a long-line equation is adopted to accurately describe the voltage and current transmission physical properties of a power transmission line; the ratio of the fault impedance between the protection installation position of the power transmission line and a phase-to-phase short-circuit fault point to the line impedance between the protection installation position of the power transmission line and the protection setting range position of the power transmission line is calculated to obtain the phase-to-phase fault location factor b of the power transmission line; whether the phase-to-phase short-circuit fault point is within the protection setting range position of the power transmission line or not is judged by judging whether the phase-to-phase fault location factor b of the power transmission line is smaller than 1 or not, so that whether an action trip signal is sent out or not is determined. The method eliminates the influence on the protective action performance from the voltage, transition resistance and load current of the phase-to-phase short-circuit fault point in principle, and is particularly applicable to relay protection of phase-to-phase short-circuit faults of extra-high voltage alternating-current power transmission lines.

Description

Based on the circuit phase fault relay protecting method of the abort situation factor

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of circuit phase fault relay protecting method based on the abort situation factor.

Background technology

Distance protection due to by power system operation mode and structural change little, moment selectively can excise transmission line various fault, be applied widely in power system transmission line protection.On ultra-high-tension power transmission line, distance protection is used as transmission line main protection, and on ultra-high/extra-high voltage transmission line of alternation current, distance protection is used as transmission line backup protection.The distance protection of current power system transmission line extensive use mainly comprises the protection of power frequency variation distance and impedance distance protection.

The protection of power frequency variation distance forms distance protection by reaction operating voltage amplitude Sudden Changing Rate, and the method has affects the advantages such as little and anti-transition resistance ability is strong by power system operation mode.But the operating voltage amplitude Sudden Changing Rate adopted due to the method only exists at the fault initial stage, cannot be used as the backup protection of ultra-high/extra-high voltage transmission line of alternation current.

Impedance distance protection is positioned at protection zone according to fault impedance size faults distance length to distinguish fault point or is positioned at outside protection zone.Impedance distance protection due to by power system operation mode and structural change little, being total failure component for calculating the electric parameters of fault impedance, being applicable to whole failure process.Therefore, impedance distance protection both can be used for ultra-high-tension power transmission line main protection, also can be used as the backup protection of ultra-high/extra-high voltage transmission line of alternation current.

But Conventional impedance distance protection hypotheses fault point voltage is zero, calculate fault impedance by current ratio between fault voltage between phases and fault phase, and whether the distance carrying out faults point according to fault impedance size sends trip signal with decision.In fact, in electric power system, except the metallic short circuit fault of arteface, fault point voltage may be zero hardly, and therefore, fault point voltage can cause impedance distance protection performance and have a strong impact on.

In practical power systems, the voltage of ultrahigh voltage alternating current transmission lines, current delivery have obvious wave process, and capacitance current along the line is large, can not ignore the impact of impedance distance protection performance.Consider the impact of circuit direct-to-ground capacitance along the line, fault impedance and fault distance are hyperbolic tangent function relation, hyperbolic tangent function characteristic determines the resistance to transition resistance ability of impedance relay, and the additional impedance that transition resistance brings will have a strong impact on the performance of impedance relay.Extreme pressure transmission line of alternation current conveying Large Copacity electric energy, be heavy load transmission line, heavy load electric current can make the action sensitivity of impedance distance protection reduce, and the impact of heavy load electric current on impedance distance protection performance can not be ignored.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, a kind of circuit phase fault relay protecting method based on the abort situation factor is provided.The inventive method first computing electric power line protection installation place to the fault impedance of phase fault point and line protection installation place to the ratio of the line impedance at line protection setting range place, obtain electric transmission line phase fault location factor b, then by judge electric transmission line phase fault location factor b be less than 1 whether become Rob Roy to judge whether phase fault point is positioned at line protection setting range, to determine whether send action trip signal, principle eliminates phase fault point voltage, transition resistance and load current are on the impact of Perfomance of protective relaying, be specially adapted to the relaying protection of ultrahigh voltage alternating current transmission lines phase fault.

For completing above-mentioned purpose, the present invention adopts following technical scheme:

Based on the circuit phase fault relay protecting method of the abort situation factor, it is characterized in that, comprise following sequential steps:

(1) the fault voltage between phases of protector measuring line protection installation place fault three-phase current and negative-sequence current between fault phase wherein, φ φ=AB, BC, CA phase;

(2) protective device calculates γ ₁l _sethyperbolic cosine function value ch (γ ₁l _set), calculate γ ₁l _sethyperbolic tangent function value th (γ ₁l _set); Wherein, l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient;

(3) protective device computing electric power line phase-to phase fault location factor b:

$b=\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}{\mathrm{Re}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}$

Wherein, φ φ=AB, BC, CA phase; l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient; Z _c1for electric transmission line positive sequence wave impedance; for real part; for imaginary part; for real part; for imaginary part; for real part; for imaginary part;

(4) protective device judges that transmission line malfunction location factor b is less than 1 and whether sets up, if set up, then protective device sends action trip signal, the circuit breaker at tripping transmission line two ends.

The present invention compared with prior art, has following positive achievement:

The inventive method adopts long-line equation accurately to describe the physical characteristic of transmission line, has the ability of natural anti-distributed capacitance impact.The inventive method first computing electric power line protection installation place to the fault impedance of phase fault point and line protection installation place to the ratio of the line impedance at line protection setting range place, obtain electric transmission line phase fault location factor b, by judge electric transmission line phase fault location factor b be less than 1 whether become Rob Roy to judge whether phase fault point is positioned at line protection setting range, to determine whether send action trip signal, principle eliminates phase fault point voltage, transition resistance and load current are on the impact of Perfomance of protective relaying, be specially adapted to the relaying protection of ultrahigh voltage alternating current transmission lines phase fault.

Accompanying drawing explanation

Fig. 1 is application multi-line power transmission system schematic of the present invention.

Embodiment

According to Figure of description, technical scheme of the present invention is expressed in further detail below.

Fig. 1 is application multi-line power transmission system schematic of the present invention.In Fig. 1, CVT is voltage transformer, CT is current transformer.The current waveform of protective device to the potential and current transformers CT of the voltage transformer CVT of line protection installation place carries out sampling and obtains voltage, current instantaneous value.

The voltage that protective device obtains sampling, current instantaneous value utilize Fourier algorithm computing electric power line to protect the fault voltage between phases of installation place fault three-phase current and negative-sequence current between fault phase wherein, φ φ=AB, BC, CA phase.

Protective device calculates γ ₁l _sethyperbolic cosine function value ch (γ ₁l _set).

Protective device calculates γ ₁l _sethyperbolic tangent function value th (γ ₁l _set).

Wherein, l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient.

Protective device computing electric power line phase-to phase fault location factor b:

$b=\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}{\mathrm{Re}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}$

Wherein, φ φ=AB, BC, CA phase; l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient; Zc1 is electric transmission line positive sequence wave impedance; for real part; for imaginary part; for real part; for imaginary part; for real part; for imaginary part.

Protective device judges that transmission line malfunction location factor b is less than 1 and whether sets up, if set up, then judge that phase fault point is positioned at line protection setting range, protective device sends action trip signal, the circuit breaker at tripping transmission line two ends.

The inventive method adopts long-line equation accurately to describe the physical characteristic of transmission line, has the ability of natural anti-distributed capacitance impact.The inventive method first computing electric power line protection installation place to the fault impedance of phase fault point and line protection installation place to the ratio of the line impedance at line protection setting range place, obtain electric transmission line phase fault location factor b, then by judge electric transmission line phase fault location factor b be less than 1 whether become Rob Roy to judge whether phase fault point is positioned at line protection setting range, to determine whether send action trip signal, principle eliminates phase fault point voltage, transition resistance and load current are on the impact of Perfomance of protective relaying, be specially adapted to the relaying protection of ultrahigh voltage alternating current transmission lines phase fault.

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

Claims (1)

1., based on the circuit phase fault relay protecting method of the abort situation factor, it is characterized in that, comprise following sequential steps:

(1) the fault voltage between phases of protective device protector measuring line protection installation place fault three-phase current and negative-sequence current between fault phase wherein, φ φ=AB, BC, CA phase,

(2) protective device calculates γ ₁l _sethyperbolic cosine function value ch (γ ₁l _set), calculate γ ₁l _sethyperbolic tangent function value th (γ ₁l _set); Wherein, l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient;

(3) protective device computing electric power line phase-to phase fault location factor b:

$b=\frac{\mathrm{Re}\left({\stackrel{\·}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left({\stackrel{\·}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}{\mathrm{Re}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{\·}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)-\mathrm{Im}\left(Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right){\stackrel{\·}{I}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right)}$

Wherein, φ φ=AB, BC, CA phase; l _setfor line protection setting range, get 0.85 times of transmission line length; γ ₁for electric transmission line positive sequence propagation coefficient; Z _c1for electric transmission line positive sequence wave impedance; for real part; for imaginary part; for real part; for imaginary part; for real part; for imaginary part;

(4) protective device judges that transmission line malfunction location factor b is less than 1 and whether sets up, if set up, then protective device sends action trip signal, the circuit breaker at tripping transmission line two ends.