CN103248019B - Electric transmission line phase fault relay protecting method - Google Patents

Abstract

The invention discloses a kind of electric transmission line phase fault relay protecting method.Between the fault phase that the inventive method utilizes line protection installation place, electric parameters calculates line protection installation place to the voltage drop of phase fault point and line protection setting range place to the voltage drop of phase fault point; if line protection installation place is positioned at (90 ° to the voltage drop leading line protection setting range place of phase fault point to the angle of the voltage drop of phase fault point; 270 °) in interval, then protective device sends action trip signal.The present invention overcomes transition resistance and load current and affect problem to Perfomance of protective relaying, when alternate high resistant short trouble occurs transmission line, the inventive method can correct action message, and action sensitivity is high, and protection range is stablized.

Description

Electric transmission line phase fault relay protecting method

Technical field

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

Background technology

The additional impedance that transition resistance produces can have a strong impact on the performance of impedance distance protection.If the additional impedance that transition resistance produces is resistance sense, then impedance distance protection tripping when easily causing phase fault in protection zone; If the additional impedance that transition resistance produces be capacitance-resistance, then when easily causing phase fault outside protection zone, impedance distance protection action generation surmounts.

High/super/extreme pressure transmission line of alternation current is also often heavy load transmission line, heavy load electric current can make impedance distance protection malfunction or tripping, and the impact of heavy load electric current on impedance distance protection performance can not be ignored.Overload transmission of electricity situation line is normally run; the measurement impedance of Conventional impedance distance protection is owing to affecting meeting substantial deviation actual measurement impedance by overload electric current; easily cause traditional distance protection misoperation; cause grid power blackout expanded range; even cause load to shift in a large number thus threaten circuit normally to run, causing huge potential safety hazard to power grid security.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, provide a kind of performance not by the electric transmission line phase fault relay protecting method that transition resistance and load current affect.

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

Electric transmission line phase fault relay protecting method, its main points are, comprise the steps:

(1) provide a kind of protective device, it measures the fault voltage between phases of 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 computing electric power line protection installation place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{\·}{U}}_1={\stackrel{\·}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]}{\mathrm{Re}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; Re [z ₁] be z ₁real part; Im [z ₁] be z ₁imaginary part; for real part; for imaginary part; for imaginary part; for real part;

(3) protective device computing electric power line protection seting scope place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{\·}{U}}_2={\stackrel{\·}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}]}{\mathrm{Re}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}-x_{\mathrm{set}}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}{z}_1$

Wherein, x _setfor protection seting scope;

(4) protective device computing electric power line protection installation place is to the voltage drop of phase fault point leading line protection setting range place is to the voltage drop of phase fault point angle if set up, then protective device sends action trip signal.

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

Between the fault phase that the inventive method utilizes line protection installation place, electric parameters calculates line protection installation place to the voltage drop of phase fault point and line protection setting range place to the voltage drop of phase fault point; if line protection installation place is positioned at (90 ° 270 °) interval to the voltage drop leading line protection setting range place of phase fault point to the angle of the voltage drop of phase fault point, then protective device sends action trip signal.The present invention overcomes transition resistance and load current and affect problem to Perfomance of protective relaying, when alternate high resistant short trouble occurs transmission line, the inventive method can correct action message, and action sensitivity is high, and protection range is stablized.

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, PT is voltage transformer, CT is current transformer.The current waveform of protective device to the voltage waveform summation current transformer CT of the voltage transformer pt of line protection installation place carries out sampling and obtains voltage, current instantaneous value, and utilizes 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 computing electric power line protection installation place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{\·}{U}}_1={\stackrel{\·}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]}{\mathrm{Re}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; Re [z ₁] be z ₁real part; Im [z ₁] be z ₁imaginary part; for real part; for imaginary part; for imaginary part; for real part.

Protective device computing electric power line protection seting scope place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{\·}{U}}_2={\stackrel{\·}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}[\frac{{\stackrel{\·}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}]}{\mathrm{Re}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}2}-x_{\mathrm{set}}{\stackrel{\·}{I}}_{\mathrm{\φ\φ}}{z}_1$

Wherein, x _setfor protection seting scope.

Protective device computing electric power line protection installation place is to the voltage drop of phase fault point leading line protection setting range place is to the voltage drop of phase fault point angle

Protective device judges whether set up, if set up, then protective device sends action trip signal.

The present invention overcomes transition resistance and load current and affect problem to Perfomance of protective relaying, when alternate high resistant short trouble occurs transmission line, the inventive method can correct action message, and action sensitivity is high, and protection range is stablized.

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. electric transmission line phase fault relay protecting method, is characterized in that, comprises the steps:

(1) provide a kind of protective device, it measures the fault voltage between phases of 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 computing electric power line protection installation place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{.}{U}}_1={\stackrel{.}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{.}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}\left[\frac{{\stackrel{.}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]}{\mathrm{Re}\left[\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; Re [z ₁] be z ₁real part; Im [z ₁] be z ₁imaginary part; for real part; for imaginary part; for imaginary part; for real part;

(3) protective device computing electric power line protection seting scope place is to the voltage drop of phase fault point

$\mathrm{\Δ}{\stackrel{.}{U}}_2={\stackrel{.}{U}}_{\mathrm{\φ\φ}}-\frac{\mathrm{Im}\left[z_1\right]\mathrm{Re}\left[\frac{{\stackrel{.}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]-\mathrm{Re}\left[z_1\right]\mathrm{Im}\left[\frac{{\stackrel{.}{U}}_{\mathrm{\φ\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]}{\mathrm{Re}\left[\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Im}\left[z_1\right]-\mathrm{Im}\left[\frac{{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}}{{\stackrel{.}{I}}_{\mathrm{\φ\φ}}}\right]\mathrm{Re}\left[z_1\right]}{\stackrel{.}{I}}_{\mathrm{\φ\φ}2}-x_{\mathrm{set}}{\stackrel{.}{I}}_{\mathrm{\φ\φ}}{z}_1$

Wherein, x _setfor line protection installation place is to the circuit distance setting parameter at line protection setting range place;

(4) protective device computing electric power line protection installation place is to the voltage drop of phase fault point leading line protection setting range place is to the voltage drop of phase fault point angle if set up, then protective device sends action trip signal.