CN103248019A - Relay protection method for interphase short circuit faults of electric transmission line - Google Patents

Abstract

The invention discloses a relay protection method for interphase short circuit faults of an electric transmission line. The relay protection method comprises the following steps: a voltage drop from an electric transmission line protection mounting part to an interphase short circuit fault point and a voltage drop from an electric transmission line protection setting range to the interphase short circuit fault point are calculated by using fault interphase electrical capacity at the electric transmission line protection mounting part, and if the angle between the voltage drop from the electric transmission line protection mounting part to the interphase short circuit fault point and the voltage drop from the electric transmission line protection setting range to the interphase short circuit fault point ranges from 90 degrees to 270 degrees, an action tripping signal is given out by a protection device. The method solves the problem of the influence of transition resistance and load current on the protection action performance, and when interphase high-resistance short circuit faults occur to the electric transmission line, the method can act correctly and reliably, the action sensitivity is high, and the protection range is stable.

Description

Transmission line phase fault relay protecting method

Technical field

The present invention relates to the relay protection of power system technical field, specifically relate to a kind of 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, impedance distance protection tripping when then causing in the protection zone phase fault easily; If the additional impedance that transition resistance produces is capacitance-resistance, impedance distance protection action generation surmounts when then causing alternate short trouble easily the protection zone outside.

High/super/the extreme pressure transmission line of alternation current often also is the heavy load transmission line, and the heavy load electric current can make impedance distance protection malfunction or tripping, and the heavy load electric current can not be ignored the influence of impedance distance protection performance.Circuit normally moves under the overload transmission of electricity situation; the measurement impedance of tradition impedance distance protection is owing to be subjected to overload current affects meeting substantial deviation actual measurement impedance; cause the traditional distance protection misoperation easily; cause the grid power blackout expanded range; thereby even cause a large amount of transfer of load to threaten circuits normally to move, caused huge potential safety hazard to power grid security.

Summary of the invention

The objective of the invention is to overcome the deficiency that prior art exists, the transmission line phase fault relay protecting method that provides a kind of performance not influenced by transition resistance and load current.

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

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

The fault three-phase current

Alternate negative-sequence current with fault 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 ₁Be unit length 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 setting range 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 _SetBe the protection setting range;

(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 the would trip signal.

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

The inventive method is utilized the alternate electric parameters of the fault of line protection installation place to calculate the line protection installation place and is arrived the voltage drop of phase fault point and the voltage drop that line protection setting range place arrives phase fault point; be positioned at (90 ° 270 °) interval if the line protection installation place takes the lead line protection setting range place to the voltage drop of phase fault point to the angle of the voltage drop of phase fault point, then protective device sends the would trip signal.The inventive method has overcome transition resistance and load current to the problem that influences of protection performance, and the inventive method can correct action message when alternate high resistant short trouble took place transmission line, the action sensitivity height, and protection range is stable.

Description of drawings

Fig. 1 is for using circuit transmission system schematic diagram of the present invention.

Embodiment

According to Figure of description technical scheme of the present invention is done further detailed presentations below.

Fig. 1 is for using circuit transmission system schematic diagram of the present invention.PT is that voltage transformer, CT are current transformer among Fig. 1.Protective device is sampled to the current waveform of the voltage waveform summation current transformer CT of the voltage transformer pt of line protection installation place and is obtained voltage, current instantaneous value, and utilizes the fault voltage between phases of Fourier algorithm computing electric power line protection installation place

The fault three-phase current

Alternate negative-sequence current with fault

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 ₁Be unit length 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 setting range 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 _SetBe the protection setting range.

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 is judged

Whether set up, if set up, then protective device sends the would trip signal.

The inventive method has overcome transition resistance and load current to the problem that influences of protection performance, and the inventive method can correct action message when alternate high resistant short trouble took place transmission line, the action sensitivity height, and protection range is stable.

The above only is 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 variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.

Claims (1)

1. 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

The fault three-phase current

Alternate negative-sequence current with fault

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 ₁Be unit length 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 setting range place is to the voltage drop of phase fault point

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

Wherein, x _SetBe the protection setting range;

(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 the would trip signal.

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