CN103219714B - Based on the line interphase fault relay protection method of voltage drop phase characteristic - Google Patents

Abstract

The invention discloses a kind of line interphase fault relay protection method based on voltage drop phase characteristic.It utilizes the fault voltage between phases of line protection installation place, between fault three-phase current and fault phase, negative-sequence current calculates phase fault point respectively to the voltage drop at line protection setting range place and the voltage drop of unit length transmission line; then judge that phase fault point is positioned at (-90 ° 90 °) scope to the angle of the voltage drop leading unit length transmission line voltage drop at line protection setting range place and whether sets up; if set up, then protective device sends action trip signal.The inventive method considers the impact of phase fault point voltage in algorithm design; transmission line voltage drop phase characteristic along the line is utilized to achieve the relaying protection of electric transmission line phase fault; eliminate transition resistance and load current to the impact of Perfomance of protective relaying, be applicable to the relaying protection of the whole failure process of electric transmission line phase fault.<!--1-->

Description

Based on the line interphase fault relay protection method of voltage drop phase characteristic

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of line interphase fault relay protection method based on voltage drop phase characteristic.

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 line protection district; If the additional impedance that transition resistance produces be capacitance-resistance, then when easily causing phase fault outside line protection district, 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 fault-free; the measurement impedance of traditional 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 other transmission lines normally to run, bringing 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 line interphase fault relay protection method based on voltage drop phase characteristic that transition resistance and load current affect.

Based on the line interphase fault relay protection method of voltage drop phase characteristic, its main points are, comprise the steps:

(1) 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 to its voltage, current instantaneous value obtained of sampling , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase;

(2) protective device calculates the voltage drop of phase fault point to line protection setting range place :

$\mathrm{\&Delta;}\stackrel{\&CenterDot;}{U}=\frac{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}+z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}$

Wherein, for imaginary part; for imaginary part; z ₁for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range;

(3) protective device calculates the voltage drop of phase fault point to line protection setting range place the voltage drop of leading unit length transmission line angle , judge whether set up, if set up, then protective device sends action trip signal.

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

First the inventive method utilize the fault voltage between phases of line protection installation place, between fault three-phase current and fault phase, negative-sequence current calculates phase fault point respectively to the voltage drop at line protection setting range place and the voltage drop of unit length transmission line; then judge that phase fault point is positioned at (-90 ° 90 °) scope to the angle of the voltage drop leading unit length transmission line voltage drop at line protection setting range place and whether sets up; if set up, then protective device sends action trip signal.The inventive method considers the impact of phase fault point voltage in algorithm design; transmission line voltage drop phase characteristic along the line is utilized to achieve the relaying protection of electric transmission line phase fault; eliminate transition resistance and load current to the impact of Perfomance of protective relaying, be applicable to the relaying protection of the whole failure process of electric transmission line 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, 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 to its voltage, current instantaneous value obtained of sampling , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase.

Protective device calculates the voltage drop of phase fault point to line protection setting range place :

$\mathrm{\&Delta;}\stackrel{\&CenterDot;}{U}=\frac{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}+z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}$

Wherein, for imaginary part; for imaginary part; z ₁for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range.

The voltage drop of protective device unit of account length transmission line .

Protective device calculates the voltage drop of phase fault point to line protection setting range place the voltage drop of leading unit length transmission line angle .

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

First the inventive method utilize the fault voltage between phases of line protection installation place, between fault three-phase current and fault phase, negative-sequence current calculates phase fault point respectively to the voltage drop at line protection setting range place and the voltage drop of unit length transmission line; then judge that phase fault point is positioned at (-90 ° 90 °) scope to the angle of the voltage drop leading unit length transmission line voltage drop at line protection setting range place and whether sets up; if set up, then protective device sends action trip signal.The inventive method considers the impact of phase fault point voltage in algorithm design; transmission line voltage drop phase characteristic along the line is utilized to achieve the relaying protection of electric transmission line phase fault; eliminate transition resistance and load current to the impact of Perfomance of protective relaying, be applicable to the relaying protection of the whole failure process of electric transmission line 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 line interphase fault relay protection method of voltage drop phase characteristic, it is characterized in that, comprise the steps:

(1) 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 to its voltage, current instantaneous value obtained of sampling , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase;

(2) protective device calculates the voltage drop of phase fault point to line protection setting range place :

$\mathrm{\&Delta;}\stackrel{\&CenterDot;}{U}=\frac{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\mathrm{Im}\left[\frac{{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}}{z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}}\right]}{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{\&phi;\&phi;}}+z_1{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}$

Wherein, for imaginary part; for imaginary part; for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range;

(3) protective device calculates the voltage drop of phase fault point to line protection setting range place the voltage drop of leading unit length transmission line angle , judge whether set up, if set up, then protective device sends action trip signal.