CN103187719A - Electric transmission line interphase fault full-component voltage protection method - Google Patents

Abstract

The invention discloses an electric transmission line interphase fault full-component voltage protection method. The method realizes electric transmission line interphase short circuit fault full-component voltage protection by utilizing the along-the-line voltage drop distribution characteristic, eliminates the influence of the operating method of the system, transition resistance and load current on the protection action performance, and is suitable for protecting the whole fault process of the electric transmission line interphase fault, wherein the along-the-line voltage drop distribution characteristic is as follows: when the fault occurs in a protection area, the along-the-line voltage drop amplitude from a protection mounting position to an interphase short circuit fault point is less than the voltage drop amplitude from the protection mounting position to a protection setting range; and when the fault occurs outside the protection area, the along-the-line voltage drop amplitude from a protection mounting position to the interphase short circuit fault point is more than the voltage drop amplitude from the protection mounting position to the protection setting range.

Description

The full component voltage guard method of a kind of transmission line phase-to phase fault

Technical field

The present invention relates to the relay protection of power system technical field, specifically relate to the full component voltage guard method of a kind of transmission line phase-to phase fault.

Background technology

Transmission line distance protecting is according to adopting the electric parameters difference can be divided into based on the circuit distance protection of sudden change amount with based on circuit distance protection two classes of full component.It is strong to be subjected to system operation mode to influence little and anti-transition resistance ability based on the circuit distance protection of sudden change amount; this type of protection performance reliability height; but because electric sudden change amount only exists in two cycles after fault; the relaying protection effect can't be played based on the circuit distance protection of the sudden change amount line fault after for two cycles, the protection of the whole failure process of circuit can't be applicable to.Though based on the circuit distance protection of the full component protection applicable to the whole failure process of circuit, because the autoprotection algorithm is subjected to the influence of transition resistance serious, protection tripping or malfunction take place easily when high resistance earthing fault, the protection reliability is not high.

Summary of the invention

The objective of the invention is to overcome the deficiency that prior art exists, provide a kind of transmission line phase-to phase fault full component voltage guard method.

The full component voltage guard method of a kind of transmission line phase-to phase fault, its step is as follows:

(1) the fault phase voltage between phases of measurement line protection installation place

, fault phase three-phase current

With the normal phase negative-sequence current

Wherein, φ φ=AB, BC, CA phase,

=C, A, B phase.

(2) computing electric power line protection installation place is to the voltage drop of phase fault point

Real part

And imaginary part

:

$\mathrm{Re}\left(\mathrm{\Δ}{\stackrel{.}{U}}_f\right)=\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\cos \mathrm{\β}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\sin \mathrm{\β}}\cos \mathrm{\β}$

$\mathrm{Im}\left(\mathrm{\Δ}{\stackrel{.}{U}}_f\right)=\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\cos \mathrm{\β}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\sin \mathrm{\β}}\sin \mathrm{\β}$

Wherein,

Be fault phase voltage between phases;

Be fault phase three-phase current;

Be the normal phase negative-sequence current; φ φ=AB, BC, CA phase;

=C, A, B phase; β is the normal phase negative-sequence current

Through being rotated counterclockwise the phase angle after 90 °; z ₁Be unit length transmission line positive sequence.

(3) relatively protect criterion

Whether set up, if set up, then protection action, wherein; x _SetBe the protection setting range.

In sum, the present invention has following advantage compared to existing technology:

When the inventive method utilization voltage landing along the line distribution character was the protection zone internal fault, amplitude was landed less than the voltage landing amplitude of protection installation place to protection setting range place to the voltage along the line of phase fault point in the protection installation place; During the protection external area error; the voltage landing amplitude at protection setting range place is arrived in the protection installation place greater than the protection installation place to the voltage landing amplitude along the line of phase fault point; realized the full component voltage protection of transmission line phase fault; eliminate the influence to the protection performance of system operation mode, transition resistance and load current, be applicable to the protection of the whole failure process of transmission line phase-to phase fault.

Description of drawings

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

Embodiment

Below in conjunction with Figure of description technical scheme of the present invention is done further detailed presentations.

CVT is that capacitance type potential transformer, CT are current transformer among Fig. 1.The fault phase voltage between phases of protector measuring line protection installation place

, fault phase three-phase current

With the normal phase negative-sequence current

Wherein, φ φ=AB, BC, CA phase,

=C, A, B phase.

Computing electric power line protection installation place is to the voltage drop real part of phase fault point

And imaginary part

:

$\mathrm{Re}\left(\mathrm{\Δ}{\stackrel{.}{U}}_f\right)=\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\cos \mathrm{\β}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\sin \mathrm{\β}}\cos \mathrm{\β}$

$\mathrm{Im}\left(\mathrm{\Δ}{\stackrel{.}{U}}_f\right)=\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\φ\φ}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\cos \mathrm{\β}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\φ\φ}}\right)\sin \mathrm{\β}}\sin \mathrm{\β}$

Wherein, β is the normal phase negative-sequence current

Through being rotated counterclockwise the phase angle after 90 °; Be fault phase voltage between phases

Real part; Be fault phase voltage between phases

Imaginary part;

For

Imaginary part; For

Real part.

Voltage landing characteristic distributions along the line behind the transmission line generation phase fault: during the internal fault of protection zone, amplitude is landed less than the voltage landing amplitude of protection installation place to protection setting range place to the voltage along the line of phase fault point in the protection installation place; During the protection external area error, amplitude is landed greater than the voltage landing amplitude of protection installation place to protection setting range place to the voltage along the line of phase fault point in the protection installation place.

Therefore, it is as follows to obtain the protection criterion of the inventive method:

$\sqrt{{\left[\mathrm{Re}\left(\mathrm{\&Delta;}{\stackrel{.}{U}}_f\right)\right]}^2+{\left[\mathrm{Im}\left(\mathrm{\&Delta;}{\stackrel{.}{U}}_f\right)\right]}^2}<\left|x_{\mathrm{set}}{z}_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right|$

If

Set up then protection action.Wherein, z ₁Be unit length transmission line positive sequence impedance.

(when being the protection zone internal fault, amplitude is landed less than the voltage landing amplitude of protection installation place to protection setting range place to the voltage along the line of phase fault point in the protection installation place to the inventive method utilization voltage landing along the line distribution character; During the protection external area error; amplitude is landed greater than the voltage landing amplitude of protection installation place to protection setting range place to the voltage along the line of phase fault point in the protection installation place) the full component voltage protection of realization transmission line phase-to phase fault; eliminate the influence to the protection performance of system operation mode, transition resistance and load current, be applicable to the protection of the whole failure process of transmission line phase-to phase fault.

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. full component voltage guard method of transmission line phase-to phase fault, its step is as follows:

(1) the fault phase voltage between phases of measurement line protection installation place

, fault phase three-phase current

With the normal phase negative-sequence current

Wherein, φ φ=AB, BC, CA phase, =C, A, B phase,

(2) computing electric power line protection installation place is to the voltage drop of phase fault point

Real part

And imaginary part

:

$\mathrm{Re}\left(\mathrm{\&Delta;}{\stackrel{.}{U}}_f\right)=\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)\cos \mathrm{\&beta;}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)\sin \mathrm{\&beta;}}\cos \mathrm{\&beta;}$

$\mathrm{Im}\left(\mathrm{\&Delta;}{\stackrel{.}{U}}_f\right)=\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)-\frac{\mathrm{Re}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)-\mathrm{Im}\left({\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}\right)\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)}{\mathrm{Im}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)\cos \mathrm{\&beta;}-\mathrm{Re}\left(z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\right)\sin \mathrm{\&beta;}}\sin \mathrm{\&beta;}$

Wherein,

Be fault phase voltage between phases;

Be fault phase three-phase current;

Be the normal phase negative-sequence current; φ φ=AB, BC, CA phase; =C, A, B phase; β is the normal phase negative-sequence current

Through being rotated counterclockwise the phase angle after 90 °; z ₁Be unit length transmission line positive sequence,

(3) relatively protect criterion

Whether set up, if set up, then protection action, wherein; x _SetBe the protection setting range.

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