CN103293442A - Line single-phase earth fault single-terminal location method implemented by aid of zero-sequence voltage distribution characteristics - Google Patents

Abstract

The invention discloses a line single-phase earth fault single-terminal location method implemented by the aid of zero-sequence voltage distribution characteristics. The line single-phase earth fault single-terminal location method includes sequentially computing an absolute value of the difference between an amplitude value of an equivalent zero-sequence voltage of each point on a power transmission line and an amplitude value of a zero-sequence voltage of the point by the aid of a one-dimensional search process and a zero-sequence voltage, a zero-sequence current, fault-phase negative-sequence voltages and fault-phase negative-sequence currents at a power transmission line protection mounting position until computation is performed on all points in the total length of the power transmission line; selecting the distance from the power transmission line protection mounting position to the point corresponding to the minimum absolute value of the difference between the amplitude value of the equivalent zero-sequence voltage of the point and the amplitude value of the zero-sequence voltage of the point as the fault distance. The line single-phase earth fault single-terminal location method has the advantages that power transmission line single-phase earth fault single-terminal location is implemented by the aid of the distribution characteristics of the zero-sequence voltages along the power transmission line, influence of transition resistance, fault positions and load currents on the location precision is eliminated in principle, and the location precision is high.

Description

Utilize the residual voltage distribution character to realize the line single phase grounding failure method of single end distance measurement

Technical field

The present invention relates to the relay protection of power system technical field, specifically relate to a kind of residual voltage distribution character that utilizes and realize the line single phase grounding failure method of single end distance measurement.

Background technology

The transmission line of electricity one-end fault ranging method mainly is divided into traveling wave method and impedance method.Traveling wave method utilizes the transmission character of fault transient travelling wave to find range, and the precision height is not influenced by system operation mode, excessive resistance etc., but very high to the sampling rate requirement, needs special wave recording device, obtains substantive application at present.The impedance that impedance method utilizes voltage after the fault, the magnitude of current to calculate fault loop is found range according to the characteristic that line length is directly proportional with impedance, and is simple and reliable, but is subjected to the influence of the factors such as transition resistance, the incomplete symmetry of circuit of fault.Have bigger capacitance current because ultra-high-tension power transmission line is along the line, during the high resistant short trouble, single-ended impedance method range finding result understands substantial deviation true fault distance, can not satisfy on-the-spot application requirements in ultra-high-tension power transmission line takes place.Therefore, the single-ended impedance method of employing lumped parameter modeling can not directly apply to the fault localization of ultra-high-tension power transmission line.

Adopt distributed parameter model research ultra-high-tension power transmission line one-end fault ranging to cause numerous scholars' concern gradually.Breathe out " discussion of ultra-high-tension power transmission line single end distance measurement new principle " that the permanent rising sun, Zhang Baohui, Lv Zhi the people such as come to deliver and adopt the distribution parameter modeling, utilize the single ended voltage electric current to calculate the adjust the distance norm distribution on the line of derivative of voltage along the line and carry out the location of trouble spot.This method has related to a large amount of derivative operation and integral operation, and required operand is big, complicated difficult realization of algorithm." based on the ratio phase formula single-phase fault single end distance measurement algorithm of distributed parameter model " that people such as Lin Xiangning, yellow small echo delivers adopts the distribution parameter modeling, carries out localization of fault according to residual voltage and the fault current same-phase feature at place, trouble spot.This method has been improved distributed capacitance to single-ended impedance method affection of fault location, but range error reaches-2.38% when high resistance earthing fault, and Error Absolute Value can not satisfy on-the-spot application requirements greater than 1.5%." the extra-high voltage long transmission line single-ended impedance method single-phase ground fault distance measuring " that people such as king guest, Dong Xinzhou delivers adopts the distribution parameter modeling, utilize the phase angle of the phase angle estimation fault point voltage of observation station place negative-sequence current, calculate the measurement impedance constantly at fault point voltage instantaneous value zero crossing then.This method is when the medium or low resistance short trouble, because voltage along the line descends obviously, the error of utilizing observation station place negative-sequence current phase angle estimation fault point voltage phase angle to exist influences not quite the range finding result; But when the high resistant short trouble, because circuit each point voltage phase difference along the line is very little, the error of utilizing observation station place negative-sequence current phase angle estimation fault point voltage phase angle to exist adds the influence of transient state process, and this method range error is bigger.

Summary of the invention

The objective of the invention is to overcome the deficiency that prior art exists, the residual voltage distribution character that utilizes that provides a kind of distance accuracy not influenced by capacitance current, transition resistance, abort situation and load current is realized the line single phase grounding failure method of single end distance measurement.

Utilize the residual voltage distribution character to realize the line single phase grounding failure method of single end distance measurement, it is characterized in that, comprise following sequential steps:

(1) the fault phase negative sequence voltage of protector measuring line protection installation place

, fault phase negative-sequence current

, residual voltage

And zero-sequence current

Wherein, φ=A phase, B phase, C phase;

(2) to choose the fault distance initial value be l to protective device _x, calculate apart from line protection installation place l _xThe equivalent residual voltage of point

:

${\stackrel{\·}{U}}_0^{\′}=Z_{c0}\tanh \left({\mathrm{\γ}}_0{l}_x\right)\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}2}\cosh \left({\mathrm{\γ}}_1{l}_x\right)-{\stackrel{\·}{I}}_{\mathrm{\φ}2}{Z}_{c1}\sinh \left({\mathrm{\γ}}_1{l}_x\right)}{Z_{c1}\tanh \left({\mathrm{\γ}}_1{l}_x\right)}$

Wherein, φ=A phase, B phase, C phase; γ ₁Be transmission line of electricity positive sequence propagation constant; γ ₀Be transmission line of electricity zero sequence propagation constant; Z _C1Be transmission line of electricity positive sequence wave impedance; Z _C0Be transmission line of electricity zero sequence wave impedance; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function; Tanh (.) is hyperbolic tangent function;

(3) protective device calculates apart from line protection installation place l _xThe residual voltage of point

:

${\stackrel{\·}{U}}_0\left(l_x\right)={\stackrel{\·}{U}}_0\cosh \left({\mathrm{\γ}}_0{l}_x\right)-{\stackrel{\·}{I}}_0{Z}_{c0}\sinh \left({\mathrm{\γ}}_0{l}_x\right)$

(4) protective device calculates apart from line protection installation place l _xThe equivalent residual voltage of point Amplitude

With distance line protection installation place l _xThe residual voltage of point

Amplitude The absolute value of difference

(5) fault distance increases one by one with step delta l, returns step (2), successively the equivalent residual voltage of every bit on the computing electric power line Amplitude

With residual voltage

Amplitude

The absolute value of difference

Until the transmission line of electricity total length, choose on the transmission line of electricity

The point of minimum correspondence is fault distance apart from the distance of line protection installation place.

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

The inventive method adopts the linear search method; residual voltage, zero-sequence current and the fault of utilizing the line protection installation place be negative sequence voltage, the fault phase negative-sequence current absolute value of the difference of the amplitude of the amplitude of the equivalent residual voltage of every bit and residual voltage on the computing electric power line successively mutually; until the transmission line of electricity total length, the minimum corresponding point of the amplitude of choosing equivalent residual voltage and the absolute value of the difference of the amplitude of residual voltage is fault distance apart from the distance of line protection installation place.The inventive method physical model adopts distributed parameter model, has the ability of natural anti-capacitance current influence, is applicable to UHV (ultra-high voltage), UHV transmission line.The inventive method utilizes transmission line of electricity residual voltage distribution character along the line to realize the single end distance measurement of transmission line one-phase earth fault, has eliminated the influence to distance accuracy of transition resistance, abort situation and load current on the principle, has very high distance accuracy.The inventive method is a kind of distance-finding method of search type, does not have the pseudo-root problem of the method for solving equation and the not convergence problem of process of iteration, and range measurement principle is simple, and is practical.

Description of drawings

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

Embodiment

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

Fig. 1 is for using circuit transmission system synoptic diagram of the present invention.CVT is that voltage transformer (VT), CT are current transformer among Fig. 1.Protective device is sampled to the current waveform of the voltage and current mutual inductor CT of the voltage transformer (VT) CVT of line protection installation place and is obtained voltage, current instantaneous value, and protective device utilizes the fault phase negative sequence voltage of Fourier algorithm computing electric power line protection installation place to its voltage that collects, current instantaneous value then , fault phase negative-sequence current

, residual voltage

And zero-sequence current

Wherein, φ=A phase, B phase, C phase.

It is l that protective device is chosen the fault distance initial value _x, calculate apart from line protection installation place l _xThe equivalent residual voltage of point

:

${\stackrel{\·}{U}}_0^{\′}=Z_{c0}\tanh \left({\mathrm{\γ}}_0{l}_x\right)\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}2}\cosh \left({\mathrm{\γ}}_1{l}_x\right)-{\stackrel{\·}{I}}_{\mathrm{\φ}2}{Z}_{c1}\sinh \left({\mathrm{\γ}}_1{l}_x\right)}{Z_{c1}\tanh \left({\mathrm{\γ}}_1{l}_x\right)}---\left(1\right)$

Wherein, φ=A phase, B phase, C phase; γ ₁Be transmission line of electricity positive sequence propagation constant; γ ₀Be transmission line of electricity zero sequence propagation constant; Z _C1Be transmission line of electricity positive sequence wave impedance; Z _C0Be transmission line of electricity zero sequence wave impedance; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function; Tanh (.) is hyperbolic tangent function.

Protective device calculates apart from line protection installation place l _xThe residual voltage of point

:

${\stackrel{\·}{U}}_0\left(l_x\right)={\stackrel{\·}{U}}_0\cosh \left({\mathrm{\γ}}_0{l}_x\right)-{\stackrel{\·}{I}}_0{Z}_{c0}\sinh \left({\mathrm{\γ}}_0{l}_x\right)---\left(2\right)$

Protective device calculates apart from line protection installation place l _xThe equivalent residual voltage of point

Amplitude

With distance line protection installation place l _xThe residual voltage of point Amplitude

The absolute value of difference

Fault distance increases one by one with step delta l, recycles formula (1) and formula (2), successively the equivalent residual voltage of every bit on the computing electric power line Amplitude

With residual voltage

Amplitude

The absolute value of difference

Until the transmission line of electricity total length, choose on the transmission line of electricity

The point of minimum correspondence is fault distance apart from the distance of line protection installation place.

The inventive method adopts the linear search method; residual voltage, zero-sequence current and the fault of utilizing the line protection installation place be negative sequence voltage, the fault phase negative-sequence current absolute value of the difference of the amplitude of the amplitude of the equivalent residual voltage of every bit and residual voltage on the computing electric power line successively mutually; until the transmission line of electricity total length, the minimum corresponding point of the amplitude of choosing equivalent residual voltage and the absolute value of the difference of the amplitude of residual voltage is fault distance apart from the distance of line protection installation place.The inventive method physical model adopts distributed parameter model, has the ability of natural anti-capacitance current influence, is applicable to UHV (ultra-high voltage), UHV transmission line.The inventive method utilizes transmission line of electricity residual voltage distribution character along the line to realize the single end distance measurement of transmission line one-phase earth fault, has eliminated the influence to distance accuracy of transition resistance, abort situation and load current on the principle, has very high distance accuracy.The inventive method is a kind of distance-finding method of search type, does not have the pseudo-root problem of the method for solving equation and the not convergence problem of process of iteration, and range measurement principle is simple, and is practical.

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. utilize the residual voltage distribution character to realize the line single phase grounding failure method of single end distance measurement, it is characterized in that, comprise following sequential steps:

(1) the fault phase negative sequence voltage of protector measuring line protection installation place

, fault phase negative-sequence current , residual voltage

And zero-sequence current Wherein, φ=A phase, B phase, C phase;

(2) to choose the fault distance initial value be l to protective device _x, calculate apart from line protection installation place l _xThe equivalent residual voltage of point

:

${\stackrel{\·}{U}}_0^{\′}=Z_{c0}\tanh \left({\mathrm{\γ}}_0{l}_x\right)\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}2}\cosh \left({\mathrm{\γ}}_1{l}_x\right)-{\stackrel{\·}{I}}_{\mathrm{\φ}2}{Z}_{c1}\sinh \left({\mathrm{\γ}}_1{l}_x\right)}{Z_{c1}\tanh \left({\mathrm{\γ}}_1{l}_x\right)}$

Wherein, φ=A phase, B phase, C phase; γ ₁Be transmission line of electricity positive sequence propagation constant; γ ₀Be transmission line of electricity zero sequence propagation constant; Z _C1Be transmission line of electricity positive sequence wave impedance; Z _C0Be transmission line of electricity zero sequence wave impedance; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function; Tanh (.) is hyperbolic tangent function;

(3) protective device calculates apart from line protection installation place l _xThe residual voltage of point

:

${\stackrel{\·}{U}}_0\left(l_x\right)={\stackrel{\·}{U}}_0\cosh \left({\mathrm{\γ}}_0{l}_x\right)-{\stackrel{\·}{I}}_0{Z}_{c0}\sinh \left({\mathrm{\γ}}_0{l}_x\right)$

(4) protective device calculates apart from line protection installation place l _xThe equivalent residual voltage of point

Amplitude With distance line protection installation place l _xThe residual voltage of point Amplitude

The absolute value of difference

(5) fault distance increases one by one with step delta l, returns step (2), successively the equivalent residual voltage of every bit on the computing electric power line Amplitude With residual voltage

Amplitude The absolute value of difference Until the transmission line of electricity total length, choose on the transmission line of electricity

The point of minimum correspondence is fault distance apart from the distance of line protection installation place.

Images