CN103176102B - A kind of range finding yardstick minimum principle that utilizes realizes line single-phase earth fault single-terminal location method - Google Patents

Abstract

The invention discloses a kind of range finding yardstick minimum principle that utilizes and realize line single-phase earth fault single-terminal location method.First the faulted phase voltage of line protection installation place is measured , faulted phase current , fault phase negative-sequence current and zero-sequence current ; Then choosing fault distance initial value is l _x, successively increase with step delta l, successively the range finding yardstick e (l of every bit on computing electric power line _x) until transmission line of electricity total length, choose range finding yardstick e (l _x) minimum point is fault distance apart from the distance of line protection installation place.The inventive method adopts distribution parameter to describe the physical characteristics of transmission line of electricity voltage, current delivery, distance accuracy is not by the impact of transmission line of electricity ground capacitance, be applicable to any electric pressure transmission line one-phase earth fault single end distance measurement, be particularly useful for UHV (ultra-high voltage), UHV transmission line singlephase earth fault single end distance measurement.

Description

A kind of range finding yardstick minimum principle that utilizes realizes line single-phase earth fault single-terminal location method

Technical field

The present invention relates to electric system one-end fault ranging technical field, specifically relate to a kind of range finding yardstick minimum principle that utilizes and realize line single-phase earth fault single-terminal location method.

Background technology

Divide according to electric parameters source, fault distance-finding method is mainly divided into both-end distance measuring method and method of single end distance measurement.Both-end distance measuring method utilizes transmission line of electricity two ends electric parameters to carry out localization of fault, needs to obtain opposite end electric parameters by data transmission channel, strong to data transmission channel-independent, is also subject to the impact of both-end sampling value synchronization in actual use.Ultrahigh voltage alternating current transmission lines is long-distance transmission line often, and the data transmission channel laid needed for range finding needs additional investment substantial contribution, and therefore, method of single end distance measurement has more practicality than both-end distance measuring method.Method of single end distance measurement only utilizes transmission line of electricity one end electric parameters to carry out localization of fault, need not communication and data syn-chronization equipment, and the low and algorithmic stability of operating cost, obtains widespread use in high, normal, basic pressure transmission line.

At present, method of single end distance measurement is mainly divided into traveling wave method and impedance method.Traveling wave method utilizes the transmission character of fault transient travelling wave to carry out one-end fault ranging, and precision is high, does not affect by the method for operation, excessive resistance etc., but requires very high to sampling rate, and need special wave recording device, application cost is high.Impedance method utilizes the voltage after fault, the magnitude of current to calculate Fault loop impedance, one-end fault ranging is carried out according to the characteristic that line length is directly proportional to impedance, simple and reliable, but it is serious that distance accuracy is subject to the impact of the factor such as transition resistance and load current, especially when transition resistance is larger, finding range unsuccessfully, even appear in impedance method range measurement meeting substantial deviation true fault distance.Because UHV (ultra-high voltage), UHV transmission line exist larger capacitance current along the line, when UHV (ultra-high voltage), UHV transmission line occur in high resistant short trouble time, single-ended impedance method range measurement meeting substantial deviation true fault distance, can not meet on-the-spot application requirement.Therefore, the single-ended impedance method of lumped parameter modeling is adopted can not to directly apply to the one-end fault ranging of UHV (ultra-high voltage), UHV transmission line.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, and provide a kind of and overcome transition resistance and load current to the impact of distance accuracy, distance accuracy is high, range measurement principle is simple, and practical one utilizes range finding yardstick minimum principle to realize line single-phase earth fault single-terminal location method.

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

(1) faulted phase voltage of protector measuring line protection installation place , faulted phase current , fault phase negative-sequence current and zero-sequence current ; Wherein, φ=A phase, B phase, C phase.

(2) fault distance initial value is taken as l _x, calculate apart from line protection installation place l _xthe range finding yardstick e (l of point _x):

$e\left(l_x\right)=\left|\right|Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_x\right)|-|\frac{{\stackrel{.}{U}}_{\mathrm{\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ}}+\left(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right){\stackrel{.}{I}}_0}\frac{\sin \mathrm{\β}}{\sin (\mathrm{\α}+\mathrm{\γ})}\left|\right|$

Wherein, φ=A phase, B phase, C phase; for faulted phase voltage; for faulted phase current; for fault phase negative-sequence current; for zero-sequence current; l _setfor protection seting scope; Z ₀for the system zero sequence equivalent impedance of line protection installation place; γ ₁, γ ₀be respectively electric transmission line positive sequence, zero sequence propagation coefficient; Z _c1, Z _c0be respectively electric transmission line positive sequence, zero sequence wave impedance; α=Arg (Z _c1(γ ₁l _set)); ; $\mathrm{\γ}=\mathrm{Arg}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0}{{\stackrel{.}{I}}_{\mathrm{\φ}2}}\right)$ ; Th (.) is hyperbolic tangent function; Ch (.) is hyperbolic cosine function; Sh (.) is hyperbolic sine function.

(3) fault distance successively increases with step delta l, returns step (2), successively the range finding yardstick e (l of every bit on computing electric power line _x) until transmission line of electricity total length, choose range finding yardstick e (l _x) minimum point is fault distance apart from the distance of line protection installation place.

In sum, the present invention compared to existing technology tool have the following advantages:

The inventive method adopts distribution parameter to describe the physical characteristics of transmission line of electricity voltage, current delivery, distance accuracy is not by the impact of transmission line of electricity ground capacitance, be applicable to any electric pressure transmission line one-phase earth fault single end distance measurement, be particularly useful for UHV (ultra-high voltage), UHV transmission line singlephase earth fault single end distance measurement.The inventive method range finding yardstick minimum principle corresponding according to trouble spot carries out transmission line one-phase earth fault single end distance measurement, and overcome transition resistance and load current to the impact of distance accuracy, distance accuracy is high, and range measurement principle is simple, practical.

Accompanying drawing explanation

Fig. 1 is the transmission line one-phase earth fault schematic diagram of application the inventive method;

Fig. 2 is the transmission line one-phase earth fault electric vector graph of a relation of application the inventive method.

Embodiment

Below in conjunction with embodiment, technical scheme of the present invention is expressed in further detail.

In Fig. 1, TV is voltage transformer (VT), TA is current transformer.After transmission line of electricity generation singlephase earth fault, the faulted phase voltage of protector measuring line protection installation place , faulted phase current , fault phase negative-sequence current and zero-sequence current ; Wherein, φ=A phase, B phase, C phase.

Transmission line of electricity occurs single-phase through resistance R _gearth fault, earth fault point voltage , earth fault branch current , because resistive ground fault, have at earth fault branch road , thus meet .

Have at earth fault branch road with , thus have .Wherein, , , be respectively the forward-order current, negative-sequence current, the zero-sequence current that flow through earth fault branch road.

Due to the fault phase negative-sequence current of line protection installation place with the negative-sequence current of earth fault branch road same-phase, therefore can obtain $\mathrm{Arg}\left({\stackrel{.}{I}}_{\mathrm{\φ}2}\right)=\mathrm{Arg}\left({\stackrel{.}{U}}_{\mathrm{\φf}}\right)$ 。

Distributed parameter model is utilized to describe the faulted phase voltage of line protection installation place , faulted phase current , zero-sequence current with earth fault point voltage relation such as formula described in (1).

${\stackrel{.}{U}}_{\mathrm{\φ}}=\frac{{\stackrel{.}{U}}_{\mathrm{\φf}}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_f\right)}+Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)[{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_f\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_f\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_f\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_f\right)}-1){\stackrel{.}{I}}_0]---\left(1\right)$

Wherein, φ=A phase or B phase or C phase; l _ffor transmission line one-phase earth fault point is to the fault distance of protection installation place; for earth fault point voltage; γ ₁for electric transmission line positive sequence propagation coefficient: , R ₁, L ₁, G ₁, C ₁be respectively the positive sequence resistance of unit length transmission line of electricity, inductance, conductance and capacitance;

γ ₀for power transmission line zero-sequence propagation coefficient: , R ₀, L ₀, G ₀, C ₀be respectively the zero sequence resistance of unit length transmission line of electricity, inductance, conductance and capacitance;

Z _c1for electric transmission line positive sequence wave impedance: ;

Z _c0for power transmission line zero-sequence wave impedance: ;

ω is the specified angular frequency value of electric system;

Z ₀for the system zero sequence equivalent impedance of line protection installation place;

Th (.) is hyperbolic tangent function; Ch (.) is hyperbolic cosine function; Sh (.) is hyperbolic sine function.

Due to the zero sequence current compensation factor of Single-phase Ground Connection Failure with protection seting scope l _setthe zero sequence current compensation factor at place approximately equal, formula (1) can be equivalent to formula (2).

${\stackrel{.}{U}}_{\mathrm{\φ}}=\frac{{\stackrel{.}{U}}_{\mathrm{\φf}}}{\mathrm{ch}\left({\mathrm{\γ}}_1{l}_f\right)}+Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)[{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0]---\left(2\right)$

Wherein, l _setfor protection seting scope.

Fig. 2 is the transmission line one-phase earth fault electric vector graph of a relation of application the inventive method.As shown in Figure 2, by , with in the vector correlation triangle formed, obtain formula (3) relation according to triangle edges angular dependence.

$|-Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)[{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0\left]\right|=\left|\frac{{\stackrel{.}{U}}_{\mathrm{\φ}}\sin \mathrm{\β}}{\sin (\mathrm{\α}+\mathrm{\γ})}\right|---\left(3\right)$

Wherein, φ=A phase or B phase or C phase;

L _setfor protection seting scope;

α is Z _c1th (γ ₁l _set) angle, α=Arg (Z _c1th (γ ₁l _set));

Z ₀for the system zero sequence equivalent impedance of line protection installation place;

β is leading angle, ;

γ is leading angle,

$\mathrm{\γ}=\mathrm{Arg}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0}{{\stackrel{.}{I}}_{\mathrm{\φ}2}}\right)$ 。

Due to $|-Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)[{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0\left]\right|=$ $|Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)|\×|{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0|$ , therefore obtain the fault impedance amplitude of transmission line one-phase earth fault | Z _c1th (γ ₁l _f) | calculating formula (4).

$\left|Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_f\right)\right|=\left|\frac{{\stackrel{.}{U}}_{\mathrm{\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ}}+\left(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right){\stackrel{.}{I}}_0}\frac{\sin \mathrm{\β}}{\sin (\mathrm{\α}+\mathrm{\γ})}\right|---\left(4\right)$

So fault distance initial value is taken as l _x, calculate apart from line protection installation place l _xthe range finding yardstick e (l of point _x):

$e\left(l_x\right)=\left|\right|Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_x\right)|-|\frac{{\stackrel{.}{U}}_{\mathrm{\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ}}+\left(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right){\stackrel{.}{I}}_0}\frac{\sin \mathrm{\β}}{\sin (\mathrm{\α}+\mathrm{\γ})}\left|\right|---\left(5\right)$

Fault distance successively increases with step delta l, recycles formula (5) the range finding yardstick e (l of every bit on computing electric power line successively _x) until transmission line of electricity total length, choose range finding yardstick e (l _x) minimum point is fault distance apart from the distance of line protection installation place.

The inventive method adopts distribution parameter to describe the physical characteristics of transmission line of electricity voltage, current delivery, distance accuracy is not by the impact of transmission line of electricity ground capacitance, be applicable to any electric pressure transmission line one-phase earth fault single end distance measurement, be particularly useful for UHV (ultra-high voltage), UHV transmission line singlephase earth fault single end distance measurement.The inventive method range finding yardstick minimum principle corresponding according to trouble spot carries out transmission line one-phase earth fault single end distance measurement, and overcome transition resistance and load current to the impact of distance accuracy, distance accuracy is high, and range measurement principle is simple, practical.

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. utilize range finding yardstick minimum principle to realize a line single-phase earth fault single-terminal location method, it is characterized in that: comprise the following steps:

(1) faulted phase voltage of protector measuring line protection installation place , faulted phase current , fault phase negative-sequence current and zero-sequence current ; Wherein, φ=A phase, B phase, C phase,

(2) fault distance initial value is taken as l _x, calculate apart from line protection installation place l _xthe range finding yardstick e (l of point _x):

$e\left(l_x\right)=\left|\right|Z_{c1}\mathrm{th}\left({\mathrm{\γ}}_1{l}_x\right)|-|\frac{{\stackrel{.}{U}}_{\mathrm{\φ}}}{{\stackrel{.}{I}}_{\mathrm{\φ}}+\left(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}\right){\stackrel{.}{I}}_0}\frac{\sin \mathrm{\β}}{\sin (\mathrm{\α}+\mathrm{\γ})}\left|\right|$

Wherein, φ=A phase, B phase, C phase; for faulted phase voltage; for faulted phase current; for fault phase negative-sequence current; for zero-sequence current; l _setfor protection seting scope; Z ₀for the system zero sequence equivalent impedance of line protection installation place; γ ₁, γ ₀be respectively electric transmission line positive sequence, zero sequence propagation coefficient; Z _c1, Z _c0be respectively electric transmission line positive sequence, zero sequence wave impedance; α=Arg (Z _c1th (γ ₁l _set)); ; $\mathrm{\γ}=\mathrm{Arg}\left(\frac{{\stackrel{.}{I}}_{\mathrm{\φ}}+(\frac{Z_0\mathrm{ch}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)+Z_{c0}\mathrm{sh}\left({\mathrm{\γ}}_0{l}_{\mathrm{set}}\right)-Z_0\mathrm{ch}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}{Z_{c1}\mathrm{sh}\left({\mathrm{\γ}}_1{l}_{\mathrm{set}}\right)}-1){\stackrel{.}{I}}_0}{{\stackrel{.}{I}}_{\mathrm{\φ}2}}\right)$ ; Th (.) is hyperbolic tangent function; Ch (.) is hyperbolic cosine function; Sh (.) is hyperbolic sine function,

(3) fault distance successively increases with step delta l, returns step (2), successively the range finding yardstick e (l of every bit on computing electric power line _x) until transmission line of electricity total length, choose range finding yardstick e (l _x) minimum point is fault distance apart from the distance of line protection installation place.