CN104049181A - Double-circuit line non-synonymous cross-line grounding fault discrimination method - Google Patents

Abstract

The invention discloses a double-circuit line non-synonymous cross-line grounding fault discrimination method. The method comprises the steps of calculating the phase angle of a fault phase voltage ahead of an injection non-synonymous cross-line grounding fault point zero-sequence current at the circuit-I line protection installation position of double-circuit lines on the same tower and a fault phase voltage at the circuit-I line protection setting range of the double-circuit lines on the same tower though calculation of a zero-sequence compensation current of the circuit-I line of the double-circuit lines on the same tower, and achieving accurate discrimination of double-circuit line non-synonymous cross-line grounding faults by utilizing the vector phase characteristic that the phase angle of the fault phase voltage at the circuit-I line protection setting range of the double-circuit lines on the same tower lagging behind the fault phase voltage at the circuit-I line protection installation position of the double-circuit lines on the same tower is larger than the phase angle of fault phase voltage at the circuit-I line protection installation position of the double-circuit lines on the same tower ahead of the injection non-synonymous cross-line grounding fault point zero-sequence current when non-synonymous cross-line grounding fault points are located within the circuit-I line protection setting range of the double-circuit lines on the same tower.

Description

The non-same famous prime minister's cross-line earth fault method of discrimination of a kind of double-circuit line

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to the non-same famous prime minister's cross-line earth fault method of discrimination of a kind of double-circuit line based on vector phase comparison.

Background technology

Analyses for double circuits on same tower has that floor area is few, cost is low, connects operation of power networks reliable and stable, has become a kind of common transmission line of electricity connected mode of electric system.Between analyses for double circuits on same tower line, there is zero-sequence mutual inductance; zero-sequence mutual inductance exerts an influence to zero sequence compensation coefficient; and then generation additional impedance; the additional impedance causing because of zero-sequence mutual inductance can cause protector measuring to fault impedance be greater than physical fault impedance; cause in analyses for double circuits on same tower protected location while there is earth fault near protection setting range place; there is misoperation in protection, unfavorable to power network safety operation.

Even if analyses for double circuits on same tower occurs through the direct earth fault of shaft tower, at the lower regional transition resistance of soil resistivity also near 10 Ω; The local transition resistance higher in resistivity can reach 30 Ω, or even higher.Transition resistance is non-vanishing makes fault impedance that protective device calculates except the fault impedance component that comprises reaction true fault distance, has also comprised the additional impedance producing because of transition resistance.The additional impedance that transition resistance produces is resistance sense or is capacitance-resistance and easily causes impedance ground distance protection tripping or steady-state.Protection malfunction or tripping, can bring great loss to safe operation of power system, even likely can threaten the stability of electric system.

Acting characteristic round edge circle of existing analyses for double circuits on same tower ground distance protection is through true origin; because true origin is positioned on acting characteristic round edge circle; when protection forward outlet earth fault there is dead band in protection; and along with transition resistance and load current increase, protection forward outlet dead band is larger.Because true origin is positioned on acting characteristic round edge circle, protection in the other direction exports earth fault and exists possibility of malfunction, and transition resistance is larger, protects easier misoperation when protection exports earth fault in the other direction.

Owing to there being very strong zero-sequence mutual inductance between analyses for double circuits on same tower line; existing ground distance protection cannot obtain the zero-sequence current on another loop line road; in algorithm model, cannot eliminate the impact of zero-sequence mutual inductance between line; be subject to the impact of zero-sequence mutual inductance between line; when tradition ground distance protection is applied to analyses for double circuits on same tower, its protection domain will expand greatly; at protection setting range place usually there is steady-state in fault; while making to protect external area error, easily there is misoperation; easily cause the large transfer of trend, cause large area blackout and occur.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists, provide a kind of double-circuit line based on vector phase comparison non-same famous prime minister's cross-line earth fault method of discrimination, the method is taken into account the impact of zero-sequence mutual inductance between line, while utilizing non-same famous prime minister's cross-line earth fault to be positioned at analyses for double circuits on same tower I to return within route protection setting range, analyses for double circuits on same tower I returns this vector phase characteristic of phase angle that phase angle that the fault phase voltage delay analyses for double circuits on same tower I of route protection setting range place returns route protection installation place fault phase voltage is greater than analyses for double circuits on same tower I and returns the non-same famous prime minister's cross-line earth fault zero-sequence current of the route protection installation place leading injection of fault phase voltage, realize the accurate differentiation of the non-same famous prime minister's cross-line earth fault of double-circuit line, differentiate result and be not subject to zero-sequence mutual inductance between line, transition resistance, the impact of the factor such as load current and power system operation mode, be applicable to the back-up protection of analyses for double circuits on same tower single-end electrical quantity.

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

The non-same famous prime minister's cross-line earth fault method of discrimination of a kind of double-circuit line, is characterized in that, comprises following sequential steps:

(1) protector measuring analyses for double circuits on same tower I returns the fault phase voltage of route protection installation place fault phase electric current and zero-sequence current wherein, φ=I loop line road A phase or I loop line road B phase or I loop line road C phase;

(2) protective device calculates the zero sequence compensation electric current on analyses for double circuits on same tower I loop line road

$\mathrm{\Δ}\stackrel{\·}{I}={\stackrel{\·}{I}}_{1\mathrm{\φ}}+\frac{Z_{I0}-X_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{10}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}))$

Wherein, $r_1={\sin }^{-1}\left(\frac{a_3{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $r_2={\sin }^{-1}\left(\frac{a_1{b}_2-a_2{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $a_1=\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $b_1=\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $a_2=\mathrm{Re}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $b_2=\mathrm{Im}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $a_3=b_3=\left|\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right|;$ $\mathrm{\β}=\mathrm{Arg}\left|\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right|;$ Z _mfor the zero-sequence mutual inductance between analyses for double circuits on same tower I loop line road and analyses for double circuits on same tower II loop line road; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; Z _i1for the positive sequence impedance on analyses for double circuits on same tower I loop line road; φ=I loop line road A phase or I loop line road B phase or I loop line road C phase; for real part; for imaginary part; for real part; for imaginary part; J is complex operator;

(3) protective device calculates leading angle ρ:

$\mathrm{\ρ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{I}}_{I0}+{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}))}\right)$

(4) protective device calculates analyses for double circuits on same tower I and returns the route protection setting range l of place _setfault phase voltage wherein, l _setfor analyses for double circuits on same tower I returns route protection setting range; L is that analyses for double circuits on same tower I returns line length;

(5) protective device calculates leading $\stackrel{\·}{U}\left(l_{\mathrm{set}}\right)={\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}\mathrm{\Δ}\stackrel{\·}{I}$ Phase angle λ:

$\mathrm{\λ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β})))}\right)$

(6) protective device judgement leading angle ρ be less than leading phase angle λ whether set up, if set up, judge that the non-same famous prime minister's cross-line earth fault of double-circuit line is positioned within analyses for double circuits on same tower I returns route protection setting range, sends action trip signal.

Feature of the present invention and technological achievement:

The inventive method is only used single-ended single back line electric parameters, does not need to introduce another loop line road electric parameters, and differentiation result is not subject to the impact of power system operation mode, still has very high fault distinguishing accuracy in the time that larger change occurs power system operation mode.The inventive method is only used single-ended single back line electric parameters, does not need to introduce another loop line road electric parameters, and Protection secondary circuit is separate does not go here and there mutually, strengthens fault distinguishing result accuracy.The inventive method is taken into account the impact of zero-sequence mutual inductance between line, has eliminated the impact of zero-sequence mutual inductance on fault distinguishing result between line.When the inventive method is utilized non-same famous prime minister's cross-line earth fault to be positioned at analyses for double circuits on same tower I to return within route protection setting range, analyses for double circuits on same tower I returns this vector phase characteristic of phase angle that phase angle that the fault phase voltage delay analyses for double circuits on same tower I of route protection setting range place returns route protection installation place fault phase voltage is greater than analyses for double circuits on same tower I and returns the non-same famous prime minister's cross-line earth fault zero-sequence current of the route protection installation place leading injection of fault phase voltage, realize the accurate differentiation of the non-same famous prime minister's cross-line earth fault of double-circuit line, differentiate result and be not subject to zero-sequence mutual inductance between line, transition resistance, the impact of the factor such as load current and power system operation mode, be applicable to the back-up protection of analyses for double circuits on same tower single-end electrical quantity.

Brief description of the drawings

Fig. 1 is application analyses for double circuits on same tower transmission system schematic diagram of the present invention.

Embodiment

Fig. 1 is application analyses for double circuits on same tower transmission system schematic diagram of the present invention.In Fig. 1, PT is voltage transformer (VT); CT is current transformer.Protector measuring analyses for double circuits on same tower I returns the fault phase voltage of route protection installation place fault phase electric current and zero-sequence current wherein, φ=I loop line road A phase or I loop line road B phase or I loop line road C phase.

Protective device calculates the zero-sequence current on analyses for double circuits on same tower II loop line road ${\stackrel{\·}{I}}_{\mathrm{II}0}={\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}));$

Wherein, $r_1={\sin }^{-1}\left(\frac{a_3{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $r_2={\sin }^{-1}\left(\frac{a_1{b}_2-a_2{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $a_1=\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $b_1=\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $a_2=\mathrm{Re}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $b_2=\mathrm{Im}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $a_3=b_3=\left|\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right|;$ $\mathrm{\β}=\mathrm{Arg}\left(\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right);$ Z _mfor the zero-sequence mutual inductance between analyses for double circuits on same tower I loop line road and analyses for double circuits on same tower II loop line road; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; Z _i1for the positive sequence impedance on analyses for double circuits on same tower I loop line road; φ=I loop line road A phase or I loop line road B phase or I loop line road C phase; for real part; for imaginary part; for real part; for imaginary part; J is complex operator.

Protective device calculates the zero sequence compensation electric current on analyses for double circuits on same tower I loop line road

$\mathrm{\Δ}\stackrel{\·}{I}={\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0}$

Protective device calculates analyses for double circuits on same tower I and returns the route protection setting range l of place _setthe fault phase voltage of point

$\stackrel{\·}{U}\left(l_{\mathrm{set}}\right)={\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}\mathrm{\Δ}\stackrel{\·}{I}$

Protective device calculates leading angle ρ:

$\mathrm{\ρ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{I}}_{I0}+{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}))}\right)$

Protective device calculates leading phase angle λ:

$\mathrm{\λ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β})))}\right)$

Wherein, l _setfor analyses for double circuits on same tower I returns route protection setting range; L is that analyses for double circuits on same tower I returns line length;

If not be positioned within analyses for double circuits on same tower I returns route protection setting range with famous prime minister's cross-line earth fault, analyses for double circuits on same tower I returns the phase angle that phase angle that the fault phase voltage delay analyses for double circuits on same tower I of route protection setting range place returns route protection installation place fault phase voltage is greater than analyses for double circuits on same tower I and returns the non-same famous prime minister's cross-line earth fault zero-sequence current of the route protection installation place leading injection of fault phase voltage.Return outside route protection setting range if not be positioned at analyses for double circuits on same tower I with famous prime minister's cross-line earth fault, analyses for double circuits on same tower I returns the phase angle that phase angle that the fault phase voltage delay analyses for double circuits on same tower I of route protection setting range place returns route protection installation place fault phase voltage is less than analyses for double circuits on same tower I and returns the non-same famous prime minister's cross-line earth fault zero-sequence current of the route protection installation place leading injection of fault phase voltage.According to this vector phase characteristic, the non-same famous prime minister's cross-line earth fault identical criterion of double-circuit line is proposed as follows:

Judgement leading angle ρ be less than leading phase angle λ whether set up, if set up, judge that the non-same famous prime minister's cross-line earth fault of double-circuit line is positioned within analyses for double circuits on same tower I returns route protection setting range, sends action trip signal.

The inventive method is only used single-ended single back line electric parameters, does not need to introduce another loop line road electric parameters, and differentiation result is not subject to the impact of power system operation mode, still has very high fault distinguishing accuracy in the time that larger change occurs power system operation mode.The inventive method is only used single-ended single back line electric parameters, does not need to introduce another loop line road electric parameters, and Protection secondary circuit is separate does not go here and there mutually, strengthens fault distinguishing result accuracy.The inventive method is taken into account the impact of zero-sequence mutual inductance between line, has eliminated the impact of zero-sequence mutual inductance on fault distinguishing result between line.

When the inventive method is utilized non-same famous prime minister's cross-line earth fault to be positioned at analyses for double circuits on same tower I to return within route protection setting range, analyses for double circuits on same tower I returns this vector phase characteristic of phase angle that phase angle that the fault phase voltage delay analyses for double circuits on same tower I of route protection setting range place returns route protection installation place fault phase voltage is greater than analyses for double circuits on same tower I and returns the non-same famous prime minister's cross-line earth fault zero-sequence current of the route protection installation place leading injection of fault phase voltage, realize the accurate differentiation of the non-same famous prime minister's cross-line earth fault of double-circuit line, differentiate result and be not subject to zero-sequence mutual inductance between line, transition resistance, the impact of the factor such as load current and power system operation mode, be applicable to the back-up protection of analyses for double circuits on same tower single-end electrical quantity.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited to this; any be familiar with those skilled in the art the present invention disclose technical scope in, the variation that can expect easily or replacement, within all should being encompassed in protection scope of the present invention.

Claims (1)

1. the non-same famous prime minister's cross-line earth fault method of discrimination of double-circuit line, is characterized in that, comprises following sequential steps:

(1) protector measuring analyses for double circuits on same tower I returns the fault phase voltage of route protection installation place fault phase electric current and zero-sequence current wherein, φ=I loop line road A phase or I loop line road B phase or I loop line road C phase;

(2) protective device calculates the zero sequence compensation electric current on analyses for double circuits on same tower I loop line road

$\mathrm{\Δ}\stackrel{\·}{I}={\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}))$

Wherein, $r_1={\sin }^{-1}\left(\frac{a_3{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $r_2={\sin }^{-1}\left(\frac{a_1{b}_2-a_2{b}_1}{\sqrt{{\left(a_3{b}_1\right)}^2+{\left(a_1{b}_3\right)}^2}}\right);$ $a_1=\mathrm{Re}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $b_1=\mathrm{Im}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{Z_{I1}}\right);$ $a_2=\mathrm{Re}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $b_2=\mathrm{Im}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0});$ $a_3=b_3=\left|\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right|;$ $\mathrm{\β}=\mathrm{Arg}\left(\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}\right);$ Z _mfor the zero-sequence mutual inductance between analyses for double circuits on same tower I loop line road and analyses for double circuits on same tower II loop line road; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; Z _i1for the positive sequence impedance on analyses for double circuits on same tower I loop line road; φ=I loop line road A phase or I loop line road B phase or I loop line road C phase; for real part; for imaginary part; for real part; for imaginary part; J is complex operator;

(3) protective device calculates leading angle ρ:

$\mathrm{\ρ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{I}}_{I0}+{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β}))}\right)$

(4) protective device calculates analyses for double circuits on same tower I and returns the route protection setting range l of place _setfault phase voltage wherein, l _setfor analyses for double circuits on same tower I returns route protection setting range; L is that analyses for double circuits on same tower I returns line length;

(5) protective device calculates leading $\stackrel{\·}{U}\left(l_{\mathrm{set}}\right)={\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}\mathrm{\Δ}\stackrel{\·}{I}$ Phase angle λ:

$\mathrm{\λ}=\mathrm{Arg}\left(\frac{{\stackrel{\·}{U}}_{\mathrm{I\φ}}}{{\stackrel{\·}{U}}_{\mathrm{I\φ}}-\frac{l_{\mathrm{set}}}{l}{Z}_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{I0}(-\cos (r_1+r_2-\mathrm{\β})-j\sin (r_1+r_2-\mathrm{\β})))}\right)$

(6) protective device judgement leading angle ρ be less than leading phase angle λ whether set up, if set up, judge that the non-same famous prime minister's cross-line earth fault of double-circuit line is positioned within analyses for double circuits on same tower I returns route protection setting range, sends action trip signal.