CN104950228A - Double-circuit parallel transmission line single phase grounding fault point transition resistance value measuring method - Google Patents

Abstract

The invention discloses a double-circuit parallel transmission line single phase grounding fault point transition resistance value measuring method, which comprises the following steps of calculating zero-sequence current of an II circuit transmission line of a double-circuit parallel transmission line, and accurately calculating a single phase grounding fault point transition resistance value according to the linear relationship between voltage drop and fault distance from a protection installation part of a I circuit transmission line of the double-circuit parallel transmission line to a single phase grounding fault point. The method considers the influences of zero sequence mutual inductance between lines and single phase grounding fault point voltage, overcomes the influences of transition resistance, load current and zero sequence mutual inductance between the lines on single phase grounding fault point transition resistance value measuring accuracy, and has higher measurement accuracy.

Description

Analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method.

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.Analyses for double circuits on same tower running environment is complicated, failure factor is of a great variety, cause analyses for double circuits on same tower earth fault because have insulator arc-over, thunderbolt, floating thing, Huoshaoshan, villager burn the grass on waste land, circuit hangs grass to mao bamboon electric discharge, bird cause that the alternate safe distance of circuit is not enough, bird is hanged grass and causes safe distance between circuit and ground wire not enough to tree discharge, circuit.The earth fault type that different faults factor causes is different, is broadly divided into single-phase low resistance earthing, single-phase middle resistance eutral grounding and single-phase high resistance grounding three class.If a kind of analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method can be studied; can be and accurately differentiate that singlephase earth fault type provides scientific basis; be conducive to reducing failure factor scope; in conjunction with fault localization result and distance protection action situation; greatly can improve fault line walking efficiency and shorten troubleshooting time, thus improving electric power netting safe running stability.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, provide a kind of measuring accuracy not by the analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method that zero-sequence mutual inductance between line and load current affect.

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

Analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method, is characterized in that, comprise following sequential steps:

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

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

${\stackrel{\·}{I}}_{\mathrm{II}0}=\frac{(l_{\mathrm{set}}{Z}_{n0}-(l-l_{\mathrm{set}})Z_{m0}){\stackrel{\·}{I}}_{I0}}{(2l-l_{\mathrm{set}})Z_{n0}+(l-l_{\mathrm{set}})(Z_{m0}+Z_{I0}+Z_m)}$

Wherein, Z _m0for the zero sequence system equivalent impedance of this protection installation place, side, analyses for double circuits on same tower I loop line road; Z _n0for the zero sequence system equivalent impedance of analyses for double circuits on same tower I loop line road offside protection installation place; 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; L is that analyses for double circuits on same tower I returns line length; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; l _setfor analyses for double circuits on same tower I loop line road setting range, get 0.85 times of analyses for double circuits on same tower I and return line length;

(3) protective device calculates analyses for double circuits on same tower I loop line road Single-phase Ground Connection Failure transition resistance R _f:

$R_f=\frac{\mathrm{Re}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}{\mathrm{Re}\left({\stackrel{\·}{I}}_{\mathrm{\φ}2}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{I}}_{\mathrm{I\φ}2}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}$

Wherein, 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; 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; for real part; for imaginary part; for real part; for real part; for imaginary part; for imaginary part; φ=I loop line road A phase, I loop line road B phase, I loop line road C phase.

Feature of the present invention and technological achievement:

The inventive method is measured analyses for double circuits on same tower I and is returned the faulted phase voltage of route protection installation place, faulted phase current, fault phase negative-sequence current and zero-sequence current; calculate the zero-sequence current on analyses for double circuits on same tower II loop line road, go back to route protection installation place to the voltage drop of Single-phase Ground Connection Failure and fault distance linear accurate Calculation Single-phase Ground Connection Failure transition resistance value according to analyses for double circuits on same tower I.The inventive method takes into account the impact of zero-sequence mutual inductance and Single-phase Ground Connection Failure voltage between line, overcomes transition resistance, between load current and line, zero-sequence mutual inductance, on the impact of Single-phase Ground Connection Failure transition resistance value measuring accuracy, has very high measuring accuracy.According to the Single-phase Ground Connection Failure transition resistance value measured; it is single-phase through small resistor, middle resistance or high resistance grounding short trouble for accurately can differentiating that analyses for double circuits on same tower I returns line single phase grounding failure; be conducive to reducing failure factor scope; in conjunction with fault localization result and distance protection action situation; greatly can improve fault line walking efficiency and shorten troubleshooting time, improving electric power netting safe running stability.

Accompanying drawing explanation

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, and m, n are the two ends numbering of analyses for double circuits on same tower.Protector measuring analyses for double circuits on same tower I returns the faulted phase voltage of route protection installation place faulted phase current fault phase negative-sequence current and zero-sequence current wherein, φ=I loop line road A phase, I loop line road B phase, 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

${\stackrel{\·}{I}}_{\mathrm{II}0}=\frac{(l_{\mathrm{set}}{Z}_{n0}-(l-l_{\mathrm{set}})Z_{m0}){\stackrel{\·}{I}}_{I0}}{(2l-l_{\mathrm{set}})Z_{n0}+(l-l_{\mathrm{set}})(Z_{m0}+Z_{I0}+Z_m)}$

Wherein, Z _m0for the zero sequence system equivalent impedance of this protection installation place, side, analyses for double circuits on same tower I loop line road; Z _n0for the zero sequence system equivalent impedance of analyses for double circuits on same tower I loop line road offside protection installation place; 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; L is that analyses for double circuits on same tower I returns line length; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; l _setfor analyses for double circuits on same tower I loop line road setting range, get 0.85 times of analyses for double circuits on same tower I and return line length.

Protective device calculates real part

Protective device calculates imaginary part

Protective device calculates analyses for double circuits on same tower I loop line road Single-phase Ground Connection Failure transition resistance R _f:

$R_f=\frac{\mathrm{Re}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}{\mathrm{Re}\left({\stackrel{\·}{I}}_{\mathrm{\φ}2}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{I}}_{\mathrm{I\φ}2}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{3Z_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}$

Wherein, 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; 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; for real part; for imaginary part; for real part; for imaginary part; φ=I loop line road A phase, I loop line road B phase, I loop line road C phase.

The inventive method is measured analyses for double circuits on same tower I and is returned the faulted phase voltage of route protection installation place, faulted phase current, fault phase negative-sequence current and zero-sequence current; calculate the zero-sequence current on analyses for double circuits on same tower II loop line road, go back to route protection installation place to the voltage drop of Single-phase Ground Connection Failure and fault distance linear accurate Calculation Single-phase Ground Connection Failure transition resistance value according to analyses for double circuits on same tower I.The inventive method takes into account the impact of zero-sequence mutual inductance and Single-phase Ground Connection Failure voltage between line, overcomes transition resistance, between load current and line, zero-sequence mutual inductance, on the impact of Single-phase Ground Connection Failure transition resistance value measuring accuracy, has very high measuring accuracy.According to the Single-phase Ground Connection Failure transition resistance value measured; it is single-phase through small resistor, middle resistance or high resistance grounding short trouble for accurately can differentiating that analyses for double circuits on same tower I returns line single phase grounding failure; be conducive to reducing failure factor scope and close fault localization result and distance protection action situation; greatly can improve fault line walking efficiency and shorten troubleshooting time, improving electric power netting safe running stability.

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. analyses for double circuits on same tower Single-phase Ground Connection Failure transition resistance value measurement method, is characterized in that, comprises following sequential steps:

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

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

${\stackrel{\·}{I}}_{\mathrm{II}0}=\frac{(l_{\mathrm{set}}{Z}_{n0}-(l-l_{\mathrm{set}})Z_{m0}){\stackrel{\·}{I}}_{I0}}{\left({2l-l}_{\mathrm{set}}\right)Z_{n0}+\left({l-l}_{\mathrm{set}}\right)(Z_{m0}+Z_{I0}+Z_m)}$

Wherein, Z _m0for the zero sequence system equivalent impedance of this protection installation place, side, analyses for double circuits on same tower I loop line road; Z _n0for the zero sequence system equivalent impedance of analyses for double circuits on same tower I loop line road offside protection installation place; 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; L is that analyses for double circuits on same tower I returns line length; Z _i0for the zero sequence impedance on analyses for double circuits on same tower I loop line road; l _setfor analyses for double circuits on same tower I loop line road setting range, get 0.85 times of analyses for double circuits on same tower I and return line length;

(3) protective device calculates analyses for double circuits on same tower I loop line road Single-phase Ground Connection Failure transition resistance R _f:

$R_f=\frac{\mathrm{Re}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{U}}_{\mathrm{I\φ}}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{{\stackrel{\·}{Z}}_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}{\mathrm{Re}\left({\stackrel{\·}{I}}_{\mathrm{I\φ}2}\right)\mathrm{Im}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)-\mathrm{Im}\left({\stackrel{\·}{I}}_{\mathrm{I\φ}2}\right)\mathrm{Re}\left(Z_{I1}({\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{Z_{I0}-Z_{I1}}{Z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{Z_m}{{3Z}_{I1}}{\stackrel{\·}{I}}_{\mathrm{II}0})\right)}$

Wherein, 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; 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; for faulted phase voltage; for faulted phase current; for fault phase negative-sequence current; for zero-sequence current; for real part; for imaginary part; for real part; for imaginary part; for real part; for imaginary part; φ=I loop line road A phase, I loop line road B phase, I loop line road C phase.