CN103779850B - Based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method - Google Patents

Abstract

The invention discloses a kind of based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method, first measuring the II loop line road zero-sequence current of the I loop line road faulted phase voltage Sudden Changing Rate of common-tower double-circuit lines protection installation place, I loop line road faulted phase current Sudden Changing Rate, I loop line road zero-sequence current, other two normal phases voltages of I loop line road, common-tower double-circuit lines protection installation place; Calculate faulted phase voltage when I loop line road is normally run; calculate the faulted phase voltage Sudden Changing Rate at protection seting scope place, I loop line road; whether the faulted phase voltage Sudden Changing Rate amplitude that the faulted phase voltage amplitude then judging when I loop line road is normally run is greater than protection seting scope place, I loop line road is set up; if set up, then protective device sends action trip signal.Operating characteristics circle of the present invention is through third quadrant, and the origin of coordinates is positioned at operating characteristics circle, the unprotect dead band when protection exit single back line single phase ground fault, not misoperation during protection opposite direction outlet single back line single phase ground fault.

Description

Based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relating to a kind of based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method.

Background technology

Conventional transmission lines road single-phase earthing distance protection hypothesis single phase ground fault is metallic short circuit fault; by the ratio calculation measurement impedance of faulted phase voltage and faulted phase current, and the distance carrying out faults point according to measurement impedance size is to determine whether send action trip signal.In fact, in electric power system, except the metallic earthing short trouble of arteface, the transition resistance of actual transmission line one-phase earth fault point is also non-vanishing, and the additional impedance that transition resistance produces can have a strong impact on the performance of impedance distance protection.If the additional impedance that transition resistance produces is resistance sense, then impedance distance protection tripping when easily causing single phase ground fault in protection zone; If the additional impedance that transition resistance produces be capacitance-resistance, then impedance distance protection generation steady-state when easily causing single phase ground fault outside protection zone.

Operating characteristics round edge circle of existing transmission line single-phase earthing distance protection is through the origin of coordinates; because the origin of coordinates is positioned on operating characteristics round edge circle; during protection forward outlet single-phase grounding fault there is dead band in protection; and along with transition resistance and load current increase, protection forward outlet dead band is larger.Because the origin of coordinates is positioned on operating characteristics round edge circle, there is the possibility of malfunction in protection in the other direction outlet single-phase grounding fault, and transition resistance is larger, protection easier misoperation during protection opposite direction outlet single-phase grounding fault.

Owing to there is very strong zero-sequence mutual inductance between analyses for double circuits on same tower line, based on traditional transformer station of cable secondary circuit, single-phase earthing distance protection cannot obtain the zero-sequence current on another loop line road, the impact of zero-sequence mutual inductance between line cannot be eliminated in algorithm model, by the impact of zero-sequence mutual inductance between line, when traditional single phase ground distance protection is applied to analyses for double circuits on same tower, its protection range will expand greatly, at protection seting scope place usually there is steady-state in fault, make easily misoperation to occur during protection external area error, easily cause the large transfer of trend, cause large area blackout to occur.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence; unprotect dead band when a kind of protection forward outlet single back line single phase ground fault is provided; not misoperation during protection opposite direction outlet single back line single phase ground fault; without the need to remembering voltage before line fault; keep loop without the need to arranging voltage before line fault, operating characteristics in two cycles of double-circuit line generation single back line single phase ground fault be all transient state operating characteristics based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method.

The technical solution adopted for the present invention to solve the technical problems is: based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method, comprise following sequential steps:

(1) the I loop line road faulted phase voltage Sudden Changing Rate of protector measuring common-tower double-circuit lines protection installation place i loop line road faulted phase current Sudden Changing Rate with I loop line road zero-sequence current measure other two normal phases voltages of I loop line road measure the II loop line road zero-sequence current of common-tower double-circuit lines protection installation place wherein, φ α β=ACB, BAC, CBA phase;

(2) protective device calculates φ phase voltage when I loop line road is normally run wherein, φ α β=ACB, BAC, CBA phase;

(3) protective device calculates the φ phase voltage Sudden Changing Rate at protection seting scope place, I loop line road

$\mathrm{\Δ}{\stackrel{\·}{U}}_{\mathrm{I\φ}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{I\φ}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\·}{I}}_{I0}+\frac{z_{m0}}{{3z}_{11}}{\stackrel{\·}{I}}_{\mathrm{II}0})$

Wherein, x _setfor I loop line road protection seting scope; z _i1, z _i0be respectively unit length I loop line road positive sequence impedance, zero sequence impedance; z _m0for the zero-sequence mutual inductance impedance between unit length I loop line road and unit length II loop line road;

(4) protective device judges $|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{I\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{{3z}_{I1}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{II}0})|<\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}\left[0\right]}\right|$ Whether set up, if set up, then judge φ phase earth fault to occur, the circuit breaker at two ends, protective device tripping I loop line road within the scope of the protection seting of I loop line road.

The invention has the beneficial effects as follows:

The inventive method, without the need to remembering voltage before line fault, keeps loop without the need to arranging voltage before line fault.The inventive method operating characteristics circle is through third quadrant, and the origin of coordinates is positioned at operating characteristics circle, the unprotect dead band when protection exit single back line single phase ground fault, not misoperation during protection opposite direction outlet single back line single phase ground fault.The inventive method obtains another loop line road zero-sequence current based on directly adopting straight communication mode of jumping, and takes into account the impact of another loop line road zero-sequence current in algorithm model, principle to eliminate between line zero-sequence mutual inductance impedance to the impact of Perfomance of protective relaying.The inventive method operating characteristics is all transient state operating characteristics in two cycles of double-circuit line generation single back line single phase ground fault; there is the ability of very strong anti-transition resistance and load current impact, be applicable to the distance protection in two cycles of double-circuit line single back line single phase ground fault.

Accompanying drawing explanation

Fig. 1 is application common-tower double-circuit lines transmission system schematic diagram of the present invention.

Embodiment

According to Figure of description, technical scheme of the present invention is expressed in further detail below.

Fig. 1 is application common-tower double-circuit lines transmission system schematic diagram of the present invention.In Fig. 1, CVT is voltage transformer, CT is current transformer.In intelligent substation; after the ac analog that merge cells Real-time Collection voltage transformer CVT summation current transformer CT exports; the ac analog that the voltage transformer CVT summation current transformer CT collected exports is changed into sampled digital signal by merge cells, is directly transferred to protective relaying device through optical-fibre communications.

Protective relaying device measures the I loop line road faulted phase voltage Sudden Changing Rate of common-tower double-circuit lines protection installation place i loop line road faulted phase current Sudden Changing Rate with I loop line road zero-sequence current measure other two normal phases voltages of I loop line road measure the II loop line road zero-sequence current of common-tower double-circuit lines protection installation place wherein, φ α β=ACB, BAC, CBA phase, that is, when φ=A phase time, α=C phase, β=B phase; When φ=B phase time, α=A phase, β=C phase; When φ=C phase time, α=B phase, β=A phase.Above-mentioned I loop line road refers to a loop line road of fault in common-tower double-circuit lines, and II loop line road refers to normal another loop line road run in common-tower double-circuit lines.

Protective relaying device calculates φ phase voltage when I loop line road is normally run wherein, φ α β=ACB, BAC, CBA phase, that is, when φ=A phase time, α=C phase, β=B phase; When φ=B phase time, α=A phase, β=C phase; When φ=C phase time, α=B phase, β=A phase.

Protective relaying device calculates the φ phase voltage Sudden Changing Rate at protection seting scope place, I loop line road

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{I\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{{3z}_{11}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{II}0})$

Wherein, x _setfor I loop line road protection seting scope; z _i1, z _i0be respectively unit length I loop line road positive sequence impedance, zero sequence impedance; z _m0for the zero-sequence mutual inductance impedance between unit length I loop line road and unit length II loop line road;

Whether the faulted phase voltage Sudden Changing Rate amplitude that faulted phase voltage amplitude when protective relaying device judges that I loop line road is normally run is greater than protection seting scope place, I loop line road is set up, and namely judges

$|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{I\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{{3z}_{I1}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{II}0})|<\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}\left[0\right]}\right|$

Whether set up; if set up; then judge φ phase earth fault occurs within the scope of the protection seting of I loop line road; protective relaying device sends action trip signal; action trip signal is directly transferred to intelligent terminal through optical-fibre communications; the action trip signal that intelligent terminal for reception sends to protective relaying device, the circuit breaker at two ends, direct tripping I loop line road.

The inventive method, without the need to remembering voltage before line fault, keeps loop without the need to arranging voltage before line fault.The inventive method operating characteristics circle is through third quadrant, and the origin of coordinates is positioned at operating characteristics circle, the unprotect dead band when protection exit single back line single phase ground fault, not misoperation during protection opposite direction outlet single back line single phase ground fault.The inventive method obtains another loop line road zero-sequence current based on directly adopting straight communication mode of jumping, and takes into account the impact of another loop line road zero-sequence current in algorithm model, principle to eliminate between line zero-sequence mutual inductance impedance to the impact of Perfomance of protective relaying.The inventive method operating characteristics is all transient state operating characteristics in two cycles of double-circuit line generation single back line single phase ground fault; there is the ability of very strong anti-transition resistance and load current impact, be applicable to the distance protection in two cycles of double-circuit line single back line single phase ground fault.

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., based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method, it is characterized in that, comprise following sequential steps:

(1) the I loop line road faulted phase voltage Sudden Changing Rate of protector measuring common-tower double-circuit lines protection installation place i loop line road faulted phase current Sudden Changing Rate with I loop line road zero-sequence current measure other two normal phases voltages of I loop line road measure the II loop line road zero-sequence current of common-tower double-circuit lines protection installation place wherein, φ α β=ACB, BAC, CBA phase, that is, when φ=A phase time, α=C phase, β=B phase; When φ=B phase time, α=A phase, β=C phase; When φ=C phase time, α=B phase, β=A phase;

(2) protective device calculates φ phase voltage when I loop line road is normally run wherein, φ α β=ACB, BAC, CBA phase;

(3) protective device calculates the φ phase voltage Sudden Changing Rate at protection seting scope place, I loop line road

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{I\mathrm{\&phi;}}-x_{set}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{I\mathrm{\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{3z_{I1}}{\stackrel{\&CenterDot;}{I}}_{II0})$

Wherein, x _setfor I loop line road protection seting scope; z _i1, z _i0be respectively unit length I loop line road positive sequence impedance, zero sequence impedance; z _m0for the zero-sequence mutual inductance impedance between unit length I loop line road and unit length II loop line road;

(4) protective device judges $|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{I\mathrm{\&phi;}}-x_{set}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{I\mathrm{\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{3z_{I1}}{\stackrel{\&CenterDot;}{I}}_{II0})|<\left|{\stackrel{\&CenterDot;}{U}}_{I\mathrm{\&phi;}\&lsqb;0\&rsqb;}\right|$ Whether set up, if set up, then judge φ phase earth fault to occur, the circuit breaker at two ends, protective device tripping I loop line road within the scope of the protection seting of I loop line road.