CN103779850A - Double-circuit line single-phase grounding distance protection method based on direct-mining direct-jumping communication mode - Google Patents

Abstract

The invention discloses a double-circuit line single-phase grounding distance protection method based on a direct-mining direct-jumping communication mode. According to the method, a failure phase voltage break variable of a circuit line I, a failure phase current break variable of the circuit line I, a zero-sequence current of the circuit line I and other two normal phase voltages of the circuit line I in a same-rod double-circuit line protection installation position, and a zero-sequence current of a circuit line II in a same-rod double-circuit line protection installation position are firstly measured; a failure phase voltage when the circuit line I normally operates is calculated, the failure phase voltage break variable in the position of a protection setting range of the circuit line I is calculated, and then whether the failure phase voltage amplitude when the circuit line I operates normally is larger than the failure phase voltage break variable amplitude in the position of the protection setting range of the circuit line I is judged, and if yes, the protection device emits a motion tripping signal. According to the double-circuit line single-phase grounding distance protection method based on the direct-mining direct-jumping communication mode, a motion characteristic circle passes through a third quadrant, the origin of coordinates is located in the motion characteristic circle, no protection dead area exits when an outlet single-circuit line single-phase grounding failure is protected, and no error motion exits when a reverse-direction outlet single-circuit line single-phase grounding failure is protected.

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 relate to a kind of based on directly adopting straight jumping communication mode double-circuit line single-phase earthing distance protecting method.

Background technology

Tradition transmission line single-phase earthing distance protection hypothesis single phase ground fault is metallic short circuit fault; ratio calculation by fault phase voltage and fault phase electric current is measured impedance, and the distance of carrying out faults point according to measurement impedance magnitude is to determine whether to 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, impedance distance protection tripping while easily causing in protection zone single phase ground fault; If the additional impedance that transition resistance produces is capacitance-resistance, impedance distance protection generation steady-state while easily causing single phase ground fault the protection zone outside.

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; when 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, protection in the other direction exports single-phase grounding fault and exists possibility of malfunction, and transition resistance is larger, protects easier misoperation when protection exports single-phase grounding fault in the other direction.

Owing to there being 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 be obtained 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 traditional single phase ground distance protection is applied to analyses for double circuits on same tower, its protection range 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, causing large area blackout occurs.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists; unprotect dead band when a kind of protection forward outlet single back line single phase ground fault is provided; not misoperation when protection exports single back line single phase ground fault in the other direction; without voltage before line fault is remembered; keep loop without voltage before line fault is set, 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 fault phase voltage jump amount of protection installation place, protector measuring double-circuit line on same pole road

i loop line road fault phase jump-value of current

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 protection installation place, double-circuit line on same pole road

wherein, φ α β=ACB, BAC, CBA phase;

(2) φ phase voltage when protective device calculating I loop line road is normally moved

wherein, φ α β=ACB, BAC, CBA phase;

(3) protective device calculates the φ phase voltage Sudden Changing Rate that I goes back to route protection setting range place

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

Wherein, x _setfor I returns route protection setting range; 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 judgement $|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{I\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{{3z}_{I1}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{II}0})|<\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}\left[0\right]}\right|$ Whether set up, if set up, judge that I returns generation φ phase earth fault in route protection setting range, the circuit breaker at two ends, protective device tripping I loop line road.

The invention has the beneficial effects as follows:

The inventive method, without voltage before line fault is remembered, keeps loop without voltage before line fault is set.The inventive method operating characteristics circle is through third quadrant, and the origin of coordinates is positioned at operating characteristics circle, unprotect dead band in the time of protection outlet single back line single phase ground fault, not misoperation when protection exports single back line single phase ground fault in the other direction.The inventive method is obtained another loop line road zero-sequence current based on directly adopting straight jumping communication mode, takes into account the impact of another loop line road zero-sequence current in algorithm model, has eliminated the impact of zero-sequence mutual inductance impedance on Perfomance of protective relaying between line in principle.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 double-circuit line on same pole of the present invention road transmission system schematic diagram.

Embodiment

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

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

Protective relaying device is measured the I loop line road fault phase voltage jump amount of protection installation place, double-circuit line on same pole road

i loop line road fault phase jump-value of current 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 protection installation place, double-circuit line on same pole road

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 double-circuit line on same pole road, and II loop line road refers to another loop line road of normal operation in double-circuit line on same pole road.

φ phase voltage when protective relaying device calculating I loop line road is normally moved 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 that I goes back to route protection setting range place

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

Wherein, x _setfor I returns route protection setting range; 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;

Protective relaying device judges that fault phase voltage magnitude when I loop line road is normally moved is greater than the fault phase voltage jump amount amplitude that I goes back to route protection setting range place and whether sets up, i.e. judgement

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

Whether set up; if set up; judge that I returns generation φ phase earth fault in route protection setting range; protective relaying device sends action trip signal; action trip signal is directly transferred to intelligent terminal through optical-fibre communications; intelligent terminal receives the action trip signal that protective relaying device sends, directly the circuit breaker at two ends, tripping I loop line road.

The inventive method, without voltage before line fault is remembered, keeps loop without voltage before line fault is set.The inventive method operating characteristics circle is through third quadrant, and the origin of coordinates is positioned at operating characteristics circle, unprotect dead band in the time of protection outlet single back line single phase ground fault, not misoperation when protection exports single back line single phase ground fault in the other direction.The inventive method is obtained another loop line road zero-sequence current based on directly adopting straight jumping communication mode, takes into account the impact of another loop line road zero-sequence current in algorithm model, has eliminated the impact of zero-sequence mutual inductance impedance on Perfomance of protective relaying between line in principle.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 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. 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 fault phase voltage jump amount of protection installation place, protector measuring double-circuit line on same pole road

i loop line road fault phase jump-value of current

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 protection installation place, double-circuit line on same pole road

wherein, φ α β=ACB, BAC, CBA phase;

(2) φ phase voltage when protective device calculating I loop line road is normally moved

wherein, φ α β=ACB, BAC, CBA phase;

(3) protective device calculates the φ phase voltage Sudden Changing Rate that I goes back to route protection setting range place

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

Wherein, x _setfor I returns route protection setting range; 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 judgement $|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}}-x_{\mathrm{set}}{z}_{I1}(\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_{\mathrm{I\&phi;}}+\frac{z_{I0}-z_{I1}}{z_{I1}}{\stackrel{\&CenterDot;}{I}}_{I0}+\frac{z_{m0}}{{3z}_{I1}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{II}0})|<\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{I\&phi;}\left[0\right]}\right|$ Whether set up, if set up, judge that I returns generation φ phase earth fault in route protection setting range, the circuit breaker at two ends, protective device tripping I loop line road.

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