CN104459458A - Method for recognizing circuit switching on and failures through specific short window integral value of directional traveling waves - Google Patents

Abstract

The invention relates to a method for recognizing circuit switching on to a failure through a specific short window integral value of directional traveling waves, and belongs to the technical field of electrical power system relay protection. When the single-phase earth failure occurs on an electric transmission line, single-phase reclosing is adopted, the switching-on line mode current traveling waves obtained by a measuring end and switching-on line mode voltage traveling waves are used for forming forward direction current traveling waves and reverse current traveling waves, the absolute value of the forward direction current traveling waves and the absolute value of the reverse current traveling waves are solved, the integral value ration of the forward current traveling waves and the reverse current traveling waves in a window in 2 tao min to 4 tao min after switching on is carried out is calculated to build switching on to failure recognizing criteria. If the integral value ratio is smaller than the set threshold value k, the line is judged to be a switching on to non-failure line, and if the integral value ratio is larger than k, switching on to failures is judged. The simulation verifies and shows that the method is not affected by failure positions, transition resistance and initial failure phase angles, the situation of the switching on to failure line can be reliably recognized, and the line is prevented from being impacted again.

Description

The circuit of the fixed short window integrated value of the capable baud of a kind of utilization orientation closes a floodgate fault recognition method

Technical field

The circuit that the present invention relates to the fixed short window integrated value of the capable baud of a kind of utilization orientation closes a floodgate fault recognition method, belongs to Relay Protection Technology in Power System field.

Background technology

Travelling waves analysis is the basis of travelling wave ranging and traveling-wave protection, has important directive function to the new travelling wave ranging of proposition and guard method.The characteristic of domestic well-known scholar to row ripple is studied, and proposes new travelling wave ranging and protection philosophy on this basis.But these row wave property analyses and protection philosophy are mainly for situation about breaking down in normal working line, when carrying out closing operation, these protections can not the situation of correct operation by there will be, and therefore also needs research further to close a floodgate the recognition methods of fault.Early stage employing polarity of traveling wave comparison expression direction protection carries out the identification of He Zhong Library circuit; method is similar to a kind of simple travelling wave ranging, has occurred being difficult to identify to line end near fault, polarity same problem that forward and reverse row ripple occurs in asymmetric fault situation and do not consider the problems such as isolating switch breakers asynchronous closing.

Summary of the invention

The technical problem to be solved in the present invention is that the circuit proposing the capable ripple of a kind of utilization orientation short window integrated value closes a floodgate Fault Identification element method of discrimination, in order to the stability of the power supply reliability and system paired running that improve single-pole reclosing circuit.

Technical scheme of the present invention is: the circuit of the fixed short window integrated value of the capable baud of a kind of utilization orientation closes a floodgate fault recognition method, when transmission line of electricity generation singlephase earth fault, adopt single-pole reclosing, the closing line mould current traveling wave utilizing measuring end to obtain and the closing line mode voltage row capable ripple of wave structure forward current and the capable ripple of inverse current, ask for the absolute value of direct wave and backward-travelling wave respectively, and calculate rear 2 τ that close a floodgate _min~ 4 τ _mintime window in the ratio of integrated value of forward and reverse row ripple absolute value build Fault Identification criterion of closing a floodgate; If the ratio of integrated value is less than the threshold value k of setting, be then judged to the non-fault circuit that closes a floodgate; If the ratio of integrated value is greater than k, be judged to fault of closing a floodgate.

Concrete steps are:

(1) after protected circuit generation singlephase earth fault; open failure phase; now the isolating switch of fault phase is held to perform closing operation by protected circuit measuring end M; protected circuit other end N holds isolating switch to be in off-state; the popular ripple of three-phase electricity and voltage traveling wave is obtained by measuring end M; three-phase voltage and the popular wavelength-division of three-phase electricity are not utilized formula (1), (2) carry out phase-model transformation, extract three line mode voltage component Δ u _α, Δ u _βwith Δ u _γwith current component Δ i _α, Δ i _βwith Δ i _γ:

$\left[\begin{array}{c}\mathrm{\Δ}{u}_{\mathrm{\α}}\\ \mathrm{\Δ}{u}_{\mathrm{\β}}\\ \mathrm{\Δ}{u}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{u}_A\\ \mathrm{\Δ}{u}_B\\ \mathrm{\Δ}{u}_C\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}\mathrm{\Δ}{i}_{\mathrm{\α}}\\ \mathrm{\Δ}{i}_{\mathrm{\β}}\\ \mathrm{\Δ}{i}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{i}_A\\ \mathrm{\Δ}{i}_B\\ \mathrm{\Δ}{i}_C\end{array}\right]---\left(2\right)$

In formula (1), Δ u _a, Δ u _bwith Δ u _cbe respectively three-phase voltage, Δ i in formula (2) _a, Δ i _bwith Δ i _cbe respectively three-phase current;

(2) from Δ u _α, Δ u _β, Δ u _γwith Δ i _α, Δ i _β, Δ i _γin choose line mode voltage Δ u containing fault phase _mwith line mould electric current Δ i _m, utilize (3), the capable ripple of (4) formula structure forward current ripple capable of inverse current

$i_m^{+}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}+\mathrm{\Δ}{i}_m\left(n\right)---\left(3\right)$

$i_m^{-}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}-\mathrm{\Δ}{i}_m\left(n\right)---\left(4\right)$

In formula (3) and formula (4), n represents sampled point, subscript m=α or β or γ, represents the modulus chosen;

(3) characteristic quantity is extracted: calculate forward current capable ripple absolute value and the capable ripple absolute value of inverse current after closing a floodgate respectively, obtain with

(4) formula (5), (6) are utilized to calculate rear 2 τ of combined floodgate respectively _min~ 4 τ _min(τ _minfor row ripple propagates the time once used, τ herein at the shortest total track length that perfects _min=l _min/ v) time window in the integrated value S of forward current capable ripple absolute value and the capable ripple absolute value of inverse current ⁺and S ^-:

$S^{+}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{+}\left(n\right)\right|\mathrm{dt}---\left(5\right)$

$S^{-}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{-}\left(n\right)\right|\mathrm{dt}---\left(6\right)$

Formula (5) and (6) middle t ₀=2 τ _min;

(5) the ratio λ of forward and reverse current traveling wave absolute value integration is asked for according to formula (7) _∑:

λ _∑＝S ⁺/S ^－(7)

According to integration ratio λ _∑size carry out the differentiation of fault of closing a floodgate:

If λ _∑be less than the threshold value k of setting, be then judged to the non-fault circuit that closes a floodgate;

If λ _∑be greater than or equal to k, be then judged to fault of closing a floodgate.

Utilize PSCAD electromagnetic transient simulation software, along protected circuit MN, a trouble spot is set every Nkm and carries out all fronts traversal, according to the integration ratio λ calculated _∑the regularity of distribution along the line, to adjust value to threshold value k.

The invention has the beneficial effects as follows: the combined floodgate that this method adopts direction row ripple integrated value to compare closes a floodgate to Fault Identification element energy reliable recognition the situation of faulty line, avoids circuit to suffer secondary pulse, improves the reliability of component recognition, quick-action.This method is not by the impact of abort situation, transition resistance, the initial phase angle of fault.

Accompanying drawing explanation

Fig. 1 is the transmission line of electricity analogue system figure in embodiment 1,2,3;

Fig. 2 is the gained of emulation traversal completely λ _∑rule figure along the line;

Fig. 3 is the line mode voltage Δ u containing fault phase in embodiment 1 _mcurve;

Fig. 4 is the line mould electric current Δ i containing fault phase in embodiment 1 _mcurve;

Fig. 5 is the capable ripple of forward current and the capable curve line of inverse current in embodiment 1;

Fig. 6 is forward current capable ripple absolute value and inverse current capable ripple absolute value curve in embodiment 1;

Fig. 7 is the line mode voltage Δ u containing fault phase in embodiment 2 _mcurve;

Fig. 8 is the line mould electric current Δ i containing fault phase in embodiment 2 _mcurve;

Fig. 9 is the capable ripple of forward current and the capable curve line of inverse current in embodiment 2;

Figure 10 is forward current capable ripple absolute value and inverse current capable ripple absolute value curve in embodiment 2;

Figure 11 is the line mode voltage Δ u containing fault phase in embodiment 3 _mcurve;

Figure 12 is the line mould electric current Δ i containing fault phase in embodiment 3 _mcurve;

Figure 13 is the capable ripple of forward current and the capable curve line of inverse current in embodiment 3;

Figure 14 is forward current capable ripple absolute value and inverse current capable ripple absolute value curve in embodiment 3.

Embodiment

Below in conjunction with (accompanying drawing and) embodiment, the invention will be further described.

Embodiment 1 embodiment 1: 500kV transmission line of electricity Simulation Model as shown in Figure 1, protected circuit is MN, line length L _pM=150km, L _mN=150km, L _nQ=220km, sampling rate is 1MHz.If the A phase isolating switch that protected circuit N holds is in off-state; the A phase isolating switch held by protected circuit measuring end M performs closing operation; suppose circuit MN non-fault respectively and hold 149km that AG metallic earthing fault occurs apart from M, transition resistance is 0 Ω, 90 °, initial phase angle.

After protected circuit generation singlephase earth fault, open failure phase, now hold the isolating switch of fault phase to perform closing operation by protected circuit measuring end M, protected circuit other end N holds isolating switch to be in off-state.Gather circuit carrying capacity at closing and survey the end popular ripple of three-phase electricity that M produces and the capable ripple of three-phase voltage.Three-phase voltage and the popular wavelength-division of three-phase electricity are not utilized formula (1), (2) carry out phase-model transformation, extract three line mode voltage component Δ u _α, Δ u _βwith Δ u _γwith current component Δ i _α, Δ i _βwith Δ i _γ:

$\left[\begin{array}{c}\mathrm{\Δ}{u}_{\mathrm{\α}}\\ \mathrm{\Δ}{u}_{\mathrm{\β}}\\ \mathrm{\Δ}{u}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{u}_A\\ \mathrm{\Δ}{u}_B\\ \mathrm{\Δ}{u}_C\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}\mathrm{\Δ}{i}_{\mathrm{\α}}\\ \mathrm{\Δ}{i}_{\mathrm{\β}}\\ \mathrm{\Δ}{i}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{i}_A\\ \mathrm{\Δ}{i}_B\\ \mathrm{\Δ}{i}_C\end{array}\right]---\left(2\right)$

In formula (1), Δ u _a, Δ u _bwith Δ u _cbe respectively three-phase voltage, Δ i in formula (2) _a, Δ i _bwith Δ i _cbe respectively three-phase current;

From Δ u _α, Δ u _β, Δ u _γwith Δ i _α, Δ i _β, Δ i _γin choose line mode voltage Δ u containing fault phase _mwith line mould electric current Δ i _m, in this example, fault phase is A phase, therefore m=ɑ, line mode voltage Δ u _ɑ, Δ i _ɑwaveform as shown in Figure 3,4.By line mode voltage Δ u _ɑ, Δ i _ɑsubstitute into (3), the capable ripple of (4) formula structure forward current ripple capable of inverse current its waveform as shown in Figure 5.

$i_m^{+}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}+\mathrm{\Δ}{i}_m\left(n\right)---\left(3\right)$

$i_m^{-}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}-\mathrm{\Δ}{i}_m\left(n\right)---\left(4\right)$

Extract characteristic quantity: calculate forward current capable ripple absolute value and the capable ripple absolute value of inverse current after closing a floodgate, obtain with as shown in Figure 6.

Rear 2 τ that close a floodgate are calculated respectively according to formula (5), (6) _min~ 4 τ _mintime window (1ms) interior forward current capable ripple absolute value and the integrated value of the capable ripple absolute value of inverse current be S ⁺=1634.9, S ^-=1364.

$S^{+}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{+}\left(n\right)\right|\mathrm{dt}---\left(5\right)$

$S^{-}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{-}\left(n\right)\right|\mathrm{dt}---\left(6\right)$

Utilize PSCAD electromagnetic transient simulation software, along protected circuit MN, a trouble spot is set every 1km and carries out all fronts traversal, according to the integration ratio λ calculated _∑the regularity of distribution along the line, being adjusted by threshold value k is 0.5.

By S ⁺, S ^-value substitute into formula (7) λ _∑=S ⁺/ S ^-, calculate the ratio λ of forward and reverse current traveling wave absolute value integration _∑=S ⁺/ S ^-=1.20, due to λ _∑be greater than threshold value 0.5, therefore be judged as fault of closing a floodgate.

Embodiment 2: 500kV transmission line of electricity Simulation Model as shown in Figure 1, protected circuit is MN, line length L _pM=150km, L _mN=150km, L _nQ=220km, sampling rate is 1MHz.If the A phase isolating switch of N end is in off-state, the A phase isolating switch held by M performs closing operation, and suppose circuit MN non-fault respectively and hold 60km that BG metallic earthing fault occurs apart from M, transition resistance is 10 Ω, 90 °, initial phase angle.Gather circuit carrying capacity at closing and survey the end popular ripple of three-phase electricity that M produces and the capable ripple of three-phase voltage.Three-phase voltage and the popular Pohle formula (1) of three-phase electricity, (2) are carried out phase-model transformation, extracts three line mode voltage component Δ u _α, Δ u _βwith Δ u _γwith current component Δ i _α, Δ i _βwith Δ i _γ, and choose the line mode voltage Δ u containing fault phase _mwith line mould electric current Δ i _mas shown in Figure 7,8.Utilize (3), the capable ripple of (4) formula structure forward current ripple capable of inverse current as shown in Figure 9.Calculate forward current capable ripple absolute value and the capable ripple absolute value of inverse current after closing a floodgate, obtain with as shown in Figure 10.According to formula (5), (6) calculate respectively close a floodgate after 1ms time window in the integrated value of forward current capable ripple absolute value and the capable ripple absolute value of inverse current be S ⁺=1241.1, S ^-=1286.7, then the ratio λ of forward and reverse current traveling wave absolute value integration _∑=S ⁺/ S ^-=0.96, due to λ _∑be greater than 0.5, therefore be judged as fault of closing a floodgate.

Embodiment 3: 500kV transmission line of electricity Simulation Model as shown in Figure 1, protected circuit is MN, line length L _pM=150km, L _mN=150km, L _nQ=220km, sampling rate is 1MHz.If the A phase isolating switch of N end is in off-state, the A phase isolating switch held by M performs closing operation, and suppose circuit MN non-fault respectively and hold 90km that CG metallic earthing fault occurs apart from M, transition resistance is 10 Ω, 90 °, initial phase angle.Gather circuit carrying capacity at closing and survey the end popular ripple of three-phase electricity that M produces and the capable ripple of three-phase voltage.Three-phase voltage and the popular Pohle formula (1) of three-phase electricity, (2) are carried out phase-model transformation, extracts three line mode voltage component Δ u _α, Δ u _βwith Δ u _γwith current component Δ i _α, Δ i _βwith Δ i _γ, and choose the line mode voltage Δ u containing fault phase _mwith line mould electric current Δ i _mas shown in Figure 11,12.Utilize (3), the capable ripple of (4) formula structure forward current ripple capable of inverse current as shown in figure 13.Calculate forward current capable ripple absolute value and the capable ripple absolute value of inverse current after closing a floodgate, obtain with as shown in figure 14.According to formula (5), (6) calculate respectively close a floodgate after 1ms time window in the integrated value of forward current capable ripple absolute value and the capable ripple absolute value of inverse current be S ⁺=181.0, S ^-=1083.4, then the ratio λ of forward and reverse current traveling wave absolute value integration _∑=S ⁺/ S ^-=0.1671, due to λ _∑be less than 0.5, therefore be judged as the non-fault circuit that closes a floodgate.

Above the specific embodiment of the present invention is explained in detail, but the present invention is not limited to above-mentioned embodiment, in the ken that those of ordinary skill in the art possess, various change can also be made under the prerequisite not departing from present inventive concept.

Claims (2)

1. the circuit of the fixed short window integrated value of the capable baud of utilization orientation closes a floodgate fault recognition method, it is characterized in that: when transmission line of electricity generation singlephase earth fault, adopt single-pole reclosing, the closing line mould current traveling wave utilizing measuring end to obtain and the closing line mode voltage row capable ripple of wave structure forward current and the capable ripple of inverse current, ask for the absolute value of direct wave and backward-travelling wave respectively, and calculate rear 2 τ that close a floodgate _min~ 4 τ _mintime window in the ratio of integrated value of forward and reverse row ripple absolute value build Fault Identification criterion of closing a floodgate; If the ratio of integrated value is less than the threshold value k of setting, be then judged to the non-fault circuit that closes a floodgate; If the ratio of integrated value is greater than k, be judged to fault of closing a floodgate.

2. the circuit of the fixed short window integrated value of the capable baud of utilization orientation according to claim 1 closes a floodgate fault recognition method, it is characterized in that concrete steps are:

(1) after protected circuit generation singlephase earth fault; open failure phase; now the isolating switch of fault phase is held to perform closing operation by protected circuit measuring end M; protected circuit other end N holds isolating switch to be in off-state; the popular ripple of three-phase electricity and voltage traveling wave is obtained by measuring end M; three-phase voltage and the popular wavelength-division of three-phase electricity are not utilized formula (1), (2) carry out phase-model transformation, extract three line mode voltage component Δ u _α, Δ u _βwith Δ u _γwith current component Δ i _α, Δ i _βwith Δ i _γ:

$\left[\begin{array}{c}\mathrm{\Δ}{u}_{\mathrm{\α}}\\ \mathrm{\Δ}{u}_{\mathrm{\β}}\\ \mathrm{\Δ}{u}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{u}_A\\ \mathrm{\Δ}{u}_B\\ \mathrm{\Δ}{u}_C\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}\mathrm{\Δ}{i}_{\mathrm{\α}}\\ \mathrm{\Δ}{i}_{\mathrm{\β}}\\ \mathrm{\Δ}{i}_{\mathrm{\γ}}\end{array}\right]=\left[\begin{array}{ccc}1& -1& 0\\ 1& 0& -1\\ 0& 1& -1\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{i}_A\\ \mathrm{\Δ}{i}_B\\ \mathrm{\Δ}{i}_C\end{array}\right]---\left(2\right)$

In formula (1), Δ u _a, Δ u _bwith Δ u _cbe respectively three-phase voltage, Δ i in formula (2) _a, Δ i _bwith Δ i _cbe respectively three-phase current;

(2) from Δ u _α, Δ u _β, Δ u _γwith Δ i _α, Δ i _β, Δ i _γin choose line mode voltage Δ u containing fault phase _mwith line mould electric current Δ i _m, utilize (3), the capable ripple of (4) formula structure forward current ripple capable of inverse current

$i_m^{+}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}+\mathrm{\Δ}{i}_m\left(n\right)---\left(3\right)$

$i_m^{-}\left(n\right)=\frac{\mathrm{\Δ}{u}_m\left(n\right)}{Z_{c,m}}-\mathrm{\Δ}{i}_m\left(n\right)---\left(4\right)$

In formula (3) and formula (4), n represents sampled point, subscript m=α or β or γ, represents the modulus chosen;

(3) characteristic quantity is extracted: calculate forward current capable ripple absolute value and the capable ripple absolute value of inverse current after closing a floodgate respectively, obtain with

(4) formula (5), (6) are utilized to calculate rear 2 τ of combined floodgate respectively _min~ 4 τ _mintime window in the integrated value S of forward current capable ripple absolute value and the capable ripple absolute value of inverse current ⁺and S ^-:

$S^{+}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{+}\left(n\right)\right|\mathrm{dt}$

(5)

$S^{-}={\∫}_{t_0}^{t_0+2{\mathrm{\τ}}_{\min }}\left|i_m^{-}\left(n\right)\right|\mathrm{dt}$

(6)

Formula (5) and (6) middle t ₀=2 τ _min;

(5) the ratio λ of forward and reverse current traveling wave absolute value integration is asked for according to formula (7) _∑:

λ _∑＝S ⁺/S ^－(7)

According to integration ratio λ _∑size carry out the differentiation of fault of closing a floodgate:

If λ _∑be less than the threshold value k of setting, be then judged to the non-fault circuit that closes a floodgate;

If λ _∑be greater than or equal to k, be then judged to fault of closing a floodgate.