CN104155569B - Method for selecting line of double circuit lines on same tower based on current traveling wave short time window wavelet coefficient polarity comparison - Google Patents

Abstract

The invention provides a method for selecting a line of double circuit lines on the same tower based on current traveling wave short time window wavelet coefficient polarity comparison, and belongs to the technical field of electric power system relay protection. When some line of the double power transmission circuit lines on the same tower has a fault, current traveling wave data of each line are detected and recorded. A phase-mode transformation matrix is used to calculate an [alpha] mode current traveling wave of each line, then wavelet transformation of the [alpha] mode current traveling wave of each line is carried out, and a high-frequency first scale wavelet coefficient is selected as a research object; and the relative polarity of the first scale wavelet coefficient of each line within a short time window is calculated, a fault line selection and determination matrix R is formed, and then a fault line can be determined according to element in the matrix R. Simulation analysis shows that the method provided by the invention can accurately determine a fault line when a single line of the double circuit lines on the same tower fails.

Description

A kind of common-tower double-return line selection based on current traveling wave short time-window wavelet coefficient Polarity comparision Line method

Technical field

The present invention relates to a kind of common-tower double-return line selection line method based on current traveling wave short time-window wavelet coefficient Polarity comparision, Belong to Relay Protection Technology in Power System field.

Background technology

Same tower double back transmission line is because of its low engineering cost, occupancy width of corridor is little, the construction period is short, operation maintenance is simple The advantages of list, remarkable in economical benefits, therefore it is widely used.Common-tower double-return line power transmission mode has 120 kinds of fault types, Wherein, cross line fault have 98 kinds although, from species for, cross line fault occupies the majority；But, from the probability that fault occurs For, same tower double back transmission line occurs the probability of single line down to account for 70%-80%.

So, during the transmission of electricity of common-tower double-return line, if can be quick, accurately in the case of line failure Select faulty line, can not only be by quick excision faulty line, in order to avoid the extension of fault.And power failure can also be reduced Time, improve the reliability of system.The present invention utilizes the comparator matrix failure judgement of current traveling wave short time-window wavelet coefficient polarity Circuit, not only principle is simple, and accurately failure judgement can be located at bus or a certain bar outlet.

Content of the invention

The technical problem to be solved in the present invention is the situation that single line down occurs for common-tower double-return line, proposes a kind of base Common-tower double-return line selection line method in current traveling wave short time-window wavelet coefficient Polarity comparision.

The technical scheme is that：A kind of common-tower double-return line based on current traveling wave short time-window wavelet coefficient Polarity comparision Selection method, when same tower double back transmission line returns line failure, detects and records each bar line current traveling wave data； Ask for each bar circuit α mould current traveling wave respectively using phase-model transformation matrix and carry out wavelet transformation, choose high frequency first yardstick little Wave system number is as object of study；Calculate the relative polarity of each bar circuit the first multi-scale wavelet coefficient in short time-window, and form event Barrier route selection discrimination matrix R, judges faulty line according to the element in R.

Specific implementation step is：

(1) when same tower double back transmission line breaks down, using the electricity of electric current table record each bar circuit of each outgoing line side Popular wave number is according to i_a、i_b、i_c, ask for each bar circuit α mould current traveling wave i respectively using phase-model transformation matrix Q_α,

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\\ i_0\end{array}\right]=Q*\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

(2) by each bar circuit α mould current traveling wave i_αCarry out wavelet decomposition, obtain the first multi-scale wavelet coefficient of each bar outlet d_{1_n}, wherein n=1,2,3 ...；

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to formula (2)；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]---\left(2\right)$

In formula, d_{1_i}Represent circuit i high frequency the first multi-scale wavelet coefficient；d_{1_j}Represent circuit j high frequency the first multi-scale wavelet system Number；r_ijRepresent d_{1_i}And d_{1_j}The result of Polarity comparision, i=1,2,3 ...；J=1,2,3 ...；r_ij=-1 expression d_{1_i}And d_{1_j}Polarity On the contrary, r_ij=1 expression d_{1_i}And d_{1_j}Polarity is identical, and k represents wavelet coefficient length；

(4) calculated according to formula (3), form same tower double back transmission line fault route selection matrix R：

It is the number failure judgement circuit of " -1 " according to every row element：

If all of element is all " 1 " in R, it is judged as bus-bar fault；

If the element for " -1 " is n-1 in the i-th row, i-th line road is faulty circuit.

The principle of the present invention is：……

The invention has the beneficial effects as follows：

What the 1st, the present invention compared is relative polarity in short time-window for the wavelet coefficient, compared with wavelet modulus maxima Relatively, reliability is high.

2nd, the present invention only needs to can achieve failure line selection using the magnitude of current, is not required to introduce voltage.

Brief description

Fig. 1 is same tower double back transmission line structural representation of the present invention：In figure, P, M, N, Q are the bus of system, C_EFor mother Line stray capacitance over the ground, F₁、F₂、F₃、F₄It is respectively circuit PM section, simulated fault at double loop MN section I, II time and bus M Point.The long 200km of PM section, the long 140km of MN section, the long 260km of NQ section.

Fig. 2 is the route selection flow chart of the present invention；

Fig. 3 is F in the embodiment of the present invention 1₁High frequency first chi of 1,2 and 3 protection installation place α mould current traveling waves during fault Degree wavelet coefficient curve chart；

Fig. 4 is F in the embodiment of the present invention 2₂High frequency first chi of 1,2 and 3 protection installation place α mould current traveling waves during fault Degree wavelet coefficient curve chart；

Fig. 5 is F in the embodiment of the present invention 3₃High frequency first chi of 1,2 and 3 protection installation place α mould current traveling waves during fault Degree wavelet coefficient curve chart；

Fig. 6 is F in the embodiment of the present invention 4₄High frequency first chi of 1,2 and 3 protection installation place α mould current traveling waves during fault Degree wavelet coefficient curve chart.

Specific embodiment

With reference to the accompanying drawings and detailed description, the invention will be further described.

A kind of common-tower double-return line selection line method based on current traveling wave short time-window wavelet coefficient Polarity comparision, works as common-tower double-return When transmission line of electricity returns line failure, detect and record each bar line current traveling wave data；Divided using phase-model transformation matrix Do not ask for each bar circuit α mould current traveling wave and carry out wavelet transformation, choose high frequency the first multi-scale wavelet coefficient as object of study； Calculate the relative polarity of each bar circuit the first multi-scale wavelet coefficient in short time-window, and form failure line selection discrimination matrix R, according to Element in R judges faulty line.

Specific implementation step is：

(1) when same tower double back transmission line breaks down, using the electricity of electric current table record each bar circuit of each outgoing line side Popular wave number is according to i_a、i_b、i_c, ask for each bar circuit α mould current traveling wave i respectively using phase-model transformation matrix Q_α,

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\\ i_0\end{array}\right]=Q*\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

(2) by each bar circuit α mould current traveling wave i_αCarry out wavelet decomposition, obtain the first multi-scale wavelet coefficient of each bar outlet d_{1_n}, wherein n=1,2,3 ...；

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to formula (2)；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]---\left(2\right)$

In formula, d_{1_i}Represent circuit i high frequency the first multi-scale wavelet coefficient；d_{1_j}Represent circuit j high frequency the first multi-scale wavelet system Number；r_ijRepresent d_{1_i}And d_{1_j}The result of Polarity comparision, i=1,2,3 ...；J=1,2,3 ...；r_ij=-1 expression d_{1_i}And d_{1_j}Polarity On the contrary, r_ij=1 expression d_{1_i}And d_{1_j}Polarity is identical, and k represents wavelet coefficient length；

(4) calculated according to formula (3), form same tower double back transmission line fault route selection matrix R：

It is the number failure judgement circuit of " -1 " according to every row element：

If all of element is all " 1 " in R, it is judged as bus-bar fault；

If the element for " -1 " is n-1 in the i-th row, i-th line road is faulty circuit.

Embodiment 1：500kV double back transmission line system diagram is as shown in Figure 1.Its line parameter circuit value is as follows：Total track length PM section 200km, MN section 140km, NQ end 260km.Abort situation：There is A phase earth fault in PM section at the 10km of M end.Impedance ground 0 Ω, 90 ° of primary fault angle, sample rate is 1MHz.

(1) current traveling wave data i of 3 circuits is obtained according to the step (1) in description_a、i_b、i_c, and utilize phase moding Change matrix Q and ask for each bar circuit α mould current traveling wave i respectively_α.

Wherein：

(2) by 3 circuit α mould current traveling wave i in (1)_αCarry out wavelet decomposition, the frequency range obtaining each bar outlet exists The first multi-scale wavelet coefficient d of 250KHz～500KHz_{1_n}, its curve chart is as indicated at 3.

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to the step (3) in description；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]$

Obtain r₁₁=r₂₂=r₃₃=1, r₁₂=r₂₁=-1, r₁₃=r₃₁=-1, r₂₃=r₃₂=1.

(4) same tower double back transmission line fault route selection matrix R such as following formula is obtained according to the step (4) in description：

$R=\left[\begin{array}{ccc}1& -1& -1\\ -1& 1& 1\\ -1& 1& 1\end{array}\right]$

" -1 " number only having the 1st row element as can be seen from the above equation is 2, according to the flow chart shown in Fig. 2, in conjunction with Fig. 1 The position of middle protection device understands, circuit PM section is faulty line.

Embodiment 2：500kV double back transmission line system diagram is as shown in Figure 1.Its line parameter circuit value is as follows：Total track length PM section 200km, MN section 140km, NQ end 260km.Abort situation：There is A phase earth fault in MN section I loop line at the 60km of M end.Ground connection resistance Anti- 10 Ω, 90 ° of primary fault angle, sample rate is 1MHz.

(1) current traveling wave data i of 3 circuits is obtained according to the step (1) in description_a、i_b、i_c, and utilize phase moding Change matrix Q and ask for each bar circuit α mould current traveling wave i respectively_α.

Wherein：

(2) by 3 circuit α mould current traveling wave i in (1)_αCarry out wavelet decomposition, the frequency range obtaining each bar outlet exists The first multi-scale wavelet coefficient d of 250KHz～500KHz_{1_n}, its curve chart is as indicated at 3.

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to the step (3) in description；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]$

Obtain r₁₁=r₂₂=r₃₃=1, r₁₂=r₂₁=-1, r₁₃=r₃₁=1, r₂₃=r₃₂=-1.

(4) same tower double back transmission line fault route selection matrix R such as following formula is obtained according to the step (4) in description：

$R=\left[\begin{array}{ccc}1& -1& 1\\ -1& 1& -1\\ 1& -1& 1\end{array}\right]$

" -1 " number only having the 2nd row element as can be seen from the above equation is 2, according to the flow chart shown in Fig. 2, in conjunction with Fig. 1 The position of middle protection device understands, circuit MN section I loop line is faulty line.

Embodiment 3：500kV double back transmission line system diagram is as shown in Figure 1.Its line parameter circuit value is as follows：Total track length PM section 200km, MN section 140km, NQ end 260km.Abort situation：There is A phase earth fault in MN section II loop line at the 90km of M end.Ground connection Impedance 0 Ω, 90 ° of primary fault angle, sample rate is 1MHz.

(1) current traveling wave data i of 3 circuits is obtained according to the step (1) in description_a、i_b、i_c, and utilize phase moding Change matrix Q and ask for each bar circuit α mould current traveling wave i respectively_α.

Wherein：

(2) by 3 circuit α mould current traveling wave i in (1)_αCarry out wavelet decomposition, the frequency range obtaining each bar outlet exists The first multi-scale wavelet coefficient d of 250KHz～500KHz_{1_n}, its curve chart is as indicated at 3.

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to the step (3) in description；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]$

Obtain r₁₁=r₂₂=r₃₃=1, r₁₂=r₂₁=1, r₁₃=r₃₁=-1, r₂₃=r₃₂=-1.

(4) same tower double back transmission line fault route selection matrix R such as following formula is obtained according to the step (4) in description：

$R=\left[\begin{array}{ccc}1& 1& -1\\ 1& 1& -1\\ -1& -1& 1\end{array}\right]$

" -1 " number only having the 3rd row element as can be seen from the above equation is 2, according to the flow chart shown in Fig. 2, in conjunction with Fig. 1 The position of middle protection device understands, circuit MN section II loop line is faulty line.

Embodiment 4：500kV double back transmission line system diagram is as shown in Figure 1.Its line parameter circuit value is as follows：Total track length PM section 200km, MN section 140km, NQ end 260km.Abort situation：Bus M breaks down, and sample rate is 1MHz.

(1) current traveling wave data i of 3 circuits is obtained according to the step (1) in description_a、i_b、i_c, and utilize phase moding Change matrix Q and ask for each bar circuit α mould current traveling wave i respectively_α.

Wherein：

(2) by 3 circuit α mould current traveling wave i in (1)_αCarry out wavelet decomposition, the frequency range obtaining each bar outlet exists The first multi-scale wavelet coefficient d of 250KHz～500KHz_{1_n}, its curve chart is as indicated at 3.

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to the step (3) in description；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]$

Obtain r₁₁=r₁₂=r₂₁=r₂₂=r₁₃=r₃₁=r₂₃=r₃₂=r₃₃=1.

(4) same tower double back transmission line fault route selection matrix R such as following formula is obtained according to the step (4) in description：

$R=\left[\begin{array}{ccc}1& 1& 1\\ 1& 1& 1\\ 1& 1& 1\end{array}\right]$

In R, all of element is all " 1 " as can be seen from the above equation, according to the flow chart shown in Fig. 2, protects in conjunction with Fig. 1 The position of device understands, fault occurs in bus M.

Above in conjunction with accompanying drawing, the specific embodiment of the present invention is explained in detail, but the present invention be not limited to above-mentioned Embodiment, in the ken that those of ordinary skill in the art possess, can also be before without departing from present inventive concept Put that various changes can be made.

Claims (1)

1. a kind of common-tower double-return line selection line method based on current traveling wave short time-window wavelet coefficient Polarity comparision it is characterised in that： When same tower double back transmission line returns line failure, detect and record each bar line current traveling wave data；Using phase mould Transformation matrix is asked for each bar circuit α mould current traveling wave respectively and is carried out wavelet transformation, chooses high frequency the first multi-scale wavelet coefficient and makees For object of study；Calculate the relative polarity of each bar circuit the first multi-scale wavelet coefficient in short time-window, and form failure line selection and sentence Other matrix R, judges faulty line according to the element in R；

Specific implementation step is：

(1) when same tower double back transmission line breaks down, using the electric current row of electric current table record each bar circuit of each outgoing line side Wave number is according to i_a、i_b、i_c, ask for each bar circuit α mould current traveling wave i respectively using phase-model transformation matrix Q_α,

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\\ i_0\end{array}\right]=Q*\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]---\left(1\right)$

(2) by each bar circuit α mould current traveling wave i_αCarry out wavelet decomposition, obtain the first multi-scale wavelet coefficient d of each bar outlet_{1_n}, Wherein n=1,2,3 ...；

(3) relative polarity between each bar outlet the first multi-scale wavelet coefficient is calculated according to formula (2)；

$r_{ij}=sign\[\underset{k=1}{\overset{n}{\Σ}}{d}_{1\_i}\left(k\right)\·d_{1\_j}\left(k\right)\]---\left(2\right)$

In formula, d_{1_i}Represent circuit i high frequency the first multi-scale wavelet coefficient；d_{1_j}Represent circuit j high frequency the first multi-scale wavelet coefficient；r_ij Represent d_{1_i}And d_{1_j}The result of Polarity comparision, i=1,2,3 ...；J=1,2,3 ...；r_ij=-1 expression d_{1_i}And d_{1_j}Opposite polarity, r_ij=1 expression d_{1_i}And d_{1_j}Polarity is identical, and k represents wavelet coefficient length；

(4) calculated according to formula (3), form same tower double back transmission line fault route selection matrix R：

It is the number failure judgement circuit of " -1 " according to every row element：

If all of element is all " 1 " in R, it is judged as bus-bar fault；

If the element for " -1 " is n-1 in the i-th row, i-th line road is faulty circuit.