CN104253420A - Distance protection method for non-transposition double-circuit lines on same tower - Google Patents

Abstract

The invention discloses a distance protection method for non-transposition double-circuit lines on the same tower. The method comprises the following steps of firstly, according to the existing fault phase selection method, accurately identifying the fault phase of the non-transposition double-circuit lines on the same tower; then, utilizing a six-phase impedance matrix obtained by an actual pole tower structure to calculate the average self-impedance, inter-phase mutual impedance, inter-line mutual impedance, and positive sequence impedance and zero sequence impedance of a virtual line; performing the fault calculation on the occurred fault type, and performing phase division and rectification on the protection area of each fault phase. The method has the advantage that the distance protection work of the non-transposition double-circuit lines on the same tower is controlled in the excellent state, and the important realistic meaning is realized for guaranteeing the safe and stable running of power systems.

Description

A kind of distance protecting method for the multiple-circuit on same tower that do not replace

Technical field

The invention belongs to field of power, relate to the technical field of relay protection of the multiple-circuit on same tower that do not replace, be specifically related to a kind of distance protecting method for the multiple-circuit on same tower that do not replace.

Background technology

Current common-tower double-return line obtains increasingly extensive application in high-voltage fence, and distance protection plays an important role as a pair multiple-circuit on same tower safe operation of circuit main flow backup protection.There is zero-sequence mutual inductance between the multiple-circuit on same tower of desirable transposition, under this effect, the actuating range of ground distance protection can surmount and shorten, and brings a lot of Practical Project problem to relaying protection.The problem that the actuating range that can solve ground distance protection preferably by introducing adjacent line zero sequence current compensation surmounts and shortens, but it needs the electric parameters introducing another loop line, does not also obtain on-the-spot application at present.But can predict, along with the development of digital transformer substation and the extensive use of electronic instrument transformer, this band backoff algorithm can obtain the attention of engineering circles.

When desirable transposition common-tower double-return line breaks down, the distancing element of protection can calculate the impedance of protection installation place to fault point comparatively accurately after another line zero sequence current compensation.But for short distance transmission line or high pressure especially supertension line in engineer applied, for consideration technically and economically, circuit does not often replace completely, the measurement impedance now protected is not only by the impact of zero-sequence mutual inductance, also be subject to the effect of positive sequence mutual inductance and negative phase-sequence mutual inductance simultaneously, distancing element can show again the characteristic of some complexity after zero sequence compensation, distance protection scope during its different separate fault can show and significantly shorten and surmount, be difficult to meet high pressure bulk power grid not replace the backup protection requirement of common-tower double-return line, larger potential safety hazard has been buried to the safe and stable operation of electrical network.

Summary of the invention

For solving above-mentioned prior art Problems existing; the object of this invention is to provide a kind of distance protecting method for the multiple-circuit on same tower that do not replace; the asymmetry of the circuit that do not replace can be immune to; and for the operating characteristics calculating fault impedance and distance protection that various fault type can be very fast, very big reliability and the selectivity that must improve protection.

For achieving the above object, the technical solution used in the present invention is:

Step one: after elected phase module starts, the voltage of common-tower double-return line protection installation place of not replaced by the collection of voltage transformer summation current transformer and two electric currents of loop line

Step 2: separate according to the do not replace fault of common-tower double-return line of existing fault phase-selecting method accurate recognition;

Step 3: seek out six phase of impedance matrix M based on actual tower structure and wire parameter, calculates the average self-impedance Z of double loop respectively _l, mutual impedance Z _sand mutual impedance Z between line _m, and then draw virtual positive sequence impedance Z ₁with zero sequence impedance Z ₀, solving of each impedance is herein as follows:

$M=\left[\begin{array}{cccccc}{Z}_{1A}& Z_{1\mathrm{AB}}& Z_{1\mathrm{AC}}& Z_{12\mathrm{AA}}& Z_{12\mathrm{AB}}& Z_{12\mathrm{AC}}\\ Z_{1\mathrm{BA}}& Z_{1B}& Z_{1\mathrm{BC}}& Z_{12\mathrm{BA}}& Z_{12\mathrm{BB}}& Z_{12\mathrm{BC}}\\ Z_{1\mathrm{CA}}& Z_{1\mathrm{CB}}& Z_{1C}& Z_{12\mathrm{CA}}& Z_{12\mathrm{CB}}& Z_{12\mathrm{CC}}\\ Z_{21\mathrm{AA}}& Z_{21\mathrm{AB}}& Z_{21\mathrm{AC}}& Z_{2A}& Z_{2\mathrm{AB}}& Z_{2\mathrm{AC}}\\ Z_{21\mathrm{BA}}& Z_{21\mathrm{BB}}& Z_{21\mathrm{BC}}& Z_{2\mathrm{BA}}& Z_{2B}& Z_{2\mathrm{BC}}\\ Z_{21\mathrm{CA}}& Z_{21\mathrm{CB}}& Z_{21\mathrm{CC}}& Z_{2\mathrm{CA}}& Z_{2\mathrm{CB}}& Z_{2C}\end{array}\right]$

In above-mentioned six phase of impedance matrix M: 1 and 2 refer to two loop line I loop line and II loop lines respectively, A, B and C refer to the separate A phase of circuit, B phase and C phase respectively;

Z _L＝1/6*(Z _1A+Z _1B+Z _1C+Z _2A+Z _2B+Z _2C) (1)

Z _S＝1/6*(Z _1AB+Z _1BC+Z _1CA+Z _2AB+Z _2BC+Z _2CA) (2)

Z ₁＝Z _L-Z _S (3)

Z ₀＝Z _L+2Z _S (4)

Z _m＝1/9*(Z _12AA+Z _12BB+Z _12CC+Z _12AB+Z _12BC+Z _12CA+Z _21AB+Z _21BC+Z _21CA) (5)

Step 4: 1. when Fault Phase Selection is judged to single loop line earth fault occurs, formula (6) gives fault impedance computational methods during I loop line A phase earth fault, and other class single phase ground fault computational methods are identical;

$Z_d=\frac{{\stackrel{\·}{U}}_A}{({\stackrel{\·}{I}}_{1A}+{\stackrel{\·}{I}}_{1B}\·\frac{Z_{1\mathrm{AB}}}{Z_{1A}}+{\stackrel{\·}{I}}_{1C}\·\frac{Z_{1\mathrm{AC}}}{Z_{1A}}+\frac{3\·Z_m{\stackrel{\·}{I}}_{20}}{Z_{1A}})}---\left(6\right)$

$3{\stackrel{\·}{I}}_{20}={\stackrel{\·}{I}}_{2A}+{\stackrel{\·}{I}}_{2B}+{\stackrel{\·}{I}}_{2C}---\left(7\right)$

Wherein: represent the zero-sequence current of II loop line, and 80% of operational failure phase total track length self-impedance as the distance protection definite value of a section in distance protection;

2. when Fault Phase Selection is judged to fault between single loop line line occurs, formula (8) gives fault impedance computational methods during I loop line AB phase-to phase fault, and other class list loop line phase-to phase fault computational methods are identical;

$Z_x=\frac{{\stackrel{\·}{U}}_A-{\stackrel{\·}{U}}_B}{({\stackrel{\·}{I}}_{1A}-{\stackrel{\·}{I}}_{1B})}---\left(8\right)$

Now, total track length is used calculated value 80% as the distance definite value of a section;

3., when Fault Phase Selection is judged to cross line fault occurs, formula (9) gives fault impedance computational methods during I loop line A phase cross line fault alternate with II loop line B, and other class inter-line fault calculation method is identical;

$Z_k=\frac{{\stackrel{\·}{U}}_A-{\stackrel{\·}{U}}_B}{{\stackrel{\·}{I}}_{1A}-{\stackrel{\·}{I}}_{2B}+(3K-K_0)({\stackrel{\·}{I}}_{10}-{\stackrel{\·}{I}}_{20})}---\left(9\right)$

Wherein:

$3{\stackrel{\·}{I}}_{10}={\stackrel{\·}{I}}_{1A}+{\stackrel{\·}{I}}_{1B}+{\stackrel{\·}{I}}_{1C}---\left(10\right)$

$K=\frac{Z_0-Z_1}{3Z_1}---\left(11\right)$

$K_0=\frac{Z_m}{Z_1}---\left(12\right)$

Wherein: represent the zero-sequence current of I loop line, K is zero-utility theory, K ₀for mutual inductance penalty coefficient, use 80% of the virtual positive sequence impedance of total track length in distance protection as the definite value of distance protection one section;

Step 5: the action situation differentiating distance protection according to the fault impedance value calculated.

The present invention compared to the prior art comparatively, possesses following advantage:

The computational methods of fault impedance when the inventive method directly obtains single loop wire single-phase ground fault, single loop line phase-to phase fault and cross line fault based on two loop line electric quantity information and six phase of impedance matrixes; between the average self-impedance of comprehensive use, mutual impedance, line, mutual impedance and virtual positive sequence impedance and zero sequence impedance calculate; what avoids the impact of traditional phase component method in each order components circuit accident analysis that the do not replace effect of intercoupling from, obtains with this Distance Protection Algorithm being immune to circuit asymmetry.

Accompanying drawing explanation

Fig. 1 is a kind of conspectus being applicable to the inventive method.

Fig. 2 is the flow chart realizing the inventive method.

Fig. 3 is that the measurement impedance sought out according to different faults point draws out its fault impedance trajectory diagram.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in further details.As shown in Figure 1, give the 330kV/100km common-tower double-return line simulation model that do not replace of both-end common bus, M side system positive sequence impedance is 1.0914+j12.45 Ω, zero sequence impedance is 5.187+j22.574 Ω, N side system parameter is identical with M side, common-tower double-return line arranges by phase sequence IBCA-IICAB and whole process does not replace, and its six phase of impedance matrix is:

$\begin{array}{ccccc}0.075+j0.461& 0.062+j0.141& 0.058+j0.213& 0.058+j0.168& 0.056+j0.192\\ 0.062+j0.126& & & & \\ 0.062+j0.141& 0.092+j0.391& 0.066+j0.165& 0.064+j0.127& 0.062+j0.126\\ 0.069+j0.114& & & & \\ 0.058+j0.214& 0.066+j0.165& 0.079+j0.441& 0.060+0.160& 0.058+j0.168\\ 0.064+j0.127& & & & \\ 0.058+j0.168& 0.064+j0.127& 0.060+0.160& 0.091+j0.441& 0.058+j0.214\\ 0.066+j0.165& & & & \\ 0.056+j0.192& 0.062+j0.126& 0.058+j0.168& 0.058+j0.214& 0.075+j0.461\\ 0.062+j0.141& & & & \\ 0.062+j0.126& 0.069+j0.114& 0.064+j0.127& 0.066+j0.165& 0.062+j0.141\\ 0.092+j0.391& & & & \end{array}$

When various fault type occurs circuit, use the distance protecting method that the present invention proposes., carry out measuring and calculation to double loop cross line fault herein, from 15km to 85km, arrange an IA-IIB phase-to phase fault point every 10km, the Distance Protection Algorithm then using the present invention to propose is adjusted the distance protective value analysis.

As shown in Figure 2, a kind of method for distinguishing the multiple-circuit on same tower fault type that do not replace, comprises the following steps:

Step one: after elected phase module starts, the voltage of common-tower double-return line protection installation place of not replaced by the collection of voltage transformer summation current transformer and two electric currents of loop line

Step 2: there occurs IA-IIB cross line fault according to the existing fault phase-selecting method accurate recognition common-tower double-return line that do not replace;

Step 3: calculate the average self-impedance Z of double loop respectively according to above-mentioned six known phase of impedance matrixes _lfor 0.0818+j0.4311 Ω, mutual impedance Z _sfor mutual impedance Z between 0.0620+j0.1733 Ω and line _mfor 0.0613+j0.1451 Ω, and then draw virtual positive sequence impedance Z ₁for 0.0198+j0.2578 Ω and zero sequence impedance Z ₀for 0.2058+j0.7777 Ω;

Step 4: because Fault Phase Selection program has been judged to be that circuit there occurs IA-IIB cross line fault, so according to measurement impedance value during formula (9) calculating different faults point; Now K is 0.6866-j0.1878 and K ₀for 0.5777-j0.1934, get 80% of the virtual positive sequence impedance of total track length is also the protection definite value of 1.5840+j20.6240 Ω as distance one section simultaneously;

Step 5: draw out its fault impedance trajectory diagram as shown in Figure 3 according to the measurement impedance that different faults point seeks out.

As shown in Figure 3, in order to the accuracy of these computational methods is described, make the track of the actual virtual impedance of different faults point equally as a comparison, simulation result shows, the fault impedance that use formula (9) calculates presents smaller negative error characteristic, but substantially can not cause the phenomenon that line fault surmounts, its measurement impedance track can follow the tracks of the track of practical impedance well, distancing element can reflect the cross line fault occurred in district well.

Claims (1)

1. for a distance protecting method for the multiple-circuit on same tower that do not replace, it is characterized in that, comprise the steps:

Step one: after elected phase module starts, the voltage of common-tower double-return line protection installation place of not replaced by the collection of voltage transformer summation current transformer and two electric currents of loop line

Step 2: separate according to the do not replace fault of common-tower double-return line of existing fault phase-selecting method accurate recognition;

Step 3: seek out six phase of impedance matrix M based on actual tower structure and wire parameter, calculates the average self-impedance Z of double loop respectively _l, mutual impedance Z _sand mutual impedance Z between line _m, and then draw virtual positive sequence impedance Z ₁with zero sequence impedance Z ₀, solving of each impedance is herein as follows:

$M=\left[\begin{array}{cccccc}{Z}_{1A}& Z_{1\mathrm{AB}}& Z_{1\mathrm{AC}}& Z_{12\mathrm{AA}}& Z_{12\mathrm{AB}}& Z_{12\mathrm{AC}}\\ Z_{1\mathrm{BA}}& Z_{1B}& Z_{1\mathrm{BC}}& Z_{12\mathrm{BA}}& Z_{12\mathrm{BB}}& Z_{12\mathrm{BC}}\\ Z_{1\mathrm{CA}}& Z_{1\mathrm{CB}}& Z_{1C}& Z_{12\mathrm{CA}}& Z_{12\mathrm{CB}}& Z_{12\mathrm{CC}}\\ Z_{21\mathrm{AA}}& Z_{21\mathrm{AB}}& Z_{21\mathrm{AC}}& Z_{2A}& Z_{2\mathrm{AB}}& Z_{2\mathrm{AC}}\\ Z_{21\mathrm{BA}}& Z_{21\mathrm{BB}}& Z_{21\mathrm{BC}}& Z_{2\mathrm{BA}}& Z_{2B}& Z_{2\mathrm{BC}}\\ Z_{21\mathrm{CA}}& Z_{21\mathrm{CB}}& Z_{21\mathrm{CC}}& Z_{2\mathrm{CA}}& Z_{2\mathrm{CB}}& Z_{2C}\end{array}\right]$

In above-mentioned six phase of impedance matrix M: 1 and 2 refer to two loop line I loop line and II loop lines respectively, A, B and C refer to the separate A phase of circuit, B phase and C phase respectively;

Z _L＝1/6*(Z _1A+Z _1B+Z _1C+Z _2A+Z _2B+Z _2C) (1)

Z _S＝1/6*(Z _1AB+Z _1BC+Z _1CA+Z _2AB+Z _2BC+Z _2CA) (2)

Z ₁＝Z _L-Z _S (3)

Z ₀＝Z _L+2Z _S (4)

Z _m＝1/9*(Z _12AA+Z _12BB+Z _12CC+Z _12AB+Z _12BC+Z _12CA+Z _21AB+Z _21BC+Z _21CA) (5)

Step 4: 1. when Fault Phase Selection is judged to single loop line earth fault occurs, formula (6) gives fault impedance computational methods during I loop line A phase earth fault, and other class single phase ground fault computational methods are identical;

$Z_d=\frac{{\stackrel{\·}{U}}_A}{({\stackrel{\·}{I}}_{1A}+{\stackrel{\·}{I}}_{1B}\·\frac{Z_{1\mathrm{AB}}}{Z_{1A}}+{\stackrel{\·}{I}}_{1C}\·\frac{Z_{1\mathrm{AC}}}{Z_{1A}}+\frac{3\·Z_m{\stackrel{\·}{I}}_{20}}{Z_{1A}})}---\left(6\right)$

$3{\stackrel{\·}{I}}_{20}={\stackrel{\·}{I}}_{2A}+{\stackrel{\·}{I}}_{2B}+{\stackrel{\·}{I}}_{2C}---\left(7\right)$

Wherein: represent the zero-sequence current of II loop line, and 80% of operational failure phase total track length self-impedance as the distance protection definite value of a section in distance protection;

2. when Fault Phase Selection is judged to fault between single loop line line occurs, formula (8) gives fault impedance computational methods during I loop line AB phase-to phase fault, and other class list loop line phase-to phase fault computational methods are identical;

$Z_x=\frac{{\stackrel{\·}{U}}_A-{\stackrel{\·}{U}}_B}{({\stackrel{\·}{I}}_{1A}-{\stackrel{\·}{I}}_{1B})}---\left(8\right)$

Now, total track length is used calculated value 80% as the distance definite value of a section;

3., when Fault Phase Selection is judged to cross line fault occurs, formula (9) gives fault impedance computational methods during I loop line A phase cross line fault alternate with II loop line B, and other class inter-line fault calculation method is identical;

$Z_k=\frac{{\stackrel{\·}{U}}_A-{\stackrel{\·}{U}}_B}{{\stackrel{\·}{I}}_{1A}-{\stackrel{\·}{I}}_{2B}+(3K-K_0)({\stackrel{\·}{I}}_{10}-{\stackrel{\·}{I}}_{20})}---\left(9\right)$

Wherein:

$3{\stackrel{\·}{I}}_{10}={\stackrel{\·}{I}}_{1A}+{\stackrel{\·}{I}}_{1B}+{\stackrel{\·}{I}}_{1C}---\left(10\right)$

$K=\frac{Z_0-Z_1}{3Z_1}---\left(11\right)$

$K_0=\frac{Z_m}{Z_1}---\left(12\right)$

Wherein: represent the zero-sequence current of I loop line, K is zero-utility theory, K ₀for mutual inductance penalty coefficient, use 80% of the virtual positive sequence impedance of total track length in distance protection as the definite value of distance protection one section;

Step 5: the action situation differentiating distance protection according to the fault impedance value calculated.