CN101825676B - Fault ranging method by utilizing red and green colors to express traveling wave of DC power transmission circuit malfunction voltage - Google Patents

Abstract

The utility model relates to a fault location method by utilizing red and green colors to express traveling wave of DC power transmission circuit malfunction voltage, which is characterized in that: when the DC power transmission circuit has malfunction, a bipolar voltage traveling wave at a DC circuit protection place at the rectification side is respectively mapped to a red (R) channel and a green (G) channel to form a color mode pattern of the bipolar voltage traveling wave, front two color mutation places in the color mode pattern are selected, and if the mutated colors at the two places are different, the second color mutation corresponds to a fault point reflected wave; and if the mutated colors at the two places are identical, the second mutation corresponds to an opposite-end marginal reflected wave, an image processing software is used for correctly extracting the time corresponding to the mutation, the time is substituted into a single-end location formula to realize the single-end fault location. While the fault location accuracy is ensured, the fault location is more direct.

Description

The fault distance-finding method that direct current transmission line fault voltage traveling wave red and green color is represented

Technical field

The present invention relates to the fault distance-finding method that direct current transmission line fault voltage traveling wave red and green color is represented, belong to the relay protection of power system technical field.

Background technology

Fault localization [1-8] receives showing great attention to of work about electric power person all the time, and fault localization can shorten the line walking time greatly accurately, accelerates to restore electricity, and the safety and the economical operation of electric system had very important significance.Traveling wave fault location is based on the fault distance-finding method that capable ripple transmission theory realizes: when transmission line of electricity breaks down; Can produce the fault traveling wave of propagating along the line; Roll over, reflect at the wave impedance discontinuity point, utilize the transmission time of fault traveling wave to calculate fault distance.Traveling wave method can be divided into two kinds of single-ended method and both-end methods.The both-end method need the circuit two ends accurately to the time and information transfer channel, the more single-ended method of the cost of device is high.Single-ended method is that the fault transient travelling wave that utilizes circuit one end to measure calculates the trouble spot to the distance between local terminal or opposite end bus in the travel-time of round trip between trouble spot and local terminal or the opposite end bus.The single-ended method fault localization of existing capable ripple utilizes wavelet analysis [7] or mathematical morphology [8] to realize that fault traveling wave passes to the boundary of DC line basically, reflection wave several delicate after, reversal of poles, thus make the identification of reflection wave bring difficulty; Under high resistance earthing fault, second wave head is subject to noise.

List of references:

[1] Paul Gonzales. Digital Image Processing [M]. Beijing, Electronic Industry Press, 2007.

[2] Shu Hongchun; Main forces of department;

is based on the measuring distance of transmission line fault system [J] of many algorithms. electric power network technique; 2004

28(7)：49-52，57.

[3] Xu Bingyin, Li Jing, Chen Ping, etc. modern travelling wave ranging technology and application [J] thereof. Automation of Electric Systems, 2001,25 (12): 62-65.

[4]Fernando?H，Magnago，Ali?Abur.Fault?Location?Using?Wavelets[J].IEEE?Transactions?onPower?Del?ivery.Vol.13，No.4，October?1998.

[5] Dong Xinzhou, Ge Yaozhong, Xu Bingyin. utilize the measuring distance of transmission line fault research [J] of transient current travelling waves. Proceedings of the CSEE, 1999,19 (4): 76-80.

[6]Cansin?Y.

Ali?Abur，Ergun?Akleman，Ozan

Bewley?DiagramsRevisited?via?Visualization[J].IEEE?Transactions?on?Power?Systems.Vol.24，No.3，August2009.

[7] Zhao Yanhui, Wang Shaorong. based on the research [J] of the theoretical HVDC transmission line travelling wave Fault Locating Method of Wavelet Modulus Maxima. relay, 2007,35 (1): 13-17.

[8] Li Xuepeng, Quan Yusheng, yellow Xu, Ma Yanwei, Yang Junwei. mathematical morphology is used for the discussion [J] of HVDC transmission line traveling-wave protection. relay, 2006,34 (5): 5-9.

Summary of the invention

The purpose of this invention is to provide the fault distance-finding method that a kind of direct current transmission line fault voltage traveling wave red and green color is represented; When DC power transmission line breaks down; The capable wavelength-division of bipolar voltage is not mapped to red (R), green (G) two Color Channels, under the color mode figure of the capable ripple of bipolar voltage, realizes fault localization.

The present invention is not mapped to red (R) passage and green (G) passage with the capable wavelength-division of the bipolar false voltage of DC power transmission line, forms the color mode figure of the capable ripple of pole tension, through the means of Flame Image Process, extracts the failure message among the color mode figure, realizes one-end fault ranging.

Technical scheme of the present invention is:

1) when the arbitrary pole tension sudden change of DC line amount | u (n+1)-u (n) |-| u (n)-u (n-1) | during greater than setting valve; SF is that HSDA and the wave recording device of 1MHz starts; And the anodal and capable wave-wave shape of cathode voltage of the rectification side of 3ms behind the record trouble; Wherein n is a n sampled point, and u (n) is the voltage sample value of n sampled point of arbitrary utmost point in the two poles of the earth.

2) with the capable ripple u of rectification side cathode voltage _Dr1With the capable ripple u of cathode voltage _Dr2Do normalization by formula (1) respectively:

$U_{\mathrm{drx}}=\frac{u_{\mathrm{drx}}-\min \left(u_{\mathrm{drx}}\right)}{\max \left(u_{\mathrm{drx}}\right)-\min \left(u_{\mathrm{drx}}\right)}---\left(1\right)$

In the formula: x gets 1 or 2, corresponding positive pole of difference and negative pole, min (u _Drx) for getting u _DrxMinimum operation, max (u _Drx) for getting u _DrxMaximum operation, obtain the capable ripple U of cathode voltage after the normalization _Dr1With the capable ripple U of cathode voltage _Dr2

3) with U _Dr1And U _Dr2Be mapped to red (R) and green (G) two Color Channels respectively by formula (2):

f：U _drx ²→[0，255] ²(2)

In the formula: f representative function corresponding relation, the meaning cotype (1) of x, U _Drx ²For comprising the capable ripple U of cathode voltage _Dr1With the capable ripple U of cathode voltage _Dr1Two-dimensional space, [0,255] ²Be red (R) green (G) color space, obtain the color mode figure of the capable ripple of bipolar voltage.

4) the corresponding fault traveling wave in the color change place among the color mode figure of the capable ripple of bipolar voltage arrives the time of protection place.The redness and the green stack of same colourity will obtain yellow, and as shown in Figure 1,45 ° of lines are yellow line among the figure.The mode that produces color among the present invention is an additive color process, and when elected extracting yellow was benchmark, promptly R colourity-G colourity=0 be a benchmark, if color on the basis of yellow to the then corresponding zone 1 in Fig. 1 of redness sudden change, R colourity-G colourity＞0 at this moment; If color is in the zone 2 in green is suddenlyd change corresponding diagram 1 then on the basis of yellow, this moment R colourity-G colourity＜0.This shows; The voltage color mode figure that chooses behind the yellow benchmark is identical with the line mold component of pole tension in essence; Red sudden change is the positive polarity surge of corresponding pole tension traveling wave line mold component, and green sudden change is the negative polarity surge of corresponding pole tension traveling wave line mold component.Like this, the conclusion on the fault traveling wave modulus just can directly be applied among the color mode figure of the capable ripple of bipolar voltage.

Consider the border condition at DC line two ends; Because the inductance value of borderline smoothing reactor is bigger; The capable ripple of high frequency transient approaches zero at the refraction coefficient of boundary, and this makes when utilizing rectification side DC line pole tension travelling wave ranging, can not receive the influence of alternating current circuit row ripple; Simultaneously because the existence of smoothing reactor; Be equivalent to open circuit for the capable ripple of DC line fault high frequency; This just makes the voltage traveling wave reflection coefficient on border, DC line two ends near 1; So when carrying out single end distance measurement, its trouble spot reflection wave and opposite end bus reflection wave just can be distinguished through their polarity.Grid chart with Fig. 2 is explained: voltage failure initial row ripple u _FPropagate at two ends to DC power transmission line, and in protection place of rectification side DC line, the trouble spot reflection wave is β _Mβ _Fu _F, opposite end bus reflection wave is α _Fβ _Nu _F, β _M, β _NAnd β _FBe respectively the reflection coefficient at border M, border N and trouble spot F place, α _FFor the refraction coefficient of trouble spot F, in DC transmission system, β _MAnd β _NApproach 1, α _FFor just, β _FGenerally negative, so trouble spot reflection wave β _Mβ _Fu _FWith the capable ripple u of initial voltage _FReversed polarity; Opposite end boundary echo α _Fβ _Nu _FWith the capable ripple u of initial voltage _FSame polarity.Be reflected on the color mode figure of the capable ripple of bipolar voltage; The sudden change color of trouble spot reflection wave and the capable ripple of initial voltage is different; Be that the capable ripple of initial voltage is that the redness trouble spot reflection wave that suddenlys change then is green sudden change, the capable ripple of initial voltage is that green suddenlys change then that the trouble spot reflection wave is red sudden change; The sudden change color of opposite end boundary echo and the capable ripple of initial voltage is identical, and promptly the capable ripple of opposite end boundary echo and initial voltage is all red sudden change or is all green sudden change.The pairing moment t of first place's color change among the color mode figure of the capable ripple of accurate extraction bipolar voltage ₁With the corresponding t constantly of the second place color change institute ₂, obtain Δ t=t ₂-t ₁If the color change at preceding two places is different, promptly first place be red sudden change, and second place be green sudden change, or first place be green the sudden change, and second place is that redness is suddenlyd change, and the second place corresponding trouble spot reflection wave that suddenlys change then utilizes formula (3) to calculate fault distance x:

$x=\frac{\mathrm{v\Δt}}{2}---\left(3\right)$

In the formula: v is the wave velocity on the line mould; Its value is by the DC line parameter determining; Can adopt the Digital Simulation mensuration to calculate: the circuit head end injecting voltage that was engraved in 300km at 0 o'clock; Set up observation station at line end; Accurately the capable ripple of record current arrives the moment t of observation station, utilizes formula

can draw v.If the color change at preceding two places is identical, promptly all be red sudden change or green the sudden change, the second place corresponding opposite end boundary echo that suddenlys change then, utilize formula (4) to calculate fault distance:

$x=L-\frac{\mathrm{v\Δt}}{2}---\left(4\right)$

In the formula: L is a faulty line length, and other each physical quantity meaning is the same.

The present invention compared with prior art has advantage:

1) directly utilizes the capable ripple of bipolar voltage at rectification side DC line protection place to carry out single end distance measurement, need not construct voltage traveling wave line mold component;

2) utilize the capable wavelength-division of bipolar false voltage not to be mapped to red (R) passage and green (G) passage, form the color mode figure of the capable ripple of false voltage,, extract the failure message among the color mode figure, make that range finding is more directly perceived through the means of Flame Image Process, simple.

Description of drawings

Fig. 1 is RG color superposition principle figure;

Fig. 2 is row ripple grid chart; M and N are border M and border N among the figure, and F is the trouble spot, u _FBe the capable ripple of primary fault, β _Mβ _Fu _FBe trouble spot reflection wave, α _Fβ _Nu _fBe opposite end boundary echo, β _M, β _NAnd β _FBe respectively the reflection coefficient at border M, border N and trouble spot F place, α _FRefraction coefficient for trouble spot F;

Fig. 3 is straight-flow system figure;

Fig. 4 is the capable ripple figure of false voltage;

Fig. 5 is the color mode chart of the red green of the capable ripple of false voltage of the present invention.

Embodiment

With Fig. 3 ± 500kV bipolar DC system is an example, from protection 150km place, installation place generation plus earth fault, stake resistance is 5 Ω at long DC line head end for L=500km, the emulation SF is 1MHz.The practical implementation step is following:

1) when the arbitrary pole tension sudden change of DC line amount | u (n+1)-u (n) |-| u (n)-u (n-1) | during greater than setting valve; Wherein n is a n sampled point; U (n) is the voltage sample value of n sampled point of arbitrary utmost point in the two poles of the earth; SF is that HSDA and the wave recording device of 1MHz starts, and the anodal and capable ripple oscillogram of cathode voltage of the rectification side of 3ms behind the record trouble, and is as shown in Figure 4;

2) with the capable ripple u of rectification side cathode voltage _Dr1With the capable ripple u of cathode voltage _Dr2Respectively by formula

$U_{\mathrm{drx}}=\frac{u_{\mathrm{drx}}-\min \left(u_{\mathrm{drx}}\right)}{\max \left(u_{\mathrm{drx}}\right)-\min \left(u_{\mathrm{drx}}\right)}---\left(1\right)$

Do normalization, obtain the capable ripple U of cathode voltage after the normalization _Dr1With the capable ripple U of cathode voltage _Dr2

3) with U _Dr1And U _Dr2By formula

f：U _drx ²→[0，255] ²(2)

Be mapped to red (R) and green (G) two Color Channels respectively, obtain the color mode figure of the capable ripple of bipolar voltage,, change its resolution into 2563000 for ease of observing, as shown in Figure 5;

4) utilize the edge detection function of image processing software (for example Photoshop) accurately to extract preceding two place color change place moment corresponding among the color mode figure of the capable ripple of bipolar voltage; Make difference and obtain Δ t=0.001008s; If the color change at preceding two places is different, utilize formula

$x=\frac{\mathrm{v\Δt}}{2}---\left(3\right)$

Calculate fault distance x; If the color change at preceding two places is identical, then utilize

$x=L-\frac{\mathrm{v\Δt}}{2}---\left(4\right)$

Calculate fault distance x; According to the DC line parameter of Fig. 3, the wave velocity v that utilizes the Digital Simulation mensuration to calculate the line mould is 2.979146 * 10 ⁵So km/s is this routine fault distance

$x=\frac{\mathrm{v\Δt}}{2}=\frac{2.979146\×{10}^5\×0.001008}{2}=150.149\mathrm{km}.$

Claims (1)

1. fault distance-finding method that direct current transmission line fault voltage traveling wave red and green color is represented is characterized in that this method accomplishes through following steps:

1) when the arbitrary pole tension sudden change of DC power transmission line amount | u (n+1)-u (n) |-| u (n)-u (n-1) | during greater than setting valve; SF is that HSDA and the wave recording device of 1MHz starts; And the anodal and capable wave-wave shape of cathode voltage of the rectification side of 3ms behind the record trouble; Wherein n is a n sampled point, and u (n) is the voltage sample value of n sampled point of arbitrary utmost point in the two poles of the earth;

2) with the capable ripple u of rectification side cathode voltage _Dr1With the capable ripple u of cathode voltage _Dr2Do normalization by formula (1) respectively:

$U_{\mathrm{drx}}=\frac{u_{\mathrm{drx}}-\min \left(u_{\mathrm{drx}}\right)}{\max \left(u_{\mathrm{drx}}\right)-\min \left(u_{\mathrm{drx}}\right)}---\left(1\right)$

In the formula: x gets 1 or 2, corresponding positive pole of difference and negative pole, min (u _Drx) for getting u _DrxMinimum operation, max (u _Drx) for getting u _DrxMaximum operation, obtain the capable ripple U of cathode voltage after the normalization _Dr1With the capable ripple U of cathode voltage _Dr2

3) with U _Dr1And U _Dr2Be mapped to red (R) and green (G) two Color Channels respectively by formula (2):

f：U _drx ²→[0，255] ²(2)

In the formula: f representative function corresponding relation, the meaning cotype (1) of x,

For comprising the capable ripple U of cathode voltage _Dr1With the capable ripple U of cathode voltage _Dr2Two-dimensional space, [0,255] ²Be red (R) green (G) color space, obtain the color mode figure of the capable ripple of bipolar voltage;

4) accurately extract the pairing moment t of first place's color change among the color mode figure of the capable ripple of bipolar voltage ₁With the pairing moment t of second place's color change ₂, Δ t=t ₂-t ₁, if the color change at preceding two places is different, promptly first place be red sudden change, and second place be green sudden change, or first place be green the sudden change, and second place is that redness is suddenlyd change, and the second place corresponding trouble spot reflection wave that suddenlys change then utilizes formula (3) to calculate fault distance x:

$x=\frac{\mathrm{v\Δt}}{2}---\left(3\right)$

In the formula: v is the wave velocity on the line mould, and it is worth by the DC power transmission line parameter determining; If the color change at preceding two places is identical, promptly all be red sudden change or green the sudden change, the second place corresponding opposite end boundary echo that suddenlys change then, utilize formula (4) to calculate fault distance:

$x=L-\frac{\mathrm{v\Δt}}{2}---\left(4\right)$

In the formula: L is a faulty line length, and other each physical quantity meaning is the same.

Images