CN102508109A - Combined traveling wave fault location method of high-voltage overhead line and cable hybrid line - Google Patents

Abstract

The invention provides a combined traveling wave fault location method of a high-voltage overhead line and cable hybrid line. The method comprises the following steps of: firstly, carrying out fault section selection by using a double-ended principle according to time difference generated when a fault initial traveling wave of the hybrid line arrives at two ends, then carrying out initial fault location by using a single-ended principle, and finally working out an accurate result via the single-ended principle by combining with the time difference generated when the fault initial traveling wave arrives at two sides of the line. The method has the advantages that: the obtained fault location result is the result of the single-ended fault location principle, and the effects of hybrid line length error and accurate time synchronization problem of two sides of the line to the fault location accuracy are eliminated in the fault location by using the double-ended principle so that the accuracy and reliability of the fault location are improved. Therefore, the traveling wave fault location of the high-voltage overhead line and cable hybrid line is realized by using the method, the problem on how to accurately search a fault point position after the hybrid line is in the fault can be reliably solved and the traveling wave fault location method has a good application prospect.

Description

High voltage overhead lines-cable hybrid line bind lines ripple fault distance-finding method

Technical field

The invention belongs to the protecting electrical power system technical field, particularly a kind of high voltage overhead lines-cable hybrid line bind lines ripple fault distance-finding method.

Background technology

Along with the development of modern urban construction, electricity need load constantly increases, and existing overhead transmission line can't satisfy the needs of urban development, and crisscross overhead transmission line also influences the overall image in city.Therefore, the cable system power supply replaces the inexorable trend of original overhead transmission line power supply having become urban distribution network development.Along with the continuous transformation and the upgrading of urban distribution network, the city cable network is progressively to 110kV and the development of above electric pressure.Because the investment cost of high-tension cable is quite high, major part can be utilized the path of overhead transmission line, does not generally adopt simple cable power supply mode, and this joint line of many high voltage overhead lines and cable just occurred.In addition, cross over the specific question in big water channel and straits, UHV (ultra-high voltage) pole line-cable hybrid line also occurred in order to solve transmission line of electricity.Such as, Hainan networking project has just adopted the pole line-subsea cable mixed power transmission line of 500kV UHV (ultra-high voltage), long distance and larger capacity.

After the mixed power transmission line fault accurately, the position of the localization of faults rapidly, can shorten fault correction time, improve power supply reliability, reduce loss of outage.Oneself has the fault distance-finding method of multiple overhead transmission line at present, and wherein traveling wave method has the advantage that principle simply, does not receive fault type and the asymmetric factor affecting of circuit, and oneself becomes one of fault positioning method for transmission line of on-the-spot widespread usage at present.But the row ripple can be rolled over, reflect in the junction of overhead transmission line and cable in pole line-cable hybrid line, makes capable wave process complicated more.Because the wave impedance of pole line and cable is inequality, the velocity of propagation of row ripple in cable and overhead transmission line differs greatly simultaneously.Therefore the travelling wave analysis of uniline and oneself the various impedance telemetrys and the travelling wave ranging method of warp proposition are inappropriate.Generally adopt at present high voltage overhead lines-cable hybrid line Fault Locating Method based on the capable ripple principle of both-end; Because what range finding was adopted is the capable ripple principle of both-end, because of the error problem that has circuit two ends traveling-wave device precise synchronization problem and line length influences the fault localization precision.

Summary of the invention

The object of the present invention is to provide a kind of high voltage overhead lines that can overcome above-mentioned defective, be adapted to electric system-cable hybrid line bind lines ripple fault distance-finding method.Its technical scheme is:

A kind of high voltage overhead lines-cable hybrid line bind lines ripple fault distance-finding method is characterized in that adopting following steps:

(1) fault segmentation:

Represent the joint line two ends with M and N, represent the tie point of cable and pole line with P, the MP section is a cable, and the NP section is a pole line, uses L _CAnd L _ORepresent the length of cut cable and built on stilts line segment respectively, use v _CAnd v _ORepresent the velocity of propagation of transient state travelling wave in cable and pole line respectively, F representes the trouble spot; Calculate

And, when line failure, record fault traveling wave and arrive M end for the first time and remember with the time of N end bus and make t as reference value _M1And t _N1, the time note that arrives M end and N end bus is for the second time made t _M2And t _N2, as Δ T＜t _M1-t _N1The time, judge that trouble spot F is positioned at pole line NP section, otherwise judge that trouble spot F is positioned at cable MP section;

(2) preliminary survey:

When trouble spot F is positioned at cable MP section, calculate the potential range of trouble spot F to the M end according to the single-ended traveling wave principle:

Perhaps

And above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M holds and N holds for the first time after calculating fault respectively:

Perhaps ${\mathrm{\Δ\; t}}_{\mathrm{MN}2}=\frac{{{2D}_{\mathrm{MF}}}^{*}-L_C}{v_c}-\frac{L_O}{v_o};$

When trouble spot F is positioned at pole line NP section, calculate the potential range of trouble spot F:

to the N end according to the single-ended traveling wave principle perhaps

and calculate fault respectively after above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M end and N hold for the first time:

be

perhaps

(3) the final of range finding result confirmed:

When trouble spot F is positioned at cable MP section, if | t _M1-t _N1-Δ t _MN1|＜| t _M1-t _N1-Δ t _MN2|, assert that then the distance of M end bus F to the trouble spot is D _MF, otherwise assert that the distance of M end bus F to the trouble spot is D _MF ^*

When the trouble spot is positioned at pole line NP section, if | t _M1-t _N1-Δ t _MN1|＜| t _M1-t _N1-Δ t _MN2|, assert that then the distance of N end bus F to the trouble spot is D _NF, otherwise assert that the distance of N end bus F to the trouble spot is D _NF ^*

Principle of work is: at first, utilize the both-end principle to carry out the selection of fault section according to the mistiming that mixed line fault initial row ripple arrives two ends, then; The time of arrival of first, second fault traveling wave of receiving according to the bus of fault section side, divide two kinds of situation, carry out preliminary fault localization with single-ended principle; Provide two possible fault distances; At last, the mistiming that arrives the circuit both sides in conjunction with fault initial row ripple is screened the range finding result, provides final accurate result by single-ended principle.

The present invention has realized the hybrid line traveling wave localization of fault; Joint line error in length and transmission line of electricity both sides correct time stationary problem are to the influence of distance accuracy when compared with prior art having eliminated the range finding of application both-end principle; Provide final range finding result by the single-ended traveling wave principle, further improve distance accuracy.After joint line breaks down, need not the expensive time to get final product the localization of faults, improved power supply reliability, reduce loss of outage, have a extensive future.

Description of drawings

Fig. 1 be among the present invention during joint line cut cable fault the fault traveling wave surge propagate synoptic diagram.

Fig. 2 be among the present invention during the segment fault of joint line pole line the fault traveling wave surge propagate synoptic diagram.

Among the figure: MP is a cable, and PN is a pole line, and P is the tie point of pole line and cable, and F is the trouble spot, L _CAnd L _OThe length of representing cable MP section and pole line PN section respectively, t _M1 and t _N1Fault traveling wave arrives the absolute moment of M end and N end bus, t for the first time after the expression line fault _M2And t _N2The expression fault traveling wave arrives the absolute moment of M end and N end bus for the second time.

Embodiment

Below in conjunction with Fig. 1, Fig. 2 the present invention is further specified:

Embodiment 1: cable MP segment length L _C=20km, pole line NP segment length L _O=35km, the velocity of propagation v of row ripple in cable _C=172.0920km/ms, the velocity of propagation v of row ripple in pole line _O=295.0813km/ms.Suppose that t=0 moment joint line breaks down, trouble spot F is positioned at cable MP section, and it is 5km to the distance of M end.

Step 1, fault segmentation: calculate

$\mathrm{\ΔT}=\frac{L_C}{v_C}-\frac{L_O}{v_O}=-2.3945\mathrm{\μs}$

Record t _M1=30 μ s, t _M2=87 μ s, t _N1=205 μ s, t _N2=262 μ s, Δ T＞t _M1-t _N1=-175 μ s judge that trouble spot F is positioned at cable MP section.

Step 2, preliminary survey:

Calculate the potential range of trouble spot F according to the single-ended traveling wave principle to the M end:

$D_{\mathrm{MF}}=\frac{v_c(t_{M2}-t_{M1})}{2}=4.905\mathrm{km}$

Perhaps ${D_{\mathrm{MF}}}^{*}=L_C-\frac{v_c}{2}(t_{M2}-t_{M1})=15.095\mathrm{Km}$

And above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M holds and N holds for the first time after calculating fault respectively:

${\mathrm{\Δt}}_{\mathrm{MN}1}=\frac{{2D}_{\mathrm{MF}}-L_C}{v_c}-\frac{L_O}{v_o}=-177.8238\mathrm{\μs}$

Perhaps ${\mathrm{\Δ\; t}}_{\mathrm{MN}2}=\frac{{{2D}_{\mathrm{MF}}}^{*}-L_C}{v_c}-\frac{L_O}{v_o}=-59.3945\mathrm{\μ\; s}$

Step 3, the final of range finding result are confirmed: because | t _M1-t _N1-Δ t _MN1|＜| t _M1-t _N1-Δ t _MN2|, can confirm that then the distance of M end bus F to the trouble spot is D _MF=4.905km.Compare with the physical fault point, measuring error of the present invention is 95m.

Embodiment 2: cable MP segment length L _C=20km, pole line NP segment length L _O=35km, the velocity of propagation v of row ripple in cable _C=172.0920km/ms, the velocity of propagation v of row ripple in pole line _O=295.0813km/ms.Suppose that t=0 moment joint line breaks down, trouble spot F is positioned at cable MP section, and it is 25km to the distance of N end.

Step 1, fault segmentation: calculate

$\mathrm{\ΔT}=\frac{L_C}{v_C}-\frac{L_O}{v_O}=-2.3945\mathrm{\μs}$

Record t _M1=149 μ s, t _M2=217 μ s; t _N1=86 μ s; t _N2=153 μ s, Δ T＜t _M1-t _N1=63 μ s judge that the trouble spot is positioned at pole line NP section.

Step 2, preliminary survey:

Calculate the potential range of trouble spot according to the single-ended traveling wave principle to the N end:

$D_{\mathrm{NF}}=\frac{v_o(t_{N2}-t_{N1})}{2}=9.885\mathrm{km}$

Perhaps ${D_{\mathrm{NF}}}^{*}=L_O-\frac{v_o}{2}(t_{N2}-t_{N1})=25.115\mathrm{Km}$

And above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M holds and N holds for the first time after calculating fault respectively:

${\mathrm{\Δt}}_{\mathrm{MN}1}=\frac{L_C}{v_c}+\frac{L_O-2D_{\mathrm{NF}}}{v_o}=167.8238\mathrm{\μs}$

Perhaps ${\mathrm{\Δ\; t}}_{\mathrm{MN}2}=\frac{L_C}{v_c}+\frac{L_O-{{2D}_{\mathrm{NF}}}^{*}}{v_o}=64.6055\mathrm{\μ\; s}$

Step 3, the final of range finding result are confirmed: because | t _M1-t _N1-Δ t _MN1|＞| t _M1-t _N1-Δ t _MN2|, can confirm that then the distance of N end bus F to the trouble spot is D _NF ^*=25.115km.Compare with the physical fault point, measuring error of the present invention is 115m.

Claims (1)

1. high voltage overhead lines-cable hybrid line bind lines ripple fault distance-finding method is characterized in that adopting following steps:

(1) fault segmentation:

Represent the joint line two ends with M and N, represent the tie point of cable and pole line with P, the MP section is a cable, and the NP section is a pole line, uses L _CAnd L _ORepresent the length of cut cable and built on stilts line segment respectively, use v _CAnd v _ORepresent the velocity of propagation of transient state travelling wave in cable and pole line respectively, F representes the trouble spot; Calculate

And, when line failure, record fault traveling wave and arrive M end for the first time and remember with the time of N end bus and make t as reference value _M1And t _N1, the time note that arrives M end and N end bus is for the second time made t _M2And t _N2, as Δ T＜t _M1-t _N1The time, judge that trouble spot F is positioned at pole line NP section, otherwise judge that trouble spot F is positioned at cable MP section;

(2) preliminary survey:

When trouble spot F is positioned at cable MP section, calculate the potential range of trouble spot F to the M end according to the single-ended traveling wave principle:

Perhaps And above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M holds and N holds for the first time after calculating fault respectively:

Perhaps ${\mathrm{\Δ\; t}}_{\mathrm{MN}2}=\frac{{{2D}_{\mathrm{MF}}}^{*}-L_C}{v_c}-\frac{L_O}{v_o};$

When trouble spot F is positioned at pole line NP section, calculate the potential range of trouble spot F:

to the N end according to the single-ended traveling wave principle perhaps

and calculate fault respectively after above-mentioned two kinds of situation fault traveling waves arrive the mistiming that circuit M end and N hold for the first time:

be

perhaps

(3) the final of range finding result confirmed:

When trouble spot F is positioned at cable MP section, if | t _M1-t _N1-Δ t _MN1|＜| t _M1-t _N1-Δ t _MN2|, assert that then the distance of M end bus F to the trouble spot is D _MF, otherwise assert that the distance of M end bus F to the trouble spot is D _MF ^*

When the trouble spot is positioned at pole line NP section, if | t _M1-t _N1-Δ t _MN1|＜| t _M1-t _N1-Δ t _MN2|, assert that then the distance of N end bus F to the trouble spot is D _NF, otherwise assert that the distance of N end bus F to the trouble spot is D _NF ^*

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