CN101762775A - Method for positioning travelling wave fault of A type overhead line-cable joint line - Google Patents

Abstract

The invention provides a method for positioning a travelling wave fault of an A type overhead line-cable joint line, comprising the following steps of: (1) by using a connection point of the overhead line and the cable as a boundary, respectively expressing lengths of a cable section and an overhead line section by using LC and LO, respectively expressing transmission speeds of transient travelling waves in the overhead line and the cable by using vO and vC, computing the time difference of achieving both ends (M, N) of the line by an initial travelling wave surge generated by the fault of the connection point P of the overhead line and the cable to be used as a setting valve; (2) measuring the absolute time of achieving both ends (M, N) of the line by the initial travelling wave surge generated by the fault of a certain point of the line, and expressing by using tM and tN; (3) determining the position of a fault point, wherein when tM-tN equal to delta TP, a fault point is the connection point P of the overhead line and the cable; when tM-tN is less than delta TP, the fault point is positioned a line MP section, and the distances between the fault point and the N end and the M end are respectively DNF=LC+LO-DMF; and when tM-tN is more than delta TP, the fault point is positioned a line MP section, and the distances between the fault point and the N end and the M end are respectively DMF=LC+LO-DNF. The method realizes the on-line fault sectioning and the fault distance measurement of the A type overhead line-cable joint line.

Description

A type pole line-cable hybrid line traveling wave fault positioning method

Technical field

The invention belongs to the protecting electrical power system technical field, particularly a kind of A type overhead line-cable hybrid line traveling wave fault positioning method.

Background technology

Determine the position of failure point of power circuit quickly and accurately, can accelerate the reparation of permanent fault, in time remove a hidden danger, safety and stability and the economical operation that guarantees electric system had crucial meaning to avoid the generation once more of a large amount of transient faults.

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, the UHV (ultra-high voltage) overhead 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.

From version, high voltage overhead lines-cable hybrid line mainly comprises two types of A type and Type Bs, wherein A type joint line comprises one section pole line and one section cable, and the Type B joint line comprises two sections pole lines and one section cable, and cable is connected between two sections pole lines.

The feeder line fault localization method is divided into power frequency electric parameters method and transient state travelling wave method two big classes.Power frequency electric parameters method is subjected to all multifactor influences such as mutual inductor mapping fault, line distribution capacitance, fault-signal aperiodic component, and range error is big, and and is not suitable for overhead line-cable hybrid line.The transient state travelling wave method is calculated the distance of trouble spot to circuit one end by measuring the travel-time of transient state travelling wave on faulty line, this method has very high bearing accuracy for common overhead transmission line and cable, wherein the pole line positioning error can reach in the 500m, and the cable positioning error then can reach in the 1m.But the various single-ended and both-end Travelling Wave Fault Location algorithm that has proposed can not be directly used in overhead line-cable hybrid line.Therefore, after joint line breaks down, often will spend than common overhead transmission line more time and search and repair fault, this has had a strong impact on the power supply reliability of joint line.

Summary of the invention

The object of the present invention is to provide a kind of A type hybrid line traveling wave fault positioning method that can overcome above-mentioned defective, be adapted to electric system mixed line fault location.Its technical scheme is:

A kind of A type overhead line-cable hybrid line traveling wave fault positioning method is characterized in that adopting following steps: (1) is the boundary with the tie point P of pole line and cable, uses L _CAnd L _ORepresent the length of cut cable and built on stilts line segment respectively, use v _OAnd v _CRepresent the velocity of propagation of transient state travelling wave in pole line and cable respectively, the initial row wave that calculates the tie point P fault generation of pole line and cable is rushed to the mistiming that reaches circuit two ends M, N $\mathrm{\Δ}{T}_P=\frac{L_C}{v_C}-\frac{L_O}{v_O}$ As setting valve; (2) the initial row wave of mensuration circuit point failure generation is rushed to the absolute moment that reaches circuit two ends M, N, uses t _MAnd t _NExpression; (3) t is worked as in localization of faults position _M-t _N=Δ T _PThe time, the trouble spot is the tie point P of pole line and cable; Work as t _M-t _N＜Δ T _PThe time, the trouble spot is positioned at circuit MP section, and the distance between trouble spot and M end and the N end is respectively

And D _NF=L _C+ L _O-D _MFWork as t _M-t _N＞Δ T _PThe time, the trouble spot is positioned at circuit PN section, and the distance between trouble spot and N end and the M end is respectively

And D _MF=L _C+ L _O-D _NF

Described A type overhead line-cable hybrid line traveling wave fault positioning method, in the step (2), A type mixed line fault initial row wave is rushed to the absolute moment t that reaches circuit two ends M, N _MAnd t _NObtain by detecting in real time by the online Travelling Wave Fault Location device that is installed in the circuit two ends respectively.

The present invention has compared with prior art realized the online fault segmentation and the accurate fault localization of A type overhead line-cable hybrid line, has broad application prospects.

Description of drawings

Fig. 1 is that A type overhead line-cable hybrid line fault initial row wave of the present invention gushes the propagation synoptic diagram.

Fig. 2 is an A type overhead line-cable hybrid line traveling wave fault location system synoptic diagram of the present invention.

Among the figure: the tie point L of MP, cable PN, pole line P, pole line and cable _C, cable sections MP length L _O, pole line section PN length t _M, the F initial row wave that produces in trouble spot is rushed to the absolute moment t that reaches circuit M end _N, the F initial row wave that produces in trouble spot is rushed to the absolute moment 1, M end Travelling Wave Fault Location device 2, N end Travelling Wave Fault Location device 3, M end satellite synchronizing clock 4, N end satellite synchronizing clock 5, optical-fibre channel 1PPS, the satellite synchronizing clock per second that reach circuit N end and sends a pulse clock synchronizing signal to the Travelling Wave Fault Location device.

Embodiment

Make the following instructions below in conjunction with the realization of accompanying drawing A type overhead line-cable hybrid line traveling wave fault positioning method:

Step 1, P are the tie point of cable MP and pole line PN, L _C=21.7km, L _O=30km, v _C=171.99km/ms, v _O=293.91km/ms, the time difference setting valve of fault segmentation then is

Step 2, mixed line fault initial row wave are rushed to the absolute moment t that reaches circuit two ends M, N _MAnd t _NObtain by detecting in real time by the online Travelling Wave Fault Location device 1 that is installed in the circuit two ends and 2 respectively, be respectively t _M=0.151ms and t _N=0.076ms, the difference of the two is t _M-t _N=0.075 (ms);

Step 3, according to step 1,2 gained data, because t _M-t _N＞Δ T _PSo trouble spot F is positioned at pole line PN section, and the distance of trouble spot F and N end, M end is passed through formula respectively And D _MF=L _C+ L _O-D _NFCalculate, be specially D _NF=22.519km, D _MF=29.181km.

Empirical tests, this result of calculation conforms to actual.

Claims (2)

1. A type pole line-cable hybrid line traveling wave fault positioning method, it is characterized in that adopting following steps: (1) is the boundary with the tie point P of pole line and cable, uses L _CAnd L _ORepresent the length of cut cable and built on stilts line segment respectively, use v _OAnd v _CRepresent the velocity of propagation of transient state travelling wave in pole line and cable respectively, the initial row wave that calculates the tie point P fault generation of pole line and cable is rushed to the mistiming that reaches circuit two ends M, N $\mathrm{\Δ}{T}_P=\frac{L_C}{v_C}-\frac{L_O}{v_O}$ As setting valve; (2) the initial row wave of mensuration circuit point failure generation is rushed to the absolute moment that reaches circuit two ends M, N, uses t _MAnd t _NExpression; (3) t is worked as in localization of faults position _M-t _N=Δ T _PThe time, the trouble spot is the tie point P of pole line and cable; Work as t _M-t _N＜Δ T _PThe time, the trouble spot is positioned at circuit MP section, and the distance between trouble spot and M end and the N end is respectively $D_{\mathrm{MF}}=\frac{1}{2}{v}_C[(\frac{L_C}{v_C}+\frac{L_O}{v_O})+(t_M-t_N)]$ And D _NF=L _C+ L _O-D _MFWork as t _M-t _N＞Δ T _PThe time, the trouble spot is positioned at circuit PN section, and the distance between trouble spot and N end and the M end is respectively $D_{\mathrm{NF}}=\frac{1}{2}{v}_O[(\frac{L_C}{v_C}+\frac{L_O}{v_O})-(t_M-t_N)]$ And D _MF=L _C+ L _O-D _NF

2. A type pole line-cable hybrid line traveling wave fault positioning method as claimed in claim 1 is characterized in that: in the step (2), A type mixed line fault initial row wave is rushed to the absolute moment t that reaches circuit two ends M, N _MAnd t _NObtain by detecting in real time by the online Travelling Wave Fault Location device that is installed in the circuit two ends respectively.

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