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

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

technical field [0001] The invention belongs to the technical field of electric power system protection, and in particular relates to a traveling wave fault location method for an A-type overhead wire-cable hybrid line. Background technique [0002] Quickly and accurately determining the location of the fault point of the power line can speed up the repair of permanent faults, eliminate hidden dangers in time to avoid the recurrence of a large number of transient faults, and is of great significance to ensure the safety, stability and economic operation of the power system. [0003] With the development of modern urban construction, the city's electricity load continues to increase, and the existing overhead lines can no longer meet the needs of urban development, and the criss-cross overhead lines also affect the overall image of the city. Therefore, replacing the original overhead line power supply with cable network power supply has become an inevitable trend in the devel...

AI Technical Summary

Problems solved by technology

However, various single-ended and double-ended traveling wave fault location algorithms that have been proposed cannot be directly used for overhead line-cable hybrid lines.

Therefore, when a hybrid line fails, it often takes more time than ordinary overhead lines to find and repair the fault, which seriously affects the power supply reliability of the hybrid line

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