Wavelet transform and time search strategy based double-end traveling wave fault location method for hybrid power transmission line

Abstract

The invention discloses a wavelet transform and time search strategy based double-end traveling wave fault location method for hybrid power transmission line. The method comprises the following stepsof 1) determining an electrical topological structure of the hybrid power transmission line MN; 2) acquiring the motion time of traveling waves on a section line according to the length and motion wave speed of each section line; 3) according to fault traveling wave information acquired by traveling wave distance measuring devices at the two ends of the line, adopting wavelet transform to detect and identify the moment when the fault traveling wave moves to each bus measuring end for the first time so as to obtain a time difference when the traveling wave arrives at the two ends of the bus, and calculating t1 an t2 according to formulas by combining movement time of the fault traveling wave on the whole power transmission line; and 4) starts comparing from the end M of the bus, judging that the fault position is behind the xj1 section when t1>deltat1, and judging that the fault position is on the xd1 section when deltat1<t1<deltat1+deltat2, thus calculating the fault position. The method can be used to identify the initial traveling wave of a fault more accurately, and effectively solve the problem in fault distance measurement of the cable and overhead line hybrid power transmission line of the power system.

Description

technical field [0001] The invention relates to a distance measurement method for a double-terminal traveling wave fault of a hybrid transmission line in a power system, which performs precise distance measurement on the fault position of the transmission line of the power system, and belongs to the technical field of power systems. Background technique [0002] Affected by factors such as lightning shock, rain, snow and freezing, as well as low production technology level and quality defects in the manufacturing process, various problems such as mechanical damage and insulation level drop will inevitably occur during the long-term operation of power transmission lines, thus Increased chances of various short circuit faults occurring. In addition, due to the continuous expansion of power supply range, transmission lines are more prone to failure when passing through areas with high altitude, severe cold, complex weather and terrain. When a fault occurs in the transmission l...

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Problems solved by technology

[0007] The invention aims at the discontinuity of the wave impedance at the connection of the cable hybrid transmission line, which makes the movement process of the transient traveling wave generated by the fault extremely complicated in the hybrid transmission line, making it difficult to effectively detect and identify the reflection of the fault point by the single-ended traveling wave ranging method wave and the reflected wave at the opposite end, and the inconsistency of wave velocity at the same time increases the difficulty of fault location for cable hybrid transmission lines. A method for fault location of hybrid transmission lines with double-ended traveling waves based on wavelet transform and time search strategy is provided.

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