Fault line selection method based on wavelet analysis

Abstract

The invention relates to a fault line selection method based on a wavelet analysis. Sudden changing point transient signals are decomposed and extracted through sudden changing characteristics of a zero sequence current in a multi-resolution mode when single-phase faults appear on an outgoing line and a wavelet algorithm, five wavelet functions are selected to conduct multi-scale decomposition, if a plurality of high-frequency scale decomposition results are larger than a set value, and the number of the results is larger than a set number, single-phase grounding faults appear on the outgoing line. According to the method, fault positioning can be fast achieved, the automation degree of a power distribution network can be greatly improved, the power failure time of a user can be greatly shortened, losses caused by power failure can be reduced, the defect of a small-current grounding operation mode is remedied and good social and economic benefits are achieved.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a method for line selection of a single-phase ground fault in a 10kV distribution network grounded through an arc-suppression coil. Background technique [0002] At present, most of my country's distribution network adopts a non-effective neutral point grounding system (the neutral point is not grounded or grounded through the arc suppressing coil), and single-phase ground faults account for more than 80% of the overall faults. At the same time, since there is no direct electrical connection between the ground and the neutral point or a reactor is connected in series, the short-circuit current is very small, and the protection device does not need to trip immediately, thereby improving the reliability of the system operation. [0003] However, due to the installed arc suppression coil, the single-phase grounding short-circuit current of the system is very small, and the voltage and cu...

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Problems solved by technology

[0004] With the strengthening of the distribution network frame, the number of branch lines also increases, and it is very difficult to find out the location of the specific fault point with the traditional line inspection method

This not only consumes a lot of manpower and material resources, but also prolongs the power outage time and affects the reliability of power supply

Especially in severe cold winter, rainy and snowy weather, and difficult road conditions, the existing methods for finding fault points are very labor-intensive and difficult to meet the needs of current production

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