Small current grounding fault line selection method

Abstract

The invention provides a small current grounding fault line selection method. The method comprises the following steps: 1, collecting a bus three-phase voltage value and a bus zero sequence voltage; 2, judging whether a single-phase earth fault occurs or not; 3, if the single-phase earth fault does not occur, returning to the step 1, and if so, starting a wave recording device; 4, starting the wave recording device to record fault data of one cycle after an event node; 5, carrying out singularity detection on the zero sequence voltage value 3U0 of the bus by adopting a Hilbert-Huang transform technology, and confirming the fault moment of the power distribution network; 6, performing SVD filtering on the transient zero-sequence current of each outgoing line; 7, performing morphological filtering on the transient zero-sequence current of each outgoing line; 8, performing empirical mode decomposition on the transient zero-sequence current of each outgoing line and constructing a mode matrix; 9, processing the modal matrix by using a singular value decomposition technology and constructing a fault eigenvalue matrix; and 10, extracting characteristic values by adopting a PSO-FCM clustering technology to judge a fault line.

Description

Technical field [0001] The present invention relates to a small current ground fault line method, which belongs to the field of relay network relay protection. Background technique [0002] my country's distribution network neutral point is mainly excited or not grounded, and after the single-phase ground is occurred, since the grounding line failure characteristics are not obvious, the single-phase ground fault line is added; the existing fault line The means comprises artificial pull mode, and it is judged that the composed transient zero-modulus mode and conventional substation grounding option, these ground options have certain uncertainty and randomness during practical application, and even Operational overvoltage generated during artificial pull will affect power distribution equipment. [0003] Hilbert-Huang Transform (HHT) provides new ideas for single-phase fault option, HHT transform, nonlinear non-stationary signal capability, significant advantage; the core of HHT tr...

AI Technical Summary

Problems solved by technology

[0006] The present invention proposes a line selection method for small current grounding faults, and its purpose is to solve the problem that the line selection of single-phase grounding faults in small and medium current grounding systems in the prior art is easily affected by interference noise signals and uncertain disturbance signals

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