Cosine similarity-based power distribution network single-phase earth fault section positioning method

Abstract

The invention relates to a non-effective grounding power distribution network technology, and particularly relates to a cosine similarity-based power distribution network single-phase earth fault section positioning method. The method comprises the steps of establishing an electromagnetic transient digital simulation model of a to-be-positioned medium-voltage power distribution network, includinga 110kV transformer substation main transformer model, a medium-voltage power distribution line model, a power distribution transformer model and a load model; setting a single-phase earth fault at abus of a medium-voltage distribution line of the transformer substation, and obtaining standard waveform data at each sampling point; when a single-phase earth fault occurs in an actual power distribution network, acquiring actual fault transient zero-sequence current through sampling at each collection point on site; solving the similarity between the actual fault transient zero-sequence currentdata and the standard waveform data based on the cosine similarity; and analyzing the similarity difference of the fault transient zero-sequence currents of two adjacent sampling points so as to judgewhether a single-phase earth fault occurs between the two adjacent sampling points or a single-phase earth fault occurs in a bus. The method is not influenced by a branch line and a cable overhead hybrid line.

Description

technical field [0001] The invention belongs to the technical field of non-effectively grounded distribution networks, and in particular relates to a method for locating a single-phase ground fault section of a distribution network based on cosine similarity. Background technique [0002] Existing single-phase ground fault section location methods in non-effectively grounded distribution networks can be roughly divided into two categories according to their use of different information: one is the fault section location method based on externally injected signals; the other is the use of single-phase ground fault section location methods. The fault section location method can be divided into the fault section location method based on the fault steady-state component, the fault section location method based on the fault transient component and the comprehensive location method. According to the actual application experience in the field, the segment positioning method based o...

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Problems solved by technology

However, the structure of the on-site medium-voltage distribution line is complex. At the line nodes with branches, the characteristics of the zero-sequence current collected before and after the branch point will change greatly, which seriously affects the traditional transient zero-sequence current based on uploading. The Correctness of Segment Locating Method Based on Sequence Current Feature Similarity Alignment

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