Grounding Grid Potential Difference Filtering Method Based on Starting Decision Element and Wavelet Transform

Abstract

The invention discloses a grounding network potential difference filtering method based on a start-up determination element and wavelet transform. The method is aimed at collecting signals of a relay protection current transformer, and checks whether the signal meets the steady-state condition according to the constraint condition of five consecutive points of the start-up element. Judgment is carried out, and the unsatisfactory sampling data is further judged by the judgment element based on the form factor. If it is normal data, it will be output directly; if it is abnormal data, it will be processed by wavelet transform and then output. The invention adds a start-up determination element before the traditional wavelet transform, which can pre-judge the signal, greatly reduces the amount of calculation, overcomes the disadvantage of poor timeliness of the traditional filtering algorithm, and uses the wavelet transform to effectively filter out the potential difference of the grounding grid The resulting noise signal ensures the accuracy of relay protection data measurement and avoids misoperation of relay protection equipment.

Description

technical field [0001] The invention relates to a grounding network potential difference filtering method based on a start-up determination element and wavelet transform, and belongs to the technical field of relay protection equipment filtering algorithms. Background technique [0002] UHV substations generally use GIS (Gas insulated substation) switchgear. When the isolating switch is operated, there will be dozens or even hundreds of arcing and arcing at the break of the switch. The disturbance voltage generated by it is continuously refracted and reflected on the bus and short lines, forming a very fast transient overvoltage VFTO (very fast transient over-voltage). VFTO leaks into the ground grid through the protective ground wire on the primary side of the transformer, causing the local potential of the ground grid to rise. Since the secondary cables of UHV substations are generally grounded at both ends, a grounding grid potential difference will be generated at both ...

AI Technical Summary

Problems solved by technology

In the actual working conditions of substations, the proportion of disturbance signals is extremely low. If wavelet transform is directly used to filter all sampled values, the calculation efficiency is not high, which will easily lead to delays in relay protection processing.

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