High-voltage direct-current transmission line lightning stroke interference identification method based on current attenuation ratio

Abstract

The invention discloses a high-voltage direct-current transmission line lightning stroke interference identification method based on a current attenuation ratio, and the method comprises the steps: carrying out the phase-mode transformation of a rectification side positive and negative current signal fault component in a data window T with a certain length (usually 0.8-1ms), and obtaining a line-mode current fault component; secondly, solving a maximum value of an absolute value of a line mode current fault component, an absolute value integral of the line mode current fault component and a nominal average value of the line mode current fault component in sequence; and finally, calculating a line mode current fault component attenuation ratio, comparing the line mode current fault component attenuation ratio with a threshold value, and judging lightning stroke interference or faults. The lightning stroke interference can be accurately identified, and the reliability of the ultrahigh-speed transient state quantity protection of the direct-current line is improved.

Description

technical field [0001] The invention belongs to the field of power systems, relates to the field of relay protection of high-voltage direct current transmission lines, and in particular relates to a method for identifying lightning strike interference of high-voltage direct current transmission lines based on the current attenuation ratio. Background technique [0002] With the depletion of fossil energy and the prominence of global climate and environmental issues, clean energy is gradually playing an important role in the global energy structure. As an effective way to solve the problem of clean energy transmission, in addition to the advantages of low line cost, simple structure, large transmission capacity, small loss, and long transmission distance, HVDC transmission has the advantages of long-distance transmission of electric energy, asynchronous networking of power systems, distributed It is also widely used in resource grid connection and urban cable power supply. T...

AI Technical Summary

Problems solved by technology

Among them, the extraction of waveform features in the time domain needs to be based on a long time window, which is difficult to cooperate with ultra-high-speed transient protection

In the frequency domain, methods such as wavelet transform and HHT are usually used, which can effectively extract the difference in energy distribution of interference and fault spectrum. However, the selection of wavelet base and the determination of parameters in the former have strong experience, while the latter has unavoidable modal aliasing. Phenomenon

The artificial intelligence method avoids complex mathematical operations, and the purpose of distinguishing interference and faults can be achieved through offline learning of the training set, but there are few actual examples that can be used as the training set, and it needs to be based on a large number of simulation results. May not be applicable in actual power system

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