Extensible fusion identification method for lightening interference of +/-800kV direct current transmission line

Abstract

The invention relates to extensible fusion identification method for lightening interference of a + / -800kV direct current transmission line. For electromagnetic transient simulation under lightening fault, lightening interference and non-lightening fault, the characteristic of time domain waveform are extracted. For a voltage sampling value with a sampling rate of 10kHz and a time window of 5 ms, correlation degree computation is directly performed to the first two ms data and mean value computation is directly performed to the last three ms data, and finally extensible fusion is performed to the results of the correlation degree computation and mean value computation according to respective weight coefficient to compute a correlation function value so as to form a lightening interference identification criterion directly based on the sampling value. When the computation result of the correlation function is more than or equal to zero, the lightening interference is identified to be and resetting is protected; and when the computation result of the correlation function is less than zero, a line fault is identified to be. Plenty of simulations show that the method can correctly identify the lightening interference in the direct current transmission line and push the transient protection to practicability.

Description

technical field [0001] The invention relates to an extension fusion identification method for lightning strike interference of a ±800kV direct current transmission line, belonging to the technical field of electric power system relay protection. Background technique [0002] Usually, except for the DC transmission line, there is no other outgoing line on the DC bus, and the DC line voltage does not have a zero-crossing problem, and there are realistic physical boundaries composed of smoothing reactors and DC filters at both ends of the line [1] , these make the transient protection applied to DC transmission line protection have advantages. The lightning strike interference identification component of transient protection is indispensable. The lightning current is mostly negative pulse wave, which belongs to high frequency signal. Lightning strike interference is one of the main factors causing transient protection malfunction. Interference identification components still n...

AI Technical Summary

Problems solved by technology

Scholars have conducted in-depth research on this [2-3] Most of the existing lightning interference identification technologies use the different high and low frequency energy distribution characteristics of the current when the lightning strike line causes a fault or no fault to identify lightning strike interference. However, in the energy calculation process, there is no unified regulation on key parameters such as time window. This leads to misjudgments when using energy differences to identify them; at the same time, in terms of protection quickness, the existing lightning interference identification technology is still not ideal

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