Photovoltaic transmission line fault phase selection method based on IMF energy entropy

Abstract

The invention discloses a photovoltaic transmission line fault phase selection method based on an IMF energy entropy. The method comprises steps that a three-phase fault component voltage and a zero sequence fault component voltage of a photovoltaic power station transmission line are acquired; EMD of the three-phase fault component voltage and the zero sequence fault component voltage is respectively carried out, IMF components under each frequency band are adaptively acquired; a correlation coefficient sequence between each IMF component and an original signal is solved, and effective IMF components are screened through a set threshold; energy entropy fault characteristic parameters are calculated according to the effective IMF components, in combination with short circuit fault characteristics and different characteristics of the characteristic parameters, phase selection criteria are constructed, and fault phase selection is realized. The method is advantaged in that the EMD methodis combined with the energy entropy concept, the method is suitable for photovoltaic power station transmission line photovoltaic side fault phase selection, accurate motion can be carried out at thephotovoltaic side, characteristics which are not influenced by the fault position, transition resistance and a fault initial angle are realized, and accuracy of photovoltaic transmission line fault phase selection is improved.

Description

technical field [0001] The invention relates to the technical field of relay protection of photovoltaic power plants, in particular to a fault phase selection method for photovoltaic sending lines based on IMF energy entropy. Background technique [0002] With the gradual depletion of traditional fossil resources and the increasingly prominent problem of environmental pollution, the sun has attracted more and more attention due to its advantages of cleanness, environmental protection and superior resource reserves. At present, connecting large-scale photovoltaic power plants to the power system is the best way to utilize solar energy resources. way. Since large and medium-sized photovoltaic power plants have certain low-voltage ride-through (LVRT) capabilities, and their fault current does not exceed 1.2 times the rated load current of the inverter, it will have a serious impact on the operating performance of the phase selection element based on current information on the p...

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Problems solved by technology

The time-frequency window of the short-time Fourier transform cannot be adjusted adaptively, and it cannot take into account the requirements of time and frequency resolution, and is not suitable for analyzing non-stationary signals; although the wavelet transform has higher resolution in the time domain and frequency domain, However, the wavelet basis function and decomposition scale are difficult to choose, and the optimal effect cannot be guaranteed, nor is it adaptive

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