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Keywords

new power system; distributed new energy; generalized S transform; Pearson correlation coefficient; pilot protection

Abstract

As the construction of new power systems proceeds, the capacity of distributed new energy has greatly increased, and more and more power electronic devices are connected to the power system, resulting in limited current amplitude and controlled phase angle of the transmission lines during short circuits. Therefore, the traditional power frequency relay protection methods are no longer applicable. In addition, existing methods are prone to the failure of protection criteria when the output of new energy is weak. To address these issues, a pilot protection method for new energy access to the power grid based on generalized S transform and Pearson correlation coefficient is proposed. Firstly, the generalized S transform is used to obtain the fault characteristic quantities in the frequency domain for currents at both ends. Then, the Pearson correlation coefficient is utilized to calculate the correlation degree of transient energy at both ends, so as to further identify intra-zone and extra-zone faults. Finally, experiments show that the proposed method can meet the requirements of protection rapidity and has a strong ability to withstand transition resistance. This method is not affected by the new characteristics of short-circuit current caused by the connection of new energy power electronic devices and can be applied to transmission lines of new energy.

DOI

10.19781/j.issn.1673-9140.2024.06.020

First Page

194

Last Page

202

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