The Directional High-Frequency Protection Based On Regarded Load Current As Referrence And Roll Furier Algorithm

With the development of power system, there are more and more large-scale generating set and remote transmission line input in the power system , and the requisition for relay protection is higher and higher. The end earth fault of big power source and long line makes zero-sequence protection appearing serious problem that protecting refused to move because the voltage of zero-sequence is low,and become a new difficult point that zero-sequence protection in practical application. With electric network structure is growing, this question will be more outstanding . On the basis of understanding the principle of zero-sequence protection in an all-round way , this text carry on research to the compensation of voltage especially , propose compensation scheme to the voltage of zero-sequence;Analyse to protecting refusing to move , put forward a kind of directional high-frequency current protection which only regarded load current as reference;Under the low-voltage signal condition, protection's requisition for precision of Fourier algorithm will be higher, propose roll Fourier algorithm , improve filter algorithm's ability to suppress the decaying non- periodic component.