Fault line selection method based on proportion of DC component-main frequency component and amplitude-phase measurement

Abstract

The invention discloses a fault line selection method based on direct component-dominant frequency component duty cycle and amplitude-phase measure comprehensive comparison. A Prony algorithm is usedfor decomposing transient zero-sequence current of a fault line and non-fault line after single-phase grounding fault into an attenuated direct component, a power frequency component, and an attenuated transient dominant frequency component. The ratio of the direct component to dominant frequency component is calculated as direct component-dominant frequency component proportion lambada. The comprehensive value of amplitude ratio and phase ratio of the dominant frequency component is calculated as amplitude-phase measure C. Power distribution network fault line selection criterion is formed based on comparison between the direct component-dominant frequency component portion lambada and the amplitude-phase measure C. The principle is simple; two complementary criteria are combined, and therefore reliability is high; influence by transition resistance, fault closing angle and other factors does not occur; and only zero sequence current of branches is compared, and therefore applicationin engineering is easy to achieve.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and in particular relates to a fault line selection method based on the ratio of direct current component to main frequency component and amplitude and phase measurement. Background technique [0002] Most of the medium and low voltage distribution networks in my country use the neutral point to be grounded through the arc suppression coil. For the system whose neutral point is grounded through the arc suppression coil, due to the compensation effect of the arc suppression coil, the steady-state characteristics of the zero-sequence current of the fault line tend to be For non-faulty lines, it is difficult to completely distinguish faulty lines from non-faulty lines even with a single transient information, resulting in low accuracy of faulty line selection. [0003] Researchers at home and abroad have done a lot of research on the fault line selection of the arc-suppressio...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is: the traditional line selection principle has the problem of difficult line selection when the system single-phase ground fault occurs with a low fault closing angle and the reliability of line selection is not high under high-resistance faults

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