Fault direction judgment method suitable for wind power access system

Abstract

The invention provides a fault direction judgment method suitable for a wind power access system and belongs to the technical field of power transmission line protection of the wind power access system. The technical problem is that the invention provides a non-earth-fault direction judgment method which is suitable for the wind power access system, and can effectively prevent direction misjudgement caused when a direction element is applied to the wind power side of a link line of the wind power access system. The technical scheme is characterized in that the method comprises the following steps: to begin with, collecting current and voltage at the protection installation place of the wind power side of the link line of the wind power access system; after obtaining the sampling value of a voltage fault component, obtaining positive-sequence component discrete values of the current, voltage and fault voltage; and finally, carrying out judgment on the fault according to the numerical values. The fault direction judgment method is suitable for an electric system.

Description

technical field [0001] The invention proposes a method for judging the fault direction applicable to a wind power access system, and belongs to the technical field of transmission line protection for a wind power access system. Background technique [0002] With the aggravation of energy problems and environmental problems, as the most promising renewable energy, wind energy has attracted more and more attention, and with the continuous increase of the scale of wind farms, it will bring huge impact on the safe and stable operation of the power grid. challenge. [0003] In recent years, studies on the impact of wind power access on relay protection have been published in the literature. These literatures use theoretical analysis, simulation analysis, and wave data analysis to comprehensively analyze the impact of sudden change protection on large-scale wind power. The adaptability of the access system; the directional element is not only the core element of the directional c...

AI Technical Summary

Problems solved by technology

[0004] At present, the directional elements used for transmission lines can be divided into power frequency fault component directional elements, traveling wave directional elements, and transient fault component directional elements; among them, the power frequency fault component directional elements are not affected by load, act fast, and are not subject to transition It is widely used in power transmission systems due to its advantages such as the influence of resistance. The good action performance of the power frequency fault component directional element is based on the fact that the positive and negative sequence impedances of the backside system are equal and the positive sequence impedance is stable; however, the wind power system’s equal The value of the positive sequence impedance is unstable, and the positive and negative sequence impedances are not equal, which will make the direction misjudgment possible when the directional element is used on the wind power side of the tie line of the wind power access system. Therefore, a method that does not depend on the backside system impedance is proposed The directional element is particularly important

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