Improved method and system for distance protection of tie-lines in wind farms based on tls-esprit

Abstract

The invention provides a TLS-ESPRIT-based wind field tie line distance protection method and system. The system comprises an electrical quantity signal collection module, a pre-processing module, a Hankel matrix module, a TLS-ESPRIT-based parameter identification module, a measured impedance module and a distance protection module, wherein the pre-processing module obtains a data sequence of an electrical quantity signal in a failure, constructs a Hankel matrix through the Hankel matrix module, carries out singular value decomposition and determines the number of AC components; parameter identification is carried out on the AC components through the TLS-ESPRIT-based parameter identification module to obtain parameter information of the AC components; and the measured impedance is calculated through the measured impedance module and is substituted into a criterion of the distance protection module for distance protection. The TLS-ESPRIT-based wind field tie line distance protection method and system are reasonable in design and high in reliability; and the rejection rate and the maloperation rate of the distance protection are reduced.

Description

technical field [0001] The present invention relates to a technology in the field of relay protection of electric power systems, specifically a kind of wind power based on TLS-ESPRIT (Total Least Squares-estimation of Signal Parameters via Rotational Invariance Technique, total least squares-rotational vector invariance technique) Field tie line distance protection method and system thereof. Background technique [0002] my country's wind resources are mainly concentrated in Inner Mongolia, Xinjiang and other regions, which are far away from the load center and have a long transmission radius. Therefore, large-scale high-voltage centralized access schemes are mainly adopted. The connection of large-scale wind power has brought great challenges to the relay protection of wind farm tie lines, and the phenomenon of malfunction and refusal occurs from time to time. completely different characteristics. Among them, a prominent difference is that there is a large non-power frequ...

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Problems solved by technology

[0005] Aiming at the defects in the prior art that the frequency of the short-circuit current cannot be identified, and the separation of power frequency components and non-power frequency components for fault criteria used in distance protection, the present invention proposes a distance protection method for tie lines in wind farms based on the TLS-ESPRIT method And its system, through the wind farm side distance protection method based on the TLS‐ESPRIT method, extracts the power frequency components and non-power frequency components that appear on the wind farm side, determines the parameter information of each AC component of the electrical quantity, and calculates the measurement impedance. , fault location, and different transition resistance conditions to reflect the location of the fault point, reducing the rejection rate of distance protection

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