Four-quadrant power supply alternating current contact line protection method based on Hough fault coefficient

By using a method based on the Hough fault coefficient, the performance degradation and failure to operate of traditional relay protection after four-quadrant power supply is connected to the grid are solved, and the correct protection action is achieved after the four-quadrant power supply is connected to the grid, ensuring the safety and stability of the power grid.

CN122393873APending Publication Date: 2026-07-14CHINA UNIV OF MINING & TECH (BEIJING)
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Patent Information

Application Number
CN202510054763.2
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-01-14
Publication Date
2026-07-14

AI Technical Summary

Technical Problem

Traditional relay protection systems experience performance degradation or even fail to operate after four-quadrant power sources are connected to the grid, threatening the safe and stable operation of the power grid.

Method used

A four-quadrant AC tie line protection method based on Hough fault coefficients is adopted. After sampling and normalizing the current on both sides of the line, the slope indication coefficient is calculated using an improved Hough transform to form a multi-level fault coefficient. Finally, the fault type is determined by a step classification function.

Benefits of technology

Ensuring the correct operation of the protection device after the four-quadrant power supply is connected to the power grid improves the performance and reliability of the relay protection.

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Abstract

As a four-quadrant power supply represented by a battery energy storage station and a flexible direct-current power transmission system is widely connected to a power grid, the complex fault characteristic of the four-quadrant power supply brings challenges to traditional relay protection, so that the traditional current differential protection is refused to operate. In order to solve the problem, the invention discloses a protection method based on a Hough fault coefficient. According to the protection method, the slope of a two-dimensional current track is extracted by utilizing improved Hough transformation, three specific slope angles are selected to construct a Hough fault coefficient so as to quickly and sensitively identify internal and external faults, the protection method shows excellent reliability when facing various internal fault conditions on a four-quadrant power supply alternating-current connecting line, and meanwhile, the protection method has the advantages that the reliability is high, and the reliability is high. And under the condition that non-ideal working conditions such as CT saturation, CT errors, synchronization errors, noise and abnormal values exist, the protection safety is ensured.
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