Method and system for protecting alternating current filter based on dynamic time warping

By using dynamic time regularization algorithm to calculate the three-phase imbalance current distance value of the AC filter in a high-voltage DC transmission system, and setting the threshold value to judge the protection locking, the malfunction problem caused by the optical CT transmission fiber disturbance is solved, and the system is improved Stability and accuracy.

CN119093296APending Publication Date: 2024-12-06POWER RES INST OF STATE GRID SHAANXI ELECTRIC POWER CO LTD +1
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Patent Information

Application Number
CN202411265096.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-09-10
Publication Date
2024-12-06

AI Technical Summary

Technical Problem

In high-voltage DC transmission systems, when the AC filter fails, the signal distortion caused by environmental disturbances caused by the transmission fiber, which may cause protection malfunction and affect system stability.

Method used

The protection method based on dynamic time regularization is adopted, and the three-phase unbalanced current data is collected in real time through the current transformer, the dynamic time regularization distance value is calculated, and the threshold is set to judge the protection locking and avoid erroneous action.

Benefits of technology

It improves the accuracy and stability of the protection system, can correctly identify the abnormal output of the optical CT under forced vibration, prevent protection malfunctions, and adapt to various power grid operating conditions.

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    Figure CN119093296A_ABST
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Abstract

The invention provides a method and a system for protecting an alternating current filter based on dynamic time warping. The method comprises the following steps: acquiring three-phase unbalanced current at an alternating current filter end; based on the real-time unbalanced current data on the line, whether the three-phase unbalanced current characteristic quantity is larger than a current starting threshold value or not is judged; if not, continuously collecting; the starting unit controls the locking unit to start, and the locking unit calculates to obtain a dynamic time warping distance value between every two phases; the locking unit sets a regular distance threshold value of the three-phase unbalanced current, and if the dynamic time regular distance value between every two phases is smaller than or equal to the regular distance threshold value, the locking unit acts to lock protection; and if not, the locking unit does not act, and the protection unit starts protection. According to the method, the dynamic time warping algorithm is used for identification, the speed is high, the accuracy is high, and the method has good effects of improving safe and stable operation of the AC filter of the converter station and preventing protection misoperation.
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