Fault Location in H-Type AC Filters Based on Characteristics of Sudden Current Changes

The timely detection and accurate location of capacitor element breakdown faults (CEBFs) are crucial in optimizing the performance of alternating current (AC) filters and ensuring the safety and stable operation of high-voltage direct current transmission systems. In this paper, by analyzing the physical process of CEBFs and the transient fault characteristics, a mapping relationship is established between the initial phase angle of the fault, the direction of sudden changes in unbalanced current, and the current difference on the low-voltage side for CEBFs occurring in different bridge arms. A fault arm localization method is developed for CEBFs in H-type AC filters based on the direction of sudden current changes. This technique is shown to enhance both the location accuracy and reliability compared with previous methods. The feasibility and accuracy of the proposed method are validated through simulations and experimental data.