关键词:

"> 交直流混联配电网, T接负荷, 虚拟功率变化量, 线路保护

Abstract: AC/DC hybrid distribution networks can effectively reduce line losses and improve transmission efficiency, representing an important direction for modern power systems. However, the differences in fault characteristics between AC and DC sections, coupled with the presence of numerous unmetered tapped loads in distribution lines, pose significant challenges to the coordination and performance of protection schemes. To address these issues, this paper proposes a novel protection method based on power variation. By applying Tellegen’s theorem, the method analyzes the variation characteristics of electrical quantities before and after faults in lines with different types of tapped loads. Taking into account the influence of various tapped loads on fault indicators, a load proportion estimation technique is proposed, providing a theoretical basis for fault feature correction. Accurate protection of the AC/DC hybrid system is then achieved using the corrected transient power variation quantities. Theoretical analysis and simulation results demonstrate that the proposed method can accurately identify faults, effectively improve the coordination and adaptability of AC/DC protection, and provide a reliable protection solution for the safe and stable operation of hybrid distribution networks.

Key words: AC/DC hybrid distribution network, tapped loads, virtual power variation, line protection