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基于正序电流修正幅值比的含GFM-DG配网纵联保护

Modified amplitude ratio of positive-sequence current based pilot protection for distribution networks with GFM-DG

  • 摘要: 构网型分布式电源的接入使得配电网由辐射状单端网络变为复杂的多端供电网络,不同于跟网型控制策略所表现出的受控电流源外特性,构网型控制在故障期间表现为受控电压源,这对故障特征与传统保护方法产生了影响。对此,以构网型分布式电源为研究对象,分析其在相对于保护区段的不同位置接入时,区段两端正序电流幅值的变化规律与分布特征。在此基础上,引入修正因子对幅值比进行补偿,从而消除T接分布式电源造成的影响,进一步构造基于区段两端正序电流幅值比的故障检测判据。最后,在仿真平台中进行了仿真验证,结果表明,该方法在不同故障类型及位置、过渡电阻等条件下均具有适应性,且耐过渡电阻能力强,可靠性高。

     

    Abstract: The integration of grid-forming distributed generators (GFM-DGs) transforms radial, single-source distribution networks into complex networks supplied from multiple terminals. Unlike grid-following control, which exhibits controlled-current-source characteristics, grid-forming control exhibits controlled-voltage-source characteristics during faults. This behavioral difference alters fault signatures and challenges conventional protection schemes. Accordingly, this study characterizes variations in positive-sequence current magnitudes at both ends of a protected section for GFM-DGs connected at different positions relative to the section. A correction factor is introduced to compensate the current-magnitude ratio and eliminate the influence of T-connected GFM-DGs. A fault-detection criterion is then formulated based on the ratio of positive-sequence current magnitudes measured at the two ends of the protected section. Simulation results demonstrate that the proposed method remains effective across different fault types, fault locations, and fault-resistance levels, with strong tolerance to high fault resistance. These results indicate that the method provides robust and reliable fault detection across diverse fault conditions.

     

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