高压直流输电系统直流滤波器接地故障机理分析

高压直流输电系统以双极大地回线方式运行,较为典型。文中对此方式下直流滤波器电容区和调谐区的接地故障机理进行了研究,先分别构建其等效电路,然后定量分析其电气量特征,最后,以仿真实验加以验证。理论分析和仿真实验均表明,采用基尔霍夫电流平衡原理的差动保护反映直流滤波器接地故障时,选择包括直流分量在内的全波电流要比选择特征谐波电流更为合理,并具有更高的灵敏性和可靠性。

Analysis on Grounding Fault Mechanism of DC Filter in HVDC Transmission System

The high voltage direct current(HVDC)transmission system runs in a bipolar earth loop mode, which is more typical. This paper studies the mechanism of grounding fault in capacitor and tuning zones of the DC filter. Firstly, the equivalent circuit of the two zones is constructed. Then the electrical characteristics of DC filter are analyzed. Finally, the simulation experiment is carried out for verificaiton. Both theoretical analysis and simulation experiment show that it is more reasonable to choose the full wave current including the DC component than the characteristic harmonic current when using the differential protection based on the Kirchhoff current balance principle to reflect the grounding fault of the DC filter, and it has higher sensitivity and reliability.