基于高频电压突变量的特高压直流输电系统接地极引线故障监测方法

Monitoring Scheme for UHVDC Ground Electrode Line Fault on the Basis of High-frequency Voltage Variation

为快速检测并切除特高压直流输电系统接地极引线故障,提出了一种基于高频电压突变量的高压直流输电接地极引线故障监测方法。首先分析了接地极引线接地故障时高频电压的特性,在此基础上,提出了利用高频电压突变量作为判据检测接地极引线故障的新方案。所提出的故障监测方法不受高频信号下接地极引线阻抗—距离非单调性质的影响,有一定的抗过渡电阻的能力,对接地极引线参数测量误差具有较强的适应性。并且,该算法可以直接应用于现有的接地极故障监视系统(ELIS)中,无需额外的硬件投资。为验证所提出方案的性能,基于电磁暂态仿真程序PSCAD进行了数字仿真试验,结果表明,当过渡电阻小于200?时,该方法均能灵敏可靠地识别并隔离故障,其在电力系统中具有良好的应用前景。

We proposed a monitoring scheme for high-frequency voltage variation-based ground electrode hne fault m ultra high voltage DC transmission system （UHVDC） to detect and isolate ground electrode fault as rapidly as possible. Firstly, the characteristics of high frequency voltage are analyzed. Then, the high frequency voltage variation is proposed as criteria to distinguish the internal fault from normal operation conditions of the ground electrode line. The proposed method is not affected by the non-monotonic of the impendence-distance relationship, and has a good adaptation with the parameter errors of the ground electrode line. Furthermore, the algorithm can easily be implemented in the convention electrode line impedance supervision system （ELIS）. Digital simulations are conducted to verify the proposed scheme. The results show that the proposed method can detect the grounding fault in the ground electrode line sensitively if the transition resistance is less than 200 Ω, and has good practical prospective in power system.