基于暂态电流相关系数的混合多端高压直流输电线路保护

混合多端高压直流输电系统结合了传统高压直流输电与柔性直流输电技术的优势,在降低经济成本的同时可实现大容量功率输送、故障穿越与抑制换相失败等功能,是未来电网发展的重要趋势之一.但是混合多端直流输电系统拓扑相对复杂,且全控型电力电子设备耐过流能力较弱,即故障后需保护装置快速可靠地识别故障区间.因此,提出一种基于暂态电流故障...

Hybrid Multi-Terminal HVDC Transmission Line Protection Based on Transient Current Correlation Coefficient

The hybrid multi-terminal HVDC transmission system combines the advantages of conventional HVDC and flexible HVDC transmission technology, which can realize the functions of high-capacity power transmission, fault ride-through and suppression of commutation failure while reducing the economic cost. However, the hybrid multi-terminal system topology is relatively complex, and the fully controlled power electronic equipment has a low ability of enduring over current. Therefore, a kind of line protection strategy based on transient current correlation coefficient for hybrid multi-terminal HVDC transmission is proposed. Current in the three ports of T-type tandem busbar is measured to calculate correlation coefficient, which can accurately identify the fault range. The simulation results show that the proposed protection scheme does not require communication, and the protection can be triggered within 1 ms. Meanwhile, it can withstand the interference of 300 Ω transition resistance and 20 dB white noise. Therefore, the proposed method can better meet the protection requirements of the hybrid multi-terminal HVDC transmission system.