小步长采样的新型直流输电线路行波保护

A Small Sampling Interval Based New Traveling Wave Protection Scheme for HVDC Transmission Lines

为解决目前直流线路保护速动性和灵敏性难以同时满足的问题,提出了一种基于小步长采样的新型直流线路保护方案。新型保护以主流的行波保护理念为基础,保证了保护的速动性和实用性,通过使用小步长采样提高了保护的灵敏性。新型行波保护方案以电压变化率判据作为主判据,用于快速、灵敏的故障检测;以电压比判据和电压差判据作为辅助判据,用于保证在雷击线路和极间耦合情况下保护不发生误动作。在PSCAD/EMTDC环境下对新型波保护进行了仿真测试与分析,相关结果表明新型保护同时具有良好的速动性和灵敏性,并且具有较强的抗干扰能力。

At present, it is difficult for existing protective relaying for HVDC transmission lines to simultaneously meet both demands on protection sensitivity and protection quick action performance, for this reason, a small sampling interval based new protection scheme for HVDC transmission lines is proposed. Based on mainstream traveling wave protection, the proposed new protection can ensure both practicability and quick action performance and the small sampling interval of the protection can ensure its sensitivity. In the new traveling protection scheme there are one main criterion and two auxiliary criteria： the voltage variation rate is taken as the main criterion for fast and sensitive fault detection; the voltage ratio criterion and the voltage difference criterion are auxiliary criteria to ensure there is not malfunction of the protection during lightning stroke on transmission line and under electromagnetic coupling between DC lines. In PSCAD/EMTDC environment the simulation of new traveling wave protection is performed, and simulation results show that the proposed new type of traveling wave protection scheme possesses sensitivity and quick action performance simultaneously as well as stronger anti-interference ability.