基于等传变思路的超高速输电线路保护研究与开发

Research and development on the ultra-high-speed transmission line protection based on the concept of the equal transfer

提出了基于等传变思路的系列超高速线路保护新技术,包括基于单端暂态信息的输电线路解微分方程算法距离保护以及基于双端暂态信息的采样值差动保护。通过利用等传变思路有效克服了电容式电压互感器暂态传变误差以及线路分布电容干扰噪声对保护算法精度和速度的不利影响,同时针对性地提出了出口三相短路故障的加速动作方案。基于现有的保护软硬件平台实现了新型线路保护,实验室检测表明单端量保护算法针对出口三相短路故障的动作时间小于2.7 ms,双端量差动保护算法全线动作时间小于5.8 ms。所提保护新技术可以有效应对电力电子化电网中故障暂态特性复杂多变、对故障清除速度要求极高等线路保护面临的新挑战。

The ultra-high-speed transmission line protection based on the concept of the equal transfer is proposed, including the distance protection based on the differential algorithm applying the local transient information and the sample value differential protection applying the two-terminal transient information. The method of the equal transfer processes is utilized to solve the impact of the CVT transient transfer error and the transmission line distributed capacitor, in order to improve the speed and the accuracy of the protection. In addition, the accelerating operation scheme for the near-zone three-phase fault is proposed. The proposed transmission line method is realized in the existing protection hardware and software platform. The laboratory test shows that the protection based on the local information can operate within 2.7 ms for the near-zone fault, and the differential protection can cut-off the full-line fault within less than 5.8 ms. This new protection technology can effectively cope with the challenges that the fault transient is complex and the protection is demanded to operate quickly in the power-electronized grid.