Abstract：There is a very obvious mutual inductance between UHVDC bipolar long lines. When one pole line fails, the voltage of the other pole line will drop to a lower value at a faster speed due to mutual inductance. This phenomenon is basically the same as the voltage variation law of DC line when grounding fault occurs, which is easy to cause misoperation of DC line derivative protection. Firstly, this paper deeply analyzes the misoperation mechanism of DC line derivative protection. Taking advantage of the difference in recovery characteristics between the voltage drop caused by mutual inductance of bipolar line and the voltage drop caused by actual grounding fault, a blocking voltage derivative protection strategy considering the influence of mutual inductance is proposed, and the strategy is tested and verified on the real-time digital simulation test platform. The effectiveness of the proposed strategy is proved, which provides a reference for other DC projects.
龚飞, 李林, 赵森林, 邹强, 汪大全. 美丽山二期直流线路突变量保护优化研究[J]. 电气技术, 2021, 22(11): 36-41.
GONG Fei, LI Lin, ZHAO Senlin, ZOU Qiang, WANG Daquan. Optimization of line derivative protection in Belo Monte phase two ultra high voltage DC project. Electrical Engineering, 2021, 22(11): 36-41.
2021, Vol. 22 
