Protection Strategy for HVDC Transmission System

The protection strategy of DC system is the important part of engineering research and system design for HVDC transmission project and its control and protection system, whose goal is to protect equipments, avoid the equipment damage and effect on HVDC transmission caused by fault or unusual operation condition. The possible fault condition for HVDC transmission system includes converter valve fault, DC system fault and AC system fault. The DC system indicates certain characteristics under different fauh conditions, and the protection strategy for HVDC transmission system can be put forward according to the operation features and fault characteristics. The paper explains the protection strategy for long distance HVDC transmission system taken San - Chang HVDC transmission project as an example in detail, which includes function disposition, protection principles, handling mode of protection movement as well as the means adopted by the simulation study for control and protection system. Based on the above, the protection strategy for HVDC transmission system is summarized.