Longitudinal Direction Protection of Hybrid DC Transmission Lines Based on Fault Traveling Wave Characteristics
Traveling wave protection is often used as the main protection in hybrid DC transmission line.However,as a kind of single-terminal protection,traveling wave protection also has the characteristics of high misoperation and poor durability to high transition resistance.Therefore,on the basis of traveling wave protection,this paper analyzes the difference of fault current characteristics inside and outside the zone,and proposes a vertical direction protection method for hybrid DC transmission lines based on fault current characteristics.According to the similarities and differences of the mutation direction of the fault circuit on both sides of the fault,the proposed method can judge the fault as an in-zone fault or an out-of-zone fault.The simulation results show that the proposed method has a good effect on improving the line protection and transition resistance durability.
longitudinal direction protectionhybrid DC transmissiontraveling wave protectionfault current wave