摘要：In the research, a protection scheme for hybrid multiterminal UHVDC lines based on the CEEMDAN and Teager energy operator is proposed. The fault direction criterion is proposed according to the polarity difference of the sudden variable of the mode component of the current line on both sides of the T-zone after the fault of the EHV multiterminal hybrid DC system. When the fault is located on the left or right side of the T-zone, CEEMDAN is used to decompose the mode component of the fault transient current and obtain the intrinsic mode function (IMF component) at different local characteristic time scales. Then, the Teager energy operator is used to calculate the instantaneous energy of the current high-frequency IMF1 component. Finally, the faults inside and outside the line are judged by comparing the maximum value of current high-frequency IMF1 instantaneous energy with the setting value. When the fault is located in the T-zone, it is determined as a fault outside the line zone. The protection scheme of hybrid multiterminal UHVDC lines is given. The simulation model of the Kunliulong hybrid multiterminal UHVDC line system is built in a PSCAD/EMTDC simulation platform, and the proposed protection method is verified. A large number of simulation results show that the protection scheme has certain anti-transition resistance ability and high reliability.
