Abstract
Pilot protection is indispensable in multi-terminal HVDC grid to ensure its safe operation. This paper proposes a pilot protection method based on voltage polarities of current-limiting reactors at the ends of DC lines. Analysis shows that the voltage polarities of terminal reactors at the two ends of DC lines are both positive when internal fault occurs, while they are opposite for external faults. Based on the aforementioned characteristic difference, a pilot protection criterion is built to distinguish internal fault from external fault. To avoid mal operation of the healthy pole generated by the coupling effect, the fault voltage of current-limiting reactor is integrated, and its polarity can be identified based on the integration value. At last, a four-terminal modular multilevel converter (MMC)-based HVDC grid simulation model is built in PSCAD/EMTDC, and the simulation results verified the effectiveness of the protection method.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
