VSC-HVDC Transmission Line Protection Based on Dynamic State Estimation

Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) transmission line protection is of significance for the safe and stable operation of VSC-HVDC systems. In this paper, a dynamic state estimation (DSE) based VSC-HVDC line protection method is proposed. The method is an extension of the current differential protection, considers the distributed shunt capacitance through the line and can be used as the line primary protection. Specifically, the dynamic model that describes all physical laws that the VSC-HVDC line under protection should obey is first established. Afterwards, the consistency between available measurements and the dynamic model is determined by DSE and the line is tripped if the consistency is continuously low for a user-defined period of time. Numerical experiments demonstrate its dependable and fast operation during internal faults, secure refusal of operation during external faults, sensitivity for high impedance faults and robustness towards measurement noises.