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Studies of coordinated zone protection strategy for DC grid

DC grid technology is one of the effective methods for collecting, transmitting and accommodating large-scale renewable energy over long-distance. Voltage source converter (VSC) based DC grid technology has become a preferred technical scheme because of its inherent advantages, such as flexible bi-directional DC power control capability. However, VSC based DC grid is also facing many operation control and protection problems to be solved, especially the problem of fault protection for the DC grid. This paper first analyzed the fault characteristics of the DC grid, and then through a typical DC grid configuration, a zone protection strategy is proposed with the objective of using a minimum number of DCCBs. The simulation results using MATLAB/Simulink platform show that the zone protection strategy is feasible and effective. The study in this paper provides a technical reference for the research and development of fault protection and isolation for DC grid in the future.