A comparison of non-unit and unit protection algorithms for HVDC grids

From a prospect where High Voltage Direct Current systems are the most promising alternative for new grid expansion as well as for integration of renewable energies at worldwide level, this paper analyses DC protection systems and their challenges on detecting and clearing faults. The focus of this paper is a comparison between non-unit and unit protection systems. It is also presented a study case with a simple non-unit algorithm, which is enhanced with a communication system.