Voltage Waveform Comparison Longitudinal Protection Method Based on Improved Bhattacharyya Coefficient for AC / DC Hybrid Power Grid

If a fault happens on the AC line of a new form of AC/DC hybrid power grid, the fault characteristics and changes in electrical quantities after faults in a new type of power grid are completely different from traditional grids. The protection based on the electrical quantity of traditional AC systems will be affected. A method to solve the problem is put in this article. This article investigates the relationship between waveform similarity and fault location, and the improved Bhattacharyya coefficient method is applied to judge the similarity. Longitudinal protection logic is used to distinguish between the two types of faults. The simulation results which are based on PSCAD show that the method is applicable.