A new real-time negative and positive sequence components detecting method based on space vector

Based on the concept of the space vector, a new method for real-time detection of the fundamental negative and positive sequence components as well as the harmonic components of power system signals is developed in this paper. In the method, the three-phase quantity is firstly converted into a space vector, whose real part and imaginary part are filtered by two filters respectively in order to eliminate the harmonics. After filtering, the space-vector is composed of two vectors actually. The counter-clockwise rotating one corresponds to the fundamental positive sequence component, and the clockwise rotating one corresponds to the fundamental negative sequence component. A method is developed in the paper to real-time decompose the two vectors. After decomposing, rotate the two vectors a proper angle according to the phase error caused by the filters at the fundamental frequency respectively the phase error can be eliminated. So the fundamental negative and positive sequence components can be real-time detected with high precision. At the same time, the harmonics can also be detected by the method. Simulation results have validated the proposed method.