Study of Reactive Power in AC/DC Power System

Based on the mathematical model of reactive power for arbitrarily periodical voltage and current waveform, reactive power of AC/DC system is analyzed and calculated, its mathematical model is derived and physical essence is described. The model of a typical AC/DC power system is built uses PSCAD/EMTDC, output data and curves of simulation is analyzed, reactive power of the AC/DC system is formulated. The example is presented to verify the correctness and feasibility of the definition of the reactive power I/V pair and reactive power for arbitrarily periodical voltage and current. The paper points out that the physical essence of reactive power is interactions of voltages and currents of different frequencies, which suffices fundamental energy conservation law.