For three-phase system, in the case of asymmetrical three-phase voltage, the phase-lock loop in the traditional ip-iq detecting method cannot be used to detect the phase of the positive sequence voltage. At the same time, present in real-time low-pass filter such that the detected poor. As a result, there exist errors in the transient reactive currents. To solve this problem, an improved detecting method is put forward in this paper. In this method, the improvedSmethod toSobtainSthe positive sequence componentSA phaseSvoltage by usingStime delay method. Meanwhile, use the wave of positive sequence extractorSinstead of low-pass filter to attain the DC component of current.Seliminating theSfilterSlink. In this paper, using the MATLAB/SIMULINK simulation software for modeling and simulation, the simulation results show that the improved reactive current test in the asymmetric three-phase grid voltage can accurately, real-time implement reactive current detection used in the static reactive power generator.