The paper deals with the high dynamic properties of singlephase dynamic voltage restorer (DVR) using instantaneous power factor determination. Providing virtual approach and application of orthogonal transform theory the ordinary single-phase system can be transformed into equivalent two-axes system. The new thought is based on the idea that ordinary single-phase quantity can be complemented by virtual fictitious phase so that both of them will create orthogonal system, as is usual in three-phase systems. Application of above-mentioned theory makes it possible to use complex methods of analysis as instantaneous active, reactive power and power factor determination. The later is necessary for using of minimum energy control for dynamic voltage restorer. Practical application of instantaneous active, reactive power and power factor determination method uses moving average technique. The paper shows some examples of the simulation experiments results, which proved fast dynamic response of DVR.