Quick harmonic and reactive current detection method based on instantaneous reactive power theory

The invention relates to a quick harmonic and reactive current detection method based on the instantaneous reactive power theory. The method includes the step that a current disturbance system is provided. The current disturbance system comprises a control and monitoring unit. The harmonic and reactive current monitoring process of a current detection control circuit for monitoring harmonic and reactive currents in the system in the control and monitoring unit includes the steps that firstly, three-phase voltage and current instantaneous values in a three-phase power grid are collected; secondly, by the adoption of alpha-beta transformation, three-phase voltage and currents are changed into an alpha beta orthogonal stationary coordinate system; finally, virtual voltage vectors are added for replacing real voltage vectors participating in operation, instantaneous active and reactive power is calculated, and direct current power components are acquired through filtering of an LPF; fundamental components in detected currents are calculated through reverse transformation; harmonic components can be acquired by subtracting the fundamental components from the detected currents. The method can quickly detect harmonic currents and reactive currents.