Study On Harmonic And Reactive Power Current Detection Of STATCOM Based On Instantaneous Reactive Power Theory

In recent years, along with the rapid development of power electronics technology, the application in power system has become increasingly widespread. The load consuming reactive power is also increasing. It brings great convenience to our lives, at the same time, it also adds some drawbacks, for example, the emergence of harmonics and the large loss of reactive power. To ensure the power quality of the power system and reactive power compensation have become the hot spots to be solved.The main device of harmonic suppression and reactive power compensation is static synchronous compensator (STATCOM).For the harmonic and reactive current real-time accurate detection is the key of Static synchronous compensator for harmonic suppression and reactive power compensation, which is the first to do during harmonic suppression and reactive power compensation. Based on the instantaneous reactive power theory that is widely recognized and large-scale application is its detection principle, the theory derives two traditional detection methods of ip-iq and p-q method that also been large-scale applied in the market. The instantaneous reactive power theory can real-time accurate completion of harmonic and reactive current detection under what circumstances three-phase voltage without the distortion and the load keep symmetry. But the p-q method exists large detection error when three-phase voltage with the distortion or the load keep asymmetric; the ip-iq method cannot complete detection, the reason why is reactive current cannot be separated from detection current due to the influence of the phase locked loop.For the limitations of traditional detection methods, "instantaneous reactive power" as the theoretical guidance of this paper, on the basis of the detection principle and superiority of conventional method, we proposed an improved detection method to against the limitations of traditional detection methods. This method without a phase-locked loop used the math module instead of PLL to acquite phase angle and angular frequency of voltage fundamental to avoid the affection to the detection of reactive current by the PLL when the voltage become distortion, and make the detection more simplified.Compare the traditional methods when the voltage distortion and without distortion to detect in different circumstances the accuracy and the reason of the error of detection. Make simulation analysis to the improved algorithm presented in this paper at two situations, and compared the test results with the traditional methods, finally, make the comparison results in a tabular for analysis of detection results.In this paper, we set up the model under the environment of Simulink of Matlab, through the simulation results compared the accuracy of traditional detection both when the voltage become distortion and without distortion, and make simulation to the improved detection under the same simulation conditions. Compared with the simulation results of the traditional detection methods, it confirmed the method can still achieve precise detection of harmonic and reactive current under the condition of voltage distortion.