Research On Harmonics Elimination Control Strategy Based On Adaptive Algorithm In Substations

The project is about the application of APF(Active power Filter)in FACTS(Fexible AC Transmission System),whose background is the power distribution system of an oil field.The application of power electronics switching device and frequent fluctuation of load is the main interference source,which brings a lot of problem such as a low power factor,harmonic waves and voltage flicker.At the same time,many kinds of complicated and accurate electric equipment are very sensitive to power quality,proposing a higher standard of power quality.So how to raise and ensure power quality has become one of the most urgent issues which are still needed solving.The main works are shown as follows:The article is based on the statistics of reactive power and harmonics in an oil field and pay attention to the feasibility and necessity of improving power quality with APF.Also,it tries to analyze the significance for harmonic suppression and reactive compensation with APF.What the article has done is the base of following researches.The article proposes the control strategy with LMS harmonic detection method to detect load harmonics,which is based on the analysis of influence of feedback error during measurement to the operation weight and step size.This control strategy leads a higher detection precision and provides reference for improving the control precision and efficiency of APF.With the analysis of response speed and control accuracy of APF,the article obtains the design standard of capacity of main circuit,the inductance of AC side and the capacitance of DC side.The control strategy aimed to suppress harmonic and stabilize the voltage of DC side is based on hysteresis loop analysis,which can guide the design of hardware parameter and APF system.In the article,an APF experimental facility is developed.The results of experiments of harmonic suppression and reactive compensation show that the control strategy used in the article can trace the harmonic components of load current in real time with signal conditioning.So it can improve control effect of APF greatly to meet the national harmonic standard(GB/T14549-93)and prove the feasibility and practicability of APF which is developed in the article.