Research On Continuously Tuned Power Filter

As a harmonic mitigation device, passive tuned filter has been widely used in power distribution system due to its advantages of simple structure, the reliability and less investment. But the filtering performance is sensitive to the detuning caused by the change of system frequency and filter' s parameters. This paper researches a continuously tuned filter based on a continuously tunable reactor in order to compensate the detuning and limit excessive harmonic current.First, the operating principle of passive filter is expatiated, and the drawbacks and its causes of passive filter are analyzed. It is pointed out that the using of a tunable reactor to continuously compensate the filter' s detuning is a good approach to improve the filter' s performance. The prototype of tunable reactor based on the principle of orthogonal magnetization is designed, and the control characteristic and mathematic model of the tunable reactor is achieved by experiment. The controller of the continuously tuned filter, which can adaptively compensate the detuning and limit the excessive harmonic current, is developed.The experiment and simulation results show the feasibility of tuning strategy with harmonic current limitation.