Research On A Hybrid Power Filter System

Harmonics and reactive's co-existence is a universal phenomenon in the Modern power system. To deal with this situation, comprehensive treatment, including harmonic suppression and reactive power compensation, is an effective way. The researches on it mainly focused on hybrid active power filters in which active part is in series with passive branches. And the studies on hybrid system of active part paralleling with passive branches is relatively few in recent years. This paper makes a deep research on this system from the perspective of application.The detection algorithm of Harmonic and reactive power is the basis for the hybrid system. This paper presents a complex harmonic reactive detection algorithm which synthesizes wavelet packet analysis and transient reactive power theory. The algorithm calculates system' s fundamental and harmonic from wavelet packet, and then obtain fundamental reactive power by way of processing the fundamental signal using the transient reactive power theory. Advantage of this algorithm is that it can quickly calculate multiple harmonic and fundamental reactive power of three-phase system without digital filters and phase-locked loop, and also facilitate the distribution of filtering tasks among active power filters.In large capacity conditions, the active power filters are required to be paralleled with each other for expansion. This paper gives a parallel scheme. It is an intelligent parallel network with self-maintenance operation. Its distinctive feature is that this net is ruled by one master node all the time and its physical addresses were generated automatically.System harmonic amplification is a common phenomenon of power system. From this point of view, this paper analyzes the composite current detection methods including the load current and system's current just only for suppressing harmonic amplification. And then this paper derives the relationship between the feedback loop's and the real-time system topology from the perspective of stability.The final objection of the comprehensive system is to export filter and compensation current using appropriate strategy. This paper gives a detailed control scheme of the hybrid system based on the complex algorithm, including generation of active power filter's reference current, calculating real time passive branches topology. The simulation results show that the proposed complex algorithm and the corresponding control strategy are feasible.