A Filtering Technique for Three-Phase Power Systems

A novel filter for use in three-phase power systems is introduced. When the input to the filter is a three-phase balanced set of signals, the filter suppresses noise and distortions and extracts a smooth version of the fundamental components. When the input signal to the filter is unbalanced, it extracts the positive-sequence components of the input signal. The filter also estimates the magnitude, phase-angle and frequency of the input signal while adaptively accommodates variations in all these three variables. Characteristics of the filter including its mathematical equations as well as steady-state and dynamic responses are discussed in this paper. Structural simplicity and robustness of the filter make it desirable for power system application. It can specifically be used as an adaptive anti-aliasing filter