Monitoring and measurement of power quality indices using an adaptive notch filter

This paper studies the applications of an adaptive notch filter (ANF) for signal processing in transient and steady-state operating conditions of the power system in presence of disturbances, distortions and noise. By extracting fundamental and harmonic components of voltage and current signals, ANF makes it possible to estimate signal parameters such as amplitude, phase, and frequency in the presence of disturbances, distortions, and noise. The adaptive nature of the mentioned filter allows it to follow amplitude and frequency variations of the fundamental component accurately as well as the harmonic components; moreover the simplicity of the filter makes it easily implementable. Representative simulation results for frequency estimation, voltage sag and swell detection, extraction of fundamental and harmonic components, disturbance detection, flicker detection, and zero-crossing detection are shown. These simulations confirm the robustness of the filter in different operating conditions of the power system and illustrate its usefulness in power quality enhancement.