Power Quality Detection Method And Its Application Based On Mathematical Morphology

Power quality problems not only bring vast economic loss, but also endanger power system security and stability. Most power quality problems in power system relate with harmonics and power quality disturbances. These two problems are mostly studied in this dissertation. The existing methods for detecting harmonics are discussed in detail. A mathematical morphology (MM) detection method based on αβ and dq transformation is proposed to detect three-phase current harmonic components. The single-phase harmonic current components can also be detected by the method effectively through constructing a dummy symmetry three-phase power system. It is important to detect and identify power quality disturbance rapidly and accurately. The existing methods of power quality disturbance detection and location are introduced. A new fast MM method based on small angle dq transformation is proposed to locate the disturbances of the voltage signals distorted by noise. The input of the TOP-HAT transformation is the square value of the magnitude of the detected voltage, which ensures the sensitive of the method. Active power filter (APF) and dynamic voltage restorer (DVR) can effectively compensate harmonic components and voltage dip respectively. The operation principle and control strategies of the APF and the DVR are introduced. Digital simulations are employed to validate the feasibility and validity of the harmonics detection method and voltage dip detection method by using MATLAB/SIMULINK.