يك روش آناليز سيگنال هاي سينوسي ميرا مبتني بر حلقه قفل شده در فاز

چكيده انگليسي :

A method for analysis of damped sinusoidal signals based on phase locked loop Hossein Zamani hossein zamani@ec iut ac ir January 2017 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Associate Prof Mohsen Mojiri mohsen mojiri@cc iut ac ir Abstract Signal processing has essential role in features extraction of the systems In many cases signals that must be processed show some periodic properties and they can be modelled as a sinusoidal signal or a combination of sinusoidal signals withtime varying parameters amplitude frequency and phase Kalman filter phase locked loop adaptive notch filter andsecond order generalized integrator are methods that can estimate parameters of sinusoidal signals These methods mainlyfocused on sinusoidal signals with constant amplitude However in some practical applications such as the propagation ofacoustic waves and the electromechanical oscillations in power systems sinusoidal signals have relatinely fast variations inamplitude Electromechanical oscillations in power systems caused by the interaction of different parts of system Accurateestimation and characterization of these oscillations can increase situational awareness of the system and can even be usedto take appropriate control actions to maintain the balance of the system and can help to prevent instabilities In suchapplications signals can be modeled with damped sinusoidal signals These signal parameters include amplitude primaryand instantaneous frequency phase primary and instantaneous and damping factor which should be estimated in order toanalyze the signal Recently Kalman filter and second order generalized integrator have been extended and modified in orderto estimate the parameters of the damped sinusoidal signals In this study enhanced phase locked loop is modified in orderto do this work Dynamical equations of proposed method is obtained in two ways 1 Based on the equivalency in termsof mathematical formulation between enhanced phase locked loop and second order generalized integrator and 2 usingthe gradient descent method and minimization cost function Stability analysis shows that the values of the parameters of adamped sinusoidal signal instantaneous amplitude frequency instantaneous phase and damping factor are an exponentiallystable equilibrium point for the proposed method Various computer simulations confirm desirable performance of theproposed method to estimate the parameters of damped sinusoidal signals The proposed method can be used to extractelectromechanical oscillations on phasor data that provided by the phasor measurement units across the power system Also the proposed method can successfully detect low frequency oscillations at a low reporting rate with very high accuracy Thisoutperforms the conventional method significantly Key Words Electromechanical oscillations phasor measurement units damped sinusoidal signals enhanced phase lockedloop frequency estimation damping estimation

زماني، حسين

يك روش آناليز سيگنال هاي سينوسي ميرا مبتني بر حلقه قفل شده در فاز

نوسانات الكترومكانيكي , واحدهاي اندازه گيري فازور , حلقه قفل شده در فاز ارتقاء يافته , تخمين فركانس , تخمين ضريب ميرايي