Research And Realization On Fundamental Positive,negative Sequence And Harmonic Signal Detection Algorithms In Power System

With the improve of power electronic technology,the volatility,the impact electric equipment has been widely used,the proportion of nonlinear loads in power grid are increasing gradually.Result in Serious harmonic pollution in power system.Microelectronic devices are widely used in precision manufacturing industry at the same time, the user’s requirement of power quality enhances unceasingly.The harmonic detection is the key of harmonic analysis and management.Harmonic detection method applied to harmonic compensation shall meets the demand of precision under all condition of power system,and at the same time the detection speed and detection time delay should be small.Harmonic detection method satisfied the accuracy and real-time at the same time is the target of many scholars.Phase-locked loop is a necessary link in the current mainstream harmonic detection algorithm, and its performance is very important to the harmonic real-time detection system.In view of the traditional three-phase dq phase-locked loop in the ac system voltage unbalance and harmonic conditions,can not attain both the phase-locked accuracy request and the response speed request.This thesis presents a CDSC phase-locked loop(CDSC- PLL), and demonstrates the accuracy and real-time performance of this method.This thesis studied the detection method based on FBD theory,that used to extract the fundamental positive sequence, negative sequence and reactive current in unbalanced three-phase power system.The improved method based on FBD theory,adopts CDSC- PLL.Under all kinds of condition of power system, this detection method based on FBD get an accurate detection of fundamental wave and negative sequence and reactive current,at the same time, real-time performance has been great improved.the accuracy and real-time performance of this method are analyzed.The detecting experiments have been carried out to verify this method in d SPACE experiment platform.Aiming at the shortcomings of the existing harmonic detection techniques, this thesis proposes a Kalman- Fourier filtering detection algorithm.Kalman- Fourier filtering algorithm is a kind of single phase detection algorithm.This algorithm can one-off detect all major number of harmonics, and have simple calculation, good real-time performance and detection accuracy.Aiming at the shortcomings of that Kalman- Fourier filtering algorithm’s real-time performance reduced when detect the even-number-order harmonics,this thesis proposed an improve form of DSC-Kalman- Fourier filtering algorithm.And in d SPACE experiment platformexperiments have been carried out to verify this method.