Research And IP Core Design Of Transient Power Quality Disturbance Detecting Algorithm

In recent years, with a large number of electronic devices continue to introduce power system, the factors of power quality problems becoming more complex and diversified, but the power quality requirements are getting higher and higher. Power quality problems can be divided into steady-state and transient power quality power, the former research earlier also more mature, however, the latter is difficult to detect because of its uncertainty disturbances occur and randomness. Detecting transient power quality disturbances is a prerequisite for solving transient power power quality problems. Thus transient power quality disturbance detection is always important and difficult in engineering research.Based on the research results at home and abroad,this paper proposed an IP core design of transient power quality disturbance detection algorithm based on FPGA. It can fast and accurate positioning the start and end time of pulse transient disturbance, oscillation transient disturbance, voltage swells, voltage sag and voltage intermittent disturbances occur. This paper analyzes some typical transient disturbance detection method, such as RMS algorithm, calculus of differences and the Fourier transform. Then analyzes the wavelet transform from view of the mathematical principle which have better performance in time and frequency domain analysis and multi-resolution analysis and Mallat algorithm. At last the Coiflet2 wavelet is selected to detct the power quality transient disturbance, and the transient pulse, oscillatory transients, voltage swells, voltage sag, voltage interruption transient disturbance signal source is established to verify the accuracy of the algorithm, and experiments confirm the accuracy of transient power quality disturbances detection with Coiflet2 wavelet. The wavelet algorithm is implemented in hardware, by using Matlab / Simulink, DSP Builder, quartus II and other tools. The Coiflet2 wavelet algorithm is implemented based on Mallat algorithm by building a filter out. FPGA has many good characteristics, such as parallel processing, flexible strong, fast speed, by virtue of which solving the problems that wavelet algorithm implemented in software with large amount of computation and real-time is poor.By comparing the experimental results, the transient power quality disturbance detection algorithm's delay is in ms level. The relative error is within the allowable range. So this Coifet2 wavelet IP core has important practical significance in terms of transient disturbance signal detection.