Design Of Power Quality Monitoring System Based On Time-Frequency Domain Analysis Method

With the rapid development of industrial technology, the power sector and power users gradually began to focus the quality problems. On the one hand, widespread use of power electronic devices and nonlinear loads so that voltage and current waveform distortion, resulting in serious deterioration of power quality; on the other hand, a large number of microprocessors are used in industrial control, precise control of these processes are more susceptible to power system disturbances, so the power quality of modern industry has a higher requirements. In order to monitor and control power quality, research and development of high-quality power quality monitoring system become an urgent problem.This paper outlines the basic concept of power quality. Fourier transform and wavelet transform signal analysis methods are described, pointed out that the characteristics of the two methods and application conditions, and given the Mallat calculation methods and module maximum principle. Hardware system is designed with TMS320VC5509A and STM32F103ZCT6, and described the system design of key modules. In this paper, system software is completed with CCS3.3 and IAR5.2. STM32 implements part steady-state power quality parameter measurement, reducing the pressure that DSP computation, and using the lag vector error correction method to ensure good accuracy. Transient power quality monitoring uses the same time-frequency domain analysis method, designed a complete set of transient power quality monitoring solution, implemented wavelet transform with using C language, and solved effectively wavelet edge problem.The system uses the time-frequency domain analysis method to monitor power quality, having real time and high accuracy, and system can analyze effectively the phenomenon that a variety of common power quality disturbances, having good application prospect and practical value.