| Due to a lot of power electronic devices and nonlinear load widely used in the power system ,power quality issues have become prominent increasingly. Power quality problems not only endanger the safety of the power system itself and the stable operation of power grids, but also poses a serious threat to the users of the system. Therefore, the real-time monitoring of power quality is of great significance.The paper introduces the concept of power quality .The status of research of the domestic and international power quality monitoring is studied,as well as the significance of the development of new power quality monitoring devices.Meanwhile, the digital measurement principles and algorithms of parameters which have effect on power quality are deeply analyzed.On this basis, power quality monitoring devices design thinking is proposed,which use ARM9 (s3c2410) as the CPU chip and embedded Linux as the core of software.Based on arm-linux embedded development environment, the basic hardware design and software design are completed. According to characteristics of the actual data acquisition and processing of power system ,the multi-channel signal sampling and rapid conversion circuit are designed by ADS7864 chip in the front acquisition module in hardware.PLL ensure the hardware synchronous sampling of multi-channel -signals.Besides RS-232 communication,Ethernetand USB communicati -on are adopted which can improve device flexiblility.The linux core is tailoring and transplanted successfully to embedded ARM processor on the basis of functions to be achieved. Application programs are realized and the detailed flowchart is given,also the man-machine interface (GUI) is designed according to Qt / Embedde.Power quality monitor based on arm-linux embedded has such advantages as powerful function of data handling,good interface,easy upgrade,remote monitoring. On this basis,it can be further developed to be micro and highly intelligent in order to meet the diffrerent needs. It has great value and broad prospects. |
