Design And Implementation Of Power Quality Online Monitoring Equipment

In recent years, power quality (PQ) has gradually become an important concern. With the continuous development of electric power system, more and more nonlinear loads, such as rectifier loads and impulse loads, added to the modem electric power systems. The existence of these nonlinear loads in power systems will result in bad PQ, such as voltage distortion, voltage fluctuation, flicker and three-phase unbalance. On the other hand, all sorts of complex and precise apparatuses, which are sensitive to PQ, are increasingly connecting to the Power Net, therefore customers demand much higher PQ for their apparatuses. How to monitor and manage PQ and how to improve PQ to supply the customers with High-quality power has become a research focus both at home and abroad. According to the power industry's development needs, an online monitoring equipment for PQ based on fully integrated mixed-signal system-on-a-Chip MCU(C8051F064) is designed in this paper.An introduction of the status quo and development trend of PQ research both at home and abroad is given in this paper firstly, followed by a detailed description of national standards of PQ. This paper has summarized measurement theories and arithmetics of PQ indicators, in which the measurement theories on harmonics in electric power systems are studied in depth; Secondly, a new solving scheme for PQ online monitoring based C8051F064 is pointed out in this paper by analyzing the monitoring methods and implement platforms of PQ, in which the measuring of three Phase voltage, Current, Power, Frequency, parameters of Harmonic and other parameters will be realized. This paper has introduced the hardware module system of the online monitoring equipment, focusing on the design of filter circuit, A/D sample, frequency measurement and man-machine interaction module.Finally, a softwave for online monitoring equipment has been developed in the end of this paper, focusing on the FFT algorithm and its implementation.The online monitoring equipment of PQ based on C8051F064 has the advantages of good reliability, high measure definition, wide application and low cost etc. It has effectively improved flexibility and expansibility of the system.