Research On And Development Of Power Quality Monitoring And Evaluation System

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 increasing to the modem electric power systems. The existence of these nonlinear loads in power systems will result in bad power quality, 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. With the establishment of power market, power has become a peculiar commodity that provided by power faculty to customers as power supply and assist service. It is hard to get the quantization and evaluation of power commodity quality indices, because of the particularity and the diversity of the indices of PQ. So rational evaluate of PQ is one of the premise conditions to establish impartial power market. To obtain a more objective and scientific result of PQ fuzzy synthetic evaluation, this paper presents Combined Weighing method to determine weights of PQ indices.The method integrated Objective Weighing method and Subjective Weighing method and remedied the defects of both single-weighing methods. For more convenient application, Sequence Synthesis-G1method was also put forward. The Combined Weighing method is able to get more objective and sufficient weights of PQ indices which lead to a more scientific and accurate evaluation.The paper offer a design plan of the Power Quality Monitoring and Evaluation system in order that electric power departments can master PQ timely and accurately and assess the PQ of power grid properly. The system is based on computer technology and net communication technology. By integrating monitoring stations in the power grid, achieves on-line monitoring system of power quality and guarantees real-time and reliable transmission of data.