Research And Execution Of Portable Power Quality/Phasor Monitor Based On Global Positioning System

With the development of technology and economy, the requirement on quality of electrical power becomes more critical. Large index offset from the mormal situation in electrical power quality should be avoided; otherwise it will bring troubles to power generation, transportation and consumption to some extent. At the same time,as the fulfillment of West-to-East power transportation and national networking, electrical network is becoming larger and more complicated. In the normal operation of power system,power utility must fully use the current.Transmission and distribution equipments, which brings challenges to the analysis, operation and control of today’s electrical power system. Synchronized phasor measurement technique emerged recently, and it is considered to be one of the three most advancing issues in electrical power system. With the GPS based synchronized phasor measurement equipment, a new type of power angle monitor is designed in this thesis, it is possible to monitor voltage and current phasor in each key node of the power system accurately and synchronoμsly,supplies powerful way of analysis of dynamic property and economical scheduling as well as security operation and control in large power system. Structure of this thesis:First, the research status of the phasor measurement techniques at home and abroad is summarized. The classification of the current synchronized phasor measurement unit and the reason of designing the portable power quality/phasor monitor are analyzed. The power quality/phasor instrument playing an important role in improving power quality and monitoring low-frequency oscillation are described. The both ends power grid is taken as an example to describe the operational mode of the monitor in the grid.Second, the hardware structure of the portable power quality/phasor monitor based on GPS is designed in this thesis, which takes synchronization, real-time, high-speed, high precision and high reliability as the design standards. It includes the establishment of the synchronization clock, signal isolation unit, A/D analog to digital conversion unit, FPGA module, GPS units, data processing unit. The design of the power and reset unit of DSP, the design of EMIF external synchronous and asynchronous memory are completed.Finally, the code and design the program flow chart according to the DFT algorithm in the data processing unit is designed. Then it was connected to the host computer, and the experimental platform of the portable power quality/phasor monitor is designed and build. The code whether meets the requirements or not is verified by the experiments of test machine and hardware simulation, meanwhile the reliability, real-time and accuracy of the equipment are tested and analyzed.