Research And Design Of Real-Time Power Quality Monitoring Terminal Based On Ship Grid

With the development of the shipping industry, the size of ships'power system is becoming more and more large, and electric propulsion mode also increasingly becomes the development direction of shipping technology. Ship power system is a very significant part which involved with every system in the ship, it directly affects the security and the economy of the ship operation. So how to improve power quality of the ship power system, ensure safe operation of ship power system has become one of the focuses of shipbuilding industry. This paper conducts research to power quality of the special micro grid-Ship Power Grid, and then compares and analyzes the differences of it in the measurement standards between the land and the ship power grid. At last, this paper designs a real-time ship power quality monitoring terminal based on DSP+ARM, which can be used to monitor the basic ship power system parameter and power quality parameters.In the design process, first according to the measurement principle, we explains in detail the hardware and software design thought of monitoring terminal based on the dual CPU. Then the timing of data acquisition and calculation which proves that digital signal processor could meet the real-time requirement is analyzed. The hardware circuit can be divided into four modules:signal acquisition module, DSP processing module, ARM engineering module and power module. The function of signal acquisition module is to convert high voltage, high current signal into the low-voltage signal which can be directly measured, then the signal is captured and stored up through DSP processing module, at last it can be displayed and communicated by ARM engineering module. The software is divided into two parts. In the DSP part, we need to finish the calculation of the power quality parameters, and FFT is adopted to implement harmonic calculation, at last all the parameters should be deposited into dual-port RAM. The ARM part uses the embedded operation system Linux as software platform, we successfully transplants Linux2.6 kernel and imbedded graphics software into the chip S3C2410. The introduction of embedded operating system Linux, not only improves system reliability, and makes application development and expansion become relatively simple, and makes the system development cycle become shorter. In addition, this paper emphasizes the device anti-interference design, through the selection of hardware chip, the design of filter circuits, the production of printed circuit boards and software programming achieves maximum degree of anti-jamming.Finally, experimental results based on finished part which proves the correction of the design are analyzed. The device can complete long-term monitoring of high voltage, high current and frequency signal which within the range, and meet the accuracy requirements.