The Development Of The Intelligent Monitor For Electrical Terminal

With the development of the national economy, industrial and residentialelectricity consumption is increasing so fast, as a kind of resource, electric energy isgiven more attention by people, and in recent years, the majority of non-linear loadsare used in power system, making the grid nonlinearity and asymmetry and other"power pollution" factors seriously affect the power quality, even brings a great lossto the life and produce of people. Through the real-time power quality monitoringand management, we can analyze the factors that affect power quality, then takeeffective measures to improve the quality of electric energy.The paper focuses on electricity terminal, and finally completes the design of alow-cost multifunctional intelligent monitor for electricity terminal. The instrumentcan measure and display all common power parameters, and it integrates switch-in,switch-out signals, human-machine interface and digital communication interface, itis able to complete the real-time monitoring of power grid nodes independently,compares with the similar products on the market, it has the advantage of low cost,full functions, small volume, wired simple and easily communicated with.Specific job done as follows:1. Through a large number of scientific literature at home and abroad, itanalyzed the background, practical significance and the development trend of theintelligent monitor for electrical terminal, and expounded the target and content ofthe paper.2. Analyzed the requirements and major technical indicators of the instrument,and based on this, the framework of hardware and software was designed in thisinstrument.3. According to the setting goals and requirements of the instrument, the paperchose a proper control chip, and based on this, it designed the hardware circuit of theinstrument. The paper chose MSP430F29MCU as the control core, and focused onthe design of power supply module, signals acquisition module, the main control module and so on.4. Analyzed advantages and disadvantages of various algorithms for electricalparameters monitoring, it selected FFT (Fast Fourier Transform)as the analyticalgorithm. But traditional FFT is inevitable to cause the spectrum leakage and fenceeffect in the process of analysis. Based on this consideration, this paper improved thetraditional FFT algorithm, and expounded the implementation of interpolation ofwindows FFT algorithm in detail. And the algorithm was implemented in theinstrument, and it achieved good practical effect.5. Based on requirements of testing and debugging, it designed the softwarebased on subordinate computer and the software based on PC. In the design of theprogram of MSP430F249MCU, it focused on the analysis of the A/D dataacquisition method, data computing algorithm, data display program, key scanningprogram and protocols based on Modbus serial communication program; Based onthe MFC, software platform of PC was designed. Firstly it modified the layout of thePC interface, then wrote the serial driver program with the Windows API function,finally it completed the writing of response function, and the function of remotecommunication, remote sensing, remote control was come true.6. It tested accuracy, communication, insulating and the function of alarmingwhen the set limits are reached, the results of experiment proves that the instrumentmeets national standards and the requirement of accuracy, it is easy communicatingand has excellent insulation and higher security, the function of alarming is alsoachieved.7. Summarized the main techniques and research achievements of this paper,and prospected the further research, in order to meet the needs of the market further,put forward the improvement opinion.