| The widely applications of nonlinear instruments have produced many high order harmonics, they are flowing into the power network and greatly influence the quality of electric power. And the frequency isn't constant but changed around 50Hz. The conventional instruments, which measure only based on the 50Hz. couldn't meet the request of the electric power system. The research of this thesis is carrying out under that background.In this paper, some theories about intelligent instrument, DSP (Digital Signal Processing) technology and the method of measure the electric power under the influences of harmonics is first of all described. And then it focuses on discussing the design and development of hardware and software.In aspect of hardware, the system used PS (Principal and Sub-ordinate) multiprocessor architecture. The master CPU 89c51 is used as the center of control and management, the slave CPU TMS320F240 is used as the core part of data processing, dual port RAM transfer data between two pieces of CPU. Some interface circuits are also used to realize other functions. The system is consisting of Data Sampling Unit, Data Processing Unit, Master Controlling Unit and Human-machine Interface Unit. The program is also designed according to the function module. The sampling is running 128 times every cycle, and the computing algorithm of radix-2 FFT is based on DSP. The disturbances are greatly-decreased for the application of simulative low-pass filter and FIR digital filter.Finally, the summarization and prospects of the research are described. The newly multi-function power parameter measurement instrument has not only the characters of usual intelligent instrument but also the merits of high speed, high precision and good performance in anti-disturbance, so it will have a widelyapplication.
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