The Research And Manufacture Of Multi-functional Electric Energy Measuring Instrument

With the increase of the need of electric energy, the problem of electric energy shortage becomes more and more serious. In order to save and use electric energy appropriate and high efficiently, it is necessary to measure AC electric parameters accurately and real-time, so the rapid development of industrial production requires measuring instrument with high level. During the operation of industrial devices, it demands real-time and on-line measurement to get various electrical parameters. Therefore, power system and users demand urgently a new type of safe, reliable, real-time and high-speed measuring instrument of AC parameters. A new type and Multi-functional measuring instrument based on field bus are designed in this paper that included measuring method, hardware circuit, software program and error analysis. This instrument can measure and monitor electric parameters in three-phase (three-wire or four-wire) AC circuits, and it can be applied to electric devices and power plants, transformer substations with harmonic pollution. The instrument can measure current, voltage, power, energy, frequency, power factor etc. It also can detect load quality, phase sequence, alarm, display and print results, harmonic wave, as well as detect and dispose negative power.The controlling part of the comprehensive measuring instrument is 8 bits single-chip microprocessor C8051F041. It is based on sampling theory and uses synchronous sampling algorithm to measure AC parameters of power system. It has many advantages as followed: complete functions, perfect performance, high- reliability, low cost and so on.