Research And Development Of Three-phase Voltage/Current And Harmonic Monitor

Monitoring of voltage, current and their harmonic in power system is more and more important with the development of social economics and the reform of power system management. It is necessary to research and develop voltage, current and their harmonic monitoring (VCHM) system products to meet the demands of enforcing the national standards.In this paper, following a brief review of electric system development, monitoring techniques and development of voltage, current and harmonic monitoring instrument, the project of developing a new type 3-phase VCHM instrument is proposed. The application system structure, functions and performance of the 3-phase VCHM instrument are determined. The instrument inputs 3-phase voltage and current signals by means of PT and CT, so as to calculate various parameters, such as voltage, current, harmonic rate and power, in the ARM7TDMI core based LPC210x micro-controller, by using FFT. These parameters can be transmit to PC based manage information system via different communication interface, such as RS232/RS485, IC card and MODEM. The Real Time Operation System (RTOS) is adopted in software programming, to achieve multi-task scheduling, program gradation and modularization. Finally, the summary of the research work and some suggestions on further development are presented.