Study On Power Quality Detection Device

For the power quality detection needs of modern low-voltage distribution network, in this paper a new type of low voltage distribution network power quality measurement system is designed, ARM microcontroller core is used as the next crew, choice embedded real-time multitasking operating system(μc/os-Ⅱ) as a software design platform, the interface is written by VB to invoke MATLAB for processing datas on PC. This system carries out the detecting fuctions of a three-phase power grid phase/line voltage, current, active power, reactive power, apparent power, power grid frequency, power factor as well as the 20 harmonics of three-phase voltage or current.In this paper, after the analysis of the power quality basic parameters and hazards lead by inferior power, firstly, the basic parameters'measurement principles are introduced, then the system hardware and software are designed, finally, effectiveness of the system design was confirmed by experiments,and the development prospect of the subject was discussed.On the hardware design, micro-controller LPC2210 based ARM core made by Philips company is adopted as the main control unit, the hardware system also includes the power circuit, AD converter, signal conditioning circuitry, the keyboard circuit and memory circuit.On the software design, embedded real-time multitasking operating systemμc/os-Ⅱis established to connect the lower hardware layer and the upper application software; voltage quality mathematical model and flicker meter simplified model were established; FFT and db3 wavelet are applied to analyze the voltage quality of the low voltage network.. Lower computer software use C language to program, and is debugged based on ARM's ADS1.2 build environment. PC monitoring interface is adopted visual programming languages VB to program, calls MATLAB for processing datas, and then displays three-phase current, voltage, power quality information and waveforms. After design and making circuit, development and debugging software, we conducted experimental tests include voltage, current, frequency and harmonic detections, and those experiments confirmed the reliability and validity of the system.