Design and prototype development of a digital instrument for measuring single phase power quality parameters

Abstract

In present power system, the measurement of power quality is becoming necessary due to the presence of nonlinear and dynamic loads. This paper proposes a digital instrument, designed and implemented as hardware to measure basic single phase power quality parameters like voltage, current, frequency, phase angle, power factor, power and total harmonic distortion (THD). The very purpose of designing this hardware circuit is to have knowledge of measuring the above electric power quality parameters and to improve the system performance. The basic inputs for this instrument are voltage and current signals which are sensed by a Hall Effect voltage and current transducers. A micro controller development board (Mixed Signal Processor) MSP430 Launch pad manufactured by Texas Instruments is used for digital processing of the two signals. All software related programming is written in C-language code in MSP430. A 16×2 LCD display is used for displaying the power quality parameters. The implemented hardware circuit is tested with standard meters in the laboratory and with power quality meter CW240 (Clamp on meter) manufactured by YOKOGAWA and the result of the experimental work done on a prototype of a power quality measurement instrument is reported.