High-Precision Voltage Measuring Method using Fast Sampled Data for Electric Power Systems

Abstract

Control and protection equipment in power systems needs higher sensitivity and operational reliability to meet doday's changing power system requirements. The voltage measuring deviation requirement for advanced voltage and var control equipment is less than 0.1% under conditions of harmonic distortion in the voltage waveform and power system frequency variation. Studies on digital signal processing suitable for electric power systems showed these requirements are satisfied using fast sampling and very fast 32-bit floating point operations by a DSP (Digital Signal Processor).
This paper describes the design philosophy of a high-precision power system voltage measuring method using fast sampled data. In addition, total voltage measuring deviation characteristics under a combination of the techniques are described along with digital filter characteristics, frequency measuring deviation characteristics, frequency variation versus gain compensation characteristics of a digital filter, and peak value operating principles.