Frequency transient measurements in power systems

CONVENTIONAL instruments presently used for frequency transient measurements in power systems usually consist of a frequency discriminator, a direct-coupled amplifier, and an ink-writing oscillograph. Most frequency discriminators change calibration with changes of signal voltage and harmonic content. They exhibit drift as component parts age. Direct-coupled amplifiers categorically drift. Ink-writing oscillographs do not produce highly accurate records because of limitations in repeatability and readability. More accuracy may be obtained in measuring the magnitudes of frequency transients by using a recently developed system called the “AFTRAMAG” (Accurate Frequency Transient Magnitude) measuring system.