Graphic recordings of power disturbances: some recent developments and interpretations

Electronic devices can be damaged or disrupted by deviations from the expected AC mains voltage waveform and frequency. These deviations can include increases and decreases in RMS voltage (commonly referred to as surges and sags, respectively), high-frequency high-amplitude events (commonly referred to as impulses), changes in the voltage waveshape, harmonic distortion in the waveshape, and superimposed low-amplitude noise. The author examines recent developments in the field of simultaneous oscillographic recordings of power disturbances. He argues that as more practical experience accumulates with graphic recordings of mains disturbances, additional models and signatures may be developed which will further assist in disturbance diagnosis and mitigation