Interpreting recent power quality surveys to define the electrical environment

Recent AC power line monitoring projects have enabled a better understanding of the typical electrical environment within which sensitive electronic equipment must be able to operate. Voltage variations caused by utility protective and regulation devices, as well as variations caused by load equipment, contribute to the total power quality picture. Regardless of the origin of these variations, the load equipment must be able to operate with some degree of immunity. This paper presents a combined assessment of data from three of the most recent power quality surveys. Results of this assessment suggest that load equipment with reasonable voltage regulation and interruption ride-through will withstand the majority of recorded power line variations. A detailed analysis of monitor capabilities and limitations is presented, along with a discussion of the interpretation of power line variations recorded at different monitoring locations.