A survey of distribution system power quality-preliminary results

This paper presents preliminary results from a national monitoring program designed to characterize power quality levels on electric distribution systems. The monitoring program is being sponsored by the Electric Power Research Institute. Initial stages of the project resulted in the development of a new power quality monitoring instrument (designated the PQNode). This instrument permits simultaneous monitoring of steady state quantities (RMS voltage and current, harmonic distortion levels, power factor, etc.) and disturbances (voltage sags, overvoltages, transients, etc.). Approximately 200 PQNodes have been installed on distribution systems of 24 different utility companies. Monitoring data is being compiled by Electrotek Concepts in Knoxville, TN. The paper describes the monitoring system and presents preliminary results of the monitoring effort