Selected conducted electromagnetic interference issues in distributed power systems

Abstract

This paper addresses the specific issues associated with electromagnetic compatibility that should be taken into account at the developmental stage of distributed systems. The main aim is to establish how far conducted interferences can penetrate the electric grid and how the group of converters, which individually meet EMC standards, influence the mains supply. The measured results of the spread of electromagnetic interference (EMI) current over a typical local electric grid and the low and medium voltage side of the power transformer are presented. The commonly applied, in distributed power systems, four-quadrant converter has been used as a test interference source. The limitations in the applicability of standardized methods for evaluation of aggregated conducted interferences have been presented in a system consisting of a group of two-quadrant frequency converter drives.