Telecom power supplies and power quality

In this paper we address the issue of power quality in relation to the telecommunication power supply. After a general discussion of power quality and related global trends, we present a comprehensive list of line disturbances and investigate the effect of rectifier loads. Nonlinear loads, including rectifiers used in telecommunication power supplies, generate harmonic currents and, through the impedance of the line, lead to distortion of the line voltage. We review some of the existing or planned harmonic current and voltage regulations, including IEC 555-2, which concerns the equipment, and IEEE 519, which concerns the individual consumer. We point out the conceptual difference between those regulations, and emphasize the need for coordinated development of standards. Subsequently we give a brief overview of the methods used to achieve compliance with the harmonic regulations. At the end of the paper we list issues that need to be further investigated.