Voltage sag in a highly automated plants

This paper presents results from a power quality audit conducted at a highly automated plant over last year. It was found that the main problems for the equipment installed were voltage sags. Voltage sag analysis is a complex stochastic issue, since it involves a large variety of random factors, such as: type of short-circuits in the power system, location of faults, protective system performance and atmospheric discharges. Among all categories of electrical disturbances, the voltage sag (dip) and momentary interruption are the nemeses of the automated industrial process. The paper analyzes the capabilities of modern power supplies; the convenience of "embedded solution" is also discussed. Finally it is addressed the role of the standards on the protection of electronic equipment