The Second International Conference on Bioenvironment, Biodiversity and Renewable Energies BIONATURE 2011 May 22-27, 2011 - Venice/Mestre, Italy

Tutorials

T1. Voltage Dip Immunity of Equipment and Installations
by Francisc Zavoda and Robert Neumann

Voltage dips (also known as "voltage sags") are short-duration reductions in voltage magnitude. Their duration is typically between a few cycles of the powersystem frequency and a few seconds. The interest in voltage dips is mainly due to their impact on end-user equipment. Industrial processes may malfunction or shut down due to a voltage dip resulting in significant financial losses.

Voltage dips are due to short-duration increases in current magnitude; however voltage dips due to short circuits and earth faults are of most concern for customers. This tutorial presents the results from an international CIGRE, CIRED and UIE* working group, aimed at improving the understanding of the compatibility between installations and the electricity supply. The working group has addressed a number of aspects of the immunity of equipment and installations against voltage dips and also identified areas were additional work is required.

Compatibility between equipment or installations and the power supply can be improved in a number of ways: through alterations to the power grid; by installing mitigation equipment at the interface between the sensitive equipment and the grid; and by improving the equipment or the installation. This tutorial only addresses the latter way of compatibility improvement.

The tutorial consists of following parts: voltage dip characteristics, equipment and processes, immunity testing, voltage dip economics, voltage dip statistics, classification, immunity objectives.