Dynamic voltage restorer the customers´s perspective

Paper mill variable speed drives are vulnerable to power dips because of control of thyristor firing. Firing angle control has difficulty following the voltage change, with possible consequent damage to the thyristors. To prevent damage, it is common for drives to be equipped with protection that trips the drive, with settings dependent on sensitivity to voltage dips. This paper describes how Caledonian Paper, UK, installed a dynamic voltage restorer (DVR) in order to overcome such problems in its Irvine plant in Scotland