In its effort to maximize efficiency and productivity, the effects of voltage sags were a constant source of trouble. From the vast sugar cane fields in the Kwa-Zulu Natal region of South Africa, Sappi Limited, a world leader in the environmentally sound production of fine papers, gathers a second harvest. Ironically, fires in the same fields that supply bagasse also generate costly interruptions in the paper making process. As part of the harvest, the cane fields are burned over. Those fires produce flashovers on the transmission and distribution lines which feed power to the mill.
Flashovers generate voltage sags which disrupt sensitive machinery in the paper mill.
A continuous paper web runs through several independently driven, speed-synchronized units. Any interruption in a drive snaps the web, and that results in downtime for cleaning and re-threading. The Stanger mill produces 55,000 metric tons of high quality, woodfree coated paper annually, and 30,000 metric tons of tissue paper. Sappi acquired the mill in 1979 as part of a larger expansion process. Sappi has made continuous capital investments to upgrade machinery to achieve the current production capacity, including the installation of process computers.