Upgrading power distribution equipment-making the right choices for reliable paper mill operations

Most paper mills in North America were built in an era when main 15 kV power distribution switchgear was only available with air-break power circuit breakers and relatively low MVA interrupting ratings. As mill capacity grows, facilities engineers are often faced with either upgrading or replacing existing main switchgear, to support required increases in interrupting ratings. This paper includes a study of two different mill sites with experiences in upgrading power distribution equipment by replacing vintage air-break circuit breakers with new vacuum circuit breakers in existing switchgear. The long-term potential benefits of both upgrade and replacement are reviewed, including application considerations. At the end of the paper is an analysis of the total installed cost and impact on mill profitability by upgrading existing switchgear, versus replacement with new equipment.