New arc flash standards for aluminium rectiformer stations

摘要

Over the last ten years aluminium smelter construction has reached new dimensions, from formerly typically 250,000 tpy potlines to a nameplate rating of more than 500,000 tpy. Over the same time, arc flash standards and operational practices have remained at mid-2000 levels. During recent years, new and ageing rectifier stations have experienced fires. Three incidents were related to HV cable termination failures, and a further two due to ageing transformers without full rated intermediate bushing. In addition, two rectifier containers were damaged by internal arc flashes, one of them caused by a prolonged water leak. These incidents were investigated and have led to the implementation of an elaborate hazard and risk assessment. The authors list below the outcome of these studies, simulation and analyses, and they present new standards for rectifier station design and solutions.