In 1984, Schweitzer Engineering Laboratories Inc. (SEL) developed the world’s first digital protective relay. This product helps utilities minimize blackouts and electrical system damage. Since then, the company has invented, designed and built an extensive range of protection, monitoring, control, communications and metering products that cost-effectively improve the reliability of power grids and systems around the world.
Among SEL’s most popular products are fault indicators used on transformers, switchgear, sectionalizing cabinets, junction boxes and splices. A few years ago, the company faced a challenge when welding a clear lens display screen to the polycarbonate (Makrolon 2607) body of one of its indicators.