Comparison of New and Old High Voltage Diamond Coil Electrical Insulation Performance for Hydro Electric Generators

This paper compares high-voltage electrical coils from hydroelectric generators after <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 8}$</tex> years of service with newly manufactured replacement coils. The original coils are part of the US Army Corps of Engineers' renovation of the Chief Joseph Dam in Washington State, with 16 generator units (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$92,920 \text{kVA}, 13,800 ~\mathrm{V}$</tex>) being rewound. Preformed Windings will supply the new coils, designed to sustain decades of renewable energy production. With the average age of hydroelectric power station in the U.S. approaching 50 years, this paper is to create a reference for the industry of the expected benefits that can be achieved by rewinding of the fleet using resin rich coils manufactured with modern techniques.