Comparative evaluations of coil insulation systems in hydrogenerator uprates and refurbishment

In considering strictly coil design for an hydrogenerator uprating, it is not just a matter of choosing which type of insulation system to use and manufacture coils that fit the specified slot dimensions. Tradeoffs also must be made between the physical characteristics of various insulating materials-thickness, durability and strength-and their dielectric properties, and of course, their cost. Although other factors, affecting various machine components also limit the generator´s uprate potential, this paper focuses solely on providing information on coil insulation systems