Powerformer/sup TM/-experiences from the application of extruded solid dielectric cables in the stator winding of rotating machines

ABB has developed a new class of generators, Powerformer/sup TM/ which are able to deliver electric power directly at transmission voltage levels. This is achieved by changing from traditional stator windings with rectangular conductors to windings with circular conductors based on proven high voltage cable technology with solid extruded dielectric. The paper discusses the concept of Powerformer and some of the experiences gained from the application of high voltage power cables in the stator winding. The high-voltage generator prototype, rated at 45 kV and 11 MVA, has been operating since spring 1998 in Porjus hydropower plant in northern Sweden. Furthermore, two case studies are presented; one Powerformer rated 42 MVA at 136 kV, for a thermal application and one Powerformer for a hydropower application rated at 75 MVA and 155 kV; Consequences with a Powerformer applied in an underground power plant are also discussed. Finally, some future outlooks regarding application for Powerformer are presented.