Analysis and Discussion on High Insulation Performance of 20 kV Generator Motor Stator in the Large Pumped Storage Unit

The terminal voltage of 400 MW 500 r/min generator motor in a large pumped storage power station is 20 kV, in which the height of stator core is 3400 mm and the stator bar adopts less glue VPI (Vacuum Pressure Impregnating) process. The characteristic of this generator motor is high voltage level, large external size and high technical requirements. As the pumped storage unit with the highest voltage level that has been put into operation in China, its stator system of 20 kV generator motor shows excellent insulation performance during the test process. This paper analyzes and discusses from two perspectives of development and installation, and summarizes the key technologies in the process, which can be used for further reference in similar projects.