HTC insulation technology drives rapid progress of indirect-cooled turbo generator unit capacity

Hydrogen or air indirect-cooled generators are becoming popular because of their simple structure and easy maintenance. This type of generator remarkably improves operational reliability. High thermal conducting insulation (HTC) system provides the most reliable technology to realize such generators. A newly developed insulation system for the stator could double thermal conductivity with the same or higher dielectric characteristics as the usual one. The advantages of this new insulation technology has been confirmed by tests on commercial use machines. In addition to new machine application, this insulation can be applied to operating generators in order to increase their capacity or efficiency. In the course of various evaluation tests, the resistance against thermal cycling operation has finally been successfully confirmed with the full-size coil model simulating a 600 MVA class generator. This paper introduces the development concept, typical insulation system characteristics, test results on commercial use generators, and cost profit expected.