Fig.2 Temperature reduction of generator brought by high thermal conducting insulation (three-phase short circuit temperature test)

Temperature reduction of generator brought by high thermal conducting insulation (three-phase short circuit temperature test)

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Comprehensive evaluation tests (thermal conductivity, thermal cycling with full-size bars assembled into 600MVA class model slot core, bending rupture, tan-delta tip-up, voltage endurance and dielectric strength) of high thermal conducting insulation model bars and full-size coils showed the successful results as equivalent to those of conventional insulation while the thermal conductivity was doubled.

In addition to above tests, temperature measurements were conducted on a 350MVA class indirect hydrogen-cooled turbo generator with high thermal conducting insulation stator coils at shop tests, and a remarkable reduction in stator coil temperature was confirmed in comparing with the conventional design generator with the same frame size and hydrogen gas pressure as shown in Fig.2.

Furthermore, the temperature difference between the internal copper conductor and the external surfaces of high thermal conducting insulation was found to be smaller than conventional design, and the significant effects of newly developed insulation system in reduction of temperature and thermal cycling stress were confirmed. (1), (2), (3)

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