Development and Performance Evaluation of High-reliability Turbine Generator

• Volume 52 Number 2 August 2003

AUTHORS

OVERVIEW

To protect the global environment, current power generators must be highly efficient and must be able to minimize waste over long-term operation. With these circumstances in mind, Hitachi evaluated the reliability of a 250-MVA class large-capacity air-cooled generator. In this evaluation, an air-cooled generator and a large-capacity load machine were electrically connected and a rated field current was applied to reproduce field conditions. Temperature distribution in the coil slot and the coil-end was then evaluated. It was found that the stator-coil temperature rise at the specified measured points between the top and bottom coils stayed within the limitation of B class insulation; in other words, the maximum temperature of the stator coil strand was well within the permissible temperature range. Hitachi has also developed a new insulation system using “low-environmental burden epoxy resin” for the stator coil, a key component affecting generator performance. This epoxy resin has been achieved by adding a latent curing catalyst to constituent materials making for a pot life about six times longer than that of conventional products and less environmental load by reducing resin waste. The performance of this new insulation system was evaluated by various tests including a voltage-endurance test, a thermal-degradation test, and a thermal cycle test. These tests demonstrated the superior performance of the system and its contribution to long-term generator reliability.

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RELEVANT SITES

	HITACHI LARGE GENERATOR
	The Hitachi Hyoron (Japanese Only)

KEYWORDS

turbine generator, performance evaluation, high reliability, insulation system, stator coil, low-environmental burden epoxy resin