High Current and Generator Circuit Breakers with Modern Vacuum Switching Technology

Abstract:
Vacuum Circuit Breakers – not limited to distribution applications! For more than 25 years vacuum circuit breakers prevail the world-market for distribution breakers. Using the most modern technologies in research, design and manufacturing of vacuum circuit breakers and switchgears the short circuit breaking capacity as well as the rated current of vacuum circuit breakers could be continuously increased over the recent years. Short circuit currents of 72 kA and normal rated currents of 6.300 A became reality. Such circuit breakers fulfil the European standard IEC 62271-100 and the American standard for generator applications, IEEE C37.103 alike. This paper deals with the general requirements on generator circuit breakers and with the differences of the two standards. Today, well proven generator vacuum circuit breakers designed and tested according to both standards are readily available in the market. Modern switchgear designs, providing ratings of up to 12.000 A normal rated current and up to 72 kA short circuit current at a maximum of 17.5 kV are introduced. Vacuum generator circuit breakers can be used in all types of power plants: hydro, gas or coal-fired plants. The aspects of modernization of aged generator switchgears as well as life-time costs, availability and safety are addressed.