Suitability of Vacuum Circuit Breakers for Generator Switching Applications according to Dual Logo standard IEC/IEEE 62271-37-013

Today it is well known that power generators have to be protected by using accordantly designed and tested circuit breakers known as generator circuit breakers. This means the circuit-breaker is installed to protect a generator is of fundamental importance to safeguard the investment, since it protects not only the generator but also the step-up transformer, simplify the operating procedures and improve the safety and reliability of the power plant network. Due to different kinds of stresses in such generator circuits, a dedicated standard i.e., IEEE C37.013 was introduced in 1989 to address these issues. A dual logo standard IEC/IEEE 62271-37-013 is created since 2015 which combines the test procedures based on modern testing techniques from IEC 62271-100 and the generator switching applications from IEEE C37-013.Vacuum circuit breakers (VCB) serve worldwide in distribution circuits, meeting the electrical and mechanical requirements specified in the IEC and IEEE standards. Due to the technical advancements in vacuum interruption technology, vacuum circuit breakers are even applicable to generator switching applications and have been successfully tested according to the IEEE C37.013. The aim of this paper is to highlight the major differences between the two standards and that the Vacuum Generator Circuit Breakers (VGCBs) that have been certified according to IEEE C37.013 are still considered valid according to the IEC/IEEE 62271-37-013 standard when the test procedure of IEC 62271-100 is implemented during the tests done prior to 2015. The new testing methodology for asymmetrical breaking tests using major loop & minor loop and the new classification of generator source short circuit breaking tests are explained.