Air insulated vacuum generator circuit-breaker, incorporating three interrupters in parallel per pole, more than 100 kA system source short-circuit breaking current
Testing of generator circuit-breakers at this rating need to be carried out by the synthetic test method. This implies that a realistic arc duration needs to be guaranteed by artificially prolonging the arc duration by forced re-ignition. Because of the excellent high-frequency quenching interruption capability of vacuum interrupters, standard arc prolongation technology cannot be applied.
Therefore in such tests, ultra-high frequency current injection is needed to demonstrate the correct arc duration. KEMA Laboratories realized this through novel “super re-igniters”, developed in cooperation with Darmstadt Technical University, Germany. This new technology is based on a cascade of triggered vacuum- and air gaps, supplying a very fast high-current pulse.
Having verified this technology, more opportunities arise to test high-voltage vacuum circuit breakers in a synthetic method.
The photo shows the test set-up in KEMA High-Power Laboratory, with the breaker under test (and a series connected auxiliary breaker) in the foreground, and two super re-igniter units behind it.
Since the beginning of the vacuum generator circuit breakers in 1980, extensive investigations and developments have been made continuously. Result of those investigations is the most recently developed vacuum generator circuit breaker being capable of interrupting more than 100 kA system-source fault current. Switching performance test at this current level, especially for generator applications, is extremely challenging for both the test facility as well as the test object itself. With the proper preparation all the tests have been carried out reliably. All the requests of changes are quickly implemented.