THE INFLUENCE OF THE ARC VOLTAGE IN SYNTHETIC TEST CIRCUITS

In this paper different are voltage waveforms and KEMA are models are used to study the stress of the direct SLF (short line fault) test circuit and the synthetic SLF test circuit on the TB (test breaker). For the synthetic test circuit the total are energy input in the TB is less than in the direct test circuit, but just before the current zero the dI/dt and subsequently the are energy input in the TB is higher. It is demonstrated that the arc-circuit interaction plays an important role for the TB to clear the fault. For SF6 breakers with an are voltage with a significant extinguishing peak, the voltage injection synthetic test circuit produces an overstress for the TB.