Presentation of a novel and laboratory proved method to determine efficiently the minimum deionization time in hybrid circuit breaker

Abstract

The application of hybrid circuit breakers (HCB) is possible in all voltage levels of DC-grids. For high voltage direct current transmission applications, HCBs are often equipped with commutation power electronics (PE). In low voltage grids, the use of commutation PEs is mostly avoided. Thus, a longer arcing process for commutation results from the mechanical circuit breaker to the PEs. As a result, a higher energy entry of the gas within the mechanical circuit breaker occurs. However, the components and the expenditure for the control unit is significantly reduced which is highly beneficial. This contribution presents a new method to optimize the deionization time of HCBs without commutation PEs for LVDC and MVDC-grids. They are applied to different test grids to show the opportunities of this technology. To ensure a relative fast switching time, a method to determine the minimum deionization time (DI) is developed and presented in order to avoid arc reignitions. This contribution shows the functionality of this method and discusses the efficiency varying different parameters.