Comparison of advantages and disadvantages of electronic and mechanical Protection systems for higher Voltage DC 400 V

Abstract:
While the speed of operation of conventional circuit breakers for equipment (CBE) is suitable for the majority of modern day equipment applications, ultra-sensitive solid-state circuitry of the nature typically found in telecom power distribution applications will often require faster switching protection under overcurrent conditions than electromechanical CBEs can achieve. Conventional electromechanical circuit breakers as not only protect AC and DC circuitry from overload and short circuit conditions, but in parallel – importantly – additionally ensure that the required physical isolation criteria after contact separation are maintained. CBE manufacturers it is demonstrated therefore, need to be mindful, to incorporate such benefits of traditional electromechanical designs along with the enhanced solid state electronic switching requirements when considering their design options. For this reason, electronic circuit breakers are typically hybrid designs featuring an electrical contact in series with the semiconductor circuitry which remains open in the semiconductor „OFF “ state thereby ensuring the required isolation voltages can be withstood. Faced with this background this paper presents the case for solid-state electronic circuit breakers for smart datacom power distribution systems based on the concept of electronic interrupting devices. The functionality of electronic interrupting devices and their integrated serial communication bus link (enabling individual programming of the desired tripping thresholds for input under/over-voltage protection and output overload) is explained by examining integrated current limitation and protection characteristics for short circuit and overload sensing and in-built current flow interruption. The paper further illustrates the suitability of electronic interrupting devices for low switched (minus) DC 400V next generation datacom power applications whereby particular emphasis is placed on an integrated arc fault detection capability. This aspect leads into an outlook to describe how the additional benefits of an AFDM can address in terms of highlighting switching scenarios, e.g. switch off in total or switch to redundant power matrix systems etc.. Power management aspects are also highlighted on the basisof a priority load shedding capability thereby ensuring battery buffer capacity is not wasted and saved to the utmost important service. This all leads into a matured and sophisticated power and facility management in the latest state of the art datacom applications.