In many applications, like hospitals, the reliability of the emergency electrical supply is a critical issue, since the continuity has to be guaranteed at any time. The backup system usually consists of gensets and electrical starters (DC motors), supplied by lead-acid batteries. It is a fact that the latter are responsible for most genset cranking failures occurring in hospitals. Therefore, the reliability of the storage system should be improved to increase the Overall Mean Time Between Failures (MTBF) of the whole backup system. In this paper, eight different electrical storage systems have been modeled and simulated and they have been analyzed and compared from the point of view of reliability; in particular, the possibility of using supercapacitors (together with batteries or even replacing them) has been investigated. A huge number of real data regarding genset failures have been used, from both the literature and direct measurements made on purpose. An accurate statistical analysis has been performed to evaluate the MTBF for batteries, supercapacitors and other components available in the market, considering their actual characteristics. Finally, an innovative hybrid energy storage system has been proposed, based on both batteries and supercapacitors, allowing to triple the MTBF of the cranking storage system.

在许多应用中，例如医院，紧急电源的可靠性是一个关键问题，因为必须随时保证连续性。备用系统通常由发电机组和电起动器（直流电动机）组成，由铅酸电池供电。事实是后者是导致医院发生的大多数发电机组起动失败的原因。因此，应该提高存储系统的可靠性，以增加整个备份系统的总体平均故障间隔时间（MTBF）。本文对8种不同的蓄电系统进行了建模和仿真，并从可靠性的角度对它们进行了分析和比较。特别是，已经研究了使用超级电容器（与电池一起甚至更换电池）的可能性。从文献和有意进行的直接测量中，已经使用了大量有关发电机组故障的真实数据。考虑到电池，超级电容器和市场上其他可用组件的实际特性，已经进行了准确的统计分析，以评估MTBF。最后，提出了一种创新的混合动力储能系统，该系统基于电池和超级电容器，可使曲轴箱储能系统的平均无故障时间（MTBF）增至三倍。