Common DC bus concept in power plant auxiliary system: Part I reliability evaluation

With the increasing use of medium voltage drive systems in power plant, it is interesting to develop a novel internal electrification scheme based on common DC bus concept. Despite obvious improvement on efficiency increasing, one of the most concerned issues is whether reliability performance would decrease to an unacceptable level led to by introduction of common DC bus layout. To mitigate the concern, firstly detailed and generic methodology on the basis of minimal cut set was proposed in this paper with which reliability of common DC bus topologies can be evaluated and compared with conventional AC bus ones. Based on the comparison, criteria of common DC bus topology design was given to ensure the comparable reliability performance. Through proper design, the reliability of common DC bus solution can reach similar or even better level than conventional AC bus ones.