This paper deals with the analysis of fault current occurred in a power system including STS, PCS, and load, which are the part of a microgrid. In case of utility side short circuit fault a huge current may flow through a STS, which results in a severe power quality problem in the microgrid. Therefore, minimization of the fault current and STS breaking time is essential to obtain high power quality. The basic concept of the minimization method is described and the STS fault current magnitude is analyzed with the considerations of power, current direction, etc. The results can be used for the design of a high power quality power system including STS and PCSs.