Large transient overvoltages are normally caused by vacuum circuit breaker (VCB) switching operation during disconnection of induction motors. In this paper VCBs, cables, generators, busbars, induction motors and surge arresters are modeled by making use of ATP-EMTP. Switching transient overvoltages of four typical induction motors are analyzed under starting, full load and light load working conditions in a power system of a Floating Production Storage and Offloading (FPSO) vessel. A suitable protection against the switching transient overvoltage is proposed and the results are presented.