High-pulse line-commutated rectifiers are utilized in many high-power applications. Specifically, twelve-pulse rectifiers fed with six-phase synchronous generators are very popular in marine and aircraft power systems with variable frequency operation. Using numerically efficient averaged models of power electronics converters considerably saves simulation time when a large number of switching converters is used. Herein, a multi-resolution simulation methodology is presented and its application in efficient simulation of a twelve-pulse rectifier and an inverter system is demonstrated. The user can select the simulation resolution (level of details) for each components of the system, as desired. Superior performance of different switching-reduced models is demonstrated for variable frequency operation in terms of accuracy and CPU efficiency.