In North America, Most power distribution systems employ a four-wire multi-grounded neutral (MGN) design. This paper has explained the inherent characteristics of multi-grounded three-phase four-wire distribution systems under unbalanced situations .as a result, the mechanism of voltage swell and voltage sag in MGN feeders becomes difficult to understand .The simulation tool that has been used in this paper is MATLAB under Windows software . in this paper the equivalent model of a full – scale multi-grounded distribution system implemented by MATLAB is introduced . the results are expected to help utility engineers to understand the impact of MGN on distribution system operations.
