The main purpose of this paper is to analyze the operation and nature of a low-voltage AC microgrid with various distributed energy resources (DERs). First, a 400 V low-voltage AC microgrid integrated with a 30 kW microturbine generator, a 13 kW photovoltaic generation system, a 10 kW fuel cell generation system, and a 10 kVA wind turbine generator was employed as the sample system. Second, a sequential three-phase power flow program was developed by implicit ZBUS Gauss method. The program was tested in the Matlab environment to ensure its accuracy. Finally, system natural and steady-state operations of the proposed microgrid were analyzed and discussed by using the developed three-phase power flow program. The outcomes of this paper are helpful for researchers to realize the operation characteristics of AC low-voltage microgrids.