中文说明：
利用Matlab建立主电网发生故障时的交流微电网模型。交流微网运行在480V，从120 kV电网交流输入降压11kV然后走到480V。故障发生在t 10秒。
English Description：
The AC microgrid model in case of main grid failure is established by using MATLAB. The AC microgrid operates at 480v. The AC input voltage of the 120 kV grid is reduced by 11kv, and then it goes to 480v. The fault occurs in t 10 seconds.