With　the　application　of　distributed　generators　(DGs),　microgrids　(MGs)　have　gained　much　attention.　Combined　with　the　distributed　communication　of　networked　systems,　we　investigates　the　secondary　restoration　problem　in　islanded　microgrids.　The　periodic　event　-triggered　(PET)　controllers　are　designed　for　voltage　restoration　and　frequency　restoration　with　accurate　active　power　allocation,　which　can　naturally　avoid　Zeno　behavior.　By　means　of　a　common　Lyapunov　function,　a　PET　protocol　is　designed　that　requires　only　the　information　of　neighbors　for　event　detection.　Both　event　-checking　sampling　period　and　event　trigger　parameter　are　taken　into　account　to　reduce　computation　and　communication　redundancy　by　choosing　appropriate　parameters.　Furthermore,　considering　the　effect　of　communication　delay,　sufficient　conditions　are　given　to　accomplish　the　secondary　control　objectives　with　allowable　delays.　Switching　topologies　are　considered　in　an　extra　discussion.　Finally,　the　effectiveness　of　the　proposed　PET　control　strategies　is　verified　by　several　MATLAB　simulations.