Island detection method suitable for micro-grid including multiple inverter-based distributed generations

The invention relates to a self-adaptation positive sequence current quick break protection method for a distribution network containing inverter-based distributed generations (IBDGs), in particular to an island detection method suitable for a micro-grid including multiple inverter-based distributed generations (IBDGs). The island detection method includes the steps that segmented reactive power perturbations, frequency boundary values of the segmented reactive power perturbations and starting criteria used when the segmented reactive power perturbations are switched are set in an initialized mode, wherein the starting criteria comprise the first starting criterion which is set according to the situation that the first segment reactive power perturbations of the different IBDGs are synchronous, the second starting criterion which is set according to the situation that the first segment reactive power perturbations of the different IBDGs are not synchronous, but overlapping exists and the starting criterion which is set according to the situation that the first segment reactive power perturbations of the different IBDGs are not synchronous, and overlapping does not exist; whether system frequency meets the three starting criteria or not is detected, and the reactive power perturbations are exerted according to a detection result; whether the criteria for determining an island are met is detected. Reactive power perturbations when a system operates normally in a grid-connected mode are reduced.