Percentage of Islanding and Peninsulating Detection in ‎Large Microgrids with Renewable Energy Resources ‎with Multiple Connection Points to Different Grids

This paper presents the islanding and peninsulating of distributed generators (DGs), such as wind and solar ‎power plants, that feed microgrid systems. However, the paper does not focus on just an ordinary microgrid but ‎large microgrids that have several sub-microgrids with renewable energy resources and multiple connection ‎points (MCPs) to different grids. When islanding happens, the main microgrid disconnects some connection ‎points from grids whereas some connection points to other grids could be connected and divided into some sub-‎microgrids for better stability. Two new definitions are proposed for large microgrid islanding: percentage of ‎islanding and peninsulating. The former means how much it is possible that an islanding happens before it ‎happens, and the latter means that: “after separating from some connection points to grids in a large microgrid ‎with MCPs to different grids, remained large microgrid network is an island or a peninsula that is connected in ‎some connection points to other grids? So, peninsulating a large microgrid depends on the number of connection ‎points, at least two points, to different grids. This paper describes these two new definitions. The method involves ‎the measurement of utility currents, voltages, and other signals through a bidirectional communications system in ‎smart grids. These signals are used to calculate the percentage of islanding and decide on microgrid islanding or ‎peninsulating.