The purpose of this part of IEC62898 , which is a Technical Specification, is to provide guidelines for microgrid projects planning and specification. Microgrids considered in this document are alternating current (AC) electrical systems with loads and distributed energy resources (DER) at low or medium voltage level. This document does not cover direct current (DC) microgrids. Microgrids are classified into isolated microgrids and non-isolated microgrids. Isolated microgrids have no electrical connection to a wider electric power system. Non-isolated microgrids can act as controllable units to the electric power system and can operate in the following two modes: grid-connected mode; island mode. This document will cover the following areas: microgrid application, resource analysis, generation forecast, and load forecast; DER planning and microgrid power system planning; high level technical requirements for DER in microgrids, for microgrid connection to the distribution system, and for control, protection and communication systems; evaluation of microgrid projects.