Preliminary study on the technical requirements of the grid-connected microgrid

Based on existing domestic and international standards and norms, this paper conducts a preliminary study on the technical requirements as proposed from the perspective of grid on microgrids during their grid-connecting, grid-connection operation and islanding processes. The basic principles and grid-connecting norm of microgrid grid-connection is proposed, and the requirements of the access point, capacity of access and access schemes are presented based on the considerations of reliability of distribution network. The issues caused by microgrids grid-connection, such as power quality, power control, voltage regulation, relay protection, communication, monitoring, energy metering and so on are analyzed in detail. The mode of the Microgrid disconnection has been divided into intention and unintention islanding types, and the principle of region islanding and disconnection requirements of the accident islanding mode are stressed. The analysis result of the key issues of grid-connected microgrid can be used as an useful foundation for the development of standards of microgrid grid-connected in the future.