Micro grid bus differential protective device

The utility model relates to a micro grid bus differential protective device, composed of a fault detection judgement part and a protection trip part, wherein the fault detection judgement part is accessed into a micro grid-connected switching circuit, a load circuit, an energy storage circuit, current of a distributed power supply circuit and voltage of a bus voltage transformer to carry out state detection, and the micro grid protection trip part is respectively connected with the micro grid-connected switching circuit, the load circuit, the distributed power supply circuit, the energy storage circuit and an active filter circuit. According to the utility model, different start modes are set according to fault characteristics of different fault types of a micro grid system, and logical models are set according to operation characteristics of the micro grid system, and an protection action not only comprises a 'tripping' operation but also comprises micro grid operation mode switching function. The micro grid bus differential protective device disclosed by the utility model can improve economical efficiency with extensive use of a micro grid system.