Research On The DTU Model Based On IEC61850

Although the DTU lies at the lowest level in the distribution network architecture, it plays an important part, and mainly completes the acquisition and processing of a variety of information as well as the function of monitoring and protection. In the distribution network, there are lots of DTUs widely distributed, and the broad market has attracted many electrical equipment manufacturers. However, due to DTUs from different manufacturers usually supporting different communication protocols, information between DTUs is not compatible, thus it causes difficulties in the information interaction and device maintenance. In this paper, the DTU is designed and modeled basing on the object-oriented modeling method from the IEC61850standard, set with standard data formats and communication interfaces, so that it supports function extension and can share information with other intelligent electronic devices to achieve good interoperability. Thus the DTU can meet the future requirements from the distribution automation system comply with the smart grid.The IEC61850is to achieve good interoperability between intelligent electronic devices from different manufacturers by maximizing the application of existing standards and widely accepted communication principles. Basing on the IEC61850, The DTU is modeled as two logical devices LD1and LD2, respectively on behalf of the function control and protection. Information exchange between logical nodes is analyzed. SCL files describe the configuration of the DTU with a unified approach, so as to ensure mutual recognition among devices from different manufacturers, which is a prerequisite to achieve the interoperability. Communication services independent of the specific network technology and communication protocol stacks is defined by the abstract communication service. In the paper, the ACSI communication mode and its mapping to the MMS is analyzed, with the MMXU service GetDataValues as an example to demonstrate the implementation process of the ACSI services. In order to prove the interoperability of the DTU based on the IEC61850, the DTU adopts the surface protection technology to achieve the three phase short circuit fault location in dual power supply network, no dependence on the master station, only through the information sharing and cooperation with adjacent intelligent electronic devices.