Study And Application Of The Multi-agent Based Multifunctional IED In Digital Substation

China's power grid is in a phase of rapid development, with the deepening of process on power networks interconnection, distributed energy resources connection, and opening up of electric power market, the problem of security and stability in power system operation is becoming increasingly outstanding. To deploy smart grid has been necessary. As the data source and implementation terminal, digital substation should be constructed first and foremost. That would lead to revolutionary changes in primary and secondary systems by updating of IEDs'hardware and software. The technical progress of computer, network communication, information, and distributed control, as well as the constitution of uniform standards make it possible to develop multifunctional IEDs of digital substation.IEC 61850 serial standards constituted and published by International Electrotechnical Commission construct the unified information platform for electric power network on the basis of resolving interoperability issues among IEDs in substations. Meanwhile, multi-agent systems theory as a branch of distributed artificial intelligence, especially suitable for solving calculation and control problems of complex distributed system, provide a new way for the realization of smart grid. This paper focuses on how to use multi-agent technology to deal with the complexity of standards while implementing, and realize the integrated management of distributed functions. Furthermore, a common method of constructing an agent is worked out to form the software basis of multifunctional intelligent electronic devices.In this paper, the function system of digital substation is analyzed. On this basis, a function management method based on multi-agent technology is put forward, which combines multi-agent technology with IEC 61850's function models and substation's application functions organically, realizes the flexible configuration and organization of functions decomposed according to IEC 61850 standards. A scheme of multifunctional IED for three-state supervision is presented.The implementation of a multi-functional IED based on the method mentioned above is described in detail. By adopting mixed type agent model, using a "plug-in" way, the IED's agent models of various application functions are created. Its XML based configuration files and approach are also provided.An application of multi-agent based multifunctional IEDs in a digital substation project is introduced, including system configuration, network structure, functions' allocation and management, as well as the implementation results. That demonstrates the validity of the proposed method. Finally, a summary is presented, and the directions for further efforts are pointed out.