Research On Interchangeability Of Ied In Digital Substation

Digital substations are the basic link of the smart grid. They are also the data collection sources and command units when the grid is operating, so the digital substation is one of the important nodes in grid construction. In the smart gird, digital substations collect the wide–area data from different levels and gather real-time information from unified collection section, so they can realize the intelligent coordination of regional clusters and self-control and protection. The digital substations can support safe and stable operation at all levels of power and can accomplish a variety of advanced applications; realize the comprehensive interactivity of device operation information and power scheduling strategy; achieve the equipment life cycle management of integrated optimization based on condition monitoring.The implementation of exchangeability among intelligent electronic device can make the platform of information flow much stronger. Nowadays the interoperability has already achieved among IED in digital substation, but the exchangeability not yet. And the main reason is that it is limited by the present data model configuration technique of intelligent devices. Further more, how to verify the realization of exchangeability among intelligent electronic device is not mature.This paper analyzed the content of the communication standard IEC61850 and the technical characteristics of digital substation on the interchangeability theoretical basis in the operating environment, pointing out the difficulties of interchangeability among IED in the existing data model and under the present technique.Following the IEC61850 communication system and meeting the internal needs of exchangeability, this paper proposes a new definition and matching mechanism of IED resources. Resource object definition mechanism refers to the data model is considered as a resource object and the resource objects are divided into production resources and demand resources. When the demand resources are being initialized or production resources are disappearing, the demand resources drive the IEC61850 service to match the demand resources and production resources. Resource object matching mechanism is according to the property of the object to achieve automatic match between resource objects. The matching mechanism contains search, association, trading and connection. On the basis of these two mechanisms, according to communication service of IEC61850, the interface component of interchangeability on the client is programmed and the component is embedded into client part, achieving the client support for interchangeability among IED.In this paper, according to the theory nature of the IED interchangeability, the verification platform for IED interchangeability based on MMS Ethereal&OPNET was build. By analyzing the packet used in IED exchange process of the MMS Ethereal, and the impact on the substation system network in the process of exchange among IED, the paper verified the practicability and effectiveness of the method to achieve interchangeability among IED.