Research On The Information Integration Of Smart Substations Based On IEC 61850 And CIM

"Source-site Maintenance"and"Global Information Sharing"are important principles to the unified information modeling of Smart Grid. The key characteristic of the principles is using smart substations'information models to construct the power grid model of control center from in a bottom-up manner."Source-site Maintenance"can change the current situation of independent,multiple modeling of substations and control centers, making sure the configuration information of smart grid are input only once, improving the consistency and safety of information models, reducing the workload of engineering configuration and system maintenance, decreasing the risk to the system operation caused by the inconsistent models. But according to the current standard series of smart grid, the configuration information in substations and control centers follow IEC 61850-SCL and IEC 61970-CIM respectively. IEC 61850-SCL is the description and configuration language which is used to describe the configuration of IED equipments in substation,substation system and substation communication's topology; IEC 61970-301 establishes a unified public information-CIM, covering almost all aspects of power system management and information exchange. There are both overlaps and inconsistencies between the two standards, which lead to gaps when sharing the models and exchanging the data. Especially, when the models in the control centers and substations are inconsistent, it will easily lead to the error of data acquisition and control, which might have a significant impact on the electric power production. The information model inconsistency is now becoming the main obstacles of implementing the"Source-site Maintenance"technology, and one of the basic problems that must be solved for smart grid's development.Two schemes have been proposed so far. The first one is establishing a unified information model for power system to make the two standards harmonious unity, which could be realized by modifying existing standards with structural changes. It is difficult in a short term and large-scale changes for standards will undermine the existing investment. It should be noted that, different applications for substations and control centers have different requirements for modeling, thus establishing a unified model might not be feasible of in practice. The second scheme is establishing mapping rules between models. The advantage is that the existing standards never need to be modified. But this scheme also has disvantages, for example,but the mapping rules cannot be expressed explicitly and lack of standardization.Based on the second scheme, this paper firstly proposes a complete set of model mapping scheme, then builds the ontology model of IEC 61850 and IEC 61970 based on Web ontology language(OWL, Web Ontology Language). This paper expresses the ontology mapping rules using semantic Web rule language (SWRL, Semantic Web Rule Language), which makes up for the deficiency of the reasoning ability of OWL. Because of the existing inference engines cannot accept the rules expressed in the form of ontology, this paper converts the SWRL rules to the Expert System knowledge base. During the implementation phase, this paper uses object oriented characteristic of the Expert System to construct classes and instances from the ontology base, and realizes the ontology reasoning by using forward- reasoning engine of Expert System.Finally, this paper completes the model conversion of configuration information from IEC 61850 to IEC 61970 based on development environment of Java-Dom4j, which shows the effectiveness of the proposed scheme.