Research On Methods Of Ontology Modeling And Its Application For Power Grid Operation

Along with the development of technology and the progress of smart grid informatization, information management systems are playing an important role in transformation, distribution of electricity and other aspects of smart grid. However, the heterogeneity of those systems has caused the "information island" phenomenon in a certain extent, it seriously impedes the development of smart grid informatization. Hence, the research on the uniform standard information model of power system to achieve information sharing and interoperation between enterprises is of great practical significance.This paper is based on the project "Research on the Formalized Description of Smart Grid Knowledge and its Applications" that is a technology project of the State Grid Corporation in2012. It takes power grid operation knowledge as the research object, introduces the ontology technology to knowledge description, and focuses on its construction method, ontology model and applications, etc.In the paper, the basic theory of ontology is introduced detailedly. It analysis the applications based on ontology in power system, including their application features and implementations respectively. Then, according to the features and applications of power grid operation knowledge, it proposes the ontology modeling method of power grid operation that is based on the theory of software development cycle, including need analysis, ontology analysis and construction, evaluation, instance creation and maintenance and updating. It improves the quality of the constructed ontology and perfects the process of ontology construction through the loop optimization working.According to the basic ontology model that describes by RDF, this paper builds the extended ontology model of power grid operation knowledge and studies the instance of "Guide on Security and Stability for Power System" ontology. On that basis, it designs the information retrieval system based on the ontology of power grid operation knowledge, which database is "Power System Knowledge Database" developed by China Electric Power Research Institute. Then, the key technologies, such as keywords extraction algorithm, the extraction way of ontology relationship, the expansion algorithm based ontology and semantic matching algorithm based on improved vector space model, are also study in this paper.This information retrieval system is developed by using the QT platform based on C++. And it introduces design goal and principle of the system and function realization of each key modules include data storage layer, application layer and platform layer in detail, and run a test on the system to verify that the system has a favorable retrieval function.