Research On Key Techniques In Digital Power Grid

Both the more frequently happened large scope blackouts around the world and the much louder appealing on renewable energy have driven the reputable research institutes and companies to study the new generation power grid. Some new concepts of "Advanced Power System", "Smart Grid" are proposed. Chinese scholars and electrical experts put forward a new idea of 'digital power grid'. The realization of digital power grid relies on upgrading the existing grid like introducing intelligent appliances, data modeling and interfacing, information modeling and integration, offering decision-making function, enhancing cyber security level etc.In this thesis, the international researches on ''Digital Power Grid (DPG)" and "Smart Grid (SG)" are reviewed and the relations between DPG and SG are compared; A multi-level DPG architecture is designed; A new methodology to build a unified DPG data models is formulated and on which a DPG data model center is developed; The Service Oriented Architecture (SOA) frameworks of data integration platform and application integration platform are put forward; Mobile Agent technology is adopted to construct the vertical data communication & interfacing structure; The requirements of cyber security in DPG are analyzed and a new cyber security solution is proposed; And at last, the further studies on DPG are prospected.Chapter 1 makes detail analysis of the challenges facing on China power grid. The objectives and functions of DPG are well introduced. The relation between DPG and SG is contrasted. It points out that Smart Grid is not a precisely defined concept but a technology framework to comprehensively construct the next generation power grid. Digital Grid is not only the important foot stone but also the foundation of Smart Grid. By reviewing the international researches, the key technologies of digital grid are deeply analyzed. The main technical innovation and contents arrangement are outlined at the end of chapter.In Chapter 2 The concept and contents of Digital Grid is summarized systematically. Based on the physical structure of power grid and the information flow going through, A multi-layered architecture of digital power grid is proposed. Following the information flow, the digital power grid is organized into 5 layers as device-layer, transmission-layer, data-layer, application-layer and visualization-layer. With advanced communication and control technologies, digital grid support layered system integration and control. In the device-layer, intelligent electronic devices play main roles, and in transmission and data layers, technology of information integration and data center is critical. Application integration technology is the basis of application-layer while the intelligent dispatching and decision-making are the milestones. The layered Digital Grid architecture proposed in this chapter is a standardized and systematic framework for developing the future power grid.Chapter3 adopts data modeling technology to design an overall system model for Digital Grid. Based on the IEC61970/61968 CIM, a unified modeling methodology is proposed for Digital Grid. Taking the transformer and assets management process as examples, the procedures of assets data modeling and business process modeling are fully developed. Furthermore, the principle and technique to extend the Common Information Model (CIM) is also summarized, and which will be the foundation for building the unified model of Digital Grid and information integration.Chapter 4 analyzes the principles of information integration in Digital Grid, designs a comprehensive information integration platform which can satisfy the requirements of data integration and application integration. The data integration platform is constructed with the unified data models and information bus technology, and will be used to integrate transverse data. The application integration platform is developed with Service Oriented Architecture (SOA) and Enterprise Service Bus (ESB) technology, which can integrate the business processes between online systems and offline applications. The comprehensive information integration platform is open and flexible, can successfully solve the problem of information integration in Digital Grid.Chapter 5 studies the technique approaches and functional requirements in adopting the Mobile Agent (MA) into vertical intercommunication solution in Digital Grid. Three intercommunication gateways are designed and compared. A model of MA-based DPG-V1P is proposed and constructed. Data interface service that conforms to component interface specification (CIS) as well as the data interface based on API is implemented and tested. The DPG-VIP is the important foundation to realize the overall observation and control of the Digital Grid .Chapter 6 analyses the cyber security challenges and hidden problems in Digital Grid, concludes the Digital Grid cyber security into three fields as control security, information security and application security. By zoomed defense principle and role-based access control technology, a systematic cyber security and defense architecture is induced and designed. The application continuity analysis methodology and blueprint are generalized through introducing business continuity technology into the Digital Grid framework. This chapter also prospects a general structure for the more developed Digital Grid.Chapter 7 implements all the main design and key technologies into the pilot project of digital grid carried out in Shanghai Municipal Electric Power Company. Based on IEC 61970/61968 CIM /CIS and their extensions, A Digital Power Grid Integrated Data Platform (DGP-IDP) is developed, which adopts Utility Information Bus (UIB) to support CIS-compatible information services. And typical enterprise applications based on the IDP are built to empower decision-making ability. By adopting the Enterprise Application Integration (EAI) technology and Service-Oriented Architecture (SOA) , Call Center System, PMS and CMS are integrated together to support new and advanced business processes in SMEPC. This chapter also introduces the structure and solution of the cyber security and defense system implemented in Shanghai power grid and company.A comprehensive pilot project is complemented in Shanghai Municipal Electric Power Company and the results are satisfied.