Research On Key Technologies Of Communication Middleware Forsmart Grid

With the gradual reduction of non-renewable resources, the aggravation of environment pollution and the more and more frequent happening of catastrophic accidents in an interconnected power network, renewable energy sources and other distributed generation resources are becoming more and more widely used and a lot of renewable energy and intelligent power devices are incorporated into the power grid. In addition, the relationship between power network and power market becomes closer and closer, and customers’requirements on the quality of power are also gradually increased. The integration of a large number of distributed systems makes the entire network system very complicated which requires a high level of real-time system, thus "obtaining the right data in the right place at the right time (3R)" becomes a very big challenge and the traditional power network is not enough to meet the requirements of these developments. As an essential part of modern power systems and future smart grids, intelligent substation, plays an important role in the entire system. Distributed applications, which mainly concentrate on data processing, are very important in an intelligent substation system. The efficiency of data communication service directly affects the realization of system functions. The substation communication standard IEC61850defines the abstract communication service interface (ACSI) and provides a set of universal communication function, but it is just an abstract interface, without the realization of any application layer protocol that defines sending and receiving data. Therefore, the mapping from ACSI to a specific communication stack becomes a research hotspot.As discussed above, there are several difficulties existed in the developing of the smart gird communication, such as complex structure, critical requirement of real-time, and weak inter operation capability. To deal with these challenges, this dissertation has developed a new smart grid communication middleware technology based on data distribution service, and proposed a solution for the communication interface for the integration of distributed generation, information sharing and management of a power grid.. A data-centric, real-time data exchange framework has been established, which is designed to meet the new communication demand of intelligent substation, intelligent micro-grid and active distribution network in the development of the modern smart grid, which aims to improve the intelligence, reliability and adaptability of power grid, and promote the construction and expansion of smart grid.The main contributions of this dissertation are listed as follows:(1) Propose a fully publish/subscribe-based data exchange model for smart substation communication to solve the closed coupled problems existed in the traditional substation communication framework. Publish/subscribe communication structure is one of the best solutions for data exchange between one or more data sources (i.e. the publisher) and one or more receivers (i.e. the subscriber), which makes each component in a distributed system has a better interconnection and data share within the network. The adoption of publish/subscribe based data exchange model can overcome the closely coupling characteristics of the Client/Server (C/S) mode or the combination of C/S and publish/subscribe mode used in traditional substation communication.(2) Development of a service-oriented and data centric communication mapping model for the implementation of IEC61850for digital substation and solve the one to one mapping problem of the conventional mapping and the closed coupling of the object oriented program. The abstract communication service interface (ACSI) defined by IEC61850communication standard must be mapped by using the special communication service mapping methods to map the abstract communication services, objects and parameters to the current mature international communication standard for realization. This dissertation proposes an object-oriented and data-centric data mapping model for the IEC61850used in digital substation, based on publish/subscribe and data distribution service (DDS), which solves the problems of GOOSE, CORBA-TAO implementation.(3) Implement a fast-prototype, standard realization method for mapping IEC61850to a special communication network and avoid the low-level complexity of communication networks and to simplify the communication mapping process. The middleware technology can shield the operation system and underlying communication programming, effectively help the professional power system engineers who lack of communication knowledge and software programming skills, and thus simplify the implementation complexity of the underlying communication mapping process and finally reduce the implementation error.(4) Extending the DDS based mapping of IEC61850protocol to communication of smart micro grid and active distribution network According to the new communication requirements of smart grid caused by intermittent distributed generation and smart grid equipment, and the analysis of the network communication architecture, publish/subscribe mode is found to be one of the best solutions. A real time data communication simulation platform for smart micro grid is designed, and the reliability and feasibility of the proposed model is validated. The extension application of the DDS mapping IEC61850method in intelligent micro-grid and active distribution network makes the uniform interface in wider range and enhances the interoperability.