| Smart Grid is put forward under the background of the optimize allocation of energy resources。It is built on the basis of efficient and reliable communication technology, and is the integrated application of advanced sensing measurement technology, advanced computer technology, advanced communication technology, advanced information technology, advanced control methods and advanced decision support system. As a support of smart grid, it is necessary to carry on the communication technology for an in-depth analysis and research. Information flow is a key support to the closed loop chain of power system energy flow in Cyber Physical Power Systems. In conclusion, it has important significance for promotion and improvement of relevant technology to analyse the reliability of the information flow.Smart substation is the focus collection of power flow, information flow, business flow in Smart Grid. The basic requirements of smart substation are to realize digitization of information in total substation, network-based of communication system, and the standardization of information sharing. Smart substation can complete the basic function such as measurement, information collection, automatic control, protection and test. Meanwhile, some advanced functions are also borne by smart substation, for example, real-time automatic control, intelligent adjustment, on-line analysis and decision making, collaborative interaction. The realization of these advanced features will be dependent on a wider range of information collection and sharing. Furthermore, under the background of the spread of new energy and interconnection of power grid, Wide Area Protection System becomes a hotspot in research of protection in recent years.Firstly, communication network of relay protection system in smart substation is set as the research object. According to the characteristics of communication network architecture of smart substation and a series of standards-IEC 61850, the research is focused on the process layer network. Three reliability algorithms are successively used, as follow:static traffic flow and delay analysis method based on matrix iterative and network calculus algorithm, disjoint minimal path algorithm for reliability block diagram model, reliability algorithm for stochastic flow network model. These three algorithms have different emphases, but are auxiliary to each other. So modeling and analysis for reliability of communications system in smart substation can be performed from different angles.Considering that the trend of further development of smart substation relay protection is Wide Area Protection System, this paper proposed a hierarchical protection control system scheme based on Wide Area Measurements System after comprehensively analyzed some diversified definition and understanding for Wide Area Protection System at present. This scheme installed protective device on local ground level, substation level and wide-area level respectively. These three levels of protection have a clear division of responsibilities and each have particular emphasize, but through mutual cooperation, achieve safe and reliable intelligent operation of wide area power system. This article presented a method to verifing reliability for adding in new substation’s protection measurement and control device connected to Wide Area Protection System. And further, the stochastic flow network reliability algorithm is used to calculation and comparison reliability of two connected structure(star network and ring network) of new sub-station. Analysis of results provide a evidence for selecting the appropriate network configuration scheme. |
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