Research On Several Key Techniques Of Substation Automation Based IEC 61850

IEC 61850 is so far the most perfect international standard of communication network and system in substation published by IEC TC57. It will bring profound effect and reform to the operation and management of substation automation in China to realize digital substation. Compared with previous communication protocols, IEC 61850 has a huge and complicated technical system. Moreover, IEC 61850 itself and its application technologies are in continuous developing; as a complicated and systematic project with high comprehensiveness, Substation Automation System (SAS) consists of numerous devices and subsystems, at the same time, there are different degrees of correlation among these functions and subsystems. Thus, many deep researches are needed for IEC 61850's application in practical project. Many difficult problems need to be solved,such as new requirements for software scheme and development means of IED conformed to IEC 61850, how to access legacy systems and IEDs unable to conformed to IEC 61850, how to transform legacy communication network, and how to eliminate isolated island of information and to realize effective information integration, etc.In this dissertation, characteristic and connotation of IEC 61850, domestic and international research status are introduced first; A design scheme of centralized IED based on IEC 61850 is proposed later; General gateway for legacy IED to support IEC 61850 is designed, and graphic oriented development means for IED based on IEC 61850 is developed; Information Integration Platform (IIP) and its pilot site implementation in Shanghai Grid are described. At last, summary and prospect of future sduty is put forward. Main contents of this dissertation are as follows.In the first chapter, formulating background, main characteristics and present status of IEC 61850 study and application, both domestic and oversea, are introduced. Meanwhile, main technical obstacles and prevalent research problems in implementation and popularization process are analyzed. At last, the main content, innovation and chapter arrangement are stated.In the second chapter, limitations for existing IEDs based on the idea of hierarchical distributed automation to be conformed to IEC 61850 is analyzed, and then, substation global function oriented design scheme of NCIED conformed to IEC 61850, is proposed. Several existing IEDs on bay level are replaced by one NCIED with strong network interface function, which means that each existing IED is abstracted as a logical protection and control unit, named as logical device (LD). Every LD has its own functions independently and communicates with other IED through unified interface. Key technologies of software and hardware design have been studied. With the advantages of distribution and centralization, the total cost of SAS and network nodes is decreased significantly by using NCIED. It is beneficial to the coordination of different LDs and also to popularization and implementation of SAS, conformed to IEC 61850.In the third chapter, a design idea of IEC 61850 based on object model is analyzed. In order to realize communication services of IEC 61850 and ensure interoperability, software structure, external interface characteristic, and data structure of IED have its own speciality and complexity. Because of that, an advanced development tool is required for realization of IED software. A solution based on IEC 61850 is proposed in this chapter, which develops IEDs by means of IEC61131-3 standard based graphic oriented programming technique, speeds up IED software's development and enhances software's openness as well as other advantages owned by conventional graphic oriented programming technique. A software scheme is proposed and some key technologies, such as the parameter association between graphic oriented programming interface and IED's data memory, are researched. The solution is propitious to improve the flexibility of development and research, standardization and interchangeability of IEDs.In the fourth chapter, considering huge amount of legacy IEDs which are not conformed to IEC 61850, a new protocol-mapping method, named metadata-mapping using XML Schema technology to model metadata of protocol and protocol-mapping, is proposed. Then a configurable architecture of IEC 61850 gateway by metadata mapping is designed. The gateway loads files of the metadata models to realize mapping between different legacy protocols and IEC 61850. The novel gateway has generality because of flexible protocol conversion by configuration files.In the fifth chapter, an information integration platform (IIP ), conformed to IEC 61850 using primary object oriented unified modeling, is proposed. Substation automation system faced to the future could use integrated IEDs based on IEC 61850, that is, one (or more than one as redundancy) multifunction IED corresponding to one primary object realizes functions; previously realized by several IEDs corresponding to several systems. For substation with many legacy systems, IIP above every application system could be adopted to access application systems and IEDs. The IIP unifies external hardware interface and releases production and management information in a unified way, thus ensures information consistency. Key technologies, such as dynamic modeling of platform model, coordination of concept object model of heterogeneous systems, adaptation of model data of heterogeneous systems, have been studied.In the sixth chapter, as an example of utilizing partial research results in practical project, an IIP is put into implementation in an 110kV substation in Shanghai. The IIP has accessed several main systems. Several key technologies of the IIP are described in this chapter, such as architecture of the platform, step of modeling, software and hardware scheme, performance index, and so on.