Research On Networked Digital Protection Relay Based On Embedded Real Time Operation System

Along with the development of electric power automation system and publishment of substation communication standard IEC61850,the study of new digital relay protection equipment is an insistent demand.This paper is devoted in the study of composing a suit of digital relay protection equipment fitted for substation of standard IEC61850.This thesis mainly concerns about the following aspects: the development and research of networked digital relay protection platform based on communication technology of ethernet. The work includes transplant real-time operation system in networked digital relay protection flatform and devide the relay tasks ,development and realization of feeder protection relay. It also deals with the result of the test of protection relay.The thesis deals with the actuality of digital relay protection and the standard IEC61850.Look forword to intending development of digital relay protection, the function of digital relay protection is developing in the direction of platform, network and and standardization.The protection relay developed in the paper is relevant to standard IEC61850 and the development trend of substation automation system, the meaning of study is very important.Firstly, the development course of hardware platform is introduced in the paper , take part in the design of networked digital relay hardware platform based on the requests of IEC61850. In accord with the scheme of modular, including AC transform module, data sampling module, calculating & relay logic & communication module, IO module, Ethernet Hub module, power module, and MMI unit.Secondly, the paper respresents the development and character of Ethernet, analyse the feasibility of data interchange based on Ethernet in substation automation system.Introduce the internal network of dual redudant Ethernet line based on the research on improvement of Ethernet transmission performance.Particularly, the Ethernet communication interface based on the Ethernet processor LAN91C111 is designed carefully.At the same time,the paper shows software flow of initilization module,transmission module and receiving interrupt module.Thirdly, this thesis analyses the difference between foreground-backgroud processing system and real-time operation system in digital protection relay software,illuminates the advantage of using RTOS VxWorks in system of digital relay protection. The process of transplant VxWorks into AT91RM9200 is emphasis of this chapter.The thesis discusses the software design of feeder protection relay, which mainly includes the multitask division of digital relay protection and the certification of task scheduling .At last the test proves that this digiltal protection relay has excellent performance.In the end, the main work of the paper is summarized, and the intending research work is also prospected.