Research And Realization Of Embedded WEB Publishing Platform In Substation Automation System

As the development of unattended substation technology, the high maintenance cost of substations, intelligent devices and automation equipments, which are dispersed geographically, is significant. In this paper, the improvement of devices maintenance condition based on novel web communication technology is discussed and researched.Firstly, the development situation of substation automation system is analyzed and the current problems are summarized, based on which, the embedded Web information publishing platform in substation is proposed, as an effective supplement to SCADA (Supervisory Control And Data Acquisition) system, with a flexible and convenient information transmission of devices operation to maintenance personnel.Then, after the key technology of embedded Web server and substation communication characteristics is sufficiently studied, a highly-efficient embedded Web publishing platform in substation is designed. This platform can improve the practical functions and response speed of Web server, and simplify the data sent back from server-side for a better adaptability to frequent data updates.In the system, JavaScript is sent to client at the first connection to set up AJAX (Asynchronous JavaScript and XML) engine, which obtains the asynchronous message from server-side through callback function and finishes local fast refresh of web page by calling API (Application Programming Interface) of DOM (Document Object Model). With data publishing based on XML document format, remote monitoring of substation is realized through providing information to browser by local refreshing in asynchronous mode. In addition, unified XML documents are submitted to various information systems in electric power data network, for the realization of substation data share. By means of clipping and transplant ofμC/OS- II, an open source embedded real time operation system, and LwIP, a light TCP/IP protocols stack, the embedded Web information publishing platform is successfully realized based on ARM7 series SUMSUNG S3C44B0X chip and RTL8019 ethernet controller. Web performance test proves its faster user response time than traditional technology, and web function test proves it meet the designing demand as expected.