Design And Implementation Of The On-line Monitoring System For The Earth Electrode Of UHVDC Transmission

In China,ultra high voltage direct current is often used in the field of super longdistance,ultra-large-capacity power transmission field.Compared with the traditional AC transmission,the DC transmission has differences in many aspects,and the earth electrode is one of them.The working ground of UHVDC transmission is usually called “Earth Electrode”.Which has been an important component,and its normal operation directly affects the reliability of the UHVDC transmission project.At present,the monitoring of the earth electrode usually takes by artificial,which is restricted by many factors such as distance,personnel,and equipment.By this method,it takes a long time to get the data and it is difficult to accurately and timely reflect the operation status of the earth electrode.Besides,when inspecting and repairing,the normal operation of the equipment will be affected,and the equipment itself will also have a certain loss.In response to these problems,this paper designed a UHVDC transmission earth electrode on-line monitoring system by using IoT technology.By real-time monitoring and comprehensive analysis of the status of the earth electrode,the operation status will be accurately reflected,the safety and reliability of the earth electrode system will be improved.The main work of this paper is as follows.(1)Analyzed the functional requirement of this system.Determined the monitoring target and the technical that will be used after analyzing the current situation of UHVDC transmission earth electrode.(2)Generally designed the system.First,the framework of the system is designed.Then,divided the system into two sections,hardware and software,and designs of these two parts were given.When designing hardware,the system is divided into 4 modules: video monitoring,signal acquisition,security protection and data transmission.The working process,equipment selection and working principle of each module are explained.As for software,based on different function,it was split into three parts,the service program,the Web client and the database,and designed the first two items through the way of program flow chart.Last,this paper designed the system database from two aspects of Entity-Relationship diagram and data table.(3)The implementation and application of the system.The realization process and effect of the system are explained from two aspects of hardware and software.The hardware part shows the construction drawings and the ultimate installation effect of this system.The software part shows the screenshots of the Web page as well as the key code when actualizing the system.Finally,this paper explained the practical application of this system.After debugging and operating on the spot,this system has been put into use in a number of UHVDC transmission projects and has achieved good results,it fully meets the monitoring needs of power companies for UHVDC transmission earth electrode.