Research On The Model Of HVDC Transmission Control System

Although HVDC transmission is a new transmission technology,but it has inherent such as transmission of large capacity,transmission loss is smaller,long transmission distance,transmission control more flexible and fast.As a result,HVDC technologies are developing rapidly across the globe.In China,the energy distribution is uneven because of our country's wide area and the distribution of energy is uneven,and the transmission technology,which is especially suitable for China's national conditions,has been developed rapidly.At present,China's high voltage dc transmission technology is in the forefront of the world,and by 2020,China is expected to build 15 high-voltage dc transmission projects.Along with our country and the world each country to the attention of the dc transmission degree increasing,the number of high voltage dc transmission projects are put into use more and more,the connection between the ac and dc power transmission is increasingly close,which increased the complexity of the grid,at the same time,guarantee the stability of high-voltage direct current transmission system can be normal work become the top priority of HVDC technology.Of course,the above requirements can be met by the control of the high voltage dc transmission control system.In this paper,on this basis,the structure and basic principle of high-voltage direct current transmission system is illustrated,and focuses on control principle of several kinds of control mode and control process.Not only that,through the accurate using PSCAD/EMTDC simulation software,establish a high voltage dc system of the object model and the cutting control filter and inverter trigger control simulation model of the two control systems to the study of the working process of the high-voltage direct current transmission control system and control function is of great significance.Finally,through the simulation for dc transmission may occur in the operation of the three-phase ac single-phase grounding system,communication system grounding fault cases,these two trigger inverter control of built and cutting filter model is simulated.By high-voltage direct current transmission control system of the inverter control and cut filter simulation control of these two kinds of control mode,can be intuitive reflect in dc control system for the whole dc transmission fault for quick response and fast control,to ensure that the entire dc transmission is normal,stable running.The simulation results show that the control system can control the direct current transmission,so that the parameters can be kept in the proper range.Can through the establishment of simulation model and simulation,detailed understanding of the control system of the control principle and control process,also can in order to further improve control system control performance to provide some basis and experience.