Development Of Station Controller And Monitoring System On The MMC-HVDC Physical Simulation System

In recent years, VSC-HVDC(Voltage Source Converter based High Voltage Direct Current)based on fully controlled devices grows rapidly, which is called HVDC flexible(High Voltage Direct Current Flexible) in China. The converter valve of MMC comprise many series sub-modules, which have many advantages. For example, avoiding the problem of crimp series of a large number of devices, reducing the requirement for consistency of devices, saving filter. With these advantages, the technology of MMC cause great concern in academic community. However, the research about MMC is mostly carried out on the basis of theoretical calculations and numerical simulation at present. Only a few study about the controller and physical simulation system is developed and the control system of MMC is different with other VSC’s.Therefore, it is very important to build a complete MMC-HVDC physical simulation system for the study of control and protection. This paper developed the station controller and monitoring system of MMC-HVDC physical simulation system and have steady-state and dynamic experiments on the physical simulation system. The result of experiments verify the correctness of the design of station controller and monitoring system.Firstly, the station controller of MMC-HVDC physical simulation system is studied, which is the core part of the MMC-HVDC control system. The station controller cooperating with the host computer and the lower controller realize reliable control of HVDC Flexible. This paper analyzes the main function of station controller and proposes hardware architecture design for station controller. And the software program logic is designed according to the hardware structure and the functional requirements.Secondly, the MMC-HVDC monitoring system is studied. Monitoring system include data collection and host machine interface. The part of data collection needs to gather the amount of electrical quantities and switch status. This paper acquires the electrical quantities with the method of three-level transform and recognizes the switch status with the port of RS485. The host machine interface include the function of data report, switch controlling, data issuing etc. Besides, this paper designs the switching logic between all of the interfaces.With these characteristics,the host machine has a good human-computer interaction.Finally, electrical part of the MMC-HVDC physical simulation system is presented and various dynamic simulation experiments are tested on the system. The system can effectively track down the active and reactive class physical quantities issued from host machine according to the results of the experiments, which verify the correctness of controller hardware and program. The result of voltage step experiment illustrate the system has a certain dynamic response capability.