Research On Detailed HVDC Modeling And Simulation Based On ADPSS

As the±800kV UHVDC system was put into operation, the DC/AC interaction of typical system with multi-infeed DC has become more prominent. For an in-depth study into the performance of HVDC system and the complicated AC/DC hybrid characteristics, a model of HVDC with detailed control system should be established. And a reasonable simulation method can be previous for a comprehensive research of large AC/DC hybrid system.An integrated contol system of HVDC is constituted by three major parts including station control, pole control and group control. The hierarchical method is used to design the functions of controller, which ensures the reliability and flexibility of HVDC system. According to the logic diagrams and documentation of actual DC control technology, the core technology of HVDC controller is summarized and assimilated. On the basis, a model of detailed HVDC control system is designed using the electromagnetic transient user-defined function of ADPSS platform, which can simulate the actual control system. Control modules constructed in this paper mainly include the following sections:bipole sequences control, reactive power control, pole power transfer control, pole current order co-ordination control, current directive value calculation, voltage reference value set-up, current margin compensation, voltage dependent current limit control, tap changer control, emergency switch off, power modulation, converter response contol and trigger set. An in-depth analysis and detailed modeling of these modules are implemented to establish a perfect control strategy of DC transmission system. According to structure of the UHVDC system, the primary circuit model for DC simulation is built and associated to the detailed control system. By the analysis of coordination control and fault-handling logic, the correctness of the model is verified.The five DC transmission system circuits are constructed respectively, the detailed HVDC control model established is applied in commutation failure research of a certain actual power network based on the electromechanical-electromagnetic hybrid simulation technique of ADPSS. Through the comparison between electromechanical-electromagnetic hybrid simulation and electromechanical transient simulation results, it is proved that former is more accurate and has more advantages in HVDC research. In the meanwhile, compared with the traditional electromagnetic transient simulation, hybrid simulation technique eliminates the error caused by simplification of large AC system. Work done here has great significance for development of domestic DC control system and dynamic reasearch of large AC/DC power system.