Research On Modelling Of HVDC Control System For Switching Overvoltage Simulation Of Converter Station

With the development of Chinese power system, increasing number of HVDC projects are bringing into service. To insure security and stability, system performance should be evaluated via simulation methods during planning, building and operation stage. Simulation software has the advantage of cheapness and convenience, but the lack of mature control system model makes it cannot meet the ends of precisely evaluation. Modeling control system according to real control mechanism is a hard work due to the complexity of control architecture and the diversity of control systems. It's very valuable for HVDC projects that developing control system modeling guides based on the principle of HVDC control system for a particularly concerned topic. The object of the dissertation is to develop control system modeling guides for switching overvoltage simulation of converter station.First, analysis of responsive time constant has been done according to HVDC control hierarchical structure while comparisons of existing control model and real control system have been made at the same time, bring to the conclusion that the key work is to construct HVDC pole control model for HVDC switching overvoltage simulation.Secondly, the general principles of the realization and the coordination of primary HVDC pole controllers have been discussed. Then the paper researched on the relationship of control system and the electromagnetism transient process due to typical switching overvoltage faults. Control modeling demands have been proposed and primary control models for typical faults have been developed at the same time. Based on the analysis of key control component for overvoltage and arrestor energy consumption, the paper also gives guides to the modeling of some particular control module for real HVDC project.Finally, the primary control model and particular control module modeling guides were applied to ±500k V Longquan-Zhengping HVDC project. Control model used for overvoltage simulation of converter station accounting for real control characteristics was developed on PSCAD/EMTDC. Steady and typical switching overvoltage faults simulations were made. The results show that the model has reasonable control abilities. While the overvoltage characteristics and control properties during the electromagnetism transient process draw from the simulation are same with conclusions draw from theoretical analysis.