| With the rapid development of the global energy interconnection,voltage source converter based high voltage direct current(VSC-HVDC)transmission technology has been widely used in the fields of power grid interconnection,wind farm grid connection,weak AC grid and urban power supply.With a large great number of VSC-HVDC project being constructed and put into service,the penetration level of the power electronic device in the power system is increasing,the transient stability analysis will be the basis for ensuring the stable operation of the power electronic dominated power system.In recent years,the dynamic response characteristics of unidentified problems have been appearing in the power system,which greatly affects the stability of the system and highlights the importance of analyzing the mathematical modol of power electronic dominated power system in essence.The control parameters of the converter in the VSC-HVDC system play an important role in the design of controller and stability analysis.The improper selection of the parameters will affect the dynamic response performance and even cause the instability in the power system.So it is very important to select the appropriate control parameters for the stable operation in the system.At present,the parameter setting mainly satisfies the current following performance and anti-interference ability in the system,the DC transmission capacity is mainly limited by the thermal limitation of power electronic device.However,the relationship between control parameters and system power limits is still undefined.In this paper,the small signal model of the inverter station in the VSC-HVDC system is built.The influence of the control parameters of the inverter station on the power system stability is further investigated.Combining the control parameters with the response speed of control system,the influence of control system response speed on the system power limit is obtained,and based on which a simple and normalized method for control parameter setting is proposed.At last,a VSC-HVDC simulation is conducted in PSCAD/EMTDC.According to the control strategy proposed in this paper,the influence of control parameters on the stability of small signal model is analyzed.By comparing electromagnetic transient simulation and the small-signal model simulation,the results indicate the correctness and validity of the small-signal model,which provides a theoretical support for analyzing the influence of control system response speed on the system power limit. |
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