The Voltage Stability Characteristic Of Terminal Power Grid Fed By HVDC

Modern power systems are moving towards large gird,large units,ultra voltage,AC/DC transmission direction.HVDC has been widely used gradually because of its unique advantages in large capacity and long-distance transmission.At the same time,the introduction of more and more HVDC has put foward a great test to the voltage stability of the terminal system.The following research is carried out in this paper for voltage stability of terminal system fed by HVDC.At first,this paper proposes some quantitative analysis indexs of transient voltage stability considering the average and dropping of transient voltage,it can analyse the transient voltage stability of the same bus with different faults and the same fault with different bus.The effectiveness and accuracy of the index are verified by changing the load proportion and time of fault removal.Secondly,the influence of DC fault on the voltage stability of the terminal grid is analyzed from the view of the interaction between the reactive voltage characteristic of the DC converter station and apparent power transmission characteristic of the AC network.Combining with Shandong power grid planning data,using PSD-BPA electromechanical transient simulation software,this paper analyzes the influence of the single pole locking fault and the double pole blocking failure of the DC system on the power angle of the terminal system,the excitation of the unit,the terminal voltage and the frequency.This paper a lso proposes corresponding measure to improve the influence of DC fault on transient voltage.Finally,under the support of the planning data of shandong power grid,this paper analyzes the influence of the reactive power compensator and different VDCOL parameters on the voltage stability characteristics.The voltage stability of the terminal system is analyzed from the mechanism against the starting voltage,the exit voltage and the minimum interpolation current and verifying the influence of VDCOL parameters on voltage stability through simulation of the actual system.In the end of the article,the research results of this article are summarized,for the existing main problems and the development direction of the future about this topic,the author put forward its own proposals.