柔性直流引发火电机组次同步振荡的电气负阻尼关键因素分析

Key Factors Analysis of Negative Electrical Damping for Sub-synchronous Oscillation in Thermal Power Units Induced by Flexible-HVDC

  • 摘要: 电力电子装置大量接入电力系统,会产生电气负阻尼,而电气负阻尼是导致机组产生次同步振荡的直接原因。确定引起电气负阻尼的关键环节和参数,对于理解电气负阻尼产生机理、制定抑制措施十分重要。针对这个问题,首先采用改进复转矩系数的电气阻尼分析方法,基于模式解耦展开复转矩系数传递函数,定义电气阻尼极值,确定引起负阻尼的关键振荡模式及分式。其次,引入电气阻尼相关因子和灵敏度,确定电气负阻尼的关键影响环节和参数,根据灵敏度分析结果给出参数调整方案以抑制次同步振荡。最后,通过PSCAD模型进行时域仿真验证。

     

    Abstract: The negative electrical damping is the direct reason for the sub-synchronous oscillation in the near area where a large number of power electronic devices are connected to the power system. It is very important to understand the mechanism of electrical negative damping and to formulate suppression measures that determine the key links and parameters that cause electrical negative damping. To address this problem, firstly, the complex torque coefficient transfer function was expanded; the extreme value of electrical damping was defined; the key oscillation modes and fractions causing negative damping were determined based on mode decoupling by the electrical damping analysis method with improved complex torque coefficients. Secondly, the electrical damping correlation factor and sensitivity were introduced to determine the key influencing links and parameters of electrical negative damping, and the parameter adjustment scheme was given to suppress sub-synchronous oscillation according to the sensitivity analysis results. Finally, the time domain simulation of this method is verified by the PSCAD model.

     

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