基于虚拟电阻的混合直流输电系统振荡抑制策略

An oscillation suppression strategy for hybrid DC systems based on virtual resistance

针对混合直流输电系统在其定直流电流控制器参数增大时容易发生直流电流振荡的问题,提出一种基于虚拟电阻的振荡抑制策略。该策略基于电流振荡分量和引入的虚拟电阻,产生与扰动分量反相的附加电压,实现对直流电流振荡的抑制。首先,建立混合直流输电系统的小信号模型,分析定直流电流控制器参数对系统小信号稳定性的影响。其次,提出基于虚拟电阻的振荡抑制策略,研究虚拟电阻对系统小信号稳定性的影响,并通过PSCAD/EMTDC仿真验证了所提控制策略的有效性。最后,分析在不同定直流电流控制参数下虚拟电阻的稳定范围。研究结果表明,所提控制策略能够有效解决直流电流振荡的问题,提高系统稳定性。

Hybrid DC transmission systems are prone to DC current oscillations as the parameters of constant DC current controller increase,an oscillation suppression strategy based on virtual resistance is proposed.This strategy generates an additional voltage that is in phase opposition to the disturbance component by leveraging the current os⁃cillation component and an introduced virtual resistance,thereby achieving suppression of the DC current oscilla⁃tions.Initially,a small-signal model of the hybrid DC transmission system is established to analyze the impact of pa⁃rameters of the constant DC current controller on the stability of small signals.Subsequently,an oscillation suppres⁃sion strategy based on virtual resistance is put forward to study the influence of virtual resistance on the stability of small signals in the system.The effectiveness of the proposed strategy is verified through PSCAD/EMTDC simula⁃tions.Lastly,the stability range of the virtual resistance under different constant current controller parameters is analyzed.The research findings indicate that the proposed control strategy can effectively eradicate DC current oscil⁃lations and improve system stability.