直接电压控制构网型变流器控制参数暂态稳定影响分析

Analysis of transient stability effects of control parameters for direct voltage control grid-forming converters

目前针对直接电压控制构网型变流器暂态失稳模式的演化和控制参数对暂态稳定的影响机理尚需进一步深入研究。首先,分析了两种常见电流限幅策略对变流器暂态稳定性的影响,归纳总结出3种暂态失稳演化路径。其次,通过极限切除时间、极限切除角揭示了变流器有功环节不同参数对暂态稳定的影响规律,并针对直接电压控制构网型变流器的内电势和并网点电压之间的非线性关系,使用变流器临界势能为指标,揭示了变流器无功环节不同参数对稳定性的影响规律。在此基础上,解释了不同控制环节参数对变流器暂态稳定性的影响出现反常规律的机理。最后,在PSCAD仿真平台上通过算例验证了理论分析的正确性。

The current understanding of the evolution of transient instability modes and the mechanism by which control parameters affect transient stability in direct-voltage-controlled grid-forming inverters still requires further in-depth study.First,the impact of two common current limiting strategies on the transient stability of the inverter is analyzed,and three transient instability evolution paths are summarized.Secondly,using the critical clearing time and angle,the rules of how different parameters in the active power section of the inverter affect transient stability are revealed.In the context of the nonlinear relationship between the internal and grid-connected point voltage of direct-voltage-controlled grid-forming inverters,the critical potential energy of the inverter is used as an indicator to disclose the influence rules of different parameters in the reactive power section on transient stability.The mechanisms behind the anomalous patterns of how different control loop parameters affect the transient stability of the inverter are explained.Finally,the correctness of the theoretical analysis is verified through case studies on the PSCAD simulation platform.