TCSC抑制次同步谐振的机理研究及其参数设计

正确地分析TCSC频率阻抗特性是评价TCSC抑制SSR能力的基础。该文给出了考虑导通角变化的三维频率阻抗图,该图清晰地表明:当目标导通角小于临界导通角时,TCSC低频阻抗特性存在一个容性曲面,只有越过临界导通角后低频视在阻抗才表现为感性。基于IEEE第一基准模型的数字仿真分析验证了频率阻抗计算方法和结果的正确性,深入阐明了TCSC抑制SSR的物理机理以及要实现完全抑制SSR需满足的工作条件。在此基础上还讨论了TCSC主电路的参数设计原则,使得TCSC不仅能满足工频基波阻抗调节特性的要求,而且能最大限度地提高对SSR的抑制能力。

THE MECHANISIM RESEARCH OF SSR MITIGATION BY TCSC AND ITS PARAMETER DESIGN

The correct analysis of frequency impedance characteristic of Thyristor Controlled Series Compensation (TCSC) is acknowledged as being essential to evaluate the ability for mitigating Subsynchronous Resonance (SSR). In this paper, a three-dimensional diagram of frequency impedance characteristic considering the variation of the conduction angle is obtained. The diagram shows that there is a capacitive zone among the curving surface of low-frequency impedance characteristic when the desired conduction angle is less than a critical conduction angle defined. Only if the conduction angle is greater than the critical conduction angle, TCSC appears inductive at subsynchronous frequencies. The digital simulation analysis based on the IEEE first benchmark system verifies the calculating method and results of frequency impedance, and thoroughly clarified both the mechanism of mitigating SSR and the operation condition under which the mitigation of SSR is completely realized. This paper further discusses the parameter design rule of the main circuit of TCSC, which not only meets the modulatory characteristic of the fundamental impedance, but also greatly improves the SSR mitigating ability of TCSC.