The maximum active power that a Line-Commutated-Converter High Voltage Direct Current (LCC-HVDC) can provide instantly, called LCC-HVDC-MC Maximum Emergency Power Capacity, is an important information for determining the emergency control strategy of a power system subject to a large disturbance. However, it is a challenging task to calculate this capacity accurately due to system model uncertainties and contingencies. To address this problem, we propose to estimate this capacity by real-time tracking the Thevenin equivalent (TE) parameters of the AC system based on local PMUs. This new TE estimation method can handle the large disturbances and yield an accurate HVDC-MC while considering various constraints. Specifically, we first investigate the impacts of the TE potential changes on the TE impedance estimation under a large disturbance. To reduce the estimation error caused by the TE potential change, we develop an adaptive current screening process of the current measurements. Moreover, we use the total least square estimation method to further filter out the PMU errors. Finally, we calculate LCC-HVDC maximum emergency power capacity while accounting for the limitations of the control performance, voltage dependent current order limit, the converter capacity, and the AC voltage. The simulations show that the proposed method can accurately track the TE parameters and the real-time LCC-HVDC maximum emergency power capacity following a large disturbance.

中文翻译：

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基于本地PMU的实时LCC-HVDC最大应急功率容量估计

线路换流器高压直流（LCC-HVDC）可以立即提供的最大有功功率，称为LCC-HVDC-MC最大应急功率容量，是确定电力系统主体应急控制策略的重要信息。受到很大的干扰。但是，由于系统模型的不确定性和偶然性，准确地计算此容量是一项艰巨的任务。为解决此问题，我们建议通过基于本地PMU实时跟踪AC系统的戴维宁当量（TE）参数来估计此容量。在考虑各种约束条件的同时，这种新的TE估计方法可以处理大的干扰并产生准确的HVDC-MC。具体来说，我们首先研究在大扰动下TE电位变化对TE阻抗估计的影响。为了减少由TE电位变化引起的估计误差，我们开发了电流测量的自适应电流筛选过程。此外，我们使用总最小二乘估计方法进一步滤除PMU误差。最后，我们在计算LCC-HVDC最大应急功率容量的同时，还要考虑控制性能，电压相关电流阶跃限制，转换器容量和交流电压的限制。仿真结果表明，该方法能够准确跟踪大扰动下的TE参数和实时LCC-HVDC最大应急功率。最后，我们在计算LCC-HVDC最大应急功率容量的同时，还要考虑控制性能，电压相关电流阶跃限制，转换器容量和交流电压的限制。仿真结果表明，该方法能够准确跟踪大扰动下的TE参数和实时LCC-HVDC最大应急功率。最后，我们在计算LCC-HVDC最大应急功率容量的同时，还要考虑控制性能，电压相关电流阶跃限制，转换器容量和交流电压的限制。仿真结果表明，该方法能够准确跟踪大扰动下的TE参数和实时LCC-HVDC最大应急功率。