As power systems transit to a state of high renewable penetration, little or no presence of synchronous generators makes the prerequisite of well-regulated frequency for grid-following inverters unrealistic. Thus, there is a trend to resort to grid-forming inverters which set frequency directly. We propose a novel grid-forming frequency shaping control that is able to shape the aggregate system frequency dynamics into a first-order one with the desired steady-state frequency deviation and Rate of Change of Frequency (RoCoF) after a sudden power imbalance. The no overshoot property resulting from the first-order dynamics allows the system frequency to monotonically move towards its new steady-state without experiencing frequency Nadir, which largely improves frequency security. We prove that our grid-forming frequency-shaping control renders the system internally stable under mild assumptions. The performance of the proposed control is verified via numerical simulations on a modified Icelandic Power Network test case.

中文翻译：

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并网频率整形控制

随着电力系统过渡到可再生能源渗透率较高的状态，同步发电机很少或根本不存在使得为并网逆变器提供良好调节频率的先决条件变得不切实际。因此，有一种趋势是求助于直接设置频率的并网逆变器。我们提出了一种新颖的电网形成频率整形控制，它能够在突然的功率不平衡之后将总系统频率动态整形为具有所需稳态频率偏差和频率变化率 (RoCoF) 的一阶动态。一阶动力学产生的无过冲特性允许系统频率单调地向其新的稳态移动，而不会经历频率最低点，这在很大程度上提高了频率安全性。我们证明了我们的网格形成频率整形控制在温和的假设下使系统内部稳定。通过在修改后的冰岛电力网络测试案例上进行数值模拟，验证了所提出的控制的性能。