Cascading failures in power systems propagate non-locally, making the control of outages extremely difficult. In Part III of this work, we leverage the properties of tree partitioning developed in Parts I and II to propose a distributed control strategy that offers strong guarantees in both the mitigation and localization of cascading failures. Specifically we adopt a recently developed distributed frequency regulation approach, called the Unified Control, that integrates primary and secondary control as well as congestion management at frequency control timescale. When the balancing areas over which the Unified Control operates form a tree partition, our proposed strategy will regulate the system to a steady state where the impact of initial line outages is localized within the areas where they occur whenever possible and stop the cascading process. When initial line outages cannot be localized, the proposed strategy provides a configurable design that involves and coordinates progressively more balancing areas for failure mitigation in a way that can be optimized for different priorities. We compare the proposed control strategy with the classical automatic generation control (AGC) on the IEEE 118-bus and 2736-bus test networks. Simulation results show that our strategy greatly improves overall reliability in terms of the N-k security standard, and localizes the impact of initial failures in majority of the load profiles that are examined. Moreover, the proposed framework incurs significantly less load loss, if any, compared to AGC, in all of our case studies.

中文翻译：

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电力系统级联故障的定位和缓解，第三部分：实时缓解

电力系统中的级联故障会在非本地传播，这使得对停电的控制变得极其困难。在这项工作的第三部分，我们利用第一部分和第二部分中开发的树分区的特性来提出一种分布式控制策略，该策略为级联故障的缓解和定位提供了强有力的保证。具体来说，我们采用了最近开发的分布式频率调节方法，称为统一控制，它在频率控制时间尺度上集成了主要和次要控制以及拥塞管理。当统一控制操作的平衡区域形成树分区时，我们提出的策略将把系统调节到一个稳定状态，在这种状态下，初始线路中断的影响尽可能集中在它们发生的区域内，并停止级联过程。当初始线路中断无法定位时，所提出的策略提供了一种可配置的设计，该设计涉及和协调更多的平衡区域，以一种可以针对不同优先级进行优化的方式来缓解故障。我们将所提出的控制策略与 IEEE 118 总线和 2736 总线测试网络上的经典自动发电控制 (AGC) 进行比较。仿真结果表明，我们的策略极大地提高了 Nk 安全标准的整体可靠性，并在所检查的大多数负载配置文件中定位了初始故障的影响。而且，