Integrated Framework for Detection and Mitigation of GPS Spoofing Attacks in Smart Grids

全球定位系统是国家最关键的基础设施之一，它为许多系统和应用程序提供精确的时间和位置。例子包括空运、海运和陆运、电信、金融交易、实时工业控制系统，以及最重要的电网。具体来说，未来电网的可靠运行取决于全球定位系统时间同步技术实现的精确定时电网测量的可用性。虽然该系统非常可靠，但它容易受到恶意欺骗网络攻击，从而破坏测量的时间同步。因此，这误导了依赖于它的基础设施的无缝运行。例如，这些攻击对电网造成影响，包括电力中断，造成严重的社会经济影响。该项目的主题是实时检测和减轻对电网中应用的全球定位系统的此类攻击。欺骗攻击表现在不同的物理层，包括由全球定位系统接收器聚合的信号，由接收器计算的时间和位置，以及最终从电网中的相量测量单元收集的电压和电流相量测量。提出了一种新颖、严谨、全面的全球定位系统接收机欺骗效应模型和电网运行模型。利用这些新模型，本研究还提供了检测攻击的先进方法，并最终保护电网免受其有害影响。具体来说，利用基于稀疏性的优化公式开发了在线欺骗检测方案。这些方案能够检测和隔离接收到的卫星信号的非自然变化以及相关的时间和位置解决方案。基于一种新的测量模型，将欺骗攻击与电网状态直接联系起来，开发了动态算法来保持对电网的准确状态估计，同时在存在攻击的情况下无缝地恢复电网稳定性。

The Global Positioning System is one of the nation's most critical infrastructures, which provides precise timing and location to a host of systems and applications. Examples include air, sea, and land transportation, telecommunications, financial transactions, real-time industrial control systems, and most importantly, the electrical power grid. Specifically, reliable operation of the future electrical power grids depends on the availability of grid measurements with precise timing that is enabled by the Global Positioning System's time-synchronization technology. Although this system is very reliable, it is vulnerable to malicious spoofing cyber-attacks that disrupt the time synchronization of measurements. This consequently misleads the seamless operation of the infrastructures relying on it. For example, these attacks have ramifications on the electrical power grid, including power outages with dire socio-economic implications. The theme of this project is the real-time detection and mitigation of such attacks on the Global Positioning System with applications in power grids. Spoofing attacks manifest themselves at different physical layers including the signals aggregated by the Global Positioning System receiver, the time and location computed by the receiver, and eventually the voltage and current phasor measurements collected from Phasor Measurement Units in the electrical grid. Novel, rigorous, and comprehensive models of the spoofing effects on the Global Positioning System receiver as well as the power grid operation are put forth. Leveraging the novel models, this research additionally furnishes advanced methods to detect the attacks and ultimately protect the grid from their harmful effects. Specifically, online spoofing detection schemes are developed using sparsity-based optimization formulations. These schemes are able to detect and isolate unnatural changes in the received satellite signals and the associated time and location solutions. Based on a novel measurement model that directly relates the spoofing attack with the electrical network state, dynamic algorithms are developed to maintain an accurate state estimate of the power grid, while seamlessly restoring grid stability in the presence of attacks.