Xiaoyuan Fan
Published: 2016
Total Pages: 90
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Power system state estimation (SE) is one of the most fundamental applications at the control center, since it helps the system operator to monitor, control and optimize the performance of the power grid. Motivated by the advancements in synchronized phasor measurement units and the urgent need of a better state estimator to address the corresponding system complexity and computational burden, we focus on improving the resilience and efficiency of SE while incorporating synchrophasor measurements. Different types of cyber attacks are threatening the resilience of power system control and operations, while GPS spoofing attack (GSA) has been proved to be one of the most imminent threats to the recent modernization of the power grid. More specifically, it may greatly jeopardize the benefits brought by the pervasively installed phasor measurement units (PMUs). We consider the case where synchrophasor data from PMUs are compromised due to the presence of single or multiple GSAs, and show that this can be corrected by signal processing techniques. We introduce a statistical model for synchrophasor-based power system SE, then derive the spoofing-matched algorithms for GPS-spoofed synchrophasor data correction. Different testing scenarios based on IEEE 14-, 30-, 57-, 118-bus systems are simulated to show the proposed algorithms' performance on GSA detection as well as state estimation. Numerical results demonstrate that our proposed algorithms can consistently locate and correct the spoofed synchrophasor data with good accuracy. The accuracy of state estimation is significantly improved compared with the traditional weighted least square method and approaches the performance of Genie-aided method. To improve the efficiency of SE, we focus on a potential solution for the state estimation in the control room: decentralized multi-area state estimation (MASE) with synchrophasor measurements. A synchrophasor-assisted hybrid MASE algorithm has been proposed to tackle this problem, where the boundary bus state estimates generated from the tie-line based synchrophasor-only linear SE are transformed into the equality constraints imposed upon the local SE in each area, which makes it truly independent from others. Numerical simulations have been implemented in the IEEE 14-bus and 30-bus systems, and the simulation results show that the proposed algorithm can not only provide system state estimates with good accuracy, but also can speed up the computational process of SE for the entire system.