Low Latency Intrusion Detection in Smart Grids

The transformation of traditional power grids into smart grids has seen more new technologies such as communication networks and smart meters (sensors) being integrated into the physical infrastructure of the power grids. However, these technologies pose new vulnerabilities to the cybersecurity of power grids as malicious attacks can be launched by adversaries to attack the smart meters and modify the measurement data collected by these meters. If not timely detected and removed, these attacks may lead to inaccurate system state estimation, which is critical to the system operators for control decisions such as economic dispatch and other related functions. This dissertation studies the challenges associated with cyberattacks in power grids and develops solutions to effectively and timely detect these attacks to ensure an accurate state estimation. One of the common approaches to improving the state estimation accuracy is to incorporate phasor measurement unit (PMU) devices into the system to provide extra and more secure measurements. In this research, we design algorithms that place PMUs at strategic locations to enhance the system\u27s state estimation accuracy and its capability to detect cyberattacks. This approach of installing PMU devices in power grids, nonetheless, does not guarantee a timely attack detection that is critical for a timely deployment of countermeasures to prevent catastrophic impacts from the attacks. Thus, the low latency intrusion detection problem is studied to reduce attack detection delays. The state estimation and intrusion detection problem is further extended to a dynamic power system, where there are sudden changes in system loads

PMU Placement Optimization for Efficient State Estimation in Smart Grid

© 1983-2012 IEEE. This paper investigates phasor measurement unit (PMU) placement for informative state estimation in smart grid by incorporating various constraints for observability. Observability constitutes an important property for PMU placement to characterize the depth of the buses' reachability by the placed PMUs, but addressing it solely by binary linear programming as in many works still does not guarantee a good estimate for the grid state. Some existing works have considered optimization of some estimation indices by ignoring the observability requirements for computational ease and thus potentially lead to trivial results such as acceptance of the estimate for an unobserved state component as its unconditional mean. In this work, the PMU placement optimization problem is considered by minimizing the mean squared error or maximizing the mutual information between the measurement output and grid state subject to observability constraints, which incorporate operating conditions such as presence of zero injection buses, contingency of measurement loss, and limitation of communication channels per PMU. The proposed design is thus free from the fundamental shortcomings in the existing PMU placement designs. The problems are posed as large scale binary nonlinear optimization problems involving thousands of binary variables, for which this paper develops efficient algorithms for computational solutions. Their performance is analyzed in detail through numerical examples on large scale IEEE power networks. The solution method is also shown to be extendable to AC power flow models, which are formulated by nonlinear equations

On PMU Location Selection for Line Outage Detection in Wide-area Transmission Networks

The optimal PMU locations to collect voltage phase angle measurements for detecting line outages in wide-area transmission networks are investigated. The problem is established as one of maximizing the minimum distance among the voltage phase angle signatures of the outages, which can be equivalently formulated as an integer programming problem. Based on a greedy heuristic and a linear programming relaxation, a branch and bound algorithm is proposed to find the globally optimal PMU locations. Using this algorithm, the optimal tradeoff between the number of PMUs and the outage detection performance is characterized for IEEE 14, 24 and 30 bus systems. The algorithm is shown to find the globally optimal PMU locations in a small number of iterations. It is observed that it is sufficient to have roughly one third of the buses providing PMU measurements in order to achieve the same outage detection performance as with all the buses providing PMU measurements.Comment: In Proc. of IEEE PES general meeting, 201

電力系統の静的および動的セキュリティ評価増強のための同期位相計測装置の最適配置

九州工業大学博士学位論文 学位記番号：工博甲第490号 学位授与年月日：令和2年3月25日1 INTRODUCTION|2 PMU-BASED POWER SYSTEM MONITORING AND CONTROL|3 OPTIMAL PMU PLACEMENT PROBLEM AND STATE ESTIMATION|4 MULTI OBJECTIVE PMU PLACEMENT WITH CURRENT CHANNEL SELECTION|5 INFLUENCE OF MEASUREMENT UNCERTAINTY PROPAGATION IN PMU PSEUDO MEASUREMENT|6 PHASOR-ASSISTED VOLTAGE STABILITY ASSESSMENT BASED ON OPTIMALLY PLACED PMUS|7 PMU PLACEMENT FOR DYNAMIC VULNERABILITY ASSESSMENT|8 CONCLUSIONS九州工業大学令和元年