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1. Energy management algorithm for resilient controlled delivery grids

   https://doi.org/10.1109/IAS.2017.8101777  

   Saleh, Mahmoud; Esa, Yusef; Mohamed, Ahmed A.; Grebel, Haim; Rojas-Cessa, Roberto (October 2017, 2017 IEEE Industry Applications Society Annual Meeting)

   Resilience of the power grid is most challenged at power blackouts since the issues that led to it may not be fully resolved by the time the power is back. In this paper, a Real-Time Energy Management Algorithm (RTEMA) has been developed to increase the resilience of power systems based on the controlled delivery grid (CDG) concept. In a CDG, loads communicate with a central controller, periodically sending requests for power. The central controller runs an algorithm, based on which it may decide whether to grant the requested energy fully or partially. Therefore, the CDG limits loads discretionary access to electric energy until all problems are resolved. The developed algorithm aims at granting most or all of the requested loads, while maintaining the health of the power system (i.e. the voltage at each bus, and the line loading are within acceptable limits), and minimizing the overall losses. An IEEE 30-bus standard Test Case, encountering a blackout condition, with high penetration of microgrids, has been used to test the developed algorithm. Results proved that the developed algorithm with the CDG have the potential to substantially increase the resilience of power systems. 

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2. A Graph Theoretic Approach to Power System Vulnerability Identification

   https://doi.org/10.1109/TPWRS.2020.3010476  

   Sen Biswas, Reetam; Pal, Anamitra; Werho, Trevor; Vittal, Vijay (July 2020, IEEE Transactions on Power Systems)

   During major power system disturbances, when multiple component outages occur in rapid succession, it becomes crucial to quickly identify the transmission interconnections that have limited power transfer capability. Understanding the impact of an outage on these critical interconnections (called saturated cut-sets) is important for enhancing situational awareness and taking correct actions. This paper proposes a new graph theoretic approach for analyzing whether a contingency will create a saturated cut-set in a meshed power network. A novel feature of the proposed algorithm is that it lowers the solution time significantly making the approach viable for real-time operations. It also indicates the minimum amount by which the power transfer through the critical interconnections should be reduced so that post-contingency saturation does not occur. Robustness of the proposed algorithm for enhanced situational awareness is demonstrated using the IEEE-118 bus system as well as a 17,000+ bus model of the Western Interconnection (WI). Comparisons made with different approaches for power system vulnerability assessment prove the utility of the proposed scheme for aiding power system operations during extreme exigencies. 

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3. Sensitivity of Distributed Optimization Convergence Performance to Reference Bus Location

   https://doi.org/10.1109/PESGM40551.2019.8973576  

   Mohammadi, A.; Safdarian, F.; Kargarian, A. (January 2020, 2019 IEEE Power & Energy Society General Meeting (PESGM))

   Distributed optimization is becoming popular to solve a large power system problem with the objective of reducing computational complexity. To this end, the convergence performance of distributed optimization plays an important role to solve an optimal power flow (OPF) problem. One of the critical factors that have a significant impact on the convergence performance is the reference bus location. Since selecting the reference bus location does not affect the result of centralized DC OPF, we can change the location of the reference bus to get more accurate results in distributed optimization. In this paper, our goal is to provide some insights into how to select reference bus location to have a better convergence performance. We modeled the power grid as a graph and based on some graph theory concepts, for each bus in the grid a score is assigned, and then we cluster buses to find out which buses are more suitable to be considered as the reference bus. We implement the analytical target cascading (ATC) on the IEEE 48-bus system to solve a DC OPF problem. The results show that by selecting a proper reference bus, we obtained more accurate results with an excellent convergence rate while improper selection may take much more iterations to converge. 

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4. A Framework to Evaluate PMU Networks for Resiliency Under Network Failure Conditions

   https://doi.org/10.1109/SmartGridComm52983.2022.9961035  

   Raj, Reuben Samson; Jin, Dong (October 2022, IEEE SmartGridComm, October 2022)

   Phasor Measurement Units (PMU), due to their capability for providing highly precise and time-synchronized measurements of synchrophasors, have now become indispensable in wide area monitoring of power-grid systems. Successful and reliable delivery of synchrophasor packets from the PMUs to the Phasor Data Concentrators (PDCs) and beyond, requires a backbone communication network that is robust and resilient to failures. These networks are vulnerable to a range of failures that include cyber-attacks, system or device level outages and link failures. In this paper, we present a framework to evaluate the resilience of a PMU network in the context of link failures. We model the PMU network as a connected graph and link failures as edges being removed from the graph. Our approach, inspired by model checking methods, involves exhaustively checking the reachability of PMU nodes to PDC nodes, for all possible combinations of link failures, given an expected number of links fail simultaneously. Using the IEEE 14-bus system, we illustrate the construction of the graph model and the solution design. Finally, a comparative evaluation on how adding redundant links to the network improves the Power System Observability, is performed on the IEEE 118 bus-system. 

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5. Probabilistic Network Observability of a Hybrid Power System with Communication Irregularities

   https://doi.org/10.1109/NAPS46351.2019.8999986  

   Svenda, Vanja G.; Stankovic, Alex M.; Saric, Andrija T.; Transtrum, Mark K. (October 2019, 2019 North American Power symposium)

   This paper explores power system network observability while taking into account realistic communication network behavior. The overall information is obtained by combining SCADA- and phasor measurement unit-derived data, where time stamping (based on Global Positioning System or an equivalent local clock) for all measurements is assumed. Based on simulations performed in communication Network Simulator 2, empirical cumulative distribution functions can be associated with transfer times of measurement packets, which will reflect communication parameters and irregularities. This is further used to form an algorithm which maximizes the number of successful network observability checks, and thus the number of possible state estimations, in a certain time period. Application is demonstrated on the IEEE 14-bus test power system example. 

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