@misc{AlghamdiSmithAristidouetal., author = {Alghamdi, Sultan and Smith, Nathan and Aristidou, Petros and Schiffer, Johannes}, title = {Delay-Robust Distributed Secondary Frequency Control: A Case Study}, series = {IEEE PES PowerTech Conference 2019, Milano, Italy}, journal = {IEEE PES PowerTech Conference 2019, Milano, Italy}, address = {Milano}, isbn = {978-1-5386-4722-6}, doi = {10.1109/PTC.2019.8810821}, pages = {6}, abstract = {With the purpose of enabling a low-carbon future, power systems worldwide are undergoing major transformations. These developments require new advanced control and operation approaches to ensure a stable and efficient system operation. Distributed consensus-based algorithms are a promising option to provide the necessary flexibility and scalability to cope with these challenges and have, thus, been widely investigated in the literature. Yet, most available results are limited to scenarios with reduced-order models and ideal communication. Motivated by this, we perform a case study using a detailed dynamic model of the well-known Nordic test system equipped with a consensus-based distributed secondary frequency controller. Our main objectives are to analyse the robustness of the closed-loop system with respect to unmodelled (voltage and higher-order generator) dynamics as well as communication delays. To facilitate the later property, we employ robust-stability conditions in the control design. Then, the performance of the proposed controller is assessed through detailed dynamic simulations covering several disturbances leading to large frequency and voltage excursions.}, language = {en} } @misc{SchifferAristidouOrtega, author = {Schiffer, Johannes and Aristidou, Petros and Ortega, Romeo}, title = {Online Estimation of Power System Inertia Using Dynamic Regressor Extension and Mixing}, series = {IEEE Transactions on Power Systems}, volume = {34}, journal = {IEEE Transactions on Power Systems}, number = {6}, issn = {1558-0679}, doi = {10.1109/TPWRS.2019.2915249}, pages = {4993 -- 5001}, abstract = {The increasing penetration of power-electronic-interfaced devices is expected to have a significant effect on the overall system inertia and a crucial impact on the system dynamics. In future, the reduction of inertia will have drastic consequences on protection and real-time control and will play a crucial role in the system operation. Therefore, in a highly deregulated and uncertain environment, it is necessary for transmission system operators to be able to monitor the system inertia in real time. We address this problem by developing and validating an online inertia estimation algorithm. The estimator is derived using the recently proposed dynamic regressor and mixing procedure. The performance of the estimator is demonstrated via several test cases using the 1013-machine ENTSO-E dynamic model.}, language = {en} } @misc{AlghamdiMarkovicStanojevetal., author = {Alghamdi, Sultan and Markovic, Uros and Stanojev, Ognjen and Schiffer, Johannes and Hug, Gabriela and Aristidou, Petros}, title = {Wide-area oscillation damping in low-inertia grids under time-varying communication delays}, series = {ScienceDirect}, volume = {189}, journal = {ScienceDirect}, issn = {0378-7796}, doi = {10.1016/j.epsr.2020.106629}, pages = {9}, abstract = {Wide-Area Control (WAC) can be efficiently used for oscillation damping in power systems. However, to implement a WAC, a communication network is required to transmit signals between the generation units and the control center. In turn, this makes WAC vulnerable to time-varying communication delays that, if not appropriately considered in the control design, can destabilize the system. Moreover, with the increasing integration of renewable energy resources into the grid, usually interfaced via power electronics, power system dynamics are becoming drastically faster and making WAC more vulnerable to communication delays. In this paper, we propose a design procedure for a delay-robust wide-area oscillation damping controller for low-inertia systems. Its performance is illustrated on the well-known Kundur two-area system. The results indicate that the obtained WAC successfully improves the oscillation damping while ensuring robustness against time-varying communication delays.}, language = {en} } @misc{AlghamdiMarkovicStanojevetal., author = {Alghamdi, Sultan and Markovic, Uros and Stanojev, Ognjen and Schiffer, Johannes and Hug, Gabriela and Aristidou, Petros}, title = {Wide-Area Oscillation Damping in Low-Inertia Grids under Time-Varying Communication Delays}, series = {21st Power Systems Computation Conference, Porto, Portugal — June 29 - July 3, 2020}, journal = {21st Power Systems Computation Conference, Porto, Portugal — June 29 - July 3, 2020}, pages = {8}, abstract = {Wide-Area Control (WAC) can be efficiently used for oscillation damping in power systems. However, to implement a WAC, a communication network is required to transmit signals between the generation units and the control center. In turn, this makes WAC vulnerable to time-varying communication delays that, if not appropriately considered in the control design, can destabilize the system. Moreover, with the increasing integration of renewable energy resources into the grid, usually interfaced via power electronics, the power system dynamics becoming drastically faster and making WAC more vulnerable to communication delays. In this paper, we propose a design procedure for a delay-robust wide-area oscillation damping controller for low-inertia systems. Its performance is illustrated on the well-known Kundur two-area system. The results indicate that the obtained WAC successfully improves the oscillation damping while ensuring robustness against time-varying communication delays.}, language = {de} }