TY - GEN A1 - Fügenschuh, Armin A1 - Hiller, Benjamin A1 - Humpola, Jesco A1 - Koch, Thorsten A1 - Lehmann, Thomas A1 - Schwarz, Robert A1 - Schweiger, Jonas A1 - Szabó, Jácint T1 - Gas Network Topology Optimization for Upcoming Market Requirements N2 - Gas distribution networks are complex structures that consist of passive pipes, and active, controllable elements such as valves and compressors. Controlling such network means to find a suitable setting for all active components such that a nominated amount of gas can be transmitted from entries to exits through the network, without violating physical or operational constraints. The control of a large-scale gas network is a challenging task from a practical point of view. In most companies the actual controlling process is supported by means of computer software that is able to simulate the flow of the gas. However, the active settings have to be set manually within such simulation software. The solution quality thus depends on the experience of a human planner. When the gas network is insufficient for the transport then topology extensions come into play. Here a set of new pipes or active elements is determined such that the extended network admits a feasible control again. The question again is how to select these extensions and where to place them such that the total extension costs are minimal. Industrial practice is again to use the same simulation software, determine extensions by experience, add them to the virtual network, and then try to find a feasible control of the active elements. The validity of this approach now depends even more on the human planner. Another weakness of this manual simulation-based approach is that it cannot establish infeasibility of a certain gas nomination, unless all settings of the active elements are tried. Moreover, it is impossible to find a cost-optimal network extension in this way. In order to overcome these shortcomings of the manual planning approach we present a new approach, rigorously based on mathematical optimization. Hereto we describe a model for finding feasible controls and then extend this model such that topology extensions can additionally and simultaneously be covered. Numerical results for real-world instances are presented and discussed. T3 - ZIB-Report - 11-09 KW - Mathematical Optimization KW - Gas Distribution Networks KW - Topology Planning Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-12348 ER - TY - JOUR A1 - Janata, M. A1 - Loebl, M. A1 - Szabó, Jácint T1 - A Gallai-Edmonds type theorem for the k-piece packing problem JF - Electron. J. Combin Y1 - 2005 VL - 12 SP - 1 ER - TY - JOUR A1 - Janata, M. A1 - Szabó, Jácint T1 - The superstar packing problem JF - Combinatorica Y1 - 2009 VL - 29 IS - 1 SP - 27 EP - 48 PB - Springer ER - TY - JOUR A1 - Szabó, Jácint T1 - Upgrading edge-disjoint paths in a ring JF - Discrete Optimization Y1 - 2010 PB - Elsevier BV ER - TY - JOUR A1 - Hartvigsen, D. A1 - Hell, P. A1 - Szabó, Jácint T1 - The k-piece packing problem JF - Journal of Graph Theory Y1 - 2006 VL - 52 IS - 4 SP - 267 EP - 293 PB - John Wiley & Sons ER - TY - JOUR A1 - Bíró, István A1 - Szabó, Jácint T1 - Latent Dirichlet Allocation for Automatic Document Categorization JF - Machine Learning and Knowledge Discovery in Databases Y1 - 2009 SP - 430 EP - 441 PB - Springer ER - TY - JOUR A1 - Frank, A. A1 - Chi Lau, L. A1 - Szabó, Jácint T1 - A note on degree-constrained subgraphs JF - Discrete Mathematics Y1 - 2008 VL - 308 IS - 12 SP - 2647 EP - 2648 PB - Elsevier ER - TY - JOUR A1 - Recski, A. A1 - Szabó, Jácint T1 - On the generalization of the matroid parity problem JF - Graph Theory in Paris Y1 - 2007 SP - 347 EP - 354 PB - Springer ER - TY - JOUR A1 - Szabó, Jácint T1 - Matroid parity and jump systems JF - SIAM Journal on Discrete Mathematics Y1 - 2008 VL - 22 SP - 854 ER - TY - JOUR A1 - Király, T. A1 - Szabó, Jácint T1 - A note on parity constrained orientations JF - Combinatorica Y1 - 2009 VL - 29 IS - 5 SP - 619 EP - 628 PB - Springer ER - TY - JOUR A1 - Makai, M. A1 - Pap, G. A1 - Szabó, Jácint T1 - Matching problems in polymatroids without double circuits JF - Integer Programming and Combinatorial Optimization Y1 - 2007 SP - 167 EP - 181 PB - Springer ER - TY - JOUR A1 - Makai, M. A1 - Szabó, Jácint T1 - The parity problem of polymatroids without double circuits JF - Combinatorica Y1 - 2008 VL - 28 IS - 6 SP - 679 EP - 692 PB - Springer ER - TY - JOUR A1 - Szabó, Jácint T1 - Packing Trees with Constraints on the Leaf Degree JF - Graphs and Combinatorics Y1 - 2008 VL - 24 IS - 5 SP - 485 EP - 494 PB - Springer ER - TY - JOUR A1 - Király, Z. A1 - Szabó, Jácint T1 - Induced graph packing problems JF - Graphs and Combinatorics Y1 - 2010 VL - 26 IS - 2 SP - 243 EP - 257 PB - Springer ER - TY - JOUR A1 - Szabó, Jácint T1 - Good characterizations for some degree constrained subgraphs JF - Journal of Combinatorial Theory, Series B Y1 - 2009 VL - 99 IS - 2 SP - 436 EP - 446 PB - Elsevier ER - TY - CHAP A1 - Fügenschuh, Armin A1 - Hiller, Benjamin A1 - Humpola, Jesco A1 - Koch, Thorsten A1 - Lehmann, Thomas A1 - Schwarz, Robert A1 - Schweiger, Jonas A1 - Szabo, Jacint T1 - Gas Network Topology Optimization for Upcoming Market Requirements T2 - International Conference on the European Energy Market (EEM) N2 - Gas distribution networks are complex structures that consist of passive pipes, and active, controllable elements such as valves and compressors. Controlling such network means to find a suitable setting for all active components such that a nominated amount of gas can be transmitted from entries to exits through the network, without violating physical or operational constraints. The control of a large-scale gas network is a challenging task from a practical point of view. In most companies the actual controlling process is supported by means of computer software that is able to simulate the flow of the gas. However, the active settings have to be set manually within such simulation software. The solution quality thus depends on the experience of a human planner. When the gas network is insufficient for the transport then topology extensions come into play. Here a set of new pipes or active elements is determined such that the extended network admits a feasible control again. The question again is how to select these extensions and where to place them such that the total extension costs are minimal. Industrial practice is again to use the same simulation software, determine extensions by experience, add them to the virtual network, and then try to find a feasible control of the active elements. The validity of this approach now depends even more on the human planner. Another weakness of this manual simulation-based approach is that it cannot establish infeasibility of a certain gas nomination, unless all settings of the active elements are tried. Moreover, it is impossible to find a cost-optimal network extension in this way. In order to overcome these shortcomings of the manual planning approach we present a new approach, rigorously based on mathematical optimization. Hereto we describe a model for finding feasible controls and then extend this model such that topology extensions can additionally and simultaneously be covered. Numerical results for real-world instances are presented and discussed. Y1 - 2011 U6 - https://doi.org/10.1109/EEM.2011.5953035 SP - 346 EP - 351 ER - TY - GEN A1 - Szabó, Jácint T1 - The set of solutions to nomination validation in passive gas transportation networks with a generalized flow formula N2 - In this paper we give an analytical description on the structure of solutions to the gas nomination validation problem in gas transportation networks. These networks are assumed to contain no active devices, only certain hypothetical pipelines, where the flow of gas is modeled by a generalized version of the quadratic Weymouth's equation. The purpose of considering generalized flow formulas is to be able to adapt our results to various gas network optimization problems involving gas flow formulas beyond Weymouth's equation. Such formulas can appear in leaves of branch and bound trees, or they can stem from discretization and linearization carried out at active devices. We call a balanced supply-demand vector a nomination, and the passive nomination validation problem is to decide whether there exist pressures at the nodes generating a given nomination. We prove that in our setup the pressure square vectors generating a given nomination form a one-dimensional connected and continuous curve in the pressure square space, and this curve is a line for the classical Weymouth's equation. We also present a visual approach for the easy comprehension of how this solution curve arises; we give a short investigation of the set of feasible nominations; and finally we give a proof that the nomination validation problem in gas networks with active devices is NP-complete. T3 - ZIB-Report - 11-44 KW - pressure drop equation KW - gas networks KW - generalized flow formula Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-15151 SN - 1438-0064 ER -