References of "Sachau, Jürgen 50002967"
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See detailOverloads Management in Active Radial Distribution Systems: an Optimization Approach Including Network Switching
Bilibin, Ilya UL; Capitanescu, Florin UL; Sachau, Jürgen UL

in 2013 IEEE PES PowerTech (2013, June)

This paper focuses on the real-time overloads management in active radial distribution systems that host a significant amount of distributed generators (DGs). In order to possibly reduce the amount of ... [more ▼]

This paper focuses on the real-time overloads management in active radial distribution systems that host a significant amount of distributed generators (DGs). In order to possibly reduce the amount of generation curtailed to remove congestion, and hence harvest as much renewable energy as possible, we propose a centralized optimization approach that includes the option to use remotely controlled grid switches and breakers so as to transfer distributed generation between feeders. To mitigate the computational burden posed by modeling the switching actions as binary variables we build upon a very convenient existing optimization framework that, for a radial distribution grid, transforms precisely the original mixed integer nonlinear programming (MINLP) problem into a much simpler mixed integer quadratically constrained (MIQC) one. Although the approach focuses on overload removal in course of optimization it also pays attention not worsening other operational constraints such as voltage limits. We prove the interest and feasibility of our approach using a 33-bus benchmark distribution system as well as a 61-bus real-life distribution system model. [less ▲]

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See detailDistributed Generator Status Estimation for Adaptive Feeder Protection in Active Distribution Grids
Margossian, Harag UL; Capitanescu, Florin UL; Sachau, Jürgen UL

in Proceedings of the CIRED2013 conference (2013, June)

This paper proposes a framework for adaptive feeder protection in distribution grids with a high amount of distributed generators (DGs) installed. The scheme adapts the feeder protection relay settings ... [more ▼]

This paper proposes a framework for adaptive feeder protection in distribution grids with a high amount of distributed generators (DGs) installed. The scheme adapts the feeder protection relay settings according to the changes in the connection status of those DGs that have a significant impact on the fault current. The core of the method consists in the identification of the connection status of the DGs using an iterative modified state estimation (SE) program. The approach is illustrated using a realistic 31-node distribution network model. [less ▲]

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See detailTowards optimal post-fault self-healing in future smart distribution grids
Capitanescu, Florin UL; Bilibin, Ilya UL; Sachau, Jürgen UL

in Renewable Energy & Power Quality Journal (2013)

This paper deals with a key functionality of the future distribution smart grids namely the automatic post-fault network self-healing. To this end we propose an optimization approach that aims finding the ... [more ▼]

This paper deals with a key functionality of the future distribution smart grids namely the automatic post-fault network self-healing. To this end we propose an optimization approach that aims finding the post-fault grid topology that minimizes the amount of unsupplied energy to consumers. The approach extends existing optimization models, developed in the context of losses minimization, for our particular application and proposes ways to overcome their limitations. We prove the interest of the approach on a 33-bus benchmark distribution system as well as on a 61-bus real-life distribution grid. [less ▲]

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See detailFrequency Coupling in Inverter Grids Modeling the Mutual Interference of Voltage Source Inverters in Island Grids
Jostock, Markus UL; Sachau, Jürgen UL

in Abstract book of 5th International Conference on Integration of Renewable and Distributed Energy Resources (2012)

This paper presents a model to describe the mutual frequency disturbance of meshed and interconnected voltage source inverters during transient phases. The model provides a weighted mutual frequency ... [more ▼]

This paper presents a model to describe the mutual frequency disturbance of meshed and interconnected voltage source inverters during transient phases. The model provides a weighted mutual frequency coupling matrix taking into account that the mutual frequency measurement disturbance decreases for increasing electric distance between the inverters (i.e. depend on the line admittance) and depends on the respective inverter’s rated power, meaning that stronger inverters have more influence than small ones on the other inverters frequency perception. [less ▲]

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See detailCompound Model of Inverter Driven Grids Stability Analysis of Island Power Grids Containing Only Voltage Source Inverters
Jostock, Markus UL; Sachau, Jürgen UL

in Abstract book of 5th International Conference on Integration of Renewable and Distributed Energy Resources (2012)

This paper presents a structured development of a compound state space model of an inverter driven power grid. It allows to perform stability investigations on power grids, depending on the inverter ... [more ▼]

This paper presents a structured development of a compound state space model of an inverter driven power grid. It allows to perform stability investigations on power grids, depending on the inverter parameters influencing their dynamich behavior and on the grid structure. The general approach is to separate the active components, i.e. the inverters, from the passive components, i.e. the grid, and model them separately. A state space model of a single voltage source inverter is developed and then extended into a multi-inverter model. Based on the linearized power equations of one grid branch, a matrix representation of the grid is developed, based on the sorted node incidence matrix. The grid matrix model and the multi-inverter state space model are joined into one compound control model for inverter driven power grids. [less ▲]

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See detailNetPower DemoLab A Test Bed Infrastructure for Security and Reliability Investigations of SCADA Systems
Jostock, Markus UL; Sachau, Jürgen UL

in Abstract paper of 2011 Grande Region Security and Reliability Day (2011)

The purpose of this paper is to present the capabilities of the new NetPower DemoLab of the Interdisciplinary Centre for Reliability and Trust at the University of Luxembourg, operated by the Systems and ... [more ▼]

The purpose of this paper is to present the capabilities of the new NetPower DemoLab of the Interdisciplinary Centre for Reliability and Trust at the University of Luxembourg, operated by the Systems and Control group, and to stimulate potential public or private collaborations in the area of SCADA security and reliability investigations. [less ▲]

Detailed reference viewed: 126 (10 UL)