The Experts below are selected from a list of 1179 Experts worldwide ranked by ideXlab platform
Dirk Witthaut - One of the best experts on this subject based on the ideXlab platform.
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dual theory of transmission line outages
IEEE Transactions on Power Systems, 2017Co-Authors: Henrik Ronellenfitsch, Debsankha Manik, Jonas Horsch, Tom Brown, Dirk WitthautAbstract:A new graph dual formalism is presented for the analysis of line outages in electricity networks. The dual formalism is based on a consideration of the flows around closed cycles in the network. After some exposition of the theory is presented, a new formula for the computation of line outage distribution factors is derived, which is not only computationally faster than existing methods, but also generalizes easily for multiple line outages and arbitrary changes to line Series Reactance. In addition, the dual formalism provides new physical insight for how the effects of line outages propagate through the network. For example, in a planar network a single-line outage can be shown to induce monotonically decreasing flow changes, which are mathematically equivalent to an electrostatic dipole field.
Riko Safaric - One of the best experts on this subject based on the ideXlab platform.
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major improvements of quartz crystal pulling sensitivity and linearity using Series Reactance
Sensors, 2009Co-Authors: Vojko Matko, Riko SafaricAbstract:This paper presents a new method of substantially improving frequency pullability and linearity using Reactance in Series with an AT fundamental crystal operated with a Series load capacitance in the range of 3 to 50 pF and frequencies in the range of 3.5 to 21 MHz. The research describes high quartz pullability and linearity by varying the load capacitance. The paper also gives impedance circuits for crystal unit (3.5 MHz) together with load capacitance and compensation Reactance. The experimental results show that the new approach using compensation method of quartz crystal connected in Series Reactance increases the frequency pulling range by ×25 to ×100 depending on the type of oscillator and compensation factor ˝k˝ in the temperature range of 10 to 40 °C.
Henrik Ronellenfitsch - One of the best experts on this subject based on the ideXlab platform.
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dual theory of transmission line outages
IEEE Transactions on Power Systems, 2017Co-Authors: Henrik Ronellenfitsch, Debsankha Manik, Jonas Horsch, Tom Brown, Dirk WitthautAbstract:A new graph dual formalism is presented for the analysis of line outages in electricity networks. The dual formalism is based on a consideration of the flows around closed cycles in the network. After some exposition of the theory is presented, a new formula for the computation of line outage distribution factors is derived, which is not only computationally faster than existing methods, but also generalizes easily for multiple line outages and arbitrary changes to line Series Reactance. In addition, the dual formalism provides new physical insight for how the effects of line outages propagate through the network. For example, in a planar network a single-line outage can be shown to induce monotonically decreasing flow changes, which are mathematically equivalent to an electrostatic dipole field.
Lennart Angquist - One of the best experts on this subject based on the ideXlab platform.
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estimation of grid parameters for the control of variable Series Reactance facts devices
2006 IEEE Power Engineering Society General Meeting, 2006Co-Authors: Nicklas Johansson, Hanspeter Nee, Lennart AngquistAbstract:For high performance control of flexible AC transmission system (FACTS) devices with controllable Reactances, a representation of the surrounding grid is essential. Using such a model, an adaptive control strategy can be developed which optimizes the control in real time as the grid parameters change. This paper proposes such a generic grid model and derives the theory of how to estimate the main parameters using measurements of the line active power response from small step Reactance changes. The estimation methods are verified using simple grid models in PSCAD simulations and more advanced grid models using SIMPOW simulations of a modified version of the CIGRE Nordic 32 grid. This work should be thought of as a foundation for developing control systems for variable Series Reactance FACTS devices.
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an adaptive model predictive approach to power oscillation damping utilizing variable Series Reactance facts devices
International Universities Power Engineering Conference, 2006Co-Authors: Nicklas Johansson, Hanspeter Nee, Lennart AngquistAbstract:This paper describes an adaptive method of controlling FACTS devices for power oscillation damping. The method is based on step-wise Series Reactance modulation. Here, a reduced model of the power system with only two rotating masses is used as a basis for the control design. The model parameters are updated using local measurements of the active power on the controlled line. An adaptive closed loop controller is developed based on the principle that it is possible to stabilize an oscillation in a power system which is characterized by one major mode of oscillation by switching a Reactance in Series with one transmission line in a small number of steps. The reduced model parameters are recomputed when new information of the system response is known making the control scheme an adaptive one. The paper also includes the derivation of a damping controller with a power flow control feature and a verification of the controllers using digital simulations of power system models of different complexities.
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Discrete Open Loop Control for Power Oscillation Damping Utilizing Variable Series Reactance Facts Devices
Proceedings of the 41st International Universities Power Engineering Conference, 2006Co-Authors: Nicklas P. Johansson, Lennart AngquistAbstract:This paper describes an open loop method of controlling FACTS devices for power oscillation damping. The method is based on step-wise Series Reactance modulation. The principle of the method is to stabilize an oscillation in a power system which is characterized by one major mode of oscillation by switching a Reactance in Series with one transmission line, thereby changing the total Reactance between the areas participating in the oscillation. In order to stabilize the system during an oscillation, the stationary voltage angle difference between the areas is changed to coincide with the present angle at a point where the speed of the lumped machine representations of the areas is nominal. This is the case at the peaks of the oscillation. To determine the required size of the Reactance step, a reduced model of the power system is used. The model parameters are continuously updated using local measurements of the active power on the Reactance controlled line. Several approaches for damping with different numbers of steps are presented and verified using digital simulations of power system models
F. Luis Pagola - One of the best experts on this subject based on the ideXlab platform.
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an eigenvalue sensitivity approach to location and controller design of controllable Series capacitors for damping power system oscillations
IEEE Transactions on Power Systems, 1997Co-Authors: Luis Rouco, F. Luis PagolaAbstract:This paper presents tools and methods to study the application of controllable Series capacitors for damping power system electromechanical oscillations. Two problems are discussed-location and controller design. The location of a controllable Series capacitor consists of determining the Series capacitor of the power system where the modulation of its Series Reactance will be more effective to damp out the modes of interest. It also involves the selection of the input variable to the controller. The basic design of the controller requires the design of the phase compensation network and the calculation of the controller gain. Small signal models of the power system and the corresponding eigenvalue sensitivities are used to address both problems.
