| 1. |
- Billinton, R., et al.
(författare)
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Bibliography on the application of probability methods in power system reliability evaluation 1996-1999
- 2001
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 16:4, s. 595-602
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a bibliography of papers on the subject of power system reliability evaluation. Papers in such areas as: probabilistic load flow, probabilistic production costing, probabilistic transient stability evaluation etc. have not been included except where they specifically address power system reliability evaluation. It includes material which has been made available since the publication of six previous papers Bibliography on the Application of Probability Methods in Power System Reliability Evaluation, IEEE Transactions on Power Apparatus and Systems PAS-91, 1972, pp. 649-660, Pas-97, 1978, pp. 2235-2242, PAS-103, 1984, pp. 275-282, IEEE Transactions on Power Systems, Vol. 3, no. 4, Nov. 1988, pp. 1555-1564, Vol. 9, No. 1, Feb. 1994, pp. 41-49, and Vol. 14, no. 1, Feb. 1999, pp. 51-57.
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| 2. |
- Bompard, E., et al.
(författare)
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Congestion-management schemes : A comparative analysis under a unified framework
- 2003
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 18:1, s. 346-352
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Tidskriftsartikel (refereegranskat)abstract
- The restructuring of the electricity industry has spawned the introduction of new independent grid operators (IGOs), typically called transmission system operators (TSOs); independent system operator (ISOs); or regional transmission organizations (RTOs), in various parts of the world. An important task of an IGO is congestion management (CM) and pricing. This activity has significant economic implications on every. market participant in the IGO's region. The paper briefly reviews the CM schemes and the associated pricing mechanism used by the IGOs in five representative schemes. These were selected to illustrate the various CM approaches in use: England and Wales, Norway, Sweden, PJM, and California. We develop a unified framework for the mathematical representation of the market dispatch and redispatch problems that the IGO must solve in CM in these various jurisdictions. We use this unified framework to develop meaningful metrics to compare the various CM approaches so as to assess their efficiency and the effectiveness of the market signals provided to the market participants. We compare, using a small test system, side by side, the performance of these schemes.
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| 3. |
- Ghandhari, Mehrdad, et al.
(författare)
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Control Lyapunov functions for Controllable Series Devices
- 2001
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 16:4, s. 689-694
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Tidskriftsartikel (refereegranskat)abstract
- Controllable Series Devices (CSD), i.e., series-connected Flexible AC Transmission Systems (FACTS) devices, such as Unified Power Controller (UPFC), Controllable Series Capacitor (CSC) and Quadrature Boosting Transformer (QBT) with a suitable control scheme can improve transient stability and help to damp electromechanical oscillations. For these devices, a general model, which is referred to as injection model, is used. This model is valid for load flow and angle stability analysis and is helpful for understanding the impact of the CSD on power system stability. Also, based on Lyapunov theory a control strategy for damping of electromechanical power oscillations in a multi-machine power system Is derived. Lyapunov theory deals with dynamical systems without inputs. For this reason, it has traditionally been applied only to closed-loop control systems, that is, systems for which the input has been eliminated through the substitution of a predetermined feedback control. However, in this paper, we use Lyapunov function candidates in feedback design itself by making the l.yapunov derivative negative when choosing the control. This control strategy is called Control Lyapunov Function (CLF) for systems with control inputs.
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| 4. |
- Knazkins, Valerijs, et al.
(författare)
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On the parameter estimation and modeling of aggregate power system loads
- 2004
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 19:2, s. 1023-1031
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Tidskriftsartikel (refereegranskat)abstract
- This paper addressed some theoretical and practical issues relevant to the problem of Power system load modeling and identification. Two identification techniques are developed in the theoretical framework of stochastic system identification. The identification techniques presented in this paper belong to the family of output error models; both techniques are based on well-established equations describing load recovery mechanisms having a commonly recognized physical appeal. Numerical experiments with artificially created data were first performed on the proposed techniques and the estimates obtained proved to be asymptotically unbiased and achieved the corresponding Cramer-Rao lower bound. The proposed techniques were then tested using actual field measurements taken at a paper mill, and the corresponding results were used to validate a commonly used aggregate load model. The results reported in this paper indicate that the existing load models satisfactorily describe the actual behavior of the physical load and can be reliably estimated using the identification techniques presented herein.
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| 5. |
- Larsson, Mats
(författare)
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ObjectStab - An educational tool for power system stability studies
- 2004
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Ingår i: IEEE Transactions on Power Systems. - 0885-8950. ; 19:1, s. 56-63
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, the simulation of transient and voltage stability in power systems has been constrained to domain-specific tools such as Simpow, PSS/E, ETMSP, and EuroStag. While being efficient and thereby able to simulate large systems, their component models are often encapsulated and difficult or impossible to examine and modify. Also, these simulators often require substantial training and are therefore not ideal for normal classroom use. For academic and educational use, it is more important that the component modeling be transparent and flexible, and that students quickly get started with their simulations. This paper describes a freely available power system library called ObjectStab intended for power system stability simulations written in Modelica, a general-purpose object-oriented modeling language. All component models are transparent and can easily be modified or extended. Power system topology and parameter data are entered in one-line diagram form using a graphical editor. The component library has been validated, using comparative simulations with EuroStag.
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| 6. |
- Navarro, I R, et al.
(författare)
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Influence of normalization in dynamic reactive load models
- 2003
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Ingår i: IEEE Transactions on Power Systems. - 0885-8950. ; 18:2, s. 972-973
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Tidskriftsartikel (refereegranskat)abstract
- As an extension of previous studies on modeling and identification of nonlinear dynamic load models, this letter describes the influence of the normalization in dynamic reactive load models. Using measured data from normal operation, it is shown that the reactive power level, which has previously used as normalization factor is inappropriate. If instead apparent power level is used, the variability in the parameters that describe the, reactive load response is drastically reduced.
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| 7. |
- Terzija, V, et al.
(författare)
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Synchronous and asynchronous generators frequency and harmonics behavior after a sudden load rejection
- 2003
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Ingår i: IEEE Transactions on Power Systems. - 0885-8950. ; 18:2, s. 730-736
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes load rejection tests, done at two hydro power plants in Sweden, one equipped with synchronous and the other with asynchronous generators. During the tests voltages and currents are digitized, recorded and thereafter off-line processed. By this, in the processing of distorted and fast parameter-varying voltages and currents the powerful estimation technique, the Newton type algorithm, is applied. It was intended to investigate the frequency changes and the distortions of the measured signals. The transient processes at both generators are compared. In particular, the frequency changes after the instance of load rejection are investigated and discussed from the signal processing and physical nature point of view.
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