Showing papers in "Electric Power Systems Research in 2006"

TL;DR: In this article, two different control strategies are investigated and compared with each other, both with respect to the power that is needed to limit the frequency drop and the electrical and mechanical stress of the turbine.

TL;DR: In this paper, a comparison of transmission losses for different technical transmission solutions for large offshore wind farms is presented, and further analysis regarding the economical feasibility can be performed in order to determine the most economic solutions for the transmission system of an offshore wind farm.

TL;DR: The proposed coordination problem is formulated as a mixed integer nonlinear problem to take into account the discrete values for the pickup current settings and a modified particle swarm optimization (PSO) algorithm is proposed to calculate the optimal relay settings.

TL;DR: In this paper, a doubly-fed induction generator drive for variable speed wind power generation is described, where a wound rotor induction machine with back-to-back three phase power converter bridges between its rotor and the grid forms the electrical system.

TL;DR: In this article, the authors developed models of various types of wind turbine generating units (WTGU) used as distributed generation (DG) sources and demonstrated their application for steady state analysis.

TL;DR: This paper presents the development of a dynamic artificial neural network model (DAN2) for medium term electrical load forecasting (MTLF), a yearly model that uses past monthly system loads to forecast future electrical demands and a seasonal model that provides excellent fit and forecasts without reliance upon weather variables.

TL;DR: In this paper, the problem of finding the optimal topological configuration of a power transmission system is considered with the aim of providing system operators with a tool suited for congestion management, and the solution of the resulting large-scale mixed-integer programming problem is carried out both by a deterministic branch-and-bound algorithm included in the CPLEX optimization package and by a genetic algorithm.

TL;DR: In this paper, the time and temperature of the day are taken as inputs for the fuzzy logic controller and the forecasted load is the output, which is used to provide load predictions for generation scheduling, economic load dispatch and security assessment.

TL;DR: An approach to solving the unit commitment (UC) problem is presented based on a matrix real-coded genetic algorithm (MRCGA) with new repairing mechanism and window mutation and shows an improvement in the solution cost compared with the results obtained from other algorithms.

TL;DR: In this paper, the authors present a method to find the optimum maintenance policy for a component using Markov processes, the state probabilities are calculated and the optimal value of the mean time to preventive maintenance is determined by maximizing the availability of single component with respect to minimum preventive maintenance.

TL;DR: In this article, a new approach for unit commitment problem using stochastic priority list method is presented, rapidly some initial unit commitment schedules are generated by Priority List method and priority-based Stochastic Window System, then schedules are modified gradually using problem specific heuristics to fulfill constraints.

TL;DR: In this paper, a new approach for protection of transmission lines has been presented, which consists of preprocessing the fault current and voltage signal sample using hyperbolic S-transform (HS-transform) to yield the change in energy and standard deviation at the appropriate window variation.

TL;DR: In this paper, the authors utilized the newly developed evolutionary particle swarm optimization in solving the optimization problem of finding the margin from the current operating point to the maximum loading point of the system.

TL;DR: In this article, the authors used the rate of dissipation of transient energy as a measure of system damping and applied the above concept to determine the additional damping provided by a static synchronous compensator (STATCOM) and a Static Synchronous Series Compensator (SSSC).

TL;DR: In this article, a novel online diagnostic algorithm for mechanical faults of electrical machines with variable speed drive systems is presented, using Wavelet Packet Decomposition (WPD) to extract a set of feature coefficients, represented with different frequency resolutions, related to the mechanical faults.

TL;DR: In this article, a method based on nonlinear programming (NLP), namely quadratic programming, was applied to solve a test case based on a realistic cascaded hydro system with a negligible computational time requirement and is also applied to show that the role played by reservoirs in the hydro chain do not depend only on their relative position.

TL;DR: In this paper, a pattern recognition based algorithm for electric distribution high impedance fault detection is presented, where the analysis using discrete wavelet transform (DWT) yields three phase voltage and current in the low frequency range which fed to a classifier for pattern recognition.

TL;DR: This efficient and robust approach combines the advantages of the time–domain integration schemes and artificial neural network for on-line transient stability assessment of the power system and demonstrates the potential for neural network to be a part of any on- line dynamic security assessment tool.

TL;DR: In this article, a decision tool for utilities to perform the optimal generation expansion planning in a deregulated electricity market is proposed, which combines the immune algorithm (IA) and Tabu search (TS) to solve this problem.

TL;DR: In this paper, a power injection model of STATCOM for power flow and voltage stability analysis is presented, where PWM control and phase control strategies are handled, and the operating limit is enforced.

TL;DR: In this article, a method for uncertainty analysis in power system state estimation is proposed, where the uncertainty is expressed in both measurements and network parameters and the problem is formulated as a constrained non-linear optimization problem.

TL;DR: The key idea is to decompose the fault signals, de-noised using the adaptive whitening filter, into effective detailed and smoothed version using the multiresolution signal decomposition technique based on discrete wavelet transform.

TL;DR: This paper presents a new regression tree method for short-term load forecasting that is implemented according to the historical data to provide the data space partition and input variable selection.

TL;DR: In this paper, a fault location scheme for transmission systems consisting of an overhead line combined with an underground power cable is presented, which can be used on-line or off-line using the data stored in the digital fault recording apparatuses.

TL;DR: In this paper, the dynamic operation of both static synchronous compensator (STATCOM) and static synchronized series compensators (SSSC) based on a new model comprising full 48-pulse GTO voltage source converter for combined reactive power compensation and voltage stabilization of the electric grid network is investigated.

TL;DR: Techniques of applying wavelet transform into combined model for short-term load forecasting are presented and it is found that even the model works well for certain load components, it will be not suitable for other components because it cannot consider every factor.

TL;DR: In this article, a new method for transmission loss allocation in a deregulated electrical power market is presented, which is based on physical flow through transmission lines and the contributions of individual loads to the line flows are used as basis for allocating transmission losses to different loads.

TL;DR: In this article, a new method for removing the exponential component associated with electrical signals in transient states is described, which results in a low computational load as compared with other methods, which makes this new method suitable for application in real time on protection devices.

TL;DR: In this article, the authors proposed a switchable tariff for wind energy in the Spanish electricity market, which provides wind generators more flexibility in operating wind generation assets and provides option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement.

TL;DR: In this article, the point-on-wave control methodology presented in this paper has been elaborated to eliminate the inrush currents of 132/15 kV, Y/delta connected generator step-up transformers, which are switched very often in quick start, gas-turbine power stations.