The main purpose of this research is to allow doubly fed induction generator (DFIG) to participate effectively in interconnected power systems load frequency control via improved harmony algorithm (IHA). In order to tune the parameters of the PI controllers without considering the complexity associated with the modeling of the power system, the corresponding optimization problem is formulated in terms of an objective function, which represents the norm of the closed-loop area control error signal. A three-area interconnected power system subjected to major disturbances is investigated to verify the effectiveness of the developed algorithm of DFIG wind turbine participation in load frequency regulation. Time domain simulation results are presented to prove the improved performance of the developed IHA-based controller compared with genetic algorithm, simulated annealing, and a conventional integral controller. The results show that the developed IHA controller has better behavior over other algorithms in terms of settling times and other indices

The recent seismic events have led to concerns on safety and vulnerability of Reinforced Concrete Moment Resisting Frame "RC-MRF" buildings. The seismic design demands are greatly dependent on the computational tools, the inherent assumptions and approximations introduced in the modeling process. Thus, it is essential to assess the relative importance of implementing different modeling approaches and investigate the computed response sensitivity to the corresponding modeling assumptions. Many parameters and assumptions are to be justified for generation effective and accurate structural models of RC-MRF buildings to simulate the lateral response and evaluate seismic design demands. So, the present study aims to develop reliable finite element model through many refinements in modeling the various structural components. The effect of finite element modeling assumptions, analysis methods and code provisions on seismic response demands for the structural design of RC-MRF buildings are investigated. where, a series of three-dimensional finite element models were created to study various approaches to quantitatively improve the accuracy of FE models of symmetric buildings located in active seismic zones. It is shown from results of the comparative analyses that the use of a calibrated frame model which was made up of line elements featuring rigid offsets manages to provide estimates that match best with estimates obtained from a much more rigorous modeling approach involving the use of shell elements.

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame “RC-MRF” buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element (FE) models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

This article describes a new method for dynamic simulation of multi-converter systems.This simulation is based on symmetrical components in time domain analysis and general representation of converter transformers to meet Y/, Y/Y, and Y/Z connections. The simulation is suitable for harmonic analysis of balanced and unbalanced AC voltages. The computed currents and voltages agreed reasonably with those measured and reported in the literature for the characteristic and non-characteristic harmonics.

This article describes a new method for dynamic simulation of multi-converter systems.This simulation is based on symmetrical components in time domain analysis and general representation of converter transformers to meet Y/, Y/Y, and Y/Z connections. The simulation is suitable for harmonic analysis of balanced and unbalanced AC voltages. The computed currents and voltages agreed reasonably with those measured and reported in the literature for the characteristic and non-characteristic harmonics.

Locating and classifying partial discharge due to sharp-edges, polluted insulators and loose-contacts in power systems significantly reduce the outage time, impending failure, equipment damage and supply interruption. In this paper, based on wavelet packets features of their modulated ultrasound emissions, an efficient novel scheme for neural network recognition of partial discharges is proposed. The employed preprocessing, wavelet features and near-optimally sized network led to successful classification up to 100%, particularly when longer duration signals are processed.

Locating and classifying partial discharge due to sharp-edges, polluted insulators and loose-contacts in power systems significantly reduce the outage time, impending failure, equipment damage and supply interruption. In this paper, based on wavelet packets features of their modulated ultrasound emissions, an efficient novel scheme for neural network recognition of partial discharges is proposed. The employed preprocessing, wavelet features and near-optimally sized network led to successful classification up to 100%, particularly when longer duration signals are processed.

Saturated profiles of the field intensity, current density and charge density at the ground surface and underneath monopolar HVDC transmission lines are calculated by using simple expressions. These expressions give the relation between the saturated values and the length of the field lines emanating from or terminating at the energized conductor. The calculated values are compared with those previously calculated and measured experimentally. Both absolute and normalized saturated corona profiles at the ground surface and underneath HVDC monopolar transmission lines are calculated using simple expressions. Relations between the saturated values at any position on the ground surface and the length of the field line emanating from or terminating at the conductor are given. These relationships are used for both outdoor and indoor models.

This paper is aimed at detecting the weak points in the distribution system of MEEC, "Middle Egypt Electricity Company". These include loose connections, polluted insulators and micro-roughness on line conductors and insulator hardware. The detection methodology is based on measuring ultrasound emissions from these weak points to warn against impending failures and subsequent supply interruptions. Laboratory testing made it possible to discriminate between loose-connection arcing, polluted-insulator "baby arcs" and sharp-edge corona according to the sound pattern. However, there can be occasions where sound pattern may prove confusing in discrimination between baby arcs and loose-connection arcing. In this case, recording of acoustic signals was found to be a useful tool for such discrimination.

The solution of monopolar corona equation already reported in literature is extended for bundle conductors using a modified iterative procedure to estimate the corona current contributed by each subconductor of the bundle. The solution is based on underlying assumptions, some of which are waived in the present calculations. The variation of ion mobility with its lifetime as well as the change of the corona onset voltage from point to point on each subconductor are taken into account for the first time. The calculated corona currents from each subconductor are compared with those measured experimentally for a laboratory model.