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Beshr E.,Arab Academy for Science and Technology | Sharkawy R.M.,Arab Academy for Science and Technology | Abd El-Hamid A.S.,Higher Power Engineering
Proceedings of the Universities Power Engineering Conference | Year: 2015

Simulation and discrimination of several different types of insulation failure has been proposed. In the present paper, five types of insulation failures that are apt to occur in power transformers are simulated using PSIM. Input-output voltage as well as input current of each insulation failure type is monitored and hence constructing the (ΔV- Iin) locus diagram which is used for providing the state of the transformer. A discrimination process utilizing neural networks is developed to distinguish any deviations of the locus with respect to the reference one. © 2015 IEEE.

Wu B.,Higher Power Engineering | Ren Y.,Higher Power Engineering | Mu D.,Higher Power Engineering | Liu X.,China Academy of Engineering Physics | And 2 more authors.
RSC Advances | Year: 2014

An electrolyte (LiPF6-EC/PC/DEC) containing a lithium carbonate (Li2CO3) additive is used to enable the high cycling stability of a lithium cobalt oxide (LiCoO2) cathode which is charged to 4.5 V for a higher capacity. A capacity as high as 162.8 mA h g-1 (1 C) is maintained after 116 cycles, which is twice as high as the capacity of 88.5 mA h g-1 which was achieved in the Li2CO3 free instance. The interface properties of the electrode are investigated by cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. It is found that the solid electrolyte interphase (SEI) film tends to be thin and steady, and that the electrolyte decomposition is suppressed with the addition of Li2CO3. A possible mechanism is proposed according to the DFT calculation. The results indicate that the Co4+...CO3 2- coordination may decrease the oxidizability of Co4+ on the electrode surface so that the electrolyte decomposition could be suppressed. © 2014 The Royal Society of Chemistry.

Wheeler K.A.,University of Saskatchewan | Faried S.O.,University of Saskatchewan | Elsamahy M.,Higher Power Engineering
Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference | Year: 2016

This paper proposes a technique for assessment of distributed generation (DG) influences on radial distribution network fuse-recloser protection coordination and recloser pick up sensitivity. The assessment methods employ the use of sequential algorithms in conjunction with protection system models to determine synchronous machine based DG penetration levels that yield loss of non-DG system protection infrastructure adequacy. The assessment techniques are demonstrated through time-domain simulations on a test system using the PSCAD/EMTDC program. © 2016 IEEE.

Elsamahy M.,Higher Power Engineering
Proceedings - 2014 Electrical Power and Energy Conference, EPEC 2014 | Year: 2014

In this paper, extensive dynamic simulation studies are carried out to explore the performance of turbo generator loss of excitation (LOE) protection (Relay (40)) in FACTS Controller incorporated transmission networks. These studies have included the performance of LOE protection (Relay (40)) during two LOE modes, a complete LOE (due to field short circuit) and partial LOE (sudden drop of the excitation supply) during different generator loading conditions. The results of these investigations have shown that the presence of a FACTS Controller has a remarkable delay impact on the operation of the turbo generator LOE protection during LOE conditions. In addition, such a delay varies according to the generator loading and the LOE mode. Results have also shown that this delay is dramatically increased during partial LOE for all loading conditions. The dynamic simulations of a test benchmark have been conducted using the PSCAD/EMTDC software. © 2014 IEEE.

Elsamahy M.,Higher Power Engineering
Proceedings - 2014 Electrical Power and Energy Conference, EPEC 2014 | Year: 2014

In this paper investigations are carried out to explore the generalization of the adverse impact of the existing setting of the generator distance phase backup protection (Relay (21)) according to the existing standards on generator over excitation thermal capability during system disturbances. These investigations are conducted in two stages, the first includes a SMIB system incorporating a midpoint STATCOM in order to increasing its power transfer capability. The second includes a multi-generator power plant configuration. Both stages have included the performance of Relay (21), during two common system disturbances, namely a system fault and a sudden application of a large system load while the generator over excitation limiter (OEL) is in service. The results of this paper have generalized the restricting impact of the current setting of Relay (21) on the over excitation thermal capability of the generator during system disturbances. Moreover, results also have proven that in-depth stability studies are of high paramount for selecting Relay (21) setting which will allow the generator to ful fill adequate level of voltage stability during system disturbances. © 2014 IEEE.

Poryan S.Z.,Higher Power Engineering
SPEEDAM 2010 - International Symposium on Power Electronics, Electrical Drives, Automation and Motion | Year: 2010

It is necessary to plan for estimating and determining the power and energy loss to decrease the loss in distribution companies. It is not simply possible to obtain a comprehensive model and satisfy with theoretical equations, because there are different uses and special environmental conditions in different points of system. Usually, there are differences between accounted amounts of loss and determined amounts. Therefore, dependence on available models and their usage for distribution system, especially for feeders, which have low load or used in special situations causes some mistakes and incorrect results. In this paper, we evaluate accuracy of models in addition to modeling loss at 20kw network model and compare it with the evaluation and measurement method. © 2010 IEEE.

Aziz M.S.A.,Dar Al Handasah Shair and Partners | Elsamahy M.,Higher Power Engineering | Hassan M.A.M.,Cairo University | Bendary F.,Benha University
Proceedings of the 19th International Conference on Soft Computing and Measurements, SCM 2016 | Year: 2016

This paper explains the talented impact of utilizing the Adaptive Neuro Fuzzy Inference System (ANFIS) technique on enhancing the performance of the generator Loss-of-Excitation (LOE) protection. In this context, investigations are conducted on a two-hydro generator power station model under a complete Loss of Excitation (LOE) conditions and a partial Loss of Excitation (LOE) conditions. The positive sequence components of the terminal voltage magnitude, phase current magnitude and angle (|V+ve|, |I+ve| and ?I+ve) are used as inputs to the ANFIS. The obtained results are compared with those obtained from other techniques to prove the effectiveness of the proposed scheme. The time-domain simulation studies are conducted using PSCAD/EMTDC software. The obtained results are promising. © 2016 IEEE.

Hatami H.,Higher Power Engineering | Sharifian M.B.B.,University of Tabriz
India International Conference on Power Electronics, IICPE | Year: 2012

This paper is aimed to determine a general model for simulating single-phase induction machines operation and investigates the vector control of them. This proposed vector control method is based upon rotor-flux orientation concepts. Iron loss traditionally ignored in vector control schemes. If we neglect the iron loss, then it detunes the overall vector controller and results in an error in the torque control. The iron loss is modeled, in general, by a parallel resistor RM to the magnetizing inductor LM. In this paper a series R-L model that accounts for the effects of the iron loss in presence of magnetizing inductance, in the single-phase induction motor is proposed and a rotor-flux oriented control scheme of this proposed model is investigated. In this paper first the iron loss in a mathematical model of induction machines has been modeled and then applies the control methods. For this reason, the conventional method of operation (with run capacitor) and a vector controlled method for SPIM; both with equivalent element (series resistance RM) to presence of iron loss have been used. Simulation results are provided to illustrate the system operation. © 2012 IEEE.

Gargouri K.,Higher Power Engineering
International Journal of Electrical Power and Energy Systems | Year: 2012

Conventional DC motors are highly efficient and their characteristics make them suitable for use. However, their major drawback is that they need a commutator and brushes which are subject to wear and require maintenance. Today new technology is attempting to replace these components and reduce permanently these maintenance costs. When the task of commutator and brushes are replaced by solid-state switches, free maintenance motors are invented and the new motor called brushless DC motors emerged. This paper describes another motor which uses an electronic commutator substituting the mechanical commutator and brushes in the DC machine. This electronic commutator is formed with a series of static converters mounted along a bridge structure connected between the two rings and the windings of the machine. The polarities of the machine are obtained using two brushes in contact with the two rings. The control of the converter transistors is achieved by phototransistors controlled by two light sources replacing the brushes, so the sliding electrical contact between brushes and commutator was removed. © 2012 Elsevier Ltd. All rights reserved.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.96K | Year: 2014

Higher Power Engineering proposes to develop a compact and lightweight prime power plant operating from JP-8 fuel. Capacity of 155kW continuos, which exceeds the Navy duty-cycle requirements. Unit exceeds all specifications of size, weight, and fuel efficiency. The proposed unit is projected at 24"Wx24"Hx46"L, weighs 470 pounds. Design utilizes a dual-bank rotary diesel engine operating on a high efficiency hybrid thermal cycle. Engine design has only 4 moving parts and provides a thermal efficiency of>55%. Engine is coupled to a high-speed permanent-magnet generator by a planetary gearbox. The generator doubles as starter. The high-frequency AC power produced is rectified & filtered to provide 345VDC+10%. Voltage regulation is accomplished by variable speed engine operation, providing a load-following design. The design is scalable and modular, making application to other size generators simple and easy. Phase I effort includes technical studies which model the proposed configuration. This work will validate the feasibility of the proposed technical approach. The proposed Phase I Option effort leads into the Phase II task by confirming the earlier engineering design, updating market research on advanced engine designs, and procurement of some basic components for use in the Phase II testing tasking. Monthly progress reports are proposed.

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