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| Articles
by
H. Shareef |
Total Records (
4 ) for
H. Shareef |
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R. Sirjani
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A. Mohamed
and
H. Shareef
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Capacitors in power systems are generally used to supply reactive power for the purpose of loss minimization and voltage profile improvement. The appropriate placement of capacitors is also important so as to ensure that system power loss and total capacitor costs can be reduced. The main objective of this study is to determine optimal placement of capacitors so as to reduce the power loss and improve the voltage profile. Presently, the capacitor placement problem is widely solved by using heuristic optimization methods. In this study, the Harmony Search (HS) algorithm which is a relatively new meta-heuristic method is applied to solve the optimal capacitor placement problem. An effective and simple power flow method based on the backward/forward sweep power flow is also employed for the power flow simulations. The performance of the proposed HS algorithm is validated on the 9 and 34-bus radial distribution systems and the obtained capacitor placement results using HS are compared with other optimization methods. |
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H. Zayandehroodi
,
A. Mohamed
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H. Shareef
and
M. Mohammadjafari
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High penetration of Distributed Generation (DG) units will have unfavorable impacts on the traditional fault location methods because the distribution system is no longer radial in nature and is not supplied by a single main power source. This study presents an automated fault location method using Radial Basis Function Neural Network (RBFNN) for a distribution system with DG units. In the proposed method, the fault type is determined first by normalizing the fault currents of the main source. Then to determine the fault location, two RBFNNs have been developed for various fault types. The first RBFNN is used for detraining fault distance from each source and the second RBFNN is used for identifying the exact faulty line. Several case studies have been used to verify the accuracy of the method. Furthermore, the results of RBFNN and the conventional Multi Layer Perception Neural Network (MLPNN) are also compared. The results showed that the proposed method can accurately determine the location of faults in a distribution system with several DG units. |
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M. Farhoodnea
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A. Mohamed
and
H. Shareef
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This study presents a method for determining the contribution of harmonic distortions generated by utility and customer at the Point of Common Coupling (PCC) in power distribution systems. The method is known as the RLC method as the customer load is modeled with RLC components using measured voltage and current at the PCC and the system is represented by a Norton equivalent circuit. The contributions of harmonic voltage and current distortions from utility and customer sides of the system are derived by estimating the customer impedance and then calculating the harmonic currents at customer and utility sides. Several case studies have been made to verify the accuracy of the proposed RLC method in determining the contribution of utility and customer harmonic distortions by making a comparison with the IEEE1459–2000 standard based method. Results showed that the proposed RLC method can accurately determine the harmonic contributions of utility and customer for measurements made at the PCC. |
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E. Tayrab
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A.K. Ashmaig
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H. Shareef
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S.B. Bedawi
and
I.E. Aradaib
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Schistosomaisis is a chronic debilitating infection of humans and animals and hence the disease is of a public health importance. In the present study, a male farmer from Barakat of the Gezera State, a schistosomiasis endemic area in Central Sudan was admitted to the Reproductive Health Care Center (RHCC) in Khartoum, Sudan. The patient complains of history of primary infertility for 18 years with complain of painful ejaculation, he had several semen analysis, all showed a picture of azoospermia and no sperm was detected neither in the sample nor in the pellet after centrifugation. On genital examination both testes are of average size, enlargement of epidedimis on both sides vasa differences were present in both sides. Semen analysis showed that the semen was turbid, infilterated with inflammatory cells. Hence, the patient was diagnosed with infertility due to azoospermia. In addition, numerous Schistosoma mansoni eggs were detected in the semen pellet. This study suggested that physician should consider schistosoma mansoni as a cause of male infertility in schistosomiasis endemic areas. |
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