نتایج جستجو برای: phase to ground faults

تعداد نتایج: 10815997  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

Symmetrical nature of mean of electrical signals during normal operating conditions is used in the fault detection task for dependable, robust, and simple fault detector implementation is presented in this work. Every fourth cycle of the instantaneous current signal, the mean is computed and carried into the next cycle to discover nonlinearities in the signal. A fault detection task is complete...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

2003
Ibrahim M. El-Amin M. H. Al-Mubarak

High impedance faults (HIF) on electric power distribution feeders are of a great concern to electric power utilities. These faults often occur when a bare conductor breaks and falls to ground through a high impedance current path [1]. Some HIFs draw sufficient current to be cleared by overcurrent protection, however, many HIFs draw only small amount of current, which makes them difficult to de...

2015
Tarun Chopra

Transmission lines forms the backbone of the transmission and distribution networks which powers the nation. No modern society can imagine its existence without power supplies which runs everything ranging from consumer electronics to bullet trains. Electrical power systems suffer from unexpected failures due to various random causes. Unpredicted faults that occur in power systems are required ...

Journal: :فیزیک زمین و فضا 0
بیژن شورچه دانشجوی دکترای ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران مهدی معتق استادیار، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری و مقابله با سوانح طبیعی، پردیس دانشکده های فنی، دانشگاه تهران، ایران محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری و مقابله با سوانح طبیعی، پردیس دانشکده های فنی، دانشگاه تهران، ایران

many earthquakes occur in iran every year and some of these earthquakes cause loss of life and property. consequently earthquake is one of challenging topics not only in iran but also in other active tectonic regions in the world. investigating the mechanism of earthquake as a natural disaster is the first and important step. to study earthquakes, different information such as geometry and beha...

Journal: :زمین شناسی اقتصادی 0
مصطفی دهقانی احمدآباد سید حسین مجتهدزاده علیرضا یاراحمدی بافقی

determining the promising area for ore deposits is one of the most important steps of prospecting in regional scales. there are many different methods for identifying these areas including geochemical and geophysical methods, remote sensing and sophisticated statistical methods. based on the theory of spatial relations between the dispersion pattern of ore deposits and metallogenic provinces, m...

Journal: :the modares journal of electrical engineering 2003
mohammad mahdi homayounpour darush hakimzadeh

rotating machines in particular induction electrical machines are important industry instruments. in manufacturing, electrical motors are exposed to many damages, and this causes stators and rotors not to work correctly. in this paper we addressed modal analysis and an intelligent method to detect motor load condition and also the stator faults such as turn-to-turn and coil-to-coil faults using...

2009
B. Ravindhranath Reddy Vijay Kumar Venkata Raju

Power transmission and distribution lines are the vital links that achieve the essential continuity of service of electrical power to the end users. Transmission lines connect the generating stations and load centers. As the generating stations are far away from the load centers they run over hundreds of kilometers. Hence, the chances of fault occurring in transmission lines are very high. Sinc...

1997

259 Lines are protected by overcurrent-, distance-, or pilot-relaying equipment, depending on the requirements. Overcurrent relaying is the simplest and cheapest, the most difficult to apply, and the quickest to need readjustment or even replacement as a system changes. It is generally used for phaseand ground-fault protection on station-service and distribution circuits in electric utility and...

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