نتایج جستجو برای: power distribution line

تعداد نتایج: 1423270  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده مهندسی 1392

چکیده رساله/پایان نامه : تاکنون روش‏های متعددی در ارتباط با مکان یابی خطا در شبکه انتقال ارائه شده است. استفاده مستقیم از این روش‏ها در شبکه توزیع به دلایلی همچون وجود انشعاب‏های متعدد، غیر یکنواختی فیدرها (خطوط کابلی، خطوط هوایی، سطح مقطع متفاوت انشعاب ها و تنه اصلی فیدر)، نامتعادلی (عدم جابجا شدگی خطوط، بارهای تک‏فاز و سه فاز)، ثابت نبودن بار و اندازه گیری مقادیر ولتاژ و جریان فقط در ابتدای...

Journal: :international journal of environmental research 0
p. nassiri occ. hyg. dept., school of public health, tehran university of medical sciences, tehran, iran m.r. monazzam department of environmental health engineering, school of public health, tehran university of medical sciences, tehran, iran m. yunesian department of environmental health engineering, school of public health, tehran university of medical sciences, tehran, iran, center for environmental research, school of public health, tehran university of medical sciences, tehran, iran m.h. sowlat department of environmental health engineering, school of public health, tehran university of medical sciences, tehran, iran m.h. safari islamic azad university, science and research branch, tehran, iran s. momen bellah fard department of environmental science, graduate school of the environment and energy, science and research branch, islamic azad university, tehran, iran s.a. hosseini

the ever increasing rate of power consumption has led to an increase in public exposure to extremely low frequency magnetic fields (elf-mfs) and brought severe concerns about their health effects. considering previous studies and the facts about potential health effects of these fields, the present study aimed to evaluate the elf-mf flux densities from power distribution lines near hospitals in...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعت آب و برق (شهید عباسپور) - دانشکده مهندسی برق و کامپیوتر 1392

abstract according to increase in electricity consumption in one hand and power systemsreliability importance in another , fault location detection techniqueshave beenrecentlytaken to consideration. an algorithm based on collected data from both transmission line endsproposed in this thesis. in order to reducecapacitance effects of transmission line, distributed parametersof transmission line...

Journal: :international journal of environmental research 2011
p. nassiri m.r. monazzam m. yunesian m.h. sowlat m.h. safari

the ever increasing rate of power consumption has led to an increase in public exposure to extremely low frequency magnetic fields (elf-mfs) and brought severe concerns about their health effects. considering previous studies and the facts about potential health effects of these fields, the present study aimed to evaluate the elf-mf flux densities from power distribution lines near hospitals i...

 Insufficient electrical endurance of equipment and insulation failure against overvoltage is one of the most effective reasons for failure the power line. Lightening, switching or other disruptive parameters can cause line outage or distribution substation failure. There are different devices used to improve the safety, reliability, and power quality of the system. Surge arresters are one of t...

Journal: :international journal of smart electrical engineering 2012
ehsan sadeghian ramtin sadeghi

optimal capacitor placement, considering power system loss reduction, voltage profile improvement, line reactive power decrease and power factor correction, is of particular importance in power system planning and control. the distribution system operator calculates the optimal place, number and capacity of capacitors based on two major purposes: active power loss reduction and return on invest...

دشتی, رحمن, صالحی زاده, سید مهدی,

Power distribution feeders contains many laterals, sub-laterals, different number of circuit line, load taps, balanced and unbalanced load, different type of lines (cable or overhead), different cross-sections and numerous distribution transformers with different capacities. Moreover, the voltage and current are measured only at the beginning of the feeder. Thus, fault location is very complex....

Optimal capacitor placement, considering power system loss reduction, voltage profile improvement, line reactive power decrease and power factor correction, is of particular importance in power system planning and control. The distribution system operator calculates the optimal place, number and capacity of capacitors based on two major purposes: active power loss reduction and return on invest...

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