Rijit katener sisteminin modellenerek yolcu üzerindeki elektrik ve manyetik alan etkisinin incelenmesi
Modelling of the rigid catenary system and electrical and magnetics field effects on passengers
Yazar: SALİH SARISAKAL
Danışman: PROF. DR. ÖZCAN KALENDERLİ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Elektrik Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Elektrik ve Elektronik Mühendisliği = Electrical and Electronics Engineering

Özet:
Gelişen teknolojiyle beraber raylı sistemlere gösterilen ilgi de artmıştır. Şehirlerin havasını değiştiren geliştiren raylı sistem çözümleri ulaşımı kolaylaştırmış, çevreye dost bir ulaşım şeklini almıştır. Bu tezde raylı sistemlerin elektriklendirilmesinde kullanılan yöntemler tanıtılmış ve bunlardan birisi olan rijit katener sistemi modellenerek, sonlu elemanlar yöntemiyle manyetik ve elektriksel alan analizleri yapılmıştır. Birinci bölümde demiryolu elektrifikasyonun tarihçesi anlatılmıştır. İkinci bölümde elektriklendirmede kullanılan iki temel yaklaşım olan AC ve DC besleme tanıtılmış, bu yaklaşımların ayrım ve benzerliklerinden faydalanarak karşılaştırmalar yapılmıştır. Örnek olarak kullanımda olan bazı sistemlerin özellikleri verilmiştir. DC ve AC besleme sistemlerinin yapıları hakkında bilgi verilmiştir. Avrupada kullanılan elektrifikasyon sistemleri tablo halinde verilmiştir. Geri kazanımlı frenleme tanıtılmış kısaca yapısı verilmiştir. İkinci bölümün sonlarında havai hatlarda kullanılan kablolardan söz edilmiş bunların görevleri tanıtılmıştır. Üçüncü kısımda elektriğin araca alınmasında kullanılan pantografın tarihçesi anlatılmış ve pantografı oluşturan parçaların isimleri ve görevlerinden bahsedilmiştir. Üçüncü bölümün sonunda elektrikli otobüslerde elektriğin alınmasını sağlayan tramvay kolundan söz edilmiş yapısı, tarihçesi ve işleyişiyle ilgili bilgi verilmiştir. Dördüncü kısımda, özellikle metro sistemlerinin beslemesinde kullanılan üçüncü ray teknolojisi tanıtılmış; bu sistemin kurulması, bakımı ve işletilmesine ilişkin bilgiler verilmiştir. Beşinci kısımda rijit katener sistemi ve onu oluşturan yapılar tanıtılmış, rijit katener sisteminin diğer besleme sistemlerinden farklılıkları, üstünlükleri karşılaştırmalı olarak verilmiştir. Kullanımda olan bir sistemin yapısına ilişkin bilgiler verilmiştir. Altıncı bölümün ilk kısmında örnek olarak kullanımda olan bir sistemin modellenmesine ilişkin kullanılacak bilgiler verilmiş. Öncelikle modellemenin yapılacağı program ve onun özellikleri tanıtılmıştır. Öncelikle profil çevresindeki elektriksel ve manyetik büyüklükler incelenmiştir. Daha sonraysa geniş çerçevede, rijit katener sisteminin kullanıldığı 750V, 1500V, 3000V DC gerilimler için örnek analizler yapılmış ve elektriksel ve manyetik büyüklüklerin değişimi ifade edilmiştir. Daha sonra ise tezin asıl konusunu oluşturan metro istasyonunda tren bekleyen bir yolcunun, tren peronda yokken ve tren geldiği zaman maruz kalabileceği akımlar, simux programında oluşturulan Kadıköy-Kartal hattında iki dakika işletme aralığında çalışan bir trene ilişkin, trenin hat boyunca çektiği maksimum akımlar ve bu akımların bir dakikalık ortalamalar için rms değerleri belirlenmiş ve bu değerler kullanılarak elektrostatik ve manyetik analizler yapılmış. Yolcunun vücudunun maruz kalacağı elektrik alan şiddeti, manyetik alan şiddeti, manyetik akı yoğunluğu değerleri belirlenmiştir. Son bölüm olan yedinci kısımda ise statik alanlar için belirlenmiş referans değerlere göre, benzetim sonucunda ortaya çıkan değerlerin etkisi değerlendirilmiş ve insan sağlığına etkisi tartışılmıştır.

Abstract:
In our country, the increase in the investments and interest in rail transit systems comes with a developing technology. Railway system solutions are friendship to environment and makes transportation easier for years. In this thesis, electrification systems for railways were examined and one of them rigid catenary system was modeled and made electrostatic and magneto static analysis with finite element method. 
At first chapter, the history of railway electrification was explained. This term occurred at the late of 19th century. The first electrical locomotive was made in 1837. Many countries of Europe have been met with electrification from 1923 to 1960. 
At second chapter, Alternative and direct current feeding systems were explained. Feeding systems based alternative current are used commonly for long way transportation. DC feeding systems are used for short distance transportation. An example dc feeding systems' structure was given and explained how to work and then was mentioned power regeneration how to work. Electrification classification in Europe as a table was given. Towards late of this chapter, was expressed to be used cables properties and their roles on an overhead catenary line. 
In third chapter pantographs'stracture, components and specifications were explained. The pantograph is a device used in order to collect current from overhead lines. Nowadays the most common type of pantograph is named Z shaped (half pantograph). Pantograph easily can be adapted for various heights. 
In the final section of third chapter trolley pole and its working were mentioned. Especially modern trolley poles are used on the roof of electrical trolleybus and nowadays have still been used. 
In fourth chapter, third rail electrification method was introduced. Third rail provides electrical energy to a railway train through a continuous rigid conductor. Mostly third rail systems supply direct current electricity. Trains have equipments to provide energy named shoes that make contact with conductor rail. The structure of these shoes was shown and explained.
In fifth chapter, overhead rigid conductor system was introduced. An overhead rigid conductor is formed by an aluminum alloy profile and copper wire attached it. Firstly, some terms interested in rigid catenary system were explained. Then components of this structure and advantages comparing the others electrification methods are introduced. An example used system was explained with structual specifications. 
In sixth chapter, firstly finite element method and its basic approaching were explained and then femm programme used in this thesis for analysis was introduced. Theorical basics of the finite element method with formulas were expressed. 
How to use Femm programme was introduced. Firstly, an example magnetic problem was modeled on the programme.
Aluminum alloy and copper wire were modeled with them width length and then its electrical conductivity described measure in Megasiemens over meter. The model was scratched measure in millimeter. The cross sectional area of copper wire is 150 square millimeters. Nominal current goes from wire is 1200 ampers. Frequency O Hz was taken seeing that DC feeding was applied. Depth of the problem is 11 meters. Outside and inside of aluminum alloy includes air. Aluminum alloy and copper wire were described as a series circuit. Together with these values, magnetic analysis was made and found results from the points of current density, magnetic flux density and field intensity. 
On the next section of this chapter was taken width is 3 meters, length is 4,7 meters. Ground level was described as zero voltage. For electrostatic analysis, the boundary conditions were described with voltage information. Respectively for 750 V, 1000 V, 1500 V and 3000 V DC voltages, analyses were made and found distribution of voltage, electrical flux density and field intensity. The results of analyses were given with the graphics. In the next section, a passenger has been waited on the platform in the height of 1 meter from level of rails at the underground stations. 
The height of passenger is 1,86 meters. In this section, two different conditions were exanimated. First of them, when train has been not come to the station yet. Secondly when train came to the station. Due to simux railway simulation program, Kadıköy-Kartal line was modeled and given some information about drawn maximum and rms currents for a minute from this line. Train which includes eight rolling stocks, works at two minutes operating range. 
For different parts of body, the magnetic permeability of human body was taken between 0,99999096 and 0,99999221 being too close to 1. Then along the all line, the locations of stations were determined. In the light of this information, the moment that train takes passengers, maximum currents drawn from line were determined. By use of this information that a passenger is exposed to how much magnetic flux density and field intensity were determined. All line is 21 kilometers and there are 16 stations on the line. As return conductor, a third rail in parallel with other two carrier rails was drawn. The passenger has been waited on the concrete platform. The carrier rails were made of steel. Third rail was made of copper and ceramic isolator was founded at its below. It was supposed that were at same values but reverses direction of drawn currents from overhead rigid conductor and return conductor. The carrier rails' gauge is 1,3 meters. 
The biggest value of the maximum currents was measured in Cevizli station. For each station, repeatedly analyses were made and found magnetic flux density and field intensity values at head and foot regions. Currents drawn by trains change depending on geometry of the line. The reason of current drawn at values less is giving back current to mutual dc bus bar system. Also in these systems, regenerative power acquired during the breaking is transferred to line. Others trains near in the related region can use transferred back currents. For a better consideration in next section, using rms values of currents, analyses had been repeated. Firstly, for this purpose, rms values of currents in the region at a minute had been determined by the aid of simux programme. The biggest value of rms currents is in Cevizli station and then second biggest value had been seen in Ayrılıkcesme station. According to currents, exposed magnetic flux densitys'gap is between 100 and 250 T values.
In the next section, according to second situation: when train came to the station, using the same current values. Analyses have been repeated. It has been researched whether was dangerous of results for human health. The properties of this model are same such as previous one. Differently this model includes a train which its made of pure iron and was modeled such as a cage which its inside was air. 
Trains' height is 3,5 meters and its weight is 1,5 meters. Aluminum alloy and copper wire are as a series circuit and current of this circuit changes in accordance with stations. Firstly for maximum currents and then for rms values of currents in a minute period analyses had been made. Results had given as a table. 
When we evaluated these results, at the head region was the nearest part of the body to catenary line, magnetic flux density and field intensity have increased further by comparison with previous condition (no train). At foot region was the longest part of the body to rigid line, magnetic flux density and field intensity have decreased by comparison with previous condition (no train). The reason is that train makes a shielding. Iron is a powerful ferromagnetic material and because of this reason, it has been increased flux density and field intensity values for the upper part of body in the region near to catenary line. 
In the next section, electrostatics analyses were made for different situations (there is train in the station and no train in the station). According to standards, for 1500 Volts nominal voltage, lowest permanent voltage is 1000 Volts, highest permanent voltage is 1800 Volts. Respectively, it was supposed to these values were on the bus bar and the return conductors' voltages were 60 Volts for 1500 Volts on the rigid bus, 100 Volts for 1800 Volts on the rigid bus, 40 Volts for 1000 Volts on the rigid bus. In this model the return conductors' below exists porcelain isolator. The carrier rails and waiting platform were grounded. After analyses, it was determined between head and foot, distribution of voltage, electrical flux density and field intensity values. These results were given as graphics and tables. When we have evaluated these results, if voltage increase, electrical field intensity increase, too. For 1800 Volts on the rigid bus, the highest field intensity value is near to 562,2 V/m.
In the next section, there is a train in the station and others modeling features are same as previous one. The biggest value of field intensity is 47 V/m for 1800 Volts highest permanent voltage.
In seventh section, static fields had described and its properties mentioned. Natural origin and artificial fields and non-ionizing fields had mentioned. ICNIRP has published some standards about static fields. If there is a train in the station, magnetic flux density on the body is near 497 µT, if there is no train, flux density on the body is near 362 µT. These values are below of standards published by ICNIRP and Council of European Union. However, these values can be dangerous for humans who are wearing implanted ferromagnetic and electronic medical devices sensitive to magnetic fields.
Especially for a better assessment of the effects of DC railway systems to human health must be done more studies. Technical personals work in railway sector should be well trained. Magnetic fields measurement and controls should be done effectively. In our world developing in same speed with technology, we should protect the public health.