Petri ağları yaklaşımı ile raylı sistemler anklaşman sistemlerinin PLC ile gerçeklenmesi ve simülasyonu
PLC application of railway interlocking systems with petri net approach and simulation
Yazar: OZAN CAN BEHMERANREZAİ
Danışman: DR. ÖĞR. ÜYESİ SIDDIK MURAT YEŞİLOĞLU
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Raylı Sistemler Mühendisliği Ana Bilim Dalı / Raylı Sistemler Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Ulaşım = Transportation

Özet:
PETRİ AĞLARI YAKLAŞIMI İLE RAYLI SİSTEMLER ANKLAŞMAN SİSTEMLERİNİN PLC İLE GERÇEKLENMESİ VE SİMÜLASYONU
ÖZET
Günümüzde raylı sistemler her geçen gün hızla gelişmekte ve daha geniş alanlara yayılmaktadır. Kent içi, şehirler arası ve uluslararası ulaşımda birçok yapılmakta olan projeler ve yeni planlanan projeler bulunmaktadır. Her geçen gün kilometrelerce yeni hatlar yapılmaktadır. Raylı sistemler için yeni sistemler ve teknolojiler geliştirilmekte ve uygulanmaktadır. Raylı sistemlerin bu kadar tercih edilmesinin, popüler olmasının nedeni güvenli, dakik ve konforlu bir ulaşım sağlıyor olmasıdır. İnsan hayatına verilen önem en üst seviyededir. SIL 4 (Safety Integrity Level) seviyesinde yüksek güvenlik seviyelerine sahip bir ulaşım alt yapısına sahiptir. Güvenli ve dakik olmasını sağlayan en önemli unsuru sinyalizasyon sistemidir. Sinyalizasyon hayati önemi olan bir konudur.İnsan hayatının korunması için oldukça önemli bir sistemdir. Trenlerin çarpışması ve hemzemin geçitlerde olan çarpışmalar gibi büyük ve ölümcül kazalar sinyalizasyonla önlenebilmektedir.
Sinyalizasyon sistemleri 3 temel parçadan oluşmaktadır.Bu parçalar anklaşman sistemi, kumanda merkezi ve saha ekipmanlarıdır. Sinyalizasyon sistemlerinde, temel yönetim unsuru anklaşman sistemleridir. Anklaşman sistemlerinin görevi, Kumanda Merkezinden (KM) gelen güzergâh tanzim isteklerini değerlendirmek için ilgili sistem elemanlarından; ray devresi, sinyal ve makas gibi ekipmanlardan gerekli bilgileri toplayıp gerekli şartlar sağlanıyorsa tanzimin gerçekleşmesini eğer sağlanmıyorsa reddedilmesini sağlamaktır. Bu hayati karar verme sistemlerinin güvenli bir şekilde çalışabilmeleri için hem donanımsal hem yazılımsal olarak yüksek güvenlik seviyelerine sahip olmaları gerekmektedir. Bu nedenle donanım olarak HIMA, Siemens, Mitsubishi gibi üreticilerin raylı sistemlere özel üretilmiş ve bu konuda SIL 4 güvenlik sertifikalarına sahip güvenli PLC (programmable logic controller) gibi ürünleri mevcuttur. Yazılımın güvenli olması için ise, sezgisel tasarım yöntemleri yerine belli kriterleri belli uygulama şekilleri olan bilimsel yöntemler kullanılarak gerçeklenmesi gerekmektedir.
Bu çalışmada, raylı sistemler anklaşman sistemleri için petri ağı yaklaşımı ile HIMA PLC de SFC (Sequential Function Chart) ve FBD (Function Block Diagram) dilleri kullanılarak raylı sistem elemanları için kontrol blokları ve rota tanzim blokları gerçeklenmiştir. Ayrıca bu blokların doğruluğunu kontrol etmek için İstanbul Teknik Üniversitesi Raylı Sistemler Mühendisliği laboratuvarında yer alan anklaşmatik adlı özel bir program kullanılarak simülasyonu gerçekleştirilmiştir.

Abstract:
PLC APPLICATION OF RAILWAY INTERLOCKING SYSTEMS WITH PETRI NET APPROACH AND SIMULATION
SUMMARY
Nowadays railway systems are more and more developing and they have many new area of utilization. There are many new urban, intercity and international transport projects under construcion and in develompment phase. Miles of new railway lines are being built every day. More and more new systems and technologies are being developed and implemented for railway systems. Why should we choose railway systems for trasportation.? There are many reasons to prefer railway systems for transportation. Railway systems provide comfortable travel. Unlike air transport, it is usually possible to travel from a city centre to another. Railway systems are more economic than other transporation systems. Railway systems support sustainable economy. Railway systems are more energy efficient than other transporation systems. Also railway systems provide ecologically friendly transportaion option. Railway systems have less energy resource consumption rates than other transporation systems. Railway systems have less emission of carbon dioxide rates than other transporation systems. Railway systems have less emission of particular matter rates than other transporation systems. They are toxic for humans. Railway systems have less emission of nitrogen oxides rates than other transporation systems.Nitrogen oxides causes acidification, nutrification and summer smog. Railway systems have less emission of nonmethane hydrocarbons rates than other transporation systems. Nonmethane hydrocarbons cause summer smog. Railway systems are more punctual than other transporation systems. The most important reasons to prefer railway systems for transportation is that railway systems are safer than other transportation systems. Railway systems have less lifetime risk of dying than other transporation systems. Railway systems have less traffic accident rates than other transporation systems. Railway systems have a transportation infrastructure with high security levels.
Most important part of railway systems that provides safety and punctuality is railway signalling system. Railway signalling system is vital issue. Railway signalling systems are very important system for the protection of human life. Railway signalling is a system used to control railway traffic safely to prevent trains from colliding. Railway signalling systems are more important than road traffic systems.Road vehicles, which encounter a higher level of friction between their rubber tyres and the road surface, have much shorter braking distances than railway vehicles. Usually the deceleration rate of a train is around ten times less than of a vehicle with tyres and braking distances for railway vehicles can be ten times longer than road vehicles.As a result, Being guided by fixed rails which generate low friction, trains are uniquely susceptible to collision since they frequently operate at speeds that do not enable them to stop quickly or within the driver's sighting distance so we need signalling systems in order to ensure that the trains are moving safely on the tracks. Major and fatal accidents such as collision of trains and collisions at level crossings can be prevented by railway signalling systems.
Railway signaling systems consist of three parts. These parts are interlocking system, traffic control center and field equipments. The following field elements are commonly used in a signalling system: Points (switches), signals, Track clear / occupied detection systems (track circuits,axle counters), level crossings and Automatic train protection systems (such as balises). These elements are designed as safety critical and connected to controlling and monitoring units of local interlocking station.
Traffic control center is usually a large room where all the operation on the related railway is managed. Centralized Traffic Control is a form of railway signalling where train routing decisions for a given line are made at a centre (instead of by local signal operators). The operators that direct train traffic using centralized traffic control are called as dispatchers. In some cases a restricted area of a railway yard is required to be controlled locally from local command centre. This could be due to operation principles (permanent) or a temporary condition. Officers called signalman operate a
local command centre and arrange the traffic in that area by commanding switches and signals. When there is a problem in communication a local command centre may be required to take the authority to run the operations in a station.
Main management part of railway signallig systems is interlocking system. An interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. An interlocking is designed so that it is impossible to display a signal to proceed unless the route to be used is proven safe. All the communication between the CTC and the field passes through the interlocking system. Interlocking technically enforces two basic principles in addition to other country and area specific rules. A signal can only permit a train movement if all movable track elements are in proper position and locked (dependence between points and signals), and the elements must remain locked as long as they are being used by the train. (protection against derailment). A train can only be permitted to enter a section which is clear of other rolling stock. (protection against train collision).
Railway signalling systems must have a high level of security, both hardware and software, so that they can operate safely. They have special hardwares that product by HIMA, Siemens, Mitsubishi. PLC (programmable logic controller) with SIL 4 certificates are example of these hardwares. Safety integrity level is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function .The requirements for a given SIL are not consistent among all of the functional safety standards. Four SILs are defined, with SIL 4 the most dependable and SIL 1 the least. A SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management. The International Electrotechnical Commission's standard defines SIL using requirements grouped into two broad categories: hardware safety integrity and systematic safety integrity. A device or system must meet the requirements for both categories to achieve a given SIL. The SIL requirements for hardware safety integrity are based on a probabilistic analysis of the device. In order to achieve a given SIL, the device must meet targets for the maximum probability of dangerous failure and a minimum safe failure fraction. The concept of 'dangerous failure must be rigorously defined for the system in question, normally in the form of requirement constraints whose integrity is verified throughout system development. The actual targets required vary depending on the likelihood of a demand, the complexity of the device(s), and types of redundancy used. Probability of dangerous failure on demand and risk reduction factor of low demand operation for SIL 4 are 0.0001–0.00001 and 10000-100000. In order for the software to be safe, it must be implemented by using scientific methods with certain application criteria, rather than intuitive design methods. For example, petri nets are among these methods. A Petri net, also known as a place/transition net, is one of several mathematical modeling languages for the description of distributed systems. It is a class of discrete event dynamic system. A Petri net is a directed bipartite graph, in which the nodes represent transitions (events that may occur, represented by bars) and places (conditions, represented by circles). The directed arcs describe which places are pre- and/or postconditions for which transitions (signified by arrows).
In this thesis, control blocks and routing blocks for railway system field equipments are realized by using SFC (Sequential Function Chart) and FBD (Function Block Diagram) languages in HIMA PLC with petri network approach for rail systems interlocking systems. In order to check the accuracy of these blocks, We made simulation of these blocks with a special program called as anklaşmatik.