Sarıyer-çayırbaşı Karayolu Tüneli Elektrik Sistemi Harmonik Analizi Ve Filtre Tasarımı

Abstract

Genel olarak güç sistemleri incelendiğinde, günümüzdeki teknolojik gelişmelere paralel olarak sisteme entegre olan nonlineer elemanlar aracılığıyla harmoniğin etkileri elektrik enerjisi üretim, iletim ve dağıtımında artarak devam etmektedir. İster nonlineer yük ister nonlineer kaynak olsun, sistem içerisinde doğrusal olmayan elemanın varlığı, elemanın karakteristiğine bağlı olarak akım veya gerilim harmoniklerine sebep olmaktadır. Elektrik mühendisliğinin temeli, verimlilik esasına dayanır ve bu sistem kararlılığı ile doğru orantılıdır. Sistemin kararlı bir Şekilde çalışabilmesi için bir durum da, elektrik sisteminin kabul edilebilir sınırlar içerisinde ve nominal çalışma değerlerinde olmasıdır. İlgili değerleri önemli ölçüde etkileyen ve rastlantısal sürece zemin hazırlayan harmonikler, işletme şartlarında meydana gelen durumlar incelenerek hazırlanan gerek ulusal gerek uluslararası standart ve yönetmeliklerle sınırlandırılmıştır. Bahse konu limitlere uyulmaması beraberinde cezai yaptırımları da getirmektedir. Sonuçta hem idari boyutuyla hem de teknik anlamda harmoniklerin elektrik güç sisteminden elimine edilmesi gereklidir. Bu kapsamda değerlendirildiğinde, harmonik filtre tasarımı kendi içinde opsiyonları olsa da kararlılık için zorunlu ihtiyaç haline gelmiştir. Bu amaçla, 2012 yılında resmi açılışı yapılarak işletmeye alınan Sarıyer-Çayırbaşı Karayolu Tünelinin elektrik sistemi harmonik analizi yönünden incelenmiştir. Elektrik güç sistemine ilişkin veriler ilgili enerji analizörlerinden elde edilmiş ve ayrıca tünele ait tüm elektromekanik sistemler SCADA sisteminden de incelenmiştir. Ölçüm değerlerinden varılan sonuca göre, düşük mertebeli harmonikler sistemde yer aldığından tek veya çift ayarlı pasif filtre kullanılması uygun görülerek tesise özel pasif filtrenin MATLAB simülasyonu ile tasarımı ve teorik uygulaması yapılmıştır. Tünele ilişkin elektrik sistemi, pasif filtre öncesi ve pasif filtre sonrası durumları karşılaştırılarak son durumun ilgili yönetmeliklere ve standartlara uygunluğu irdelenmiştir. İkinci olarak, tünele ilişkin tüm sistemlerin tek bir yerden kontrol edildiği SCADA sisteminin işletmeye getirdiği kolaylıklar ve özellikleri incelenmiŞtir. Özellikle tünel elektromekanik sistemlerinin tek bir yerden izleme, kontrol, veri toplama ve veri saklanması iŞlemlerinin yapılabilmesi tünel iŞletmesinde oldukça esnek bir çalıŞmaya zemin hazırlamaktadır. Tüm sistemlerin SCADA ile tam entegre çalıŞmasının, özellikle ilgili kontrol bölgesi ile kontrol edilen cihazlar arasındaki mesafenin büyük olduğu tünel iŞletmesinde hem fiziki anlamda enerji ve zaman kaybını azalttığı, hem de iŞletme anlamında pratik ve esnekliği sağladığı görülmüŞtür. Bu sayede personel ihtiyacının ve ilgili personellerin doğru zamanda ve doğru mekanda yer alabilmesi, personellerin etkin kullanımı gibi faydaları da mümkün kıldığı görülmüŞtür.

Generally, when we search the electrical power system, harmonics on electrical systems are spreading and rising up because of growing usage of nonlinear loads. Harmonics effect not only power generation, transmission but also power distribution systems. Because, if the electrical system include either nonlinear source or nonlinear load, it causes voltage or current harmonics with respect to components characteristics. Firstly, one of the main topics of electrical engineering is efficiency. Likewise, it has a direct corelation with the power system stability. For the purpose of the power system stability, system components should run on the conditon that nominal process and acceptable workout interval. Harmonics which effect related values tremendously and manifest a stochastic process, limited with respect to related national and international standards. Exceeding standard limits comes with official penalties. As a result, harmonics should be eliminated at acceptable limits from the electrical system not only for administrative obligation but also for technical necessity. Secondly, harmonic filter design is a necessity for power system stability even if it has lots of options. For this purpose, Electrical system of Sarıyer-Çayırbaşı Road Tunnel which was opened at June 2012 is researched with respect to harmonic analysis fundamentals. Measurement values of the electrical power system are received from related energy analyzer. Also, whole tunnel electromechanical systems are researched from SCADA system. According to measurement values, single tuned passive harmonic filter is designed theoretically and simulated with MATLAB simulation program. As a result, comparison with passive filter included system and without filter is done and substantiated availability of the filter with respect to related national regulations and international standards. Moreover, whole existing tunnel electromechanical systems on Sarıyer – Çayırbaşı tunnel were explained, briefly. Especially, tunnel lighting and control system is the main system and have most continous operation with respect to other tunnel electromechanical systems. Technically, A PLC or a special lighting controller gets related and sensed values and it compares them to arrange the luminaries triggering according to required light levels. This system works based on CIE 88 standards to make the lighting level comfortable for the drivers. According to environmental lighting level at the outside the tubes, 5 lighting zones are dynamically arranged. It is accepted to apply 5 switching steps as 100%; 75%; 50%; 25%; and night time in Sarıyer - Çayırbaşı tunnel. The lighting luminaires can be installed in single roe or as two rows along side the tunnel. In single row application, preliminary calculation results show that uniformity is not as good as two rows application. Furthermore, maintenance of the luminaires is more difficult in single row application, since two of the lanes whole tunnel section must be closed to traffic during the maintenance. As a result it is decided on two rows of application in Sarıyer – Çayırbaşı tunnel. Another lighting system is safety lighting system. Safety lighting system is provided to allow a minimum visibility for tunnel users to evacuate the tunnel in their vehicles in the event of a breakdown of the power supply. To do this there are some methods. One of them is to connect some or all of the normal lighting luminaries to UPS. This was applied in Sarıyer – Çayırbaşı tunnel. In addition to this, the border line lighting with LED's so called “guidance lighting” is a very effective way of safety lighting. These are also very useful in the case of evacuation if there is smoke in the tunnel. Since their height level is very close to ground, lights cannot be affected by heavy smoke, so uni-colour (red) or bi-colour (red and white) LED road studs are proposed to apply for every 12 or 24 meters (compatible with the section lengths) at the right side of the traffic direction. Moreover, there are also evacuation lighting system. In order to give visual messages in static form to the tunnel users, the internally illuminated information signs are distributed which are named as evacuation along the tunnel tubes. These signs are illuminated always. Most of them are used only in emergency conditions while some of them are required in normal conditions also. Evacuation lighting, such as evacuation marker lights, at a height of no more than 1,5 meter, is provided to guide tunnel users to evacuate the tunnel on foot, in the event of emergency. Furthermore, another vital tunnel electromechanical system is ventilation system. Longitudinal ventilation system and jetfans are used in the tunnel. Because there are two main aims. First one is to supply fresh air into the tunnel, second one is to smoke-out in the case of fire in the tunnel. There are many techniques and different types of applications of tunnel ventilation systems. The suitable system must be selected according to design criteria. On the other hand, CO (Carbonmonoxide) and VI (Visibility or dust particle) measurement devices are continuously check the levels of CO and dust particles inside the tunnel tube. Based on these dynamic values, if the predefined limits are reached then the related ventilation system will automatically operate to supply fresh air into the tunnel tube. For this process, usually PLC systems are used as a ventilation controller unit. The data collected by CO, Visibility and wind speed and direction devices is sent to the PLC as input to PLC. Then the PLC checks them if they are in the desired range or not. If the level of the toxic gases are higher than the predefined limits or the visibility range is less than to see the desired distance then the ventilation system must automatically start an action to supply fresh air into the tube meanwhile the same system sends away these toxic gases and dust particles outside the tube. By doing this the existing wind speed and direction is another base input to the system so that the system decides to thrust the toxic air to easiest direction. For some emergency cases like fire in the tunnel tubes, there must be an emergency manual control panels. These panels are in the PLC including scenarios. Relevant scenarios and the operations programmed into the PLC must be in contact with main SCADA system via telecontrol and networking system in the tunnel. So SCADA make it possible to operate and control all the system components from the main control centre. The SCADA collects data not only from ventilation sensors but from all other sensors in the tunnel. As a result SCADA scenarios must be detailed studied before the emergency conditions occur and the ventilation control is only one part of the whole control system of the tunnel and it must be fully integrated to SCADA to get better benefits. This is one of the most critical points of the tunnel safety and control: Integration. Moreover, other integrated system is CCTV and Video detection system in the tunnel. In fact CCTV system and AID (Automatic Incident Detection) system are so close and relative systems connected to each other. The most important point for the CCTV system is to cover the whole tunnel tube without leaving any “blind” point in the traffic area in the tunnel. So the exact locations of the cameras must be selected by considering the curves of the tunnel tube in terms of traffic view. According to this approach next camera must be located at just before the end point of the area of the view of the former camera. CCTV sytems camera equipment were located along the Sarıyer – Çayırbaşı tunnel at every 50-60 meters. Finally, for all integrated electromechanical systems at SCADA, there should be a control centre for monitoring, controlling and managing of the tunnel and the road connections. It must have modern and technologic features in a separate building or room. All the stuff in the center must have trained for operating and managing to the tunnel systems. Especially to view the CCTV system videos, to see the fire alarms, to run the special scenarios by operator command, whole system confirmations are needed. As a result, SCADA integration is a vital advantage for a road tunnel such as Sarıyer – Çayırbaşı not only to monitor, control, manage the integrated systems, but also to make a flexible operation control with effective usage of technical staff and to achieve electrical analysis.