SCADA System Traffic Light - Case Study Example

Contents Contents 0 1.0.Introduction 0 2.0.Data Acquisition 1 3.0.Data Conversion 2 4.0.Data communication 2 5.0.Data presentation and control 3 6.0.Applicability of SCADA System Traffic Light 3 7.0.SCADA System Traffic Light Projects to be borrowed 5 7.1.SCADA System using Intelligent Traffic Lights Controlled by Fuzzy Logic 5 7.2.SCADA System using Induction-loop Traffic Sensors 6 8.0.Recommendations 9 9.0.Reference Lists 10 1.0. Introduction Traffic lights are the most convenient method that can guarantee the control of traffic in a busy road or junction. In most cases, policemen fail to effectively control traffic especially when a particular lane is congested than others. If personnel deployed to regulate traffic fail to allot different lanes to specific vehicles then it equally becomes difficult to solve traffic congestions. In other words, modern roads are so integrated that it becomes difficult for traffic police to monitor the entire scenario round the clock. However, there are a lot that happens on highways and city traffic that traffic police is almost becoming null. It is for this reason that SCADA System for traffic light needs to be introduced. SCADA is Supervisory Control And Data Acquisition used for the purposes of generating and analysing real time data (Fundamentals of Utilities Communication Architecture, 2008). Being a system, it is made with some components among them, Remote Telemetry Units, sensors and SCADAmaster units among others. In as much, SCADA system requires Remote Terminal Models (RTU) to monitor traffic light (McDonald, 2003). Based on this, this project seeks to critically asses how SCADA System can be developed to monitor traffic light. In so doing, the project will begin by assessing different components of the system then detailed analysis on how the system works. 2.0. Data Acquisition This will be the first component in the system. Graham and Mayno (2006) explain that SCADA Systems controlling traffic light have this component for acquiring the needed data. Modern junctions have these data acquisition components fitted with different sensors such as photo, pressure and flow. Depending on the quality of SCADA System installed and the nature of the road, this project intends to allocate this component miles away from each other. The primary role of this component is to detect physical parameter and send the signal to the respective department. Taking an example of the Light Horse Interchange at the junction of the M7 and M4 in Sydney, this component will send analog signal about the weight and numbers of vehicles on either lane of the road. 3.0. Data Conversion This is the second component that comes with SCADA System. Cheng (1999) clarifies that this component receives data generated by the acquisition component. A junction such as Light Horse Interchange needs intelligent electronic devices (IEDs), Remote terminal unit (RTU) and programmable logic controllers (PLC) respectively which are good examples of data collection devices. Cheng adds that at the initiation of SCADA system traffic light at junctions, such needs to be fitted with analog to digital conversions. However, this project considers networking conversions which are now available. The function of remote terminal unit is to monitor field digital or in some cases, analog parameters. This information will later be transmitted to the central data control. Latest research shows that data conversion component has a two way communication with data presentation component and control through the data communication. 4.0. Data communication This component will consist of detailed communication mediums that have the ability of transferring data back and forth between data control and data conversion. In most cases, traffic lights are fitted with radio, wireless, wired or satellites to necessitate this process. Taking practical example, Oetiker (1998) explains that some junctions are fitted with wireless gadgets therefore this project intends to use data communication that will communicate using one of the system’s protocols. In a separate research, Chen and Qian (2008) add that data communication is fitted to estimate the volume of traffic between the point of origin and destination within a given network. This will help this project with further capacity planning. Recently, traffic lights are fitted with two types of protocols; open standard and the proprietary protocols. The difference between the two is the range they need to transmit the data. ControlNet, DeviceNet and ModBus are good examples of these protocols. 5.0. Data presentation and control As the name goes, these components will be fitted to monitor and control received information from different data communication channels. Lately, engineers prefer using Human Machine Interface (HMI) as data presentation and control component (Bruce and Lee, 2008). These HMIs enable operator to monitor and respond to specific alerts and alarms from different roads or traffic positions. In addition, the information relayed through HMI is always graphical in nature. For instance, the operator can tell that traffic light X connected to street Y and such is on and shows number of vehicle or people passing at one particular time. In case of a problem, the operator can switch off or attend to the light depending on the signal sent. A good example is Burke road, north from Camberwell Junction which consists of historian databases and other support systems. 6.0. Applicability of SCADA System Traffic Light SCADA system is currently seen as new method of managing traffic light. Taking a case study of Italy, traffic flow and safety have enhanced most of Italy’s motorway tunnels. Through the use of SCADA System, the country has managed to commission a new system based on Products4Automation’s Movicon 1 (one of the SCADA technology). Each of the tunnels passing through mountainous landscape is fitted with unique traffic arrangement that can handle congestion in the tunnel. However, this project notices expanding usage volume. Due to this, SCADA system will not only used as traffic light but also as a tool for regularly maintaining and developing these tunnels. Taking Spogliamonaco Tunnel on the Lauria–Lagonegro motorway in Basilicata as an example, Barr (2011) explains that engineers have been concerned about traffic light that could be controlled from local, on-site and remote from the head office. He adds that these engineers settled on SCADA system and a bus architecture as the optimum solution. This will be the same case with this project but it will settled for one of the SCADA system software namely the Movicon 11 which is considered to be appropriate to the needs. Movicon 11 is considered because it is a XML-based and since it can combine SCADA with Human Machine Interface; operators can get all-in-one ability of checking all traffic lights. It also necessitates highly flexible and attractive characteristic in an application where constant evolution and maintenance of these lights is required. Another reason why Movicon 11 has been considered is due to the fact that all operating data is logged by the software and analysis for trends and alarms is possible. This can enable optimisation of service and helps in effective traffic flow. Interestingly, Spogliamonaco Tunnel has landline telephone that gives straightforward means of communication. The landline are integrated into the SCADA system to enable user be logged alongside rest of operating data. Traffic lights along this tunnel also have the system fitted in a manner that it can send short messages and even pre-recorded cell phone messages to staff on call. Building from this, this project will also add sensor network based on SCADA system to effectively be used in such tunnels so as to manage traffic lights especially during rush hours. However, this project has to admit security concerns regarding the introduction of sensor network based on SCADA system (measures to reduce such threats have been addressed in the recommendations). Even though researches have documented thorough study regarding security in SCADA systems (Panja et al., 2012; Barr, 2011) none shows how these systems can provide security in the integrated traffic system and this tunnel provides such example. It is because of this reason that SCADA system intended by this project will be updated to a more secure wireless sensor based on intelligent traffic systems that can use fuzzy logic to deal with heavy traffic conditions. In a different research, Panja et al., 2012 add that fuzzy logic can be used in major junction or busy roads. They give an example of South Africa where such technology was used to control traffic moving from one stadium to another during 2010 world cup. 7.0. SCADA System Traffic Light Projects to be borrowed 7.1. SCADA System using Intelligent Traffic Lights Controlled by Fuzzy Logic These are SCADA systems that implement traffic lights using fuzzy logic technology (fuzzy logic technology is explained in the next topic). This technology uses specified software and is highly graphical in nature. Borrowing this, the project may use windows system which will allow simulation of different traffic conditions at a particular point or junction. Fundamentals of Utilities Communication Architecture (2008) explains that fuzzy logic traffic lights is an alternative to conventional traffic lights since it has ability to be used for a wider array of traffic patterns at an intersection. By devising SCADA system to have fuzzy logic technology, the system will be made to have sensors that can count cars unlike the proximity sensors which were only able to indicate presence of cars. Giving an example of Burke Road north from Camberwell Junction, fuzzy logic technology will be able to give the controller the needed traffic densities in the lanes thus allowing a better assessment of changing traffic patterns. As the traffic distribution fluctuates, the technology will respond accordingly. Figure 1.0: Structure of the fuzzy traffic light control system Source: Fundamentals of Utilities Communication Architecture 7.2. SCADA System using Induction-loop Traffic Sensors This is another option that the project may consider. Though it works like fuzzy logic technology, sensors (induction-loop) start its operation when a vehicle crosses it. Looking at the figure below, before a vehicle crosses the sensor it opens and closes once the same vehicle runs crossing it. This is what happens the whole day but it becomes more active in the evenings and mornings when the road is fraught with vehicles. Figure 2.0: Induction loop traffic sensors Source: http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/red-light-camera1.htm (July 4, 2013) This technology should be used in the construction busy junctions around major cities. As explained author (unnamed), this technology constantly tests the inductance of the loop in the road then send the signal to Human Machine Interface (HMI) as data presentation and control component. When the inductance rises, the system is able to know there is a car waiting. Looking at the figure above, when the current starts flowing in the coil, there is tendency by the coil to build up a magnetic field. While the magnetic field is building, there is inhibition of flow of current by the coil. Once this is done, there will be normal current flow through the wires. When the switch is open, the magnetic field continues the flow of current until the field is collapsed. This concept is what the project may consider using to ensure that the traffic light is controlled. Figure 3.0: Induction loop traffic sensors Switch Board and Controller System Source: Fundamentals of Utilities Communication Architecture Figure 4.0: Metal Detector Sensor under the Road Pavement Source: Fundamentals of Utilities Communication Architecture The last two figures show switch board and metal detector sensor respectively; though they were designed for different projects, this project to consider their inclusions due to their compatibility with the SCADA system traffic light. 8.0. Recommendations First, it needs to be understood that this project needs security from hacking. This will be minimised by ensuring the system has a password so that only authorised individual(s) can access the system at one time. The computers at the central poing will have latest anti-virus softaware to prevent the system from damaging. Latest research shows that system reliability has been on test especially during road reconstrcutions. Based on this, there is need for impoving equipment reliability throguh equipment health monitirng. This needs to accomplished through automatic health check programme installed within the SCADA system that analyse the collected data so as to generate the needed alarms or warning messages to maintenance personnel. It can also be realised that modern SCADA systems have not been fully configured to capture intermittent problems. This is common to SCADA systems installed to regualte flow of water. Being system for traffic light, problems such as temporary loss of shunt or even unexpected loss of signal will be expected. To effect this, the system will need to be fitted with an analogy that resembles ‘black box’ that records data. This can be made to work in a similar manner to that of airline undustry. This project also aims at developing a system that can centralise reporting. The accumulated data from the system will the collected at the indentified central point then be easily assembled and sorted for easy planning. 9.0. Reference Lists Barr, D. (2011). Supervisory Control and Data Acquisition (SCADA) Systems." National Communication Systems. Communication Technologies, Inc., Oct. 2004. Bruce, A.G., Lee, R., A (2008). Framework for the specification of SCADA data links, Power Industry Computer Application Conference. Conference Proceedings , 4-7 May2007 Pages: 117–121. Chen, Q. and Qian, Q., (2008). The research of UNIX platform for SCADA, Power Engineering Society Winter Meeting, 2000. IEEE, Volume: 3, 23-27, Pages: 2041 - 2045 vol.3. Cheng, J.W. (1999). Power Switch Health Monitoring using Motor Current Signatures., AREMA Conference Proceedings, Baltimore. Fundamentals of Utilities Communication Architecture (2008). Computer Applications in Power, IEEE , Volume: 14 , Issue: 3 , July 2007 Pages:15 – 21. Graham, G. and Mayno, M. (2006). SCADA Security and Terrorism: We're Not Crying Wolf." Blackhat.com. TechWeb. McDonald, J.D., (2003). Developing and defining basic SCADA system concepts, Rural Electric Power Conference. Papers Presented at the 37th Annual Conference, 25-27 April 1993 Pages: B3/1 - B3/5 Oetiker, T. (1998). MRTG – the multi router traffic grapher, Proc. 12th Systems Administration Conference (LISA’98) (1998) Panja, B., Prakash, A., Meharia, P., and Schneider, B. (2012). Security in sensor network based SCADA system for adaptive traffic signal operation. Read More