BESIDES THE TUNNEL
One of the most demanding monitoring system, realized by Ismes in the last few years, is that one developed for SITraSB - Italian Company for Gran San Bernardo Tunnel.
By Maurizio Vavassori, Anna Pilenga, Claudio Sasso, Claudio Reál
The main objectives of the monitoring and remote surveillance system, developed by Ismes for the Italian side of the Gran S. Bernardo tunnel, were: improve users' safety, assure an efficient state of the road and fast assistance operations, improve the control of the technological systems as well as automized them.
The system architecture
The monitoring system consists of a main part, which is the control room located by the Italian entrance of the tunnel, and all remote surveillance and monitoring plants components, directly connected to the control room. From here operators inspect the tunnel and manage the technological plants through a supervision system.
The system architecture is based on a local optical-fiber network, used for the transmission of images, data and commands.
Optical-fiber was chosen because of the critical environmental conditions of the tunnel, in particular its location in a place exposed to lightnings and its 6 km length. This choice assures fast and reliable transmission of: television cameras' images, signals of using SOS devices (such as emergency telephones and fire extinguishers) and commands for managing technological plants, such as illumination, ventilation or antifreeze ones.
The diagram in the next page shows the connections between the monitoring system components, represented by PLCs installed in the electricity cabins along the tunnel and the panel room, and the workstations in the control room. In a similar way the connections between television cameras (installed along the tunnel and on the fore area), the video matrix (installed in the panel room) and the supervision system (in the control room) was realized.
As shown in the plan, a part of the network refers to the Swiss side of the tunnel, indicating that information about remote surveillance and monitoring systems are also collected and sent to the Swiss control room. In fact, the tunnel and its plants are contemporary controlled by Italian and Swiss technicians, constantly updated about each other's activities in order to coordinate interventions for assuring higher safety and faster assistance and maintenance operations.
Moreover, in order to assure the best safety for the tunnel's users and operators, the control room is supplied with two workstations in redundant configuration, so that a workstation is always available for the continuous control of the tunnel and its plants. Each station is able to manage all audio and video devices of the remote surveillance system as well as data and commands about the other technological components. Both stations are also able to do a reciprocal running check in order to take the other one's place automatically, if it is necessary.
The monitoring system
The system allows to control the technological components turning on and off, check the result of the given commands and have constantly updated status information about installed instruments.
These functionalities are possible thanks to the use of eight PLCs installed respectively in six electricity cabins, the panel room next to the Italian control room and the north control room on the Swiss side of the tunnel. Controllers are connected on one side with field devices and on the other with the supervision system, located in the control room, through the local Ethernet network.
The system manages 900 signals and measures acquired from the field regarding the more technological parts of the monitoring system, such as relays, switches and medium-power transformers, as well as those about safety and environment, such as traffic lights, SOS stations and carbon oxides.)
Moreover, interventions in the field are possible through the management of 600 signals and commands, automatically activated by the supervision system or manually by the operator after controls executed on the acquired measures and information.
Thanks to supplied information about running, damages and possible out of order of the single plants, the operator can also plan ordinary or exceptional maintenance interventions.
Installations and maintenance interventions correctly performed, allow operators to work in safe conditions; this is absolutely necessary considering that many operations accomplished through the supervision system directly affects the low and medium power systems.
The control system consists of a series of components; some of these are monitored, controlled and activated by the system, while others, whose use depends on the necessity of the tunnel users, are simply monitored.
In particular the system consists of: SOS telephones and fire extinguishers whose use is surveyed by the system; fans installed along the tunnel activated and deactivated automatically by the system to remove polluted air; lights (of the tunnel and the fore area) managed manually or automatically according to predefined timetables; traffic lights for the regulation of traffic in case of dangerous situations, such as the presence of many vehicles in the tunnel, traffic blocks, fire events etc.; sensors for measuring opacity and carbon oxide concentrations in the tunnel, whose measurements determine the automatic activation and deactivation of the fans; an antifreeze system at the entrance of the tunnel activated according to the temperature; a traffic counter, which supplies information about the number of vehicles in the tunnel; a power supply line with the control of power exchange between Italy and Switzerland; an anti-intrusion system applied to electricity cabins in the tunnel; a continuity groups and the local network.
The Remote Surveillance system
The remote surveillance system consists of: 44 television cameras installed along the tunnel and on the fore area, 3 motion detectors, devices located in the panel room, such as the video matrix (it acquires and arranges images managing 96 input and 24 outputs signals, 16 quad-splitters and 4 multiplexers) and other instruments for operator's activities in the control room.
The operator can manage eight monitors television cameras images, selecting them at pleasure or on the base of particular occurred events. Thanks to appropriate arrangements and quad-splitters management through the supervision system, he can contemporary display the images of all cameras or display them cyclically on one single monitor.
In case of critical events, such as a help request from SOS telephones or the use of fire extinguishers, all images from cameras located near the device are automatically shown on the monitors. So the operator in the control room, beside getting in touch with the user by telephone, is also able to evaluate visually the problem and immediately take necessary actions.
Both in normal and emergency situations, images and messages received by SOS telephones are automatically recorded, allowing subsequent investigations of particular events through time lapse video recorders and digital audio recorders available to the operator in the control room.
The supervision system
The software, which runs the entire plant, provides operators with all necessary information for managing control activities.
Based on a modular and flexible architecture it is very simple to use and reliable, as can be expected from a supervision system dedicated to the control of complex and expandable plants.
The SCADA application allows the monitoring of the 'system variables' (on/off switches, red/green traffic lights, active/inactive illumination circuits, SOS devices in use, quantity of carbon oxides and surveyed dust, functioning ventilators etc.) and the modification of the plant condition through the control of specific devices (for example turning on a switch, activating ventilators etc.).
The supervisor also continuously checks the system status in order to detect alarming situations, showing them to the operator or automatically acting on the plant, if necessary.
The operator can execute commands acting directly with the mouse on the buttons, displayed on the video pages. Each button is associated with an image representing the status of the variables affected by the command, so the operator has a dynamic, easy to use, self-explanatory and complete instruments at his disposal.
Super-Flash is the development system used for realize the Gran S. Bernardo tunnel's supervision software. The system is by Automa, a company from Bergamo which offers many products and services in the field of industrial automation, monitoring, control and computer assisted design.
Alimentary, textile, ecology, chemistry, water treatment, movement, bottling, control and remote surveillance are only some of the sectors in which Automa has been operating for ten years thanks to many products, as the well-known Super-Flash. This system is available in three versions for different users: Full-Free for ones developing applications; Run-Time for those who have to realize only one application; One-Shot for end-users needing to maintain only their own specific application (usually a single station managing a particular machine or plant).
With Super-Flash, Automa has chosen an approach not shared by everyone; in fact in the hierarchical structure of automation levels, Super-Flash is placed near to machine and process level; moreover, it has not versions for Windows 3.1 or 3.11, but only for DOS. However, this is not a limit in using the Automa's product which is installed, directly or indirectly, on about 8.000 computers.
Automa offers products able to communicate with machines and plants on the field and link with standard applications at host level, for example Excel, Access, Visual C and any other DDE applications. Automa offers also DDE-SFNet products, to manage the communication between Windows, Windows NT and OS/2 applications of the industrial informative systems with the field through a Super-Flash network.
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