1. Systems Communication Automation Energy
Site - AGN Amsteg, Los. 252
Gotthard - Basistunnel Nord
Site - AGN Amsteg, Los. 252
Gotthard - Basistunnel Nord

2. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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AlpTransit Gotthard – SCAE’s CONTRIBUTION
Site - AGN Amsteg, Los. 252
Gotthard - Basistunnel Nord
Summary
In the present report there are some signs of the consistency of the
electrical plant and its conduction in the site AGN Amsteg - Los.
252, for the realization of two railways tunnels between Amsteg
and Sedrun in Switzerland from Murer-Strabag Consortium.
We underline that the design and the realization have been possible
thanks to an active cooperation and information exchange among the
various technicians who take care about the electrical and
technological plans as far as the specialists of boring, the
manufacturers, the mechanicals and the specialists of strumentation
and conditioning. In particular we underline the application of a
management, monitoring and supervision system in order to increase
the safety level, the continuity, the vigilance and the timely
intervention on the exercise of the entire plant.
We besides underline that the optimum result has been obtained both
for the big experience and preparation of all the involved technicians
and the commitment in the coordination and programming the job in
the various phases.
font:© AplTransit San Gottardo SA.

3. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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1 . General
Scope of the present report is to illustrate in short some aspects of the
design and realization of the site’s plant with own Distribution
Medium Voltage substations and transformation Medium/Low
Voltage.
The maximum power foreseen for the plant is about 30MVA with
supply voltage of 15kV-50Hz.
The electric power is destined to main power uses particularly for the
two TBM’s supply, the backup on TBM’s, for conveyors, ventilation,
hydraulic pumps and other smaller users and, in very smaller quantity,
for the site and tunnel lighting.
The activity, for the realization of the plant, have been done between
the incoming power supply point on one side and the users on the
other. Inside these limits the distribution plan and the dimensioning of
the components have been done.
A Particular attention have been dedicated to the working and the
environment conditions in the site with the precise purpose of keeping
guaranteed the continuity, the safety and the dependability of the
entire plant.
Fundamental therefore resulted the study and realization of a control
and supervision system of the various users and of all the critical
parameters.

4. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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2 . Study and fulfilment of the electrical plant
The site has three 15kV different supply lines, provided by
AlpTransit – Gotthard and, according to the availability, we proceeded
with the design and the realization of the plant.
Briefly the logic operations provided consisted of, mainly, in the
following operations:
- total absorbed energy definition
- use and contemporarily coefficient calculation
- determination of the power to be transferred on each line
- choice of the voltages and of the internal distribution systems
- grouping of the users and dimensioning of substations
- calculation of shot circuit currents and relative protection systems
- calculation of the power factor
- calculation of the earth fault currents according to the state of neutral
- calculation of the power factor correction of the load
Open ring medium voltage lines have been realized in order to give to
the electrical system the maximum safety and exercise continuity,
with the possibility of automatic change-over from one line to the
other, in case of power loss in the incoming line.
The protections coordination on the medium voltage side is assured by
the installation, for the circuit breakers close to the eventual fault, of
selective overcurrent relays with inverse time trip, proportional to the
current value (time and current discrimination) and of directional earth
fault relays with the nearest point to the fault.

5. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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For the protection devices located into the transformation substation,
downstream the transformers, in addition to the over current relays,
differential earth fault relays have been installed, for people protection
and for the integrity of the equipment particularly against fire risks.
For this purpose, as further security, in all the distribution and
transformation substations cast resin transformers F1 – C2 – E2 class
have been installed, in addition to automatic fire fighting systems.
For the power dimensioning, referring to possible load increase and
for the limitation of the frequent instantaneous peaks of power due to
the use of boring machines as TBM’s, transformers with rated power
increasable continuously of 25% have been used.
Particular attention has been given to the correct use of the electrical
power and to the power consumption saving. For this purpose we
proceed with the installation of appropriate local power factor
correction batteries, centralized in each unit and with automatic
control relay in order to maintain the average value of power factor
about the value of 0,95.
Furthermore, being the main users based on motors supplied by
frequency AC/DC converters and, therefore, with high harmonics
content, all the power factor correction units have been equipped with
filter reactors with harmonic chord frequency at 189Hz and harmonic
distortion, admitted in continuous at 30%In for 250Hz and at 15%In
for 350Hz, with thermal protection by meand of PTC.
Depending on the location we realized containerized and armoured
structures with degree of protection IP55 with the application of
adequate air extraction fans and IP65 with the application of cooling
air/water heat exchangers.

6. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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3 . Electrical plant configuration
The electrical plant covers a very big surface with a topographic
distribution of the medium voltage lines and of the substations very
wide.
Keeping into fundamental consideration the electrical loads
distribution, the use of spaces, apart for the best supply of the
various users, the project carried to the design and the realization of
a medium voltage distribution system and of substations located in
the various areas which consistency is shown in the figure 1, here
below.
4 . Configurazione dell’impianto di controllo, automazione e
supervisione

7. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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4 . Automation, control and supervision system configuration
The big dimension and the complexity of the plant put into evidence
problems linked to the control, real time, of the installed equipment,
taking into consideration that the service continuity, the dependability
and the security of exercise are now inalienable aspects of this kind of
projects (and not only).
In order to answer in a concrete way to the above-mentioned
exigencies, the plant have been provided of a control and supervision
system studied and realized by using the most modern technologies,
which contributed with big success to obtain significant improvement
in various activity areas, as:
1) The measures control in the electrical plant
Each electrical measure is continuously keep under control: not
only, but the consumption data relative to the users of each single
substation are stored in files which are resident in a remote data
base, so that an updated archive of the consumptions is ever under
control. The above files are easily readable by means of MS Excel.
2) An intelligent system of alarms management
The supervision warns immediately the operator about a new
incoming alarm relative to any point of the plant (for example,
circuit breaker trip for fault, transformer temperature too high,
etc.) consenting to the operator to signal the people assigned in a
very short time, so that the necessary corrective actions can be
taken, according to the gravity of the alarm itself.

8. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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3) Remote control of the equipment
Pumps, ventilators, conditioning units and other equipment are
controlled not only in local mode but can be managed from the
remote supervision consoles also, with a big resources and time
saving, in view of the fact of the big distances present in the plant.
Even of this equipment are managed, by the system, the energy
consumptions and alarms level.
An optical fiber network have been designed to connect the supervision
consoles to the field; each substation have been provided with control
boards containing remote I/O devices which, by means of optical
switches and data converter are connected to the main general network.
The optical fiber has been chosen both, for the big dimension of the
area covered by the site and for the immunity of the fiber to the
interferences caused by the proximity of high power electric lines and,
in particular, by the presence of frequency cionverters.
This kind of network permits the creation of a redundant ring
architecture which guarantee the continuity of exercise of the plant even
in case of interruption of a communication line.
In figure 2 the network structure for the various devices communication
is shown:

9. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
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5 . The supervision system
The supervision system is composed by 3 operative stations, two of
them placed into control cabinets of each TBM, the other one, the main
station, installed into the surveillance office, named Leitstelle, at the
gate of the tunnel.
This system features several synoptic pages, showing general
topography of the whole building yard electric network, schemes of
each substations, pages relative to outgoing and present alarms,
visualization pages relative to electrical (power, voltage, current,
frequency) and general measures (transformers temperature, air/water
ducts flow), trends of the most important of them, analyzed and stored
using different triggers depending on the nature of the measure taken
into consideration; pages showing hydraulic systems and tunnel
ventilation systems are present too, featuring graphic icons representing
pumps, fans, cooling units and conveyors.
The person in charge of the plant, or an operator chosen by him, can
start/stop machines, modify thresholds for analog alarms, restart or modify
counters for energy consumption by using face-plate command windows
having different password levels.
A part of the general synoptic is exclusively realized to manage a fire
fighting system composed by gates and fans to which safety is entrusted
in case of fire into tunnels and ducts; about safety issues, every single
substation is equipped with apparatus against fire, composed by sensors,
cylinders, control and command unit that sends its warnings (system

10. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
scae
malfunction, presence of fire, release of fireproof material) to the
supervision system.
This system was developed using the most updated and highest level
technology and, seeing that there is the need of having several remote
operative stations, a software that allows the access (protected by
password) to the graphic pages via Internet can be installed (WebServer
technology).
6 . PLC and RemoteI/O system
Signals from field are transmitted to supervision operative stations via
optic fiber bus; two different kinds of apparatus was provided,
depending on the different operations and action that must be
performed:
a) PLC
For all that operations, including command and control,
performed onto machines on field, as pumps, fans, fire-proofing
gates and in general onto machines which require a remarkable
safety margin.
b) Remote I/O (remote bus couplers)
For simple operations, like reading and storage, relative to
measures (power, voltage, current, frequency, transformers

11. Systems Communication Automation Energy
Via Fermi n. 8/10 - 24050 GRASSOBBIO (BG) – ITALY
scae
temperature, air/water ducts flow) or circuit breaker/switch
breaker status.
The communication between supervision PCs and both kinds of
apparatus is performed via Ethernet TCP/IP protocol: PLCs, usually
equipped with serial port for data collection from field apparatus
(ModBus Protocol) are supplied with Ethernet module, while between
remote bus couplers and supervision system OPC Client/Server
structures are employed.
7. Conclusions
Using high quality and performance apparatus and correctly
dimensioned has allowed to satisfy heavy duty needs relative to the
job.
This kind of project choices guarantee a high level of safety and
liability of the plant, which can be simply managed by the operator.
Supervision and monitoring systems let the operator control and make
centralized diagnoses of several events; the final result, even due to
the large plant area, is money and time saving about malfunctions
research and repair, about measures reading and storage, about status
control of the all the electrical apparatus employed.
Event and measures archiving allows the person in charge to evaluate
critical conditions of the whole plant, improving apparatus
performance during its duty and proposing focused actions in the
maintenance program.

12. Systems Communication Automation Energy
via Fermi, 8
GRASSOBBIO (BG) ITALY
tel. ++39 035 526880
fax ++39 035 526865
www.scae.it
e-mail scae@scae.it