Transformer substations are used by suppliers
to link different voltage levels between
generators and consumers. Frequently,
however, these large industrial units are felt
to be unsightly and many landowners are
concerned that a substation close to their
property might reduce its value.
In the urban environment, this problem
is exacerbated as the demand for power
is high, but the space available for the
construction of a transformer substation
is limited. This was the starting point
for Mainova AG. The company has been
supplying its customers with power for 110
years. To cater to the rising energy demand
of customers in the densely populated center
of Frankfurt, Mainova AG wanted to expand
its existing facilities.
After weighing numerous options, Mainova
decided on a new concept that would
benefit the customers as well as the
community and the company – they built
an underground transformer substation.
Mainova‘s transformer substation, built 17
meters below street level, had to be able
to fulfill all the functions of a traditional
transformer substation and at the same time
limit the required space above ground to a
small access building. The required space at
street level was so small that Mainova was
able to place a garden above the transformer
substation, providing much needed green
space in the city center. This also made the
transformer substation‘s above-ground
building less noticeable.
For the design and implementation of the
infrastructure of the communications
network, an important part of the
project, Mainova turned to Belden. The
communications network is the basis for
reliable and safe remote management and
monitoring of the transformer substation.
Project Structure and Details
• In recent years the demand for power
has increased in the Frankfurt-Main
metropolis, as companies and service
providers have established themselves in
the city center itself.
• The transformer substation was to supply
customers in Frankfurt‘s financial quarter,
hence reliable power supply was especially
important.
Belden and Hirschmann are
Supporting German Energy
Suppliers With the Construction
of an Underground Transformer
Substation
Mainova AG, one of the largest communal
energy suppliers in Germany, along with
their subsidiary company NRM
Netzdienste Rhein Main (Rhein-Main
Network Services), has engaged Belden
with the development and implementation
of the industrial network of one of the first
underground transformer substations
across the country.
Case Study
CS00004
2
• The transformer substation had to be
operated remotely from a separate
control center, including monitoring,
control and management.
• Three transformers had to convert the
electricity from 110,000 volts to 10,000
volts for the distribution network.
• The location of the transformer
substation was in Liesel Christ Park, a
central and populated area only a few
hundred yards from the Opera House, so
safety was one of the primary concerns.
• Its position between a main road and a
river increased the risk of ground water
contamination.
• Mainova took a gamble, as it was the
first company to build an underground
transformer substation in Germany. The
energy supplier therefore needed partners
with proven expertise.
The Belden and Hirschmann Solution
At the beginning of the project, staff from
the competence centers of Belden and
Mainova gathered for strategy meetings to
develop a plan for a network configuration
that was tailored to the requirements of
this unique project, based on the urban
environment and the objectives set by
Mainova. In the planning stage, Belden also
took on board their local partner, Kapsch
Carrier Solutions GmbH (formerly ITM
GmbH), a systems integrator.
A ring topology was chosen for the
network of the underground transformer
substation. Within the plant, the compact
RS20 managed open rail Ethernet switches
installed were connected to two MACH1020
backbone ruggedized rack-mount switches
for fast Ethernet.
Belden also recommended further
network products for network design
protection, to build in redundancy and
allow for balancing during peak periods.
Redundant communication for the complete
network is guaranteed by the Media
Redundancy Protocol (MRP) that optimizes
reconfiguration time in the case of network
outage.
For control and monitoring of the
transformer substation, the local network
was designed to connect all control and
safety devices. A telecontrol system
assembles the reports and measurement
values from the individual field control
devices and transfers them to the control
center via the external backbone network.
Commands from the control center are
distributed via the local network to the
appropriate field control devices.
“This was a new approach
for us and all of Germany.
So, we wanted to choose
a partner that had a strong
reputation for network
design expertise and
high-quality products. The
decision to use Belden was
simple.”
– Andreas Hallwirth,
NRM Netzdienste Rhein-Main
GmbH, a subsidiary of Mainova
View into the depths: The 10 kV control cabinet room of the new substation is located approximately 17
meters below the surface.