In the control room, the energy providers
always have an eye on their networks
Trusting each other: Timo Beuth (Phoenix Contact)
and Reinhard Bretzke (Stadtwerke Kempen)
an expert when it comes to integrating protection and auto- the event of a fault.” Ground faults occur most frequently in
mation systems into the Kempen system. With nimble fingers, the power grid. In the private sector, for example, this could be
he calls up the appropriate display on one of the monitors and a defective cable insulation on the iron; in the medium-volt-
shows us the distribution of the local Lower Rhine power grid age distribution network, it could be an excavator that damag-
and both the feeders and the major customers who are buying. es the cable insulation or a branch that touches the overhead
Meanwhile, Reinhard Bretzke explains why we are actually line during strong winds.
here.
In the example of the iron, a ground fault current flows out
over the human body and over the ground when touching the
The challenges of the energy revolution defective line point. A residual current device (RCD) detects
“Our power grids are facing ever-growing challenges. The con- that a residual current is flowing and switches off immediate-
version of the energy supply to renewable energies is chang- ly. So quickly that you won’t even notice the electricity. The
ing the feed-in completely. For decades, we have worked with electrical supply can be quickly restored by switching on the
constant feed-ins from large power plants. Now, new energy RCD, the person survives, and the electrical system has been
sources are constantly being added that are also fed in un- protected.
evenly and distributed in a decentralized manner. At the same If a branch touches a medium-voltage overhead line due
time, however, we still need a high level of supply security on to a gust of wind, things will look a bit different. The ener-
the customer side. This means that we also have to rethink gy provider doesn’t want to immediately switch off the power
power distribution. We need smart grids in the future.” to an entire supply area, but it also doesn’t want to endanger
people and systems due to an earth fault current. Because the
When raw currents flow hazard-free forces at play here are much greater. Even getting close to the
Timo Beuth, Field Application Engineer at Phoenix Contact, source of the error can lead to a destructive electric arc. So
explains: “In energy technology, in addition to high supply re- the fault current is virtually bypassed at the “fuse.” Using the
liability, no personal injury or system damage should occur in “KOMBISAVE” protection and field control device from Phoe-
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UPDATE 4/20
The Phoenix Contact innovation magazine