IEEE Power & Energy Magazine - January/February 2015 - 90

The Spanish demonstration aims to model
consumer behavior to promote "efficiency and
the reduction of consumption."
an inventory that is 100% reliable. a bulldozer digging in the
street for water main maintenance or for the installation of
new fiber-optic cable is not at all rare in large cities. Infrastructure installations are performed so as to avoid disturbing
others, but from time to time accidents happen. The problem
is repaired, sometimes adapting the solution to the circumstances or trying to take advantage of the problem to optimize
the loads on the lines. These modifications are entered into
asset databases. This manual entry and the number of updates
for expected and unexpected work of this kind produce deviations in the inventory that are very difficult to detect.
Now, however, automation is reaching the LV grid. The
first trials of autodetected inventory in the LV grid are under
way in castellon, spain. a ZIV system installed in an ss
is able to use power line communications (pLc) to identify where a smart meter is physically connected (phase and
line). The procedure will allow automatic, periodic verification and updates in the central systems. at present, a pLc
signal from a smart meter can travel through the lines it is
connected to and through nearby lines as well. This is an
advantage for transmission, but it is still a challenge to know
where the smart meter is connected, given that it may have
been moved from its original location and the signal arrives
at the ss through several lines.
other interesting experiences at Iberdrola relate to advanced
LV monitoring (see Figure 5). equipment from various vendors
is being tested to collect information about every LV line and
every phase of an ss. This information is being made available
to the central systems and will allow the detection of operational anomalies such as fraudulent consumption, high losses,

figure 5. Advanced LV monitoring. (Source: J. Varela.)
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ieee power & energy magazine

imbalances between the loads of different lines or phases, the
presence of harmonics, and so on.
Vattenfall, in sweden, is also trying to exploit the LV
information and the improvement of LV fault detection that
can be gathered from smart metering systems and intelligent
equipment in the ss. The large amounts of data to be processed constitute a barrier by themselves, but deciding which
measurements and applications are the most useful is also
a challenge. In addition, determining the optimal sampling
rate at which to collect information greatly affects the results.

Microgrids
Microgrids can be connected to several eegI functional objectives. They can be a key element of improved defense and restoration plans, which is the fourth functional objective for both
transmission and distribution networks in the road map. They
can also be linked to efficiency at the district level, which is
the second functional objective for distribution grids, enabling
maximum energy efficiency in new or refurbished urban districts using smart distribution grids. Finally, microgrids frequently interact with storage systems, which should appear as
part of the district design solution for efficiency.
In France and the czech republic, microgrid and local
generation islanding are being studied as solutions to cope
with major events on the grid and increase the reliability of
the distribution system. on the other hand, in Italy a control
system offers the ability to avoid the undesired islanding that
can occur during grid outages (an "anti-islanding system").
before, when an outage occurred on a section of the MV grid
and the dispatcher isolated the affected branch, generally the
protection mechanisms-which were only able to acquire
local measurement-could not detect the default when there
was a local balance between generation and load in the isolated
area. In such a situation, the generators remained connected
to the supposedly denergized branch, creating an undesired
islanding operation. To avoid this unsafe and insecure islanding, the system now sends a disconnection command to the
generators, thus assuring their disconnection from the grid.
ceZ distribuce's objective is to demonstrate island operation in a zone of 2,000 consumers and the capability of the
automation devices (automatic balancers) to support it. a
predefined area equipped with a 1.6-MW combined heat
and power (chp) unit has been selected. Within this area,
the island operation can take place in the case of MV grid
failures or by decision of the dispatching operator to satisfy
grid operation needs. The system evaluates whether network
conditions are suitable for disconnection of the island and
january/february 2015

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - January/February 2015