NHP Technical News
It is perfectly feasible to connect devices of this nature to the
existing building management system on a dedicated IP address.
The facilities person from the previous example would be able to
see in near real-time what the charging equipment is doing, and
would be able to see by way of charts and downloadable excel
data what the usage had been historically.
This example, even if we assume that only a single check-meter is
installed, would let the facilities manager see:
1) When EV charging is typically happening
2) How much energy has been used, and precisely when it has
been used
3) Roughly how many chargers are in use at any time (through
looking at total loading on each phase at a given time, and
knowing how powerful the EV chargers on those phases are)
Figure 3
There are a few things that a solution of this nature won’t do:
1) Identify when the EV chargers are being used
2) Identify how many chargers are being used simultaneously
3) Identify which specific EV chargers are being used
4) Automatically record and report the information
For cases where better data is required, the next step is to add a
platform for collecting and collating this data.
Metering with Web Server to log and Report Data
into Existing Systems
Taking the distribution board with the check-meter (Figure 3) as
the starting point, it is possible to add an industrial web server
and data logger to the board, and connect it to the check-meter.
The advantage of a solution of this kind is that it will log data
from the energy meter on a periodic basis (eg. each minute, hour,
or day), store this data locally, and make this data available via a
typical web browser. Note that this device could be connected
to the internet to enable automatic periodic emailing of data and
reports, but that this is not essential.
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One of the advantages of the web server approach is that a
single web server can read multiple energy meters. So, if there
is a desire later to drill down into exactly which EV charger is
using the power, individual meters can be placed upstream of
individual chargers.
It should be noted at this point that the data in this example is
coming from an energy meter upstream of the EV charger, and
not the EV charger itself. This is an example that will work for data
reporting without any capability to communicate with the actual
EV chargers, regardless of which manufacturer’s EV chargers are
being installed.
If the system being planned includes local load management
as described in the ‘Local Smart Load Management’ section
of this article, then usage data at the level of individual EV
chargers is already going to be available in the local smart load
management device, which will remove the need for separate
energy measurement devices for this task. In this case, a separate
web server may still be desired, but consideration should first be
given to whether the data reporting required can be delivered by
the smart load management device.