IEEE Power & Energy Magazine - Grid Edge 2023 - 74

illustrate this, Figure 14 indicates the percentage level of
impact that an EV user might experience in the example
low-voltage network. For low penetrations (up to 40%,
which is the hosting capacity of the CIL network), EVs will
not be affected, i.e., their CIL is zero. However, the higher
the penetration, the more likely an EV user will have a CIL
larger than zero, i.e., reaching the expected SOC will likely
800
600
400
200
4
(a.m.)
Without Control
1-min Control Cycle
Thermal Limit
Thermal Limit
68 10 12
(p.m.)
24 68 10 12
(a.m.)
Time of Day
(a)
1.05
1
0.95
0.90
0.85
4
(a.m.)
500
400
300
200
100
4
(a.m.)
68 10 12
(p.m.)
24 68 10 12
(a.m.)
Time of Day
(c)
4
3
2
1
4
(a.m.)
4:44 p.m.
6:53 p.m.
8:24 p.m.
68 10 12
(p.m.)
4:44 p.m.
6:53 p.m.
8:24 p.m.
24
Voltage Limit
Voltage Limit
68 10 12
(p.m.)
take longer. In general, the MEA project did not find charging
delays to be of significant concern for penetration levels
up to 60% due to the low probabilities for CILs larger than
zero. Beyond this, half or more of the EV users could experience
delays, but, at most, they will be double that of what
would otherwise be needed (i.e., a CIL <5).
The studies also found that longer control cycles (5 and
10 min) increase the number of
EV users without delays; however,
30-min control cycles were found
to be too long to adequately mitigate
network impacts. On the other
hand, from the perspective of the
EV battery, using information provided
by the EV manufacturer, the
MEA project was able to recommend
a minimum on-time period
of 15 min (uninterrupted charging).
This means that if control
cycles are to be adopted, an effective
deployment should consider
the tradeoff between the benefits
from multiminute control cycles,
the capabilities of the EV batteries,
and the potential technical issues
on the networks.
520 kVA
10:38 p.m.
520 kVA
10:38 p.m.
24
24 68 10 12
(a.m.)
Time of Day
(b)
24
11:13 p.m.
12:44 a.m.
11:13 p.m
12:44 a.m
24 68 10 12
(a.m.)
Time of Day
(d)
figure 13. An example of a 24-h-period of operation and performance of the control.
Results for the (a) transmitter loading, (b) minimum voltage, (c) aggregated EV
demand, and (d) individual EV demand.
74
ieee power & energy magazine
24
Provision of Services:
To What Extent?
EVs, like other vehicles, are and
will be primarily used as a means
of transportation; however, with
the widespread adoption of EVs,
it is possible to think of them in
terms of not only disconnections
caused by distribution network
issues (as investigated in the MEA
project) but also for their provision
of grid services to help maintain
balance between demand and generation.
But if EVs are indeed to be
seriously considered for such purposes,
we need to first understand
the extent to which the provision of
grid services is possible.
Clearly, the disconnection of a
single EV will provide negligible
grid services, but hundreds of
thousands or even millions of EVs
working together can cause a significant
aggregated reduction in
electricity demand, requiring less
generation and potentially reducing
costs. However, to quantify the
potential aggregated demand that
november/december 2018
(kVA)
(kVA)
(per unit)
(kVA)
IEEE Power & Energy Magazine - Grid Edge 2023

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