Information Technology Reference
In-Depth Information
The infrastructure needed to support the proposed strategy consists of EV
charging points, local monitoring stations at the distribution transformers and a
central monitoring station at the main sub-substation. Each charge point must be
capable of running the AIMD algorithm, measure its own socket voltage
V
i
(
k
),
and maintain bidirectional communication with the local monitoring station for
its residential area. The role of each local monitoring station is to: (i) receive volt-
age capacity event signals from the EV chargers in its local residential area and
generation capacity broadcasts from the central monitoring station; (ii) detect
local infrastructure capacity events, and (iii) broadcast capacity event informa-
tion to the charge points in its area. The role of the central monitoring station is
to monitor available power in real-time and broadcast generation capacity events
via the local monitoring stations to the charge points.
With this infrastructure in place the basic AIMD algorithm running on each
charge point is modified to respond to all capacity events (voltage, infrastructure
and generation) and to transmit a voltage event message to the local monitoring
station when the voltage level drops below a minimum acceptable level,
V
min
.
The pseudo code for the algorithm is as follows:
while
battery not charged
do
if
capacity event
then
generate uniform random number,
p
if
p<p
i
then
c
i
(
k
+1)=
β
(1)
.c
i
(
k
)
else
c
i
(
k
+1)=
β
(2)
.c
i
(
k
)
end
else
c
i
(
k
+1)=
c
i
(
k
)+
α.ΔT
end
if
V
i
(
k
)
<V
min
then
transmit voltage event message
end
end
The local monitoring station for a given residential area broadcasts a capacity
event signal to the active EV charge points in its area if any of the following
conditions are satisfied: (i) A generation capacity event is broadcast by the main
substation; (ii) A voltage event message is transmitted by any of the charge
points in its residential area; or (iii) A local infrastructure constraint violation
is detected (e.g. transformer overload).
The central monitoring station is responsible for determining the power avail-
able and broadcasting a generation capacity event when this is exceeded. The
total instantaneous power consumption is given by
N
(
k
)
N
P
(
k
)=
h
j
(
k
)+
c
i
(
k
)
,
(2)
j
=1
i
=1
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