Page 242 - Decision Making Applications in Modern Power Systems

Effects of electrical infrastructures in grid with high penetration Chapter | 8 207

In this sense the capacity of these units to assist in any process, be it
peak shaving, congestion reduction, islanded operation supply, etc., is limited
by the maximum network generation contribution, as shown in the following
equation.

P supply # P G ð8:9Þ
max
Network
Once defined the respective management action to be performed, the con-
tribution of each EV and storage element must be determined. In this work a
linear contribution seeking equity in the participation of each flexible
resource based on the available stored energy and the total storage capacity
is employed. The formulation is described in the following equations.

MðnÞ
X
n ðÞ 5
ð
P G P Gmax n; mÞ ð8:10Þ
available
Node m51
ð
P supply P Gmax n; mÞ
P G n; mð Þ 5 P G max n ðÞ ð8:11Þ
P G P G n ðÞ
max Node available
Network Node
The first term, P supply =P G , determines the percentage of the network
max
Network
generating capacity provided by flexible resources necessary to addresses the
demand supply requirement, be this peak shaving, islanded operation support,
transmission congestion, ancillary service, or any other application. The second
ðnÞ, associates the maximum power contribution available in each
term, P G
max
Node
distribution system node. At last, the third parcel, P Gmax n; mð Þ=P G n ðÞ,is
available
Node
responsible to determine the power share to be assumed by each storage ele-
ment connected to the respective node. This process must be executed for all
system nodes in order to define each component supplying share.
8.4 Islanded microgrids operation

The development of distribution systems into microgrids can allow these net-
works to operate isolated from the bulk system. In this perspective, possible
outages due to failures at the main grid can be avoided if the microgrid has
local generation and control capacity to sustain the system operation. This
feature provides a significant increase in quality indexes, leading to better
social welfare and reduction of economic losses.
For this to become technically feasible, local controls must be associated
to the local DGs and flexible resources, being their responsibility to perform
the control strategies that were previously held by the main grid as phase
balancing, primary and secondary controls.