Page 237 - Decision Making Applications in Modern Power Systems

202 Decision Making Applications in Modern Power Systems

maximum generation of each flexible resource
P Gmax
P G maximum nodal generation due to flexible resources
max
Node
P G maximum network generation due to flexible resources
max
Network
V n nodal voltage
minimum nodal voltage
V n min
VT tangent vector

8.1 Introduction
New social and environmental requirements for more efficient and cleaner,
while still profitable, energy systems have positively driven the development
of new technologies for an electric power system. Among them, distributed
synchronous and renewable generators [distributed generators (DGs)], flexi-
ble loads, which can also become flexible resources, such as electric vehicles
(EVs) and storage units, have led to a major transformation of the distribu-
tion systems that now have a special branch of assets with high capacity to
support the network at various levels. In turn, novel and innovative planning
approaches are required to make the most of these new available resources.
Traditionally, distribution system planning would only consider a single
directional injection flow from the connection between the main grid and
substation into the distribution network branches. However, the insertion of
distributed sources requires the consideration of multidirectional flowing
possibilities, which calls for the development of new tools and procedures to
these systems planning, operation, and optimization [1]. Also, due to the sig-
nificant impact and importance associated to DGs, several studies are avail-
able in the literature as optimal placement [2], sitting and sizing [3],
operation [4,5], control [6], and stability [7]. Furthermore, the association of
EVs and storage units is creating a new perspective on distribution system
planning and operation. These elements may be defined as flexible loads
since their demand requirements can be adjusted over a period as well as
flexible resource that is able to supply power to the network through their
stored energy [8]. These features enable a full range of applications and pos-
sibilities, such as demand response, peak shaving, ancillary services, and
many other features, that are very important and costly for power systems
operation. Furthermore, the benefits provided by these units flexible opera-
tion may offer significant deferral of investments in many levels.
In the literature, several works addressing the aspects necessary for the
application of these elements are available. Ref. [6] presents solutions for the
control and management of hybrid AC/DC microgrids with DG penetration.
In [9,10], controlled charging processes for EVs are proposed; however, no
consideration of its operation as flexible source is presented. Instead, this
topic is studied in [11] for balancing wind power and load fluctuations.