Page 239 - Decision Making Applications in Modern Power Systems

204 Decision Making Applications in Modern Power Systems

Section 8.3 depicts the application of flexible resources to assist distribution
system operation. Section 8.4 discusses the technical challenges of islanded
microgrid operation. Section 8.5 develops the proposed smart coordination
methodology for the improvement of distribution system planning.
Section 8.6 validates the proposed methodology with a holistic operative sce-
nario with multiples events. Finally, Section 8.7 draws the final remarks and
conclusions.

8.2 Coordinated operation of local generation and flexible
resources

The coordination of local generation and flexible resources, for example, EVs
and storages, can provide significant enhancement of distribution systems ser-
vice capacity and operational conditions. These elements must be combined in
such a way that when the network requires assistance, it is possible to use the
stored energy to provide the necessary power back to the grid. However, before
taking action on the use of these powerful resources, an effective controlled
charging methodology is necessary to avoid the bad influences that the insertion
of these elements can generate [23]. As highlighted in previous works, the oper-
ation of these units without control of their charging process can lead to a sig-
nificant violation of the system operative limits possibly leading to overcurrents
in transformers, transmission lines and undervoltages at nodes [9,24]. Because
of this, controlled charging processes must be addressed.
These controllers will be responsible for sustaining the system operation
within acceptable limits with the insertion of these new elements; such control
can defer investment in new infrastructures and equipment renewal to settle
these new units. In the literature, several approaches to address the controlled
charging processes of EVs and energy storages are presented [9,10,24 26].In
this work a method based on the maximum loadability of each system node is
employed [26]. This is accomplished with the help of the continuation method
[27], being the maximum available power in the node defined as the maximum
increase in demand, Eq. (8.1), which does not break the established operational
and technical limits, as described in Eqs. (8.2) (8.5).

β 5 β0 n 1 1 Δλð Þ ð8:1Þ
n
n
β # P n max ð8:2Þ
ð8:3Þ
I n # I n max
ð8:4Þ
V n $ V n min
T
λ , VT J VT ð8:5Þ