Page 253 - Decision Making Applications in Modern Power Systems

218 Decision Making Applications in Modern Power Systems

FIGURE 8.12 Main grid generation for microgrid supply—critical phase.

penetration. From Fig. 8.12, it is possible to observe that this increase in
demand is proportional to the penetration of EVs after reconnection, since
the demand required by these units charging does not surpass the maximum
allowed limit. Yet, after performing the peak shaving, these units SOC were
significantly depleted in all scenarios of EV penetration (50% 110%). And
even though the different scenarios of EV penetration would lead to unlike
charging power requests, the actual increase in demand faced by the grid is
the same for all scenarios. This is due to the controlled charging process that
limits the maximum demand associated by these units, in order to sustain the
system operation within satisfactory limits. This is clear in Fig. 8.12, as the
charging power required by these units starting at 2220 hours is the same
regardless of the percentile of EV penetration.
From Fig. 8.12, it can be noted that the peak shaving methodology to
avoid transmission congestion is satisfactorily performed up to a penetration
rate of 70% from the EV base case (100%). However, for rates below
this level, as observed in the critical case of 50% of EV penetration, the
microgrid would not be able to avoid transmission congestion due to the
main grid supply. This result is of paramount importance as it raises concern