Page 251 - Decision Making Applications in Modern Power Systems

216 Decision Making Applications in Modern Power Systems

TABLE 8.3 Microgrid frequency variation in islanded mode.
Control response Frequency (Hz)
Primary 60.34 60.34 60.34 59.94 59.94 59.86 59.86 59.89
Secondary 59.99 59.99 59.99 59.99 59.99 60.00 60.00 60.00
Time (h) 00:20 00:30 01:00 01:30 02:00 02:30 03:00 03:20

FIGURE 8.11 Microgrid power supply in a per phase representation.
flexible resources assume the phase balancing responsibility, allowing a bal-
anced contribution by the local generation.
The second critical aspect while planning this system is due to the possi-
ble transmission congestion by the main grid supplying at peak hours.
However, with the conversion of EVs and storage units from flexible loads
into flexible resources, this problematic contingency can be completely over-
come. These units can provide the power required by the grid based on their
stored energy, being responsible to provide the surplus power that the trans-
mission line cannot conduct due technical restrictions, plus a security margin
at the discretion of the system operator. In addition, due to the distribution of
EVs in different phases, their contribution can be unbalanced, allowing a