Control and Design of Microgrid Components - Power Systems ...

The worse case scenario is represented by the microgrid energized from the grid, without
microsources and with all the possible loads inserted into the system. From an EMTP simulation
of the system as described above it is possible to obtain the results shown in Figure 6.5.
Near the
Static Switch
Near DR1
Near DR2
Figure 6.5 Voltage Profile in the Microgrid without Microsources.
Figure 6.5 shows the magnitude of the line to line voltages as the static switch is closed,
energizing the microgrid, with full load but without microsources. From top to bottom, the first
trace is the voltage immediately before the static switch, on the utility system side. It has a full
value of 208V before the switch is closed. As soon as connection takes place, the voltage on this
location falls to about 204.6V. The second trace is the magnitude of the voltage where
microsource 1 would be connected. The voltage is zero previous to connection and it is 202.2V
afterwards. The third trace is the magnitude of the line to line voltage at the location where
microsource 2 would be connected. The resulting voltage is 201.3V.
With this information in hand, it is possible to look at the Q-E droop and find all the required
values. The droop is reported on Figure 6.6 for ease of inspection.
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