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Integrated renewable energy sources with droop control techniques-based microgrid operation 43

Figure 3.3 DC micro grid.

the system. Hence the DC bipolar configuration is an enhanced selection in electrical
power system. The issue of microgrid availability is directly related to the distribution
system. The provision of DC microgrid is damaged by the circuit design for the inter-
facing devices between the DG sources and also the microgrid. Another issue of this
DC microgrid is the stability control, which can be mainly related with the intercon-
nected power electronic devices like RES, ESS, and load. Nowadays, constant loads
could be replaced by voltage oscillations into the microgrid to overcome by means of
system capacitance, and load resistance is increased and the system inductance can be
reduced [22].

3.2 AC microgrid
AC microgrid can be classified into coupled AC and decoupled AC microgrid network
configurations. The coupled AC and decoupled AC microgrid network configuration
can be initiated by the connection with the AC, DC, and the utility grid. The coupled
AC microgrid is directly connected to the utility grid through the transformer, which
is placed at the point of common coupling (PCC). In the normal mode, microgrid
directly connected to the utility grid is one of the advantages of AC coupled net-
work. This can reduce the level of the voltage then the AC and DC low voltage (LV)