Abstract:
The penetration of Renewable Energy Sources (RESs) into microgrids is gaining
huge significance in recent times. RESs are integrated with conventional grid systems to meet
the growing energy demand and to enhance the power quality. The increasing penetration of
RES into the grid system affects the stability of frequency in microgrids due to the stochastic
nature of photovoltaic (PV) and wind energy generation. Unlike in traditional power generation
systems, the lack of rotational inertia in microgrids is one of the critical concerns which affects
the integration of RES with the grid system through power electronic converters. This
introduces more uncertainties into the system and hence the operation and control of such a
system becomes more complicated. In order to maintain the stability of microgrids and to
effectively utilize RESs and distributed generation (DG) systems, it is essential to control
virtual inertia. Proper inertia control improves the flexibility of microgrid operation and as a
result various controlling strategies have been proposed in the past to control the virtual inertia.
This paper presents a new virtual inertia control (VIC) approach with a multi power level
controller (MPLC) for RES integrated microgrids. Considering the high level penetration of
RES, the proposed approach is designed to enhance the system performance under sudden load
variations and frequency variations. The efficiency of the proposed control approach is
validated with and without MPLC. Results show that the controller achieves better frequency
stability with MPLC.
