English abstract
The current trend in power system evolution involves the extensive integration of
Renewable Energy Sources (RESs) to address the environmental concerns associated
with traditional power plants. Consequently, the capacity of RESs and Distributed
Generators (DGs) is rapidly expanding worldwide, with even higher levels of
penetration planned for the next two decades. While this increased incorporation of
RESs and DGs is beneficial for renewable energy utilization, it poses challenges to
power system stability, especially regarding frequency stability. The lack of inertia in
power electronics interfaces (such as converters/inverters) means that the rising
penetration of RESs and DGs will further diminish system inertia and impact the
system's damping characteristics. Therefore, the growing presence of RESs not only
negatively affects power system stability but also creates new challenges in
maintaining power system frequency stability.
The Sultanate of Oman's government is focused on harnessing renewable energy for
electricity generation to lower carbon emissions and decrease reliance on fossil fuels.
The goal is to achieve 20% of electricity production from renewable energy sources
by 2030 [1]. The employment of inverter-based renewable energy generators impacts
the inertia and the rate of change of frequency (ROCOF) in the main interconnected
system (MIS). To support the Sultanate's vision of increasing reliance on renewable
energy sources as per the plans in this regard, this Thesis focuses on studying the
application of the virtual inertia concept to the MIS to maintain system frequency
stability and facilitate the future implementation of renewable energy projects while
ensuring network stability. The impact of the increased penetration of renewable
energy sources on the inertia level of the MIS was studied using the DIgSILENT
software. Additionally, a virtual inertia control system based on advanced algorithms
(Type 2 fuzzy-PID controller) was developed and tested on MIS model using
MATLAB/Simulink software. The efficiency of the developed controller was verified
through several tests that included scenarios with high penetration of renewable energy
sources.
