Abstract
The electric power grid crisis is kept on accelerating every day due to additional load
demand that was not initially rescheduled during power system planning. This
results in voltage dip, frequency fluctuations, poor grid performance and ultimately
results in load shedding. In earlier decade, load consumers were fully dependency
on thermal power plant and other conventional power stations which is now collapse
due to increase in load demand, lower efficiency and also has an impact on the
environmental health and life of a human being globally. The renewable energy
sources (RESs) technology such as solar photovoltaic (PV) is a primary solution that
may contribute to such cases, for its cost-effective and to deliver cleaner energy to
the modern and highly developed society and industries. However, RES technology
is not sufficient to fulfil the load demands due to its highly dependency on weather
conditions, less MW generated and due to variable nature of the load demand. To
maintain the power balanced between utilities and load demand in the power plant,
load frequency control (LFC) is essential to achieve the balance between generation
and load demand continuously. However, LFC alone is no longer sufficient for timeto-
time load fluctuations and hence need the controllers to achieve the standard
frequency and to reduce the unscheduled power exchange between control areas.
In this research work, a solar PV oriented LFC model, fuzzy logic, optimization
based LFC solutions and diverse energy storage applications are presented to
ensure a renewable oriented LFC model and a robust controller designs are shown
that can meet the requirements of LFC of the power system.
Firstly, in response to the escalating load demand for electric power and the
importance of balancing the total power being generated, this study introduces a
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variable structure fuzzy controller integrated into LFC of hydro-thermal power
system. This activity reveals that the integration of PV power into hydro-thermal
systems can improve the LFC outputs and mitigate system deviations in the face of
different disturbance scenarios. Simulation results have demonstrated the controller
as an effective tool to handle a wide range of operating conditions.
Secondly, this research study introduces a flower pollination algorithm optimized
proportional integral derivative (FPA-PID) controller incorporated with unified power
flow controller (UPFC) and redox flow battery (RFB) as a new method to improve
LFC challenges in the thermal-thermal power system. Through simulations, three
distinct error values were considered, and the performance of this method were
compared with other recent optimization techniques. The carried out results
emphasize the benefits of introducing unified power flow control (UPFC) in series
with the tie-line and incorporating redox flow battery (RFB) separately using FPAPID
scheme. Additionally, the results unequivocally highlight the effectiveness and
superiority of the approach proposed in this activity.
Thirdly, to overcome the LFC challenges, this research proposes an approach
that includes the energy storage devices (ESDs) such as battery energy storage
system (BESS) and fly-wheel energy storage system (FESS) incorporated with
stochastic fractional search algorithm optimizes proportional integral derivative
(SFS-PID) controller. In addition to standard PID, a fractional derivative is introduced
and optimized through SFS-PIDDμ for LFC. A proposed control approach was
matched with recent state of art and it is seen that the SFS-optimized PID with
fractional derivative. It is found that the SFS-PIDDμ achieves Integral of Absolute
Error (IAE)=0.006786, Integral Time Multiplied Square Error (ITSE)=1.07e-05, and
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Integral Time Absolute Error (ITAE)=0.01853, which are significantly lower than the
error values produced by other LFC techniques. inclusion of solar PV and with
application of ESDs significantly reduces settling time and mitigates undesired
oscillations in frequency and tie-line power deviations, achieving a better LFC
system. The PV integration has further decreased the ITSE to 7.872e−06, the ITAE
to 0.008953, and the IAE to 0.005376. All error levels have been further reduced
because of the integration of unified power flow control (UPFC) in series with the
tie-line and redox flow battery (RFB) separately. In addition, the robustness of the
proposed approach is also presented for various operating scenarios.