ABSTRACT:
Microgrids
being an important entity in the distribution system, and to get their full
advantages by
incorporating maximum distributed generation, standalone hybrid renewable
energy systems (HRESs), being environmentally-safe and economically-efficient,
are considered as the promising solution to electrify remote areas where the
grid power is not available. In this work, a techno-economic investigation with
an optimal design of HRES is presented to fulfill the domestic electricity need
for a residential area of the Sherani district in the Province of Baluchistan,
Pakistan. Nine case studies based on PV/wind/diesel/battery are analyzed based
on net present cost (NPC), cost of energy (COE), and emission to decide the
feasible solution. HOMER tool is utilized to accomplish modeling and simulation
for economic analysis and optimal sizing. Simulation results demonstrated that
HRES with PV-wind-battery is the most viable option for the specified area, and
the optimal sizing of components are also obtained with $ 28,620 NPC and 0.311
$/kWh COE which shows 81.65% reduction in cost and 100% preserving in toxic
emission while fulfilling 100% energy demand with 67.3% of excess energy.
Furthermore, MATLAB/Simulink modeling for the optimally designed system is
built for technical analysis while its effectiveness is proved by keeping dc and
ac buses voltage constant, safe operating range of battery state of charge
(SOC) with active power balance between HRES components, as well as efficient
ac voltage quality, regardless of generation disturbances and load fluctuations.
The output signal has total harmonic distortion (THD) of 0.30% as compared to
5.44% with the conventional control scheme. The novelty lies in the sequential
application of both HOMER and MATLAB simulations of the proposed HRES model and
validation of the proposition for the studied area; by using and implementing
model predictive control (MPC) of a reconfigurable inverter.
SOFTWARE:
MATLAB/SIMULINK
CONCLUSION:
Standalone
HRES with PV-wind-battery is proposed as the optimal and economically most
viable system, as determined by techno-economic studies carried out through
HOMER and MATLAB along with FCS-MPC of a reconfigurable inverter, to fulfill
the residential electricity requirement of Sherani district in the Province of
Baluchistan, Pakistan. Firstly, optimal sizing of HRES components and economic investigation
is performed through HOMER, while simulation studies for the suggested area
with practical and real data of load profile as well as weather is investigated
using different costs (capital, replacement, O&M), operating life, and efficiencies
of HRES components, project lifetime, meteorological data assessment, and
interest rate as the input parameters; load demand, resources availability,
operating reserves, allowable capacity shortage, GHG emission penalties as optimization
constraints; and NPC as decision variable. Out of nine possible optimal
configurations namely PV-wind-battery, PV-wind-diesel-battery, PV-battery, PV diesel-
battery, wind-diesel-battery, PV-wind-diesel, PV diesel, wind-diesel, and
diesel-battery, as examined during this work, PV-wind-battery is obtained as
the most feasible and economically viable configuration (i.e. winning plan)
with minimum NPC ($ 28,620) and COE (0.311 $/kWh) which shows 81.65% reduction
in cost and 100% preserving in toxic emission, while fulfilling 100% energy
demand with 67.3% of excess energy. The proposed optimal HRES design (winning plan)
comprises 13.4 kW PV, 4 kW wind, 3.88 kW converter, and 20 units of 2.37 kWh
lead-acid battery. Optimal sizes of HRES components are then used to design a management
and control strategy in MATLAB/Simulink with finite control set model
predictive control (FCS-MPC) of reconfigurable inverter for technical analysis
based on power balance between HRES elements, constant dc and ac voltages, safe
operating range of battery SOC, efficient ac voltage quality, during variations
of PV irradiance, wind speed, as well as load demand. The results are validated
through simulations with total harmonic distortion (THD) of 0.30% which is well
below the allowable limit according to IEEE-929 and IEEE-519 standards as
compared to 5.44% THD with the conventional PI control scheme.
The
presented scheme would be an assessing tool for the governments, energy
sector/microgrid planners, model designers, and researchers to investigate
suitable policies, mechanisms, effective and efficient design of HRESs. An increasing,
unpredictable and abrupt load demand of the society can be handled by
integrating more renewable generation in terms of a reliable, economical, and environment-friendly
scenarios with an understanding of intermittent generation profile. The future
work includes microgrid reconfiguration under inverter and rectification mode
to control the voltage and frequency during the standalone mode, and power flow
during the grid-connected mode.
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