Control Design and Management of a Distributed Energy Resources System
Corresponding email: onibonojemo@abuad.edu.ng
Published at : 04 Apr 2023
Volume : IJtech
Vol 14, No 2 (2023)
DOI : https://doi.org/10.14716/ijtech.v14i2.5884
Onibonoje, M.O., Alegbeleye, O.O., Ojo, A.O., 2023. Control Design and Management of a Distributed Energy Resources System. International Journal of Technology. Volume 14(2), pp. 236-245
| Moses Oluwafemi Onibonoje | Department of Electrical/Electronics and Computer Engineering, Afe Babalola University Ado Ekiti, Km 8.5 Afe Babalola Way, Ado-Ikare Road, Ado Ekiti, +234 Nigeria |
| Oluwafemi Oladipupo Alegbeleye | Department of Electrical/Electronics and Computer Engineering, Afe Babalola University Ado Ekiti, Km 8.5 Afe Babalola Way, Ado-Ikare Road, Ado Ekiti, +234 Nigeria |
| Adedayo Olukayode Ojo | Department of Electrical/Electronics and Computer Engineering, Afe Babalola University Ado Ekiti, Km 8.5 Afe Babalola Way, Ado-Ikare Road, Ado Ekiti, +234 Nigeria |
Energy generation,
distribution, and transmission are crucial to the development and advancement
of humans and their environment. Therefore, the need for a sustainable
environment is essential. This study focuses on designing, building, testing,
and commissioning an intelligent grid solar-powered distributed energy resource
system to serve as an alternative to powering loads with conventional energy
sources, creating a pollution-free and self-dependent system that can be built
to the capacity of the required load. The solar panels, voltage regulator,
microprocessor, solar charge controller, and batteries are all
interconnected to automatically switch between the three solar substations. The
simulation of the DER network system was executed with MATLAB, Simulink, and
Simscape Electrical. The management system was created using the Visual Studio
2019 and ASP.NET MVC software. The management system was designed to keep tabs
on the daily sales of the DER components to various clients. The results are
achieved by subjecting a load (21W rated headlight bulb and a 5W rated
fluorescent bulb) at specified time intervals (10, 20, 30 minutes). The results
showed us a particular set threshold voltage for the sub-station switch. This
project gives an insight into how good and reliable the distributed energy
resource system can be as it provides a constant power supply to the equipment.
Distributed energy; Inventory system; Modelling; Solar panel
Energy
has always been an essential factor in human civilization. However, Energy
generation and utilization are critical to ensuring rapid economic growth. With
the accelerating advancement, the energy demand is also increasing (Oyedepo, 2012).
Since conventional energy sources are limited, the inability to effectively
handle the increasing demand often leads to the energy crisis.
The
global population of about 7.674 billion people has about 940 million with out access to electricity, and
Sub-Saharan Africa has the most significant percentage. The total world energy
was 80% fossil fuels, 10% biofuels, 5% nuclear, and 5% renewable as of 2016 (Motjoadi, Bokoro, and Onibonoje, 2020; Liang et al., 2019). There
is a crucial need to start considering renewable energy sources because of the
continuous exhaustion of limited fossil fuel supply and environmental
friendliness. The distributed energy system design helps create a small-scale
unit of power generation that operates locally and is connected to a larger
power grid at the distribution level, which saves electric energy by moderatingthe usage of
grid energy, saving oil expenses sustained in using a generator (Ronak and Shah,
2018).
Nigeria's
total electricity generating capacity hovers around 13000 MW, out of which
about 4000 MW can be dispatched to its over 200 million people, which is
insufficient for the demands. Alternative means of electricity such as solar
energy could compensate for the deficit and provide cleaner and safer energy (Bolawole, Onibonoje, and
Wara, 2020; Folorunso, Onibonoje, and Wara, 2020; Ayamolowo et al., 2019).
This
study aims to model a smart grid solar-powered system, simplify the abstract
modeling components, construct the system, and implement a robust and adaptable
inventory management system. The study also intends to evaluate the performance
of the system. The scope of the paper includes
modeling and simulating a distributed energy system, in this case, a nodal
solar system, aiming to produce alternative energy means through automated
switching among three different solar nodes occasioned by present conditions.
1.1.
Distributed Generation
Figure 1
Distributed generation (Colmenar-Santos
et al., 2016)
The
systems mainly produce between 1 kW and 5 MW power supply (Ibhaze et al., 2017). Furthermore, some systems include stand-alone rural or
remote applications (such
as areas with grid access constraints), grid-connected devices that export
electricity to the grid, utility-owned devices (aimed at improving power
quality and reducing power losses in specific areas), and combined heat and
power (CHP) devices.
1.2. Distributed
Energy Resources Technologies
The exact definition of
distributed generation (DG) can vary depending on the source and capacity.
Nevertheless, it is commonly and concisely described as any limited-capacity
electric power source directly linked to the power system distribution network,
where the end customers consume it. DG is not a new notion in the growth of the
power business. Micro-turbines, combustion engines, fuel cells, wind turbines,
geothermal systems, solar systems, and other technologies
can power DG. DG occurs on two levels: the local level and the end-point level (Qurrahman
et al., 2021).
1.3. Distributed
Energy Resources Management System
Distributed energy resource
management system (DERMS), is a software platform that manages a group of
distributed energy resource (DER) assets such as rooftop photovoltaic solar
panels, behind-the-meter batteries, or a fleet of electric vehicles to deliver
vital grid services and balance demand with supply to help utilities achieve
mission-critical outcomes (Wong et al., 2018). DERMS are
used to communicate simultaneously with, control, and coordinate DER devices in
different geographic locations. For example, when excess energy is being
injected into the grid due to plentiful solar energy being produced during the
day, a DERMS can control batteries in the grid to charge using that excess
energy. On the other hand, suppose there is a lack of energy to meet demand. In
that case, DERMS can control batteries to inject energy into the grid and
control intelligent thermostats to reduce the temperature in buildings, so the
energy demand is reduced (Münz and Wu, 2021). The benefits of the DERMS
software include creating multiple, arbitrary groupings of DER and subgroups of
DER for dispatch based on whatever criteria are presented at the time, grouping
DERs and groups of DER using a recursive architecture, and providing status and
forecasting of capacity to upstream DERMS and distribution management systems
1.4. Reliability
of Distributed Energy Resource System
An entire section dedicated to energy system
reliability is warranted because it is a crucial aspect of ensuring the
sustainability of an energy system. Reliability
refers to the ability of an energy system to provide electricity at a
reasonable cost. It can be seen in how energy systems respond to problems with
energy supply. Let us examine two scenarios that frequently cause problems. In
the first scenario, a unit is rendered unable to function due to a natural
disaster or a war. The supply of imported energy is stifled in the second
scenario (Aluko, Onibonoje, and Dada, 2020; Onibonoje, 2019;
Onibonoje and Olowu, 2017). It is reasonable to assume that a unit's
failure primarily affects each consumption node that the unit serves. The
effect can manifest directly in the form of disruptions in electricity networks
or indirectly in increased electricity prices. In the worst case, a region may
remain without electricity (Alanne and Saari, 2006). Because the use of
domestic primary energy sources in the case of a centralized reference energy
system is only 1% of total primary energy use, the shutdown of a single local
primary energy source is not likely to cause significant problems. Instead, if the
import of primary energy is blocked, problems will also occur in the case of a
decentralized reference energy system. The investigations of the dynamic
modeling, stability and control of power systems with distributed energy
resources for optimal trade-offs and optimization have been conducted by (Farizal, Dachyar, and Prasetya, 2021; Onibonoje, Ojo, and Ejidokun, 2019; Sadamoto et al., 2019) The absence of a load monitoring application
was the only drawback. The work also worked on the best design and operation of
distributed energy resource systems for residential communities. However, the
main drawback was that it did not include a switching process for selecting a
distributed energy resource.
The
design layout of the distributed energy resource system is described here, with
its block diagram and that of the solar substation shown in Figures 2 and
Figure 3, respectively.
2.1. Operating
Principle of the DER System
2.2. The
Software Unit
Figure
3 Composite blocks of the solar substation
Planning: the features of the application are organized, and these
include pages, a database, and navigation.
Environment Setup: the environment is set up for development by
following the guidelines in the Visual Studio documentation. The documentation
includes creating a new project, setting up the environment for growth, and
linking the project with the database.
Writing/Coding Application: After setting up the environment, coding is
carried out using the different components of the C# Programming Language and
the ASP.NET MVC framework CRUD function to implement the functions of the
inventory system.
Debugging, Testing, and Running the Application: this phase was iterative.
Each time the code is updated, it is debugged immediately to check for bugs
that need fixing. Thus, local testing was done using the iterative model after
minor changes or updated implementations in the code. Also, different types of
tests were carried out to validate the correctness and robustness of the
application.
2.3. Solar
Modules Specification
The heart of the
photovoltaic system is the solar module. Considering the efficiency and price
of solar modules on the market, the mono-crystalline type being the most
appropriate for this project, three panels were used to analyze the system. The
PV modules typically do not require any further improvement aside from
maintenance, such as regular cleaning. Therefore, for this project, three
30W/24V panels were chosen.
The performance metrics of the DER system and its peripherals were
measured and compared to the simulated and expected values derived from
modeling and calculations.
3.1. Simulated Results of the
DER System
The island and
main utility micro-grid were subjected to dynamic disturbances by disconnecting
the island grid entirely from the primary utility grid and opening the island
grid breaker for 10 seconds. Then, at 40 seconds on the variable load, a 300 kW
load was added.
The frequency disturbances, as shown in Figure 4, occurred due to the islanding of the microgrid at 10 seconds and the additional load added at 40 seconds. The microgrid's distributed resources change over time depending on how it operates. The solar array (PV) tracks the irradiance over time. The diesel generator (GenSet) tried to hold everything steady by making up all the additional power output (maintaining unity frequency and unity voltage) as islanding occurs at 10 seconds. At 40 seconds, an extra load of 300 kW was added to the microgrid. In addition, the energy storage system maintained a steady power output of 100 kW. The microgrid voltage, however, was a flat or steady line instead of the expected three-phase AC waveform due to the use of a phasor simulation type in the simulation.
3.2. Results of the DER hardware
3.2.1. Continuity test
Results showed that continuity was achieved in all the components and the overall system, so electrical connection exists and current flows through the system.
3.2.2. Switching speed test
Figure 4 Simulation Result
3.2.3. Charging and discharging rate tests
Results showed that the solar panel would take approximately 4 hours to recharge the battery from 11.4V to 12V. Also, the result showed that the 26W car headlight bulb and 5W fluorescent bulb would take 30 minutes to discharge the battery from 12V to 11.4V.
3.3. Evaluation Procedure
After installation, the
measured output of the DER system gave the expected results. Table I presents
the run-down of the system and battery bank results we obtained. A 12V/26W car
headlight and 5W fluorescent bulbs were used as load. A stopwatch was used to
record the time at batteries got drained. The system is designed so that when
the battery voltage drops from 12.1V to 11.4V, it switches to the next
substation. The average values obtained were computed in the table.
Table I shows how the DER
system works with load; it is observed that when the sub-station passes the set
threshold, the system automatically switches to the next sub-station within a
millisecond. However, when sub-station 3 is low, the system is switched off
entirely.
Table 1 Evaluation results
|
Station |
Sub-station 1 |
Sub-station 2 |
Sub-station 3 |
|
Threshold (V) |
11.5 |
11.5 |
11.5 |
|
Load (V/W) |
12/26 |
12/26 |
12/26 |
|
Starting Voltage |
12.1 |
12.0 |
11.9 |
|
Time (0 min) |
11.9 V |
standby |
standby |
|
Time (10 mins) |
11.8 V |
standby |
standby |
|
Time (20 mins) |
11.7 V |
standby |
standby |
|
Time (30 mins) |
11.4 V |
standby |
standby |
|
Time (0 min) |
standby |
11.7 V |
standby |
|
Time (10 mins) |
standby |
11.6 V |
standby |
|
Time (20 mins) |
standby |
11.4 V |
standby |
|
Time (0 min) |
standby |
standby |
11.8 V |
|
Time (10 mins) |
standby |
standby |
11.6 V |
|
Time (20 mins) |
standby |
standby |
11.4 V |
3.4. Installation of the DER
System
The most important part of
the system is the first installed solar panels. The installation of the battery
bank quickly followed that of the panels. During the battery installation,
careful attention was paid to the possibility of a short circuit. The batteries
and their terminal voltages were also carried out during installation. This
ensures that the overall output would give us the expected output.
The output of
the terminal of the battery bank was connected to the charge controller. Tight
connections were all ensured in the process. After successfully installing the
solar panel, battery bank, and voltage regulator, the completed project was
simulated and analyzed. Pictures of the distributed energy resource system
during coupling were shown in Figure 5(a); and the assembled unit with the
solar panel was shown in Figure 5(b).
Figure 5 The hardware units: (a) Solar Charge Controller; and (b) Assembled unit with Solar Panels
3.5. Inventory Management
System
Figure 7 Sales order page
I thank the Founder and
management of Afe Babalola University Ado Ekiti (ABUAD), Nigeria for the payment
for the research publication, and the staff and students of the Department of
Electrical/Electronics and Computer Engineering of the institution for their
contributions during the data collection stage of the research.
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