Article
Design of a Partially Grid-Connected Photovoltaic Microgrid
Using IoT Technology
Mahmoud Shaban
1,2
, Imed Ben Dhaou
3,4,5
, Mohammed F. Alsharekh
1,
* and Mamdouh Abdel-Akher
1,2
Citation: Shaban, M.; Ben Dhaou, I.;
Alsharekh, M.F.; Abdel-Akher, M.
Design of a Partially Grid-Connected
Photovoltaic Microgrid Using IoT
Technology. Appl. Sci. 2021, 11, 11651.
https://doi.org/10.3390/
app112411651
Academic Editor: Pierluigi Siano
Received: 2 November 2021
Accepted: 1 December 2021
Published: 8 December 2021
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4.0/).
1
Department of Electrical Engineering, College of Engineering, Qassim University,
Unaizah 56452, Saudi Arabia; s.mahmoud@qu.edu.sa (M.S.); ma.ahmed@qu.edu.sa (M.A.-A.)
2
Department of Electrical Engineering, Faculty of Engineering, Aswan University, Aswan 81542, Egypt
3
Department of Computer Science, Hekma School of Engineering, Computing, and Informatics,
Dar Al-Hekma University, Jeddah 22246, Saudi Arabia; imed.bendhaou@utu.fi
4
Department of Future Technologies, University of Turku, 20520 Turku, Finland
5
Department of Technology, High Institute of Informatics and Mathematics, University of Monastir,
Monastir 5000, Tunisia
* Correspondence: m.alsharekh@qu.edu.sa
Abstract:
This study describes the design and control algorithms of an IoT-connected photovoltaic
microgrid operating in a partially grid-connected mode. The proposed architecture and control design
aim to connect or disconnect non-critical loads between the microgrid and utility grid. Different
components of the microgrid, such as photovoltaic arrays, energy storage elements, inverters, solid-
state transfer switches, smart-meters, and communication networks were modeled and simulated.
The communication between smart meters and the microgrid controller is designed using LoRa
communication protocol for the control and monitoring of loads in residential buildings. An IoT-
enabled smart meter has been designed using ZigBee communication protocol to evaluate data
transmission requirements in the microgrid. The loads were managed by a proposed under-voltage
load-shedding algorithm that selects suitable loads to be disconnected from the microgrid and
transferred to the utility grid. The simulation results showed that the duty cycle of LoRa and its bit
rate can handle the communication requirements in the proposed PV microgrid architecture.
Keywords: IoT; PV microgrid; partially grid-connected mode; LoRa gateway; smart-meter; ZigBee
1. Introduction
Electric power systems have been developed over the past century until they became
integrated systems in terms of planning, management, operation, and control. These
systems are characterized by central bulk power generation power plants connected to
consumers through high-, medium-, and low-voltage transmission and distribution net-
works. This complex power system forms the backbone of modern human civilization.
The existing infrastructure uses strategies and technologies that were developed many
decades ago, which utilize limited control and digital communication technologies of the
21st century [
1
]. Moreover, climate change concerns and environmental issues urged many
countries to adopt new strategies for reducing the dependency on fossil fuels to reduce car-
bon dioxide emissions. Clean energy production is achieved through enabling renewable
energy generation and integration into electrical energy systems. Power systems need to
meet changes in generation profiles to create intelligent tools that rely on advanced sensors,
ICT (information and communication technologies), and digital control technologies that
can distribute electricity effectively, economically, and securely.
Renewable power integration can provide many advantages such as lowering cost and
increasing system reliability, power quality, and energy efficiency [
2
,
3
]. The integration of
renewables is achieved in the form of either mega-sized renewable energy parks connected
to the main grid or small-sized units connected to distribution systems. Besides these,
Appl. Sci. 2021, 11, 11651. https://doi.org/10.3390/app112411651 https://www.mdpi.com/journal/applsci
