LoRa-based communication system for data transfer in microgrids

This paper proposes a LoRa-based wireless communication system for data transfer in microgrids. The proposed system allows connection of multiple sensors to the LoRa transceivers, and enables data collection from various units within a microgrid. The proposed system focuses on communications at the secondary communication level of the microgrid between local controllers of each distributed generation (DG) unit and the microgrid central controller due to the possibility of applying low-bandwidth communication systems at this level. In a proof of concept test bed setup, the data collected by the sensors are sent to the LoRa gateway, which serves as the central monitoring system from which control messages are sent to various microgrid components through their local controllers such as DG units, storage systems and load. In this work, to improve communication security, a private server has been developed using Node-Red instead of cloud servers that are currently used in most Internet-of-Things (IoT) monitoring systems. A range test of the proposed system is carried out to observe the rate of data delivery. It demonstrated over 90% data delivery at 4 km. Finally, a test bed experiment is conducted to validate key features of the proposed system by achieving one-directional data transfer in a grid monitoring system

Feasibility study, dynamic modeling, optimization, and implementation of low-cost communication systems for remote DC microgrids in Nigeria

Renewable energy-based microgrids are important contributors toward meeting the growing global energy needs in remote communities. In designing such microgrids, Supervisory Control and Data Acquisition (SCADA) systems and their communication methods are very crucial towards achieving reliable parameter control for optimal performance. A hierarchical microgrid is, in general, divided into three control levels: primary, secondary, and tertiary. Research over the years showed that control of the primary control level could be achieved without communication systems using control schemes such as droop control and other modified communication-less control schemes. On the other hand, the secondary and tertiary control levels are mostly achieved using communication systems for data transfer between the controllers. This, therefore, entails that a reliable and robust communication system that meets the requirements of each control level supported by a SCADA system is essential in achieving the optimum performance of a remote microgrid. The first part of this thesis presents a techno-economic sizing of AC and DC microgrids for a remote rural community in West Africa. In the first research, an AC microgrid was sized in Homer to meet the energy requirements of the community. Being that the community was a peasant community, it had low amount of electrical equipment and as such had lower energy needs. Further, due to the low energy requirement, a DC microgrid was sized for the same community after analysing the community. The sized DC microgrid also met the energy needs at a low financial cost. The result of the sizing showed that when the traditional AC equipment was switched to DC, the community energy needs were reduced and well met with a DC microgrid. Finally in this part of the research the sized DC microgrid was simulated in MATLAB and the control schemes were employed to observed the dynamic performance of the DC microgrid. The second part proposes a LoRa-based wireless communication system for data transfer in DC microgrids at the secondary control level. The proposed method allows the connection of multiple sensors to the LoRa transceivers and enables the data collection from various units within a microgrid. Chapter 4 and Chapter 6 focused on communications at the secondary communication level of the microgrid between local controllers of each distributed generation (DG) unit and the microgrid central controller due to the possibility of using low-bandwidth communication systems. The data transfer process and management scheme for priority data transfer in a microgrid are analyzed. Furthermore, the data transmisson time, and control action transmission between the central microgrid and the local microgrids are assessed. The third part presents an open-source, low-cost Internet of Things (IoT) based SCADA system that uses the Chirpstack IoT platform to achieve SCADA functions. The proposed system is an improvement to the existing IoT solutions by eliminating cloud-based IoT platforms and introducing an all in one system where the IoT gateway and platform are installed on one machine. This solution increases systems reliability by reducing the number of components and at the same time, reducing the costs involved. This solution eliminates the requirement for the internet for data transfer. The proposed system prototype consists of voltage and current sensors, Arduino Uno microcontroller, and Raspberry Pi. The sensors acquire data from the monitored unit. The Arduino Uno receives and processes the data for transmission to the Raspberry Pi using LoRa communication. At the Raspberry Pi, the local Chirpstack platform processes and displays the measured data using the Grafana dashboard for real-time data monitoring. The information is stored in an InfluxDB database. For system validation purposes, the prototype is designed, developed, and set up to monitor a set of solar photovoltaic (PV) panel voltages, currents, and battery voltages. The results obtained from the test setup are compared with the physical point measurements. The proposed system is featured as a low-cost, open-source, scalable, and interoperable system. This, therefore, makes the proposed SCADA system an alternative for commercial SCADA systems, especially for remote renewable energy-based microgrid applications. The system proposed in this research can be deployed for large industrial systems with appropriate upgrades and customization

An Open Source LoRa Based, Low-Cost IoT Platform for Renewable Energy Generation Unit Monitoring and Supervisory Control

SCADA provides real-time system monitoring by constant communication and data exchange between various system devices to achieve data visualization and logging. Presently, in industrial systems, commercial SCADA systems are being used for data monitoring and control. These systems can be expensive, and as such can only be afforded by select industries. Even at these costs, the commercial SCADA systems face some challenges, which include interoperability and scalability issues. Research has shown that these problems can be solved by the introduction of low-cost materials and open-source software to achieve data monitoring for all levels of processes. This paper proposes an open source, low-cost Internet of Things (IoT)-based SCADA system that employs the IoT architecture for SCADA functions. The proposed system is an improvement to the existing IoT solutions by eliminating cloud based IoT platforms and introducing a single machine system. This solution increases the robustness of the system while reducing costs. The proposed system prototype consists of voltage and current sensors, Arduino Uno microcontroller and Raspberry Pi. The sensors acquire data from the monitored unit. The Arduino Uno receives the data and processes them for transmission to the Raspberry Pi using the LoRa communication technology. At the Raspberry Pi, the local Chirpstack platform processes the data and displays the measured data using the Grafana dashboard for real-time data monitoring, and the data is stored in an InfluxDB database. For system validation purposes, the prototype is designed, developed, and set up to monitor the panel voltage, current and battery voltage of a solar photovoltaic system. The results obtained from the experimental set-up are compared with the test data from physical digital multimeters. The system presented in this paper is a low-cost, open source, scalable and interoperable system. This, therefore, makes the proposed SCADA system an alternative for commercial SCADA systems, especially for select applications. The system proposed in this paper can be deployed to large industrial systems with appropriate upgrades and customization. The main contribution of this research is the design and development of a SCADA system that performs all the functions of a proprietary SCADA system at a very low-cost with scalable and interoperability features which are the main limitations of the traditional SCADA systems