Solar-powered Microgrids Research Articles

Solar Powered DC Micro Grid for Transmission Line

Abstract: The increasing demand for sustainable and renewable energy solutions has prompted the exploration of solar power as a viable alternative to traditional fossil fuel-based energy sources. To efficiently transmit and distribute solar power, the integration of direct current (DC) transmission systems has gained attention due to their inherent advantages, such as lower losses and improved efficiency. However, the widespread adoption of solar-powered DC microgrids for transmission remains limited. This research paper aims to address this gap by investigating the feasibility and viability of a solar-powered DC microgrid for transmission. The research begins with a comprehensive review of existing power transmission systems, highlighting the advantages and limitations of DC microgrids and previous studies on solar-powered microgrids. By analysing the existing challenges and gaps in the literature, this study identifies the need for a thorough evaluation of the performance and effectiveness of solar-powered DC microgrids.

Multi Microgrid Framework for Resilience Enhancement Considering Mobile Energy Storage Systems and Parking Lots

This paper proposes a practical and effective planning approach that takes advantage of the mobility and flexibility of mobile energy storage systems (MESSs) to increase distribution system resilience against complete area blackouts. MESSs will be very useful for boosting the system’s resilience in places affected by disasters when the transmission lines are damaged. A joint post-disaster restoration strategy for MESSs and PEV-PLs is proposed, along with distributed generation and network reconfigurations, to reduce total system costs, which include customer interruption costs, generation costs, and MESS operation and transportation costs. The integrated strategy accounts for the uncertainty of the production of wind- and solar-powered microgrids (MGs) and different forms of load demand. Therefore, this paper assesses the effect of MESSs on distribution system (DS) resilience in respect of MG cost reduction and flexibility. Due to the multiple networks, PEV-PLs, DGs, and MESS limitations, the suggested restoration problem is stated as a mixed-integer linear programming problem. The suggested framework is complemented using a benchmark testing system (i.e., 33-bus DS). To assess the effectiveness of the proposed model, the model’s output is contrasted with results from typical planning and a traditional model. The comparison of the data shows that the suggested model, in addition to MESSs, effectively achieves a large decrease in cost and enhances the DS resilience level.

A Linear Regression Model for THD Sensitivity in PV Based Microgrid with Varying Insolation Levels

Solar PV systems can be used for powering small microgrids in rural area of developing countries. Generally, a solar power microgrid consists of a PV array, an MPPT, a dc-dc converter and an inverter, particularly as the general loads are A.C in nature. In a PV system, reactive current, unbalancing in currents, and harmonics are generated due to the power electronics-based converters as well as nonlinear loads (computers induction motors etc). Thus, estimation of the harmonics levels measured by the Total Harmonic Distortion (THD) is an essential aspect of performance assessment of a solar powered microgrid. A major issue that needs to be examined is the impact of PV system control parameters on the THD. In this paper, we take up this assessment for a small PV based rural microgrid with varying levels of solar irradiance. A Simulink model has been developed for the study from which the THD at equilibrium conditions is estimated. This data is in turn used to design a generalized Linear Regression Model, which can be used to observe the sensitivity of three control variables on the magnitude of the THD. These variables are: Solar Irradiance levels, Power Factor (PF) of connected load magnitude of the connected load (in kVA) The results obtained show that the greatest sensitivity is obtained for load kVA variation.

A comprehensive distance protection strategy for solar-powered textile microgrid

The power demand in textile industries is fulfilled by the utility grid and diesel generators. However, due to the low reliability and high cost of power from these resources, the industries now install solar-powered microgrids on their premises. The issues such as bidirectional power flow and changing fault current level are obvious with PV installations. The protection system in traditional textile grids employs overcurrent relays, but these relays are not suitable for PV integrated systems. Furthermore, in industrial microgrids sensitivity and selectivity are two essential requirements, which are not available in overcurrent relays. To overcome these challenges, this paper proposes a comprehensive distance protection strategy for PV-powered textile microgrids. The proposed scheme utilizes a backward and forward configuration of distance relays, tested for different types of faults and variable fault currents in different scenarios. It is observed that the designed strategy gives the best performance for any kind of fault, and there is no overlapping of protection zones during the operation. The paper also presents the distance relay setting criteria to provide the full-proof protection of textile microgrids.

A cost-oriented resource scheduling of a solar-powered microgrid by using the hybrid crow and pattern search algorithm

The tendency towards more and more employing renewable energies, particularly at the distribution system level and the residential sector has significantly increased. The growing penetration level of distributed generation (DG) units based on renewable energies has brought several challenges into power system operation and management. Thus, developing and proposing efficient energy management systems is regarded as a critical task in the area of power system operation. This issue is more highlighted in microgrids (MGs), that are mainly based on DG units. Accordingly, a day-ahead energy management system is proposed, which is operating in the grid-connected mode and equipped with a photovoltaic (PV) panel, a wind turbine (WT), and a microturbine (MT), besides the energy storage system. A detailed mathematical model was used for the PV panel and different weather circumstances and their impacts on the solar power generation and MG day-ahead resource scheduling problem are investigated. Afterward, a hybrid optimization algorithm, obtained by combining the crow search algorithm and pattern search method, known as (HCS-PS) has been proposed to deal with the problem for a 24-h scheduling period. The results, obtained from simulation show that the suggested HCS-PS method is capable of resulting in more superior solutions compared to some other well-established optimization algorithms. Moreover, the uncertainties of the problem due to the intermittent renewable power generation, load demand, and market price, have been successfully handled by deploying a scenario-based stochastic optimization technique.

Implementation of a Stable Solar-Powered Microgrid Testbed for Remote Applications

An intrinsically stable microgrid, operated by inverter-interfaced distributed energy resources (I-DERs) is introduced in this paper. The microgrid is built upon a systematic design method, which is adapted from the operation of the synchronous machine (SM). The proposed method analogizes the dynamics of the dc-link in I-DERs to the rotor dynamics in synchronous generators (SGs) and utilizes the capacitor as energy storage. Thus, the proposed mechanism relaxes battery usage for frequency control, and by using the capacitive stored energy, provides a high fault ride-through capability, which is suitable for both on-grid and off-grid applications. Based on stability analysis of the SG and the dynamic state matrix eigenvalues for multimachine power system, the dc-link capacitor of I-DERs is characterized in the context of microgrid. The dc-link capacitor stores kinetic energy similar to the rotor of the SG and provides inertia in transients without the need of battery storage. The inverter angle responds to the change of the dc link voltage (energy). The dc-link voltage is then controlled similar to the field control pertaining to the SG. Finally, a governor-like mechanism is applied to maintain dc-link voltage stability. Simulation and experimental results are provided to show the effectiveness of the proposed design mechanisms.

Demand-side management for off-grid solar-powered microgrids: A case study of rural electrification in Tanzania

This work proposes a novel and sustainable energy development strategy for addressing the energy shortages in rural areas and the low energy efficiency of off-grid solar power systems. This study combines the analysis of power consumption type with consumption anomaly detection to characterize households’ power consumption habits and ensure the safety of a system. Specifically, the proposed anomaly detection method is a hybrid nonintrusive model. The home power usage data are collected and processed by auto-data-binning without manual labeling, and thus, the training cost is reduced to enable the application of machine learning technologies in underdeveloped areas with limited computational resources. With the premise of limited energy sources in off-grid areas, the proposed power consumption analysis method divides home power usage habits into four different types. Different feedback mechanisms are adopted to extend the microgrid’s supply time according to the analysis results. The proposed method significantly increases the utilization of local renewable energy and improves residents’ experience. The proposed method is implemented in a rural village in Tanzania; after long-term monitoring, the validity of the proposed method is demonstrated.

Evaluating the Performance of Hybrid Ultra Capacitor (HUC) in a 1.5kw Solar Powered Microgrid with Hybrid Energy Storage System (HESS)

Evaluating the Performance of Hybrid Ultra Capacitor (HUC) in a 1.5kw Solar Powered Microgrid with Hybrid Energy Storage System (HESS)

ANFIS Based Smart Control of Electric Vehicles Integrated with Solar Powered Hybrid AC-DC Microgrid

In the coming years, charging of electric vehicles (EVs) may impose significant power loads on the existing utility system. Alternatively, the integration of EVs with distributed generation units may cause several uncertainties in microgrids. In such situations, controlling the frequency of microgrids will be a challenging task. Consequently, this calls for the requirement of implementing proper control techniques for utilizing EVs potential to act both as source and load. This paper proposes and evaluates the performance of the Primary ANFIS MPPT Controller for PV systems and Secondary ANFIS EV Controller for EV charging stations. The Primary ANFIS MPPT controller strictly monitors the power extracted from photovoltaic systems in different temperature and irradiance conditions. The Secondary ANFIS EV Controller schedules charging/discharging of plugged-in EVs w.r.t microgrid’s frequency and EV battery’s state of charge. To investigate the performance of proposed smart controllers, a hybrid solar-powered AC-DC microgrid is designed and tested. Dynamic simulations performed in MATLAB/Simulink demonstrate the right performance of smart ANFIS controllers in terms of frequency control. Moreover, extensive comparison studies conducted between proposed methods and existing techniques justify the higher suitability of developed controllers.

Power to the people: Assessing the potential of solar microgrids v. standalone home systems in the developing world

Ikea is working on an idea to bring electricity to the estimated 1.1 billion people on earth who currently have no grid access. The “SolarVille” concept envisions solar-powered microgrids in which users buy energy from each other using blockchain. However, a different approach that brings affordable standalone solar systems to individual households without the need for investment in a microgrid has already attracted considerable venture capital and is enjoying rapid take-up in some countries. Experts are watching to see which model has the best chance for success.

Joint Optimization of Operation and Maintenance Policies for Solar-Powered Microgrids

In a solar-powered microgrid (MG), the optimal maintenance strategy is influenced by the downtime cost of the photovoltaic (PV) system, which in turn depends on the operation PV within the MG network. Also, the dispatch policy used in the MG will influence the economic feasibility of maintenance plans. In this paper, we present an approach for optimizing the operation and maintenance policy jointly for a solar-powered MG considering the dependence between the two policies. The two-layered approach presented in this paper seeks to unify the practicality of simulation and the efficiency of analytical models. In the upper layer, we optimize the operation of MG by solving the optimal power dispatch within the MG network using linear programming approach. Then, we calculate the penalty costs under the aging conditions of PV systems. In the bottom layer, by incorporating the penalty costs as input parameters, we use a continuous-time Markov chain model to calculate the optimal maintenance policy for the PV system. The proposed approach could be used in the stipulation process between MG owner and PV system maintenance provider to minimize the money waste on both sides.

Microgrids offer flexible energy generation, for a price

In the 1990s, University of Wisconsin researcher Robert Lasseter was working in an academic no-man’s land. Lasseter was investigating small devices of less than 100 kilowatts called microturbines that were used in buildings as backup power generators. Some buildings had several of these devices, and Lasseter and his students wanted them to operate synchronously as one integrated power-generation source. A not-for-profit called Mlinda has installed about a dozen solar-powered microgrids, such as this one in Sahitoli in Jharkhand, India. Image courtesy of Mlinda. It was a big ask. The devices weren’t designed to cooperate with each other. Link too many of them, and dangerous voltage and frequency fluctuations could crash the setup. After several years of research, the scientists designed hardware, called controllers, that could regulate the voltage and frequencies such that multiple generators and loads could be added seamlessly to form a simple power grid. They set up a proof-of-concept in Columbus, OH. In 2002, Lasseter gave a talk at the Institute of Electrical and Electronics Engineers Power Engineering Society winter meeting titled, simply, “Microgrids,” and laid out his vision. Microgrids should be able to operate independently, or in “islanded” mode, from the central grid, he said. The system should be modular so that new generation sources and loads can be added to the system without additional configuration. And in many cases, microgrids could be linked to the central grid, drawing or supplying power as needed from or to the larger system (1). It was a brave new vision for electricity generation. For the past 150 years, electricity has been generated in large, centralized power plants and has travelled one-way through thousands of miles of high-voltage transmission lines into people’s homes. North American consumers consider electricity delivered at 60 hertz and 110 volts to their sockets as more …

Data-driven modeling of solar-powered urban microgrids.

Distributed generation takes center stage in today's rapidly changing energy landscape. Particularly, locally matching demand and generation in the form of microgrids is becoming a promising alternative to the central distribution paradigm. Infrastructure networks have long been a major focus of complex networks research with their spatial considerations. We present a systemic study of solar-powered microgrids in the urban context, obeying real hourly consumption patterns and spatial constraints of the city. We propose a microgrid model and study its citywide implementation, identifying the self-sufficiency and temporal properties of microgrids. Using a simple optimization scheme, we find microgrid configurations that result in increased resilience under cost constraints. We characterize load-related failures solving power flows in the networks, and we show the robustness behavior of urban microgrids with respect to optimization using percolation methods. Our findings hint at the existence of an optimal balance between cost and robustness in urban microgrids.

Targeting Villages for Rural Development Using Satellite Image Analysis.

Satellite imagery is a form of big data that can be harnessed for many social good applications, especially those focusing on rural areas. In this article, we describe the common problem of selecting sites for and planning rural development activities as informed by remote sensing and satellite image analysis. Effective planning in poor rural areas benefits from information that is not available and is difficult to obtain at any appreciable scale by any means other than algorithms for estimation and inference from remotely sensed images. We discuss two cases in depth: the targeting of unconditional cash transfers to extremely poor villages in sub-Saharan Africa and the siting and planning of solar-powered microgrids in remote villages in India. From these cases, we draw out some common lessons broadly applicable to informed rural development.

Simulation and Pricing Mechanism Analysis of a Solar-Powered Electrical Microgrid

A framework is proposed for an electrical power microgrid, such as for a colony or small township of homes that generate electrical power from solar energy and use it directly when possible, and via stored battery power at other times. The situation is described as a demand and supply problem in a multi-agent system with many consumers and suppliers and no explicit communication or coordination among the agents. Such a demand and supply problem is modeled as a Potluck Problem, a generalization of the Santa Fe Bar Problem. Power produced by PV panels and batteries may be used in the local market, in addition to being consumed locally. The proposed microgrid system model is able to determine the optimum operation of a solar-powered microgrid with respect to load demand, environmental requirements, PV panel and battery capacities. The results indicate the effect of various such parameters on the performance of these micro-grids. This paper also analyzes and proposes, based on auction theory, the most efficient and competing pricing mechanism in the proposed microgrid system model. Two important market bidding techniques, single bidding and discriminatory bidding, are considered. The microgrid is made to participate in the bidding process to serve the consumers at a reduced price and to provide better revenues. The viability of the model proposed is illustrated with analyses using realistic assumptions and published historical data.