Grid-connected Solar PV Research Articles

Buck Boost Transformer Less in PV System with Grid Connected

For single-phase grid-connected solar PV applications, a novel single-stage buck boost trans formerless inverter (BBTI) topology is presented in this paper. Leakage currents are eliminated since the input PV source and grid neutral share a common ground in this topology. In addition, the buck-boost capability of the proposed topology ensures that the maximum power point is maintained throughout a wide range of input PV voltage variations. The fact that only one energy storage inductor is used in the proposed topology makes it symmetrical during both grid half cycles. Additionally, the proposed topology's two out of five switches operate at a line frequency, resulting in low switching losses, while the remaining three switches operate in any mode with low losses. To control the proposed inverter topology, a straightforward sine-triangle pulse width modulation strategy is outlined and analyzed across all operating modes. The 300W laboratory prototype is the subject of experiments, and all of the major findings are presented in the paper. These findings demonstrate that the proposed system offers higher efficiency with lower THD in output current.

Techno-economic analysis of a PV system with a battery energy storage system for small households: A case study in Rwanda

Due to the inadequacy of distribution networks in developing countries, especially in small residential areas, there are frequent interruptions in the electrical energy provided by the grid. This problem negatively affects the life quality and productivity of the people living in these regions. This problem can be overcome by integrating BESS-supported renewable energy sources into the distribution system. These distributed energy resources contribute significantly to providing energy directly to consumers. On a small scale, such a system is supported by the grid, when possible, to ensure energy supply continuity. This study presents a techno-economic analysis, using PV*SOL simulation software, of a grid-connected solar PV system with BESS that is used to supply a small residential community in Rwanda, Muhanga district, Shyogwe sector. The consumers were a group of one hundred households around a wetland valley. The energy generated from the solar PV system was used to supply home appliances and a water pumping system for agricultural activities. The simulation results showed that the annual energy requirement is 82.34 MWh with a peak load of 30.4 kW. The simulation results also revealed that a PV system, with an installed capacity of 57.33 kWp integrated with a BESS of 89.2 kWh storage capacity, can supply the load with own power consumption of 68.65%, a level of self-sufficiency of 64.38%, and a performance ratio of 86.05% when the desired ratio is set to 110% with a year as the reference period. The financial analysis demonstrated a return on assets of 9.14% and an amortization period of 9.65 years. These results indicate that the proposed method is technically and economically feasible for use in addressing the issue of electrical power outages in developing countries.

An effective design method for grid-connected solar PV power plants for power supply reliability

This paper discusses a methodology, specifically for solar power potential areas, to effectively design and develop solar photovoltaic power plants integrated with battery banks connected to the utility grid as an additional backup to maintain power stability and reliability. To prove the effectiveness of this method regarding its use for the design and development of the proposed system, Kinshasa city in Democratic Republic of the Congo with a huge (5425 MWh) energy deficit has been considered as a case study. In fact, the method employed in this study has considered weather data, site selection, hourly load power and energy demand analysis, specifications of PV technologies and other components of the system. Economic analysis has also been carried out for the proposed system viability assessment. With a competitive LCOE, SPP < 10 years, NPV˃0, SIR˃1, and ROI ˃10 %, and a yearly PV energy output greater than the city's energy deficit, the system proposed has been found to be feasible and viable. In a search for better performance, higher efficiency and better economic values, the proposed method is highly recommended and can be regarded as one of the most effective and the easiest for sizing large-scale PV systems.

Design and Simulation of Grid-Connected Solar PV System Using PVSYST, PVGIS and HOMER Software

In this paper, the design and simulation of a 5 MW solar power plant in Ghor province, Afghanistan have been investigated. A suitable place at a distance of about 8.17 km from the center of the province was selected as the power plant location. The main objective of this study is the investigation of solar renewable energy resources' capacity for generation of electrical energy from domestic resources to provide reliable and sustainable energy in the center of the Ghor province which is currently not connected to the national electrical grid. In this power plant, 6399 kWp, STP-320 W PV module, and 5300 kW Growatt convertor type were used. The PVSYST, PVGIS, and HOMER renewable energy simulation tools were used for analyzing the system. The results obtained from each simulation tool were compared together. Analysis of the results using HOMER and PVGIS shows that the annual energy generated using each simulation tool is about 11698 MWh and 10673 MWh respectively while the result from PVSYST is 11938 MWh per year. According to the obtained values, results from PVSYST depict 240 MWh more energy generation than HOMER and 1265 MWh than PVGIS simulation tools annually. These values indicate that PVSYST produces higher annual power for this system than HOMER and PVGIS. Comparing the annual generated power results of the simulations with reference to the PVSYST results, it can be concluded that PVGIS is 10.6% lower and HOMER is 2% lower. There is about a 2% difference between PVSYST and HOMER.

Study of the Effect of the Energy Produced From a Grid-Connected Rooftop Solar PV System for Small Households

In recent years, a great popularization of the production of electricity from photovoltaic systems has been observed, which gives hope for reducing environmental pollution and tackling the shortage of natural resources used for electricity generation. This article will focus on studying the effect of energy produced by a grid-connected rooftop solar photovoltaic system for small households.

Dynamic Performance Evaluation of Grid-Connected Hybrid Renewable Energy-Based Power Generation for Stability and Power Quality Enhancement in Smart Grid

Today’s stochastic grid system is experiencing huge voltage fluctuations, which is responsible for power quality issues in the smart microgrid network due to its intermittent nature as well as penetration of hybrid renewable resources. Thus, the dynamic performance evaluation and their control are essential to sustaining the stability of the grid network. A d-q controller mechanism is suggested to maintain the balance of the distributed generation network and grid side network. A dynamic control mechanism of voltage source converter (VSC) is presented in the MPPT-based wind power generating station, where an induction generator generates the power by the optimal control of the wind energy-based subsystem. The distributed hybrid generation (solar PV and wind) subsystem’s output terminal is linked to the DC bus bar’s common link via the VSC. A VSI is utilized to convert the desired DC power to alternating current power. To regulate and improve the performance of the proposed hybrid power generating systems (HPGS), a supercapacitor (SC) is used to smooth out the ripple on the distribution side in the power grid. Furthermore, the dynamic stability of grid-connected solar PV and wind power generation systems is investigated. This article also proposed an effective control scheme for the SC in HPGS under the influence of weak grid conditions. This article aimed to validate the efficiency of the VSI topology; a PI controller stability enhancement approach is used in a proposed grid system under various disturbance conditions. Finally, the simulation results and FFT-based power quality response analysis are validated through the effective utilization of an SC.

Design Optimization Method and Performance Analysis of 90MW Grid-Connected Solar PV system in Cambodia

Large-scale PV plants have the ability to make the curtailment of cost per watt of the normal power installed. This article describes a new technique for computing the optimal contour of large PV plants. Massive infiltration of renewable energy sources is increasing because of the awareness created on environmental issues and electric power deregulation. A PV system is a renewable energy source that establishes a future sustainability in power distribution. The technical specifications details are provided by solar irradiation and performance ratio. High accuracy of energy generation followed in computations in the proposed system. The high-accuracy feature is validated using experimental data of the 90MW PV plant in Cambodia. The results obtained show that the optimisation method can lead to a reduced cost of energy generated. This enables the maximisation of the benefit obtained on the operational life period of the PV module. The model’s accuracy depends on a hierarchical structure level model, model measurement accuracy, model identification, structure accuracy, measurement accuracy, simulator algorithms metrics, and the accuracy of the calibration parameter. The paper is built based on the physical ranking of the PV power model structure, making the system a high-fidelity model.

A Two-stage Single-phase Grid-connected Solar-PV System with Simplified Power Regulation

This study focuses on the design and development of a simplified active power regulation scheme for a two-stage single-phase grid-connected solar-PV (SPV) system with maximum power point (MPP) estimation. It aims to formulate and test an improvised new control scheme to estimate the real-time MPP of the PV panel and operate only at either the MPP or on the right-hand side (RHS) of the PV characteristics of the panel. A simple active power regulatory control scheme was formulated to provide frequency control services to a single-phase grid without using an energy storage device. The plant operator provides the reserve fraction as the input for the active power regulation controller. At any time, the reserve fraction is used to determine the magnitude of the reference power to be extracted from the PV panel for injection into the grid. A simple PI controller was used to track the calculated reference power. The different modes of operation of the regulatory scheme are presented in detail. All the above control schemes are integrated and implemented through appropriate switching of the DC-DC converter alone. The DC-AC converter maintains the DC link voltage and unity power factor at the single-phase grid terminals. The proposed control schemes were tested on a 250 Wp solar panel feeding power to a 230 V, 50 Hz single-phase grid through a two-stage converter. The entire scheme was modeled using the Matlab/Simulink platform, and the same was validated by hardware experimentation using Chroma Solar Simulator and NI myRIO controller under varied irradiation, temperature, and reserve fractions. The simulation and hardware results are compared and reported.

Geospatial multi-criteria analysis for identifying optimum wind and solar sites in Africa: Towards effective power sector decarbonization

Africa has the potential to provide for its growing energy needs with renewable electricity sources. We implement a multi-criterial geospatial optimization to locate the most favorable sites for utility-scale, grid-connected onshore wind and solar PV. Legal, technical, political, environmental, socio-economic and investment risk factors were incorporated in the model. Analysis of the whole African continent revealed South Africa and Egypt to be amongst the most favorable countries for renewable investment, so these were subject to more in-depth analysis. The analysis revealed the favorable conditions offered by Egypt for solar energy installations are attributable to high yearly average insolation (278.3 W/m2), grid reliability, terrain appropriateness and political stability. Current heavy dependence on fossil fuels (165.7 billion kWh) means that there is great potential for emissions reduction from the power sector. South Africa, on the other hand, offers favorable conditions for wind installations due to high wind speeds (12 m/s at 100 m height), high fossil fuel electricity reliance (213 billion kWh), good political stability, and adequate techno-economic factors. The levelized cost of constructing wind farms in propitious sites in South Africa is 16.7% lower than building coal-fired power stations, while the levelized cost of constructing solar farms in optimum zones in Egypt is 29.7% lower than investing in combined-gas turbines and 37% lower than investing in diesel generators.

Single-Sourced Double-Stage Multilevel Inverter for Grid-Connected Solar PV Systems

Design challenges for grid-connected solar PV systems related to the power conditioning units are power quality, efficiency, reliability, cost of implementation etc. This paper deals with single dc source-based double LDN high-resolution multilevel inverter topology with the appropriate blend of switches to address most of the practical constraints of central inverter application. A two-stage high-resolution multilevel inverter solution is adapted to double the inverter utilization as well as to increase efficiency. Reactive power handling and fault blocking capability of the system are also demonstrated in this work. The converter is extensively simulated using MATLAB/Simulink. Experimental results from laboratory prototype confirm the usefulness of the proposed concepts.

Assessing Techno-Economic Value of Battery Energy Storage with Grid-Connected Solar PV Compensation Schemes for Malaysian Commercial Prosumers

Assessing Techno-Economic Value of Battery Energy Storage with Grid-Connected Solar PV Compensation Schemes for Malaysian Commercial Prosumers

The uncertainties involved in measuring national solar photovoltaic electricity generation

The measurement of near real-time national solar PV electricity output is an increasingly important component for managing electricity systems. PV systems embedded in the distribution network are problematic for system operators since their output is not directly visible through existing transmission system metering. Typically, national solar PV output is measured indirectly by upscaling the output from a sample of reference PV systems using an estimate of the national capacity. National PV output is then used, along with similar measurements for other embedded technologies such as wind, to train and validate electricity forecasts which ensure efficient electricity market operation. For the first time and using Great Britain as a case study, we investigate the accuracy of this general approach by characterising different sources of uncertainty in national PV output measurements. We find that the capacity error, at ±5%, dominates the yield calculation error, at < ±1% and leads to an overall error in GB solar PV output estimates of ±5.1%. We conclude that solar PV measurements, and consequently national electricity demand forecasts, are currently limited by the state of national PV capacity registers. To make PV output measurements more accurate nations must develop a coherent and comprehensive approach to PV system registration, and output measurement methods must move away from using static solar PV capacity registers towards estimating an operational grid-connected solar PV capacity. This could involve moving away from capacity registers altogether and instead estimating capacity from other sources, for example, from network power flows, satellite imagery, or more likely, a combination of complementary datasets.

Assessment of solar PV potential and performance of a household system in Durban North, Durban, South Africa

The potential of solar PV is location-dependent that needs to be assessed before installation. This study focuses on the assessment of a solar PV potential of a site on coordinates −29.853762°, 031.00634°, at Glenmore Crescent, Durban North, South Africa. In addition, it evaluates the performance of a 6-kWp installed capacity grid-connected rooftop solar PV system to supply electricity to a household. The results, obtained from PV design and simulation tools—PV*SOL, Solargis prospect, and pvPlanner, were used to analyze and establish the PV system’s economic and technical viability. The configuration of the system is as follows: load profile—a 2-person household with 2-children, energy consumption—3500 kWh, system size—6 kWp, installation type—roof mount, PV module type—c-Si—monocrystalline silicon, efficiency—18.9%, orientation of PV modules -Azimuth 0° and Tilt 30°, inverter 95.9% (Euro efficiency), and no transformer. The results show: meteorological parameters—global horizontal irradiation (GHI) 1659.3 kWh/m2, direct normal irradiation (DNI) 1610.6 kWh/m2, air temperature 20.6 °C; performance parameters—annual PV energy 8639 kWh, Specific annual yield 1403 kWh/kWp, performance ratio (PR) 74.9%, avoided CO2 emissions 5662 kg/year, and solar fraction 42.5%. Others are economic performance parameters—levelised cost of energy (LCOE) 0.1147 USD/kWh, internal rate of return (IRR) 17,671 USD/kWh, and return on investment (ROI) 11%. The results show that the proposed solar PV system under the current conditions is both economically and technically viable for household electrification in Durban North, South Africa.Graphical abstract

Control of grid-connected residential solar-PV system using novel adaptive linear combiner filter for power quality improvement

ABSTRACT A grid-connected residential photovoltaic (PV) system has been proposed using novel adaptive linear combiner filter-based control for power quality (PQ) improvement. In the present work, novel adaptive linear combiner (ALC) filter-based control-based control has been proposed to generate reference current. MATLAB/Simulink software is used to develop the two-stage grid-connected residential PV. The proposed control is tested in MATLAB/Simulink2018(a) under nonlinear, linear load and variable input and validated experimentally on prototype hardware. The performance of the proposed ALC filter-based control has been analyzed and compared with that of conventional synchronous d-q control. It has been observed from results that THD in grid current using proposed control is 3.74% whereas using conventional d-q control THD is 4.75%. Proposed control provides more efficient performance by improving the PQ of the system by compensating the harmonics and reactive load demand. Harmonic distortion in the grid current is within the limits as per IEEE-1547. Furthermore, proposed control has better transient response viz. settling time, under shoot and overshoot in DC link voltage during grid connection of rooftop PV system and provides, reduced complexity due to absence of phase lock loop (PLL), thus less sampling time, better accuracy, ease of implementation, and adaptability.

Techno-Economic Feasibility of Grid-Connected Solar PV System at Near East University Hospital, Northern Cyprus

The growth of populations and economy in Northern Cyprus has led to continuing utilization of fossil fuels as the primary source of electricity, which will raise environmental pollution. Thus, utilizing renewable energy, particularly solar energy, might be a solution to minimize this issue. This paper presents the potential of grid-connected solar PV power generation at Near East University Hospital (NEU Hospital), one of the largest and leading medical facilities in Northern Cyprus, to meet the energy demand during the daytime to reduce energy bills. For this purpose, the first objective of the study is to evaluate the solar energy potential as a power source for the NEU Hospital based on four datasets (actual measurement, Satellite Application Facility on Climate Monitoring (CMSAF), Surface Radiation Data Set-Heliosat (SARAH), and ERA-5, produced by the European Centre for Medium-range Weather Forecast). The results showed that the solar resource of the selected location is categorized as excellent (class 5), that is, the global solar radiation is within the range of 1843.8–2035.9 kWH/m2. The second objective is to investigate the impact of orientation angles on PV output, capacity factor, economic feasibility indicators, and CO2 emissions by using different PV modules. The results are compared with optimum orientation angles found by Photovoltaic Geographical Information System (PVGIS) simulation software. This objective was achieved by using RETScreen Expert software. The results demonstrated that the highest performance of the proposed system was achieved for orientation angles of 180° (azimuth angle) and −35° (tilt angle). Consequently, it is recommended that orientation angles, PV modules, and market prices are considered to maximize energy production and reduce electricity production costs.

Techno-Economic Analysis of Commercial Size Grid-Connected Rooftop Solar PV Systems in Malaysia under the NEM 3.0 Scheme

Commercial grid-connected rooftop solar PV systems are widely applied worldwide as part of affordable and clean energy initiatives and viable long-term solutions for energy security. This is particularly true in a crowded city where space is a constraint and at the same time, there are unutilized rooftops. With the recently announced Net Energy Metering (NEM) 3.0, commercial buildings in Malaysia can apply up to 75% capacity of the maximum demand (MD), which can be connected to the grid. Apart from reducing electricity bills, the owner can offset energy for 10 years. This paper presents a design analysis with the details of the sizing of a rooftop PV system. The PVsyst software tool is used to estimate the energy produced by a 380 kWp system, and this study provides a financial analysis to evaluate the profitability of the system with a particular interest in commercial buildings under the NEM 3.0 policy, which has resulted in 8.4 years return of investment (ROI). PVsyst is a software used to size the PV system and provides technical, financial, and environmental analysis. This in-depth analysis could provide a useful case study for asset owners in deciding the way forward for sustainable energy production, cost saving, and combating the energy security issue, since Malaysia is blessed with an abundance of sunshine throughout the year.

Techno economic analysis of microgrid with an efficient energy management system and inverter control strategies

A microgrid comprises of distributed energy resources with the capability of operating independently as an islanded mode or in a grid connected mode. The efficacy of a microgrid is based on the performance of the control strategy and the energy management strategy. Therefore, in this paper the feasibility of an efficient inverter control strategy and energy management strategy for microgrid are studied. The proposed microgridis implemented with master-slave energy management control and battery management system for effective power flow control in an islanded and grid connected mode. A three-layer hierarchical energy management strategy comprising of master-slave system to provide continuous supply at all conditions and effective switchover operations between grid connected and islanded modes of operation is proposed. The voltage-frequency control under standalone mode of operation and P-Q control using hysteresis current control under grid-connected mode of operation are developed and the system parameters like real power, reactive power and voltage at the PCC are analyzed after the implementation of proposed controllers under islanded and grid connected modes of operation. The proposed model achieves voltage and frequency regulation under varying system operating conditions. Also, a techno-economic analysis is performed in HOMER software where the cost of energy and return on investment are studied for the proposed microgrid system by which levelized cost and payback period is reduced. The proposed control algorithms are implemented through MATLAB simulation and tested in a real-time for 1 kW grid-connected solar PV system.

Power Quality and Performance Analysis of Grid-Connected Solar PV System Based on Recent Grid Integration Requirements

The electrical energy demand is steadily growing, and hence, the integration of photovoltaic system to the distribution networks is also dramatically increasing though it has a significant effect on the network’s power quality. The purpose of this paper is to analyze the impact of solar PV integration on the power quality of distribution networks. The study is conducted using ETAP software, taking one of the radial distribution networks available in Bahir Dar city during the peak of connected loads which has the least voltage profile. Furthermore, the optimal location of the PV in the network is done using particle swarm optimization. Accordingly, the appropriate location of the PV system is determined to be the farthest end bus (bus 34). Also, the impact in terms of voltage and current harmonic distortion on the distribution feeder network is comparatively discussed by comparing the distribution system parameters with different penetration levels of solar PV system. The simulation results obtained demonstrate that high harmonic distortion level is injected correspondingly as the penetration capacity of PV system increased which indicates that the solar PV system should be integrating only up to a maximum possible capacity the network can carry. The integration of the PV system beyond this maximum penetration level causes production of high harmonic distortion which adversely affects the system performance. At the maximum penetration level which allows the acceptable harmonic distortion limit, the total voltage harmonic distortion and current demand distortion are found to be 4.97% and 14.98%, respectively.

Performance of Grid-Connected Rooftop Solar PV System for Households during Covid-19 Pandemic

As we know, the need for electrical energy is increasing along with population growth and technological developments. This increase was also triggered by the growth rate of the energy demand of 6.86% per year. Most of the energy needs come from non-renewable energy, which has limitations and is not environmentally friendly. Despite being affected by Covid, this period is a momentum to start the direction of clean energy policies. The utilization of solar power can be started by utilizing a rooftop solar power system on the roof of a hotel or on the roof of other industrial buildings. As one of the research and development institutions in the housing and settlement infrastructure sector, it tries to provide alternative technology solutions through an innovative technology called PV-roof. The results of the research show that the designed roof off-grid has an average voltage and current on the first day of 13 Volts and a current of 1.8 A, and on the second day, 12.4 Volts and a current of 1.6 A, while on the third day, 12.8 Volts and current of 1.8 A. If the use of 1 battery bears a load of 450 Watts for 2.7 hours, then for users less than 5 hours, the solar charger controller capacity is 12.12 A.

Techno-economic and environmental assessment of utilizing campus building rooftops for solar PV power generation

ABSTRACT The academic institute, a huge consumer of energy, is still depending upon the grid and/or conventional fuel despite having potential areas of a solar PV installation. No such study has been reported in Nepal which has techno-economically discussed the potential use of academic institute rooftops for solar PV installation. In this study, we have investigated the techno-economic and environmental assessment of a 1 megawatt (MW) rooftop solar PV using PVsyst for Purwanchal Campus, Nepal. It has been estimated the plant will produce about 1,660 MWh of usable AC electricity annually and out of which 95% can be supplied to the grid. The remaining can fulfill the demand of the campus at sunshine hours. For this, a capital investment of about USD 961,404 is needed for the plant with an annual operating cost of USD 8,008. This project gives a 190% return of investment within its life of 25 years with a Levelized cost of energy (LCOE) of 0.069 USD/kWh. The performance ratio and payback period of the project are calculated at about 0.765 and 8.4 years, respectively. The system will produce about 97% less emission than that of diesel generator, which is currently being used for power backup. It is concluded that a 1 MW grid-connected solar PV system is feasible for the studied campus.