scholarly journals Optimum Configuration of Solar PV Topologies for DC Microgrid Connected to the Longhouse Communities in Sarawak, Malaysia

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Mohd R. M. Sharip ◽  
Ahmed M. A. Haidar ◽  
Aaron C. Jimel

In the past few years, the prime focus of supplying electricity to the longhouse communities in the rural areas of Sarawak has been initiated based on the utilization of a single-source microgrid configuration. The existing AC power supply-based solar photovoltaic (PV) systems in these areas pose many problems, mainly owing to the stages of conversion, energy losses, and the quality of power transfer. As the solar PV system is a DC source and most of the appliances in longhouse communities could be operated using DC source, an opportunity to design a microgrid with high reliability and efficiency would be achieved by the implementation of an optimal DC microgrid configuration. With this aim, the paper proposes a multiple-source DC microgrid configuration for the longhouse communities in Sarawak. Initially, a framework has been developed to design simulation models for both microgrid configurations (single and multiple sources) using MATLAB Simulink. The configuration of each system consists of a solar PV and energy storage to form a standalone microgrid. Due to the change in system configuration of DC microgrid, in the modeling approach, the standard power flow equations are modified to include solely the DC parameters. To validate the proposed configuration with the associated modeling approach in terms of the power flow reliability, system efficiency, and power-voltage curve, an experimental setup representing the Simulink model has been designed for each standalone microgrid configuration. The configurations have been assessed in the same location with different daily weather conditions. The obtained simulation and experimental results confirm that the proposed configuration of multiple sources is more reliable and efficient than the existing single-source configuration.

Author(s):  
Yuwono Bimo Purnomo ◽  
F. Danang Wijaya ◽  
Eka Firmansyah

In a standalone photovoltaic (PV) system, a bidirectional DC converter (BDC) is needed to prevent the battery from damage caused by DC bus voltage variation. In this paper, BDC was applied in a standalone solar PV system to interface the battery with a DC bus in a standalone PV system. Therefore, its bidirectional power capability was focused on improving save battery operation while maintaining high power quality delivery. A non-isolated, buck and boost topology for the BDC configuration was used to interface the battery with the DC bus. PID controller-based control strategy was chosen for easy implementation, high reliability, and high dynamic performance. A simulation was conducted using MATLAB Simulink program. The simulation results show that the implementation of the BDC controller can maintain the DC bus voltage to 100 V, have high efficiency at 99.18% in boost mode and 99.48% in buck mode. To prevent the battery from overcharging condition, the BDC stops the charging process and then works as a voltage regulator to maintain the DC bus voltage at reference value.


Author(s):  
Suraj Dahal ◽  
Ajay Kumar Jha ◽  
Nawraj Bhattarai ◽  
Anil Kumar Panjiyar

Integrating high photovoltaic (PV) on distribution grid system has a positive impact by significantly reducing the losses and improving the voltage profile at the same time reducing the pollution of the environment However, integrating high proportions of PV in the distribution grid can bring the grid to its operational limits and result in power quality issues. The maximum PV capacity that can be integrated without incurring any grid impacts is referred to as the PV hosting capacity of the grid. This paper intends to evaluate the hosting capacity of solar PV in Dodhara-Chandani (DoC) distribution feeder as one of the feeder of Integrated Nepal Power System (INPS), considering grid parameters and operating condition in Nepal. Three main criteria were investigated for determining the hosting capacity of PV; reverse power flow, maximum voltage deviation of feeder and current carrying limit of conductor. The analysis has been performed by means of static load-flow simulation in Electrical Transient & Analysis Program (ETAP) and coding in MATLAB R2017a. The study shows that PV of rated capacity 687kWp can be installed at a point of interconnection (POI) whereas an optimal placement of solar PV is found to be at 18th node (in between starting and end of the feeder) considering minimum system losses. The minimum voltage profile at end of the feeder has improved by 8 % while the active power loss reduction of network has reduced by 83.6 % after the integration of solar PV. The results indicate voltage at different buses and the ampacity of most of the conductors have been improved after the integration of PV system into DoC feeder.


The need to electrify all rural areas in India is quite compelling. However, the focus has now shifted from traditional fuel-based systems to generate electricity to renewable sources for energy generation. Though there are subsidies and policies that encourage the use of solar Photovoltaic (PV) systems, there is a need for an appropriate framework. This framework could not only offer substantial directions but it would also act as grounds to enhance rural electrification in India using solar PVs. From this perspective, the current research attempts to structure an innovative framework for solar PV system that could facilitate rural electrification in India. In particular, the district of Damoh in Madhya Pradesh was chosen as there are many villages without electricity in this district. PVsyst software was utilized to simulate the outcomes that included mathematical models and diverse components based on PV, for simulation. Three designs were developed to facilitate the simulation. These included; PVs linked with microgrid devoid of battery, individual PV systems without microgrid link and solar PVs linked to microgrid with battey. The framework for rural electrification using solar PVs will offer policy makers with insights with regards to implementing PV systems. It will also offer inputs as to the feasibility of implementing a specific system on several parameters. These would comprise of; number of households within a village, detached households etc. Nonetheless, research in future is also warranted to explore the scope for other sources of renewable energy.


Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 124 ◽  
Author(s):  
Adel El-Shahat ◽  
Sharaf Sumaiya

Recently direct current (DC) microgrids have drawn more consideration because of the expanding use of direct current (DC) energy sources, energy storages, and loads in power systems. Design and analysis of a standalone solar photovoltaic (PV) system with DC microgrid has been proposed to supply power for both DC and alternating current (AC) loads. The proposed system comprises of a solar PV system with boost DC/DC converter, Incremental conductance (IncCond) maximum power point tracking (MPPT), bi-directional DC/DC converter (BDC), DC-AC inverter and batteries. The proposed bi-directional DC/DC converter (BDC) lessens the component losses and upsurges the efficiency of the complete system after many trials for its components’ selection. Additionally, the IncCond MPPT is replaced by Perturb & Observe (P&O) MPPT, and a particle swarm optimization (PSO) one. The three proposed techniques’ comparison shows the ranking of the best choice in terms of the achieved maximum power and fast—dynamic response. Furthermore, a stability analysis of the DC microgrid system is investigated with a boost converter and a bidirectional DC-DC converter with the Lyapunov function for the system has been proposed. The complete system is designed and executed in a MATLAB/SIMULINK environment and validated utilizing an OPAL real-time simulator.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2137
Author(s):  
Mariz B. Arias ◽  
Sungwoo Bae

This paper provides models for managing and investigating the power flow of a grid-connected solar photovoltaic (PV) system with an energy storage system (ESS) supplying the residential load. This paper presents a combination of models in forecasting solar PV power, forecasting load power, and determining battery capacity of the ESS, to improve the overall quality of the power flow management of a grid-connected solar PV system. Big data tools were used to formulate the solar PV power forecasting model and load power forecasting model, in which real historical solar electricity data of actual solar homes in Australia were used to improve the quality of the forecasting models. In addition, the time-of-use electricity pricing was also considered in managing the power flow, to provide the minimum cost of electricity from the grid to the residential load. The output of this model presents the power flow profiles, including the solar PV power, battery power, grid power, and load power of weekend and weekday in a summer season. The battery state-of-charge of the ESS was also presented. Therefore, this model may help power system engineers to investigate the power flow of each system of a grid-connected solar PV system and help in the management decision for the improvement of the overall quality of the power management of the system.


2020 ◽  
Vol 39 (1) ◽  
pp. 47-58
Author(s):  
Irene H. Masenge ◽  
Francis Mwasilu

In rural areas where electric power grid network is rarely available, power generation from renewable energy resource such as solar photovoltaic (PV) is mostly accomplished in standalone mode. The standalone solar PV system requires energy storage device to achieve reliable power supply to the end users. This paper presents modelling and coordination control of solar PV with battery energy storage system (BESS) for rural-electrification applications. The proposed control is accomplished via a bidirectional buck-boost converter with the objective of maintaining voltage at the DC bus constant. Simulation results based-on MATLAB/Simulink platform confirms good performance of the proposed system.


2021 ◽  
Author(s):  
◽  
Michael Emmanuel

<p>As the solar PV technology continues to evolve as the most common distributed generation (DG) coupled with increasing interconnection requests, accurate modelling of the potential operational impacts of this game-changer is pivotal in order to maintain the reliability of the electric grid. The overall goal of this research is to conduct an interconnection impact analysis of solar PV systems at increasing penetration levels subject to the feeder constraints within the distribution network. This is carried out with a time series power flow analysis method to capture the time-varying nature of solar PV and load with their interactions with the distribution network device operations. Also, this thesis analyses multiple PV systems scenarios and a wide range of possible impacts to enable distribution system planners and operators understand and characterize grid operations with the integration of PV systems.  An evaluation of the operational and reliability performance of a grid-connected PV system based on IEC standards and industry guides is performed to detect design failures and avoid unnecessary delays to PV penetration. The performance analysis metrics in this research allow cross-comparison between PV systems operating under different climatic conditions. This thesis shows the significant impact of temperature on the overall performance of the PV system. This research conducts an interconnection study for spatially distributed single-phase grid-tied PV systems with a five minute-resolution load and solar irradiance data on a typical distribution feeder. Also, this research compares the performance of generator models, PQ and P |V |, for connecting PV-DG with the distribution feeder with their respective computational costs for a converged power flow solution.  More so, a method capable of computing the incremental capacity additions, measuring risks and upgrade deferral provided by PV systems deployments is investigated in this research. This thesis proposes surrogate metrics, energy exceeding normal rating and unserved energy, for evaluating system reliability and capacity usage which can be a very useful visualization tool for utilities. Also, sensitivity analysis is performed for optimal location of the PV system on the distribution network. This is important because optimal integration of PV systems is often near-optimal for network capacity relief issues as well.  This thesis models the impact of centralized PV variability on the electric grid using the wavelet variability model (WVM) which considers the key factors that affect PV variability such as PV footprint, density and cloud movement over the entire PV plant. The upscaling advantage from a single module and point irradiance sensor to geographic smoothing over the entire PV footprint in WVM is used to simulate effects of a utility-interactive PV system on the distribution feeder.  Further, the PV interconnection scenarios presented in this thesis have been modelled with different time scales ranging from seconds to hours in order to accurately capture and represent various impacts. The analysis and advancements presented in this thesis will help utilities and other stakeholders to develop realistic projections of PV systems impacts on the grid. Also, this research will assist in understanding and full characterization of PV integration with the grid to avoid unnecessary delays.</p>


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