The rising concerns on the impacts of greenhouse gas (GHG) emissions and global warming have forced the world to search for alternative clean and green energy resources. Renewable energy is one of the most sustainable forms of energy, and is an increasingly popular replacement to fossil fuels. In line with this, the world has witnessed tremendous growth in renewable energy technologies as well as unprecedented adoption of renewable-based electricity generation in the past few decades. This review paper focuses on the global energy demand, power generation, electricity production, electrical grid system as well as current global polices to move forward for renewable energy-based power generation. This work compiles the latest literature (i.e., journal articles, conference proceedings, reports, etc.) on global energy demand, power generation, electrical grid system as well as current global polices related to renewable energy. From the review, it is found that renewable energy is one of the potential resources to fulfill the future energy demand with mitigating GHG emissions and global warming. It is also found that many polices has been implementing globally to promote renewable energy-based power generation. WIREs Energy Environ 2017, 6:e222. doi: 10.1002/wene.222

For further resources related to this article, please visit the WIREs website.

Global electricity demand, generation, grid system, and renewable energy polices: a review

Dynamic Voltage Restorer—A comprehensive review

The most important aspect for electrical engineering is power quality in recent year. Power quality problem is an event of abnormal voltage, current or frequency. Utility distribution networks experience from various types of disturbances. The major problems dealt here are the voltage sags/swells. Now the fast developments in power electronics technology have made it possible to mitigate power quality problems. Such as, dynamic voltage restorer can provide the most mercantile solution to compensate voltage sag/swell by injecting voltage in to the sensitive system. Dynamic Voltage Restorer is a series connected power electronics based device that can mitigate the power quality issues in the system and restore the load voltage to the pre-fault value. This review paper first gives an introduction to related power quality problems for a DVR and power electronics controllers for voltage sag/swell compensation. Afterwards the operation and elements in DVR is described by using new control strategy.

Compensation of voltage sags and swells by using Dynamic Voltage Restorer (DVR)

The main development trend of wind power generation systems is large offshore wind farms (OWFs) with grid connection. However offshore wind farms have grown rapidly due to much better wind conditions. Hence, several large scale offshore wind farms are planned to be built and installed at distances greater than 100 km from the coast. Traditionally, an AC collector scheme collects energy from the wind farm and step up the voltages by power transformers and transmit power via AC submarine cables to the onshore substation. However, this is suitable for shorter distances about 50 km. When the distances are greater the AC transmission of bulk power from the wind farm to the onshore grid via undersea cables is not viable due the reactive power issues. Therefore HVDC transmission is now being considered for the grid connection of wind farms. However as wind farms constitute weak systems Line commutated converter (LCC) based HVDC is not viable and newer Modular Multilevel Converter (MMC) based Voltage Source Converters(VSC) are needed for AC-DC conversion. Opting for dc systems for both power collection and transmission pose a number of technical challenges in terms of developing HVDC breakers and DC -DC converters.

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Review of wind farm power collection schemes

Lithium-ion batteries (LIBs) are undeniably the most promising system for storing electric energy for both portable and stationary devices. A wide range of materials for anodes is being investigated to mitigate the issues with conventional graphite anodes. Among them, TiO2 has attracted extensive focus as an anode candidate due to its green technology, low volume fluctuations (<4%), safety, and durability. In this review, the fabrication of different TiO2 nanostructures along with their electrochemical performance are presented. Different nanostructured TiO2 materials including 0D, 1D, 2D, and 3D are thoroughly discussed as well. More precisely, the breakthroughs and recent developments in different anodic oxidation processes have been explored to identify in detail the effects of anodization parameters on nanostructure morphology. Clear guidelines on the interconnected nature of electrochemical behaviors, nanostructure morphology, and tunable anodic constraints are provided in this review.

https://www.mdpi.com/2079-4991/12/12/2034/pdf?version=1655278489

TiO2 as an Anode of High-Performance Lithium-Ion Batteries: A Comprehensive Review towards Practical Application

Modern electronics based on power electronic devices such as Programmable Logic Controllers (PLC), Distributed Control System (DCS) are used frequently in industrials plants to improve efficient production. These systems are extremely sensitive to power quality problem like voltage sag. Voltage sag is considered to be one of the most severe problems that cause failure, overheating and finally a total shutdown of industrial plants. It has been observed that, Dynamic Voltage Restorer (DVR) is the most efficient and effective modern custom power device exercised in power distribution networks to minimize voltage sags. The efficiency of the DVR depends on the performance of the control technique, which involved in switching the inverters. This paper presents modeling, analysis and simulation of a Dynamic Voltage Restorer (DVR) test systems using MATLAB Simulink for minimizing voltage sag by two promising controlling strategies: control using PI controller and control based on Park's Transformation. Simulation results of DVR controlling found by MATLAB Simulink here which demonstrates the well-organized plant applications. Moreover, this work shows that, control based on Park's Transformation provides better sag improvement than PI Control.

PI controller and park's transformation based control of dynamic voltage restorer for voltage sag minimization

`Fault current' is the flow of abnormal current through an improper path due to electric faults which causes enormous damages. In HVAC transmission system, Fault current due to electric faults is too large which affects the overall power system including-Receiving & Sending end bus, Transmission system, Load and even also the Power Generation Unit. HVDC transmission system dramatically reduces these effects, as the fault current due to electric faults is much lower, and only affects the individual faulty section of the overall transmission system. In favor of HVDC system, this paper presents a `fault current' (due to asymmetric faults) analysis and comparisons between HVAC and HVDC transmission system. MATLAB (Simulink) simulation software is used to simulate both HVAC & HVDC power transmission system topologies. From the comparison of the simulation output-lower fault current, less fault effect, better performance & higher reliability is demonstrated for HVDC transmission system.

HVDC over HVAC power transmission system: Fault current analysis and effect comparison

A review on binder-free NiO-Ni foam as anode of high performance lithium-ion batteries

Despite the importance of Nickel Oxide (NiO) in diverse functional applications, very little information is available on the mechanical properties of bulk or porous NiO or, mostly unnoticed. In this study, porous Ni-NiO foam was synthesized using space holding-powder metallurgy and sintering methods to produce opened-cell structure with macrogravel and Neolamarckia cadamba (Cadamba flower) like surface morphology. Four different types of porous Ni-NiO with different pore diameter of 35.65 ± 12.77, 36.10 ± 8.85, 68.20 ±7.36 and 62.45 ± 17.48 µm were fabricated for evaluating the effect of porosity on the mechanical properties of bulk porous Ni-NiO foam. The mechanical properties such as bulk crushing force of as synthesized Ni-NiO foam with various porosities such as 20.55, 27.35, 27.85 and 28.82 % exhibited the average crushing load of 115.40, 39.95, 138.10 and 151.20 N, respectively. This study suggests that crushing load of Ni-NiO foam is not only depending on the porosity but also on the sintering temperature and crystallite sizes of NiO.
HIGHLIGHTS

Ni-NiO foam is synthesized using space holding-powder metallurgy and sintering methods
Different pore diameter is fabricated for evaluating the effect of porosity on the mechanical properties of bulk porous Ni-NiO foam
Crushing strength of Ni-NiO foam is not only depending on the porosity but also on the sintering temperature and crystallite sizes of NiO

GRAPHICAL ABSTRACT

Md. Mizanur Rahman

Papers

PI controller and park's transformation based control of dynamic voltage restorer for voltage sag minimization

HVDC over HVAC power transmission system: Fault current analysis and effect comparison

A review on binder-free NiO-Ni foam as anode of high performance lithium-ion batteries

Fabrication of Ni-NiO Foams by Powder Metallurgy Technique and Study of Bulk Crushing Strength