Steady State Analysis of an Isolated Self-Excited Dual Three-Phase Induction Generator for Renewable Energy

In this paper modelling and analysis in autonomous mode of dual three-phase induction generator (DTPIG) with a new algorithm have been done. We develop the steady state model of a dual three-phase self-excited induction generator for stand-alone renewable generation dispensing with the segregating real and imaginary components of the complex impedance of the induction generator. The obtained admittance yields the adequate magnetizing reactance and the frequency. These two key parameters are then used to compute the self-excitation process requirements in terms of the prime mover speed, the capacitance and the load impedance on the one hand and to predict the generator steady state performance parameters on the other. Steady state performances and characteristics of different configurations are clearly examined and compared. The analytical results are found to be in good agreement with experimental results.

Maximum Power Extraction Control Algorithm for Hybrid Renewable Energy System

In this research,a modified fractional order proportional integral derivate(FOPID)control method is proposed for the photovoltaic(PV)and thermoelectric generator(TEG)combined hybrid renewable energy system.The faster tracking and steady-state output are aimed at the suggested maximum power point tracking(MPPT)control technique.The derivative order number(μ)value in the improved FOPID(also known as PIλDμ)control structure will be dynamically updated utilizing the value of change in PV array voltage output.During the transient,the value ofμis changeable;it’s one at the start and after reaching the maximum power point(MPP),allowing for strong tracking characteristics.TEG will use the freely available waste thermal energy created surrounding the PVarray for additional power generation,increasing the system’s energy conversion efficiency.A high-gain DC-DC converter circuit is included in the system to maintain a high amplitude DC input voltage to the inverter circuit.The proposed approach’s performance was investigated using an extensive MATLAB software simulation and validated by comparing findings with the perturbation and observation(P&O)type MPPT control method.The study results demonstrate that the FOPID controller-based MPPT control outperforms the P&O method in harvesting the maximum power achievable from the PV-TEG hybrid source.There is also a better control action and a faster response.

Quantitative analysis of distributed and centralized development of renewable energy

Global renewable energy has maintained a steady growth in recent years, mainly fostered by national policies and increasing demand. Analyzing the experience of renewable energy development in developed countries can be important to provide reference and guidance for its adoption in other countries. First, we compare and summarize definitions of distributed generation from 18 leading countries and organizations in renewable energy. On this basis, we provide three basic characteristics for successful distributed generation using renewable resources. Then, we empirically analyze the distributed and centralized development of renewable energy in Germany with focus on wind and photovoltaic power. We determined that 95% of the photovoltaic generation and 85% of the wind power generation is distributed in Germany, suggesting that the most suitable generation mode for renewable energy is the distributed approach.

Influence of stretch and temperature on the energy density of dielectric elastomer generators

Application of dielectric elastomers (DE) has remarkably increased in mechatronics because they are suitable candidates for energy harvesting due to their low cost,light weight,and high energy density.The dielectric elastomer generators (DEGs) exhibit high performance regardless of the applications scale.However,functioning as a generator,a DE may lose its efficiency due to several failure modes including material rupture,loss of tension (LT),electrical breakdown (EB),and electromechanical instability (EMI).The failure modes confine the area of allowable states for generation process.Dielectric constant and dielectric strength of such elastomers depend on the amount of applied deformation and also working temperature,which are often ignored in theoretical simulations.In this paper,variations of the above-mentioned parameters are considered in mechanical and electrical modellings to investigate their effects on energy density and efficiency of generators.Obtained results show that,ignoring the variations of material dielectric constant and dielectric strength leads to overestimation of the specific energy.Furthermore,it is shown that,for an acrylic-based generator,the specific energy sharply decreases with temperature rise.

An Assessment of Renewable Energy Options for Somalia Turkey Hospital

Somalia Mogadishu-Turkey Training and Research Hospital is only powered by diesel generator currently.In this paper,the energy demand of this hospital is supplied by determining the optimum hybrid power renewable generating system.Therefore,numerous hybrid renewable power generating systems including the components like diesel generator,wind turbine,photovoltaic(PV)and battery are considered in different configurations.Eventually,they are technically,environmentally and economically analyzed by using the well-known HOMER software.Furthermore,a sensitivity analysis is also performed considering variations in three important parameters,namely average wind speed,current diesel price and also solar radiation.According to the results,the optimal system is the standalone Wind/Diesel/Battery hybrid renewable energy system(HRES)with the configuration of 1,000 kW wind turbine,350 kW diesel generator,250 kW power converters and 750 batteries.Additionally,this system has the net present cost of$5,056,700 as well as the cost of energy as$0.191/kWh.Lastly,it is clearly occurred that the Wind/Diesel/Battery HRES is eco-friendlier than other HRESs.

Coordinated voltage control of renewable energy power plants in weak sending-end power grid

The utilization of renewable energy in sending-end power grids is increasing rapidly,which brings difficulties to voltage control.This paper proposes a coordinated voltage control strategy based on model predictive control(MPC)for the renewable energy power plants of wind and solar power connected to a weak sending-end power grid(WSPG).Wind turbine generators(WTGs),photovoltaic arrays(PVAs),and a static synchronous compensator are coordinated to maintain voltage within a feasible range during operation.This results in the full use of the reactive power capability of WTGs and PVAs.In addition,the impact of the active power outputs of WTGs and PVAs on voltage control are considered because of the high R/X ratio of a collector system.An analytical method is used for calculating sensitivity coefficients to improve computation efficiency.A renewable energy power plant with 80 WTGs and 20 PVAs connected to a WSPG is used to verify the proposed voltage control strategy.Case studies show that the coordinated voltage control strategy can achieve good voltage control performance,which improves the voltage quality of the entire power plant.

Energy Scenario: Production, Consumption and Prospect of Renewable Energy in Australia

Australia is the world’s 9th largest energy producer, 17th largest consumer of non-renewable energy resources and ranks 18th on a per person energy consumption basis.Australia’s energy consumption is primarily composed of non-renewable energy resources (coal, oil, gas and related products), which represent 96% of total energy consumption. Renewables, the majority of which is bioenergy (wood and wood waste, biomass, and biogas) combined with clear energy namely wind, solar hot water, solar electricity, hydroelectricity account for the remaining 4% consumption.Australia’s renewable energy resources are largely undeveloped which will contribute directly to the Australian economy. In this article, a review of literature on energy scenario is presented and discussed.Australia’s total energy production, consumption, storage and export (including renewable and non-renewable) data has been analyzed and discussed in this study. The main objective of the study is to analyze the prospect of renewable energy inAustralia. This study concludes that Australian economy will grow faster if its undeveloped renewable energies can be used efficiently for electricity generation and transport sector.

Synergetic Dispatch of Power System with Integration of Large-Scale Renewable Energy

This paper comes up with a concept of synergetic advanced dispatch in order to deal with the ever-increasing uncertainty in power grid: Decision is made with respecting to AGC units and active load on the basis of synergetic unit combination such that active load’s advantages in regulation speed is put to full use in achieving efficient cooperation with renewable energy power. Meanwhile, factoring in allowable frequency variation range during decision-making may help to reduce AGC units’ regulation load and improve power grid's capacity of accommodating renewable energy power. Calculation example analysis suggested that the model and technique presented in this paper is capable of efficient coordination between active loads and renewable energy power, delivering friendly transition with day-ahead dispatch and AVC control.

Method for Determination of Optimal Installed Capacity of Renewable Sources of Energy by the Criterion of Minimum Losses of Active Power in Distribution System

New method for determination of optimal placement and value of installed capacity of renewable source of energy (RES) by the criterion of minimum losses of active power, that allows taking into consideration the dependence of RES on natural conditions of region, schedule of energy supply, parameters and configuration of distribution network is suggested in the paper. Results of computations of test scheme confirm the efficiency of the proposed method and its simplicity as compared with the methods considered in literature sources.

Energy Efficiency and Renewable Energy Technologies Using Smart Grids: Study Case on NIPE Building at UNICAMP Campus

In its broadest interpretation, the smart grid vision sees the future of power industry transformed by the introduction of intelligent two-way communications, ubiquitous metering and measurement. This enables much finer control of energy flows and the integration and efficient use of renewable forms of energy, energy efficiency methodologies and technologies, as well as many other advanced technologies, techniques and processes that wouldn’t have been practicable until present. The smart grid vision also enables the creation of more reliable, more robust and more secure power supply infrastructure, and helps optimize the enormous investments required to build and operate the physical infrastructure required. The smart grid promises to revolutionize the electric power business that has been in place for the past 75 years. This work discusses the efficiency, targeted at the consumer units of electricity, with a view to sustainability and potential for technological innovation. The issue is addressed from two perspectives: the systems for generation and power distribution, and the design of a building “smart energy”. Because of the novelty of the subject in our country, the concepts presented and treated throughout this work come from material obtained at events and specialized sites on electric power system in Brazil and worldwide, being accompanied by information and data from NIPE’s building at University of Campinas’s campus case study in which it exemplifies the applicability of the techniques and recommended technologies.

Distributed generator-based distribution system service restoration strategy and model-free control methods

The rapid growth of distributed generator(DG)capacities has introduced additional controllable assets to improve the performance of distribution systems in terms of service restoration.Renewable DGs are of particular interest to utility companies,but the stochastic nature of intermittent renewable DGs could have a negative impact on the electric grid if they are not properly handled.In this study,we investigate distribution system service restoration using DGs as the primary power source,and we develop an effective approach to handle the uncertainty of renewable DGs under extreme conditions.The distribution system service restoration problem can be described as a mixed-integer second-order cone programming model by modifying the radial topology constraints and power flow equations.The uncertainty of renewable DGs will be modeled using a chance-constrained approach.Furthermore,the forecast errors and noises in real-time operation are solved using a novel model-free control algorithm that can automatically track the trajectory of real-time DG output.The proposed service restoration strategy and model-free control algorithm are validated using an IEEE 123-bus test system.

Optimal Trading Decision-Making of Power Supply Chain under Renewable Portfolio Standards

Under the background of implementing renewable portfolio standards and the ever-improving tradable green certificate scheme,the increasingly environmentally-friendly preference of power users is leading to changes in electricity demand,which,in turn,is driving changes in the decision-making behaviors of various actors in the power supply chain.Based on this,with the goal of pursuing maximum profit,consumer-power-demand functions have been introduced with some consideration of the factors of consumer preference to establish an optimal profit model for each trading subject in non-cooperative states of the power supply chain,under the constraints of meeting renewable energy portfolio standards.Here,the optimal strategy of each trading subject is presented by adopting the reverse induction method.Furthermore,examples are used to analyze factors such as the influence of environmental protection preferences,quota ratios,price substitutions,and market demand as well as the optimal profit of each trading subject in view of providing a reference for the decision-making in the power supply chain trading subjects.

The Connection of Solar Generators to the Electricity Distribution Network as a Means of Mitigating Environmental Impacts by Dispensing the Banks of Accumulators

Solar generators are known worldwide as a means of generating clean electricity. However, the existence of battery banks causes alarm in the community by the existence of materials that degrade the environment by discarding them outside the norm. With the publication of Regulatory Standards 482/12 and 687/15, solar generators can be connected to the distribution grid, which serves as a means of accumulating the generated energy. The new changes were seen as an economic possibility, but there are more benefits. This has proved very important to make solar generation greener because it no longer needs large battery banks. This has also been shown to significantly lower the final value of the solar generator, bringing economic benefits. This paper aims to analyze the economic and environmental benefits of battery bank distribution in solar generation.

Distributed generation planning for diversified participants in demand response to promote renewable energy integration

In modern distribution system,the distribution system operator(DSO)acts as a market facilitator and data manager as well as an energy supplier and operation controller.In this circumstance,the DSO should comprehensively consider the diversified participants of the modern distribution system when making investment decisions of distributed generation(DG).This paper proposes a DG planning model considering the behavior of the diversified participants,which are motivated to cooperate with distributed renewable energy resources to promote their integration,and to achieve the optimal DG investment plan.The optimization model takes a centralized structure but fully considers the preferences,profits and comfort levels of the aggregators and consumers.The model is linearized into a mixed-integer linear programming(MILP)problem and is solved by CPLEX.Results of the case study show that when the DSO spares subsidies to the aggregators and consumers to encourage their participation in demand response(DR)programs,it earns more compared with providing no subsidies for DR participation.It is also demonstrated that the overall profit increases as the subsidies increase within a certain range,but decreases when the subsidies exceed this range.Therefore,the DSO needs to carefully choose the subsidization level to achieve the optimal utilization of renewable energy and demand flexibility.The optimal subsidization level is derived from the model proposed in this paper.Therefore,this paper puts forward a new pattern to utilize the distributed renewable energy sources,and provides guidance in policy making and DR program implementation.

Recent Progress and Approaches on Carbon-Free Energy from Water Splitting

Sunlight is the most abundant renewable energy resource,providing the earth with enough power that is capable of taking care of all of humanity’s desires-a hundred times over.However,as it is at times diffuse and intermittent,it raises issues concerning how best to reap this energy and store it for times when the Sun is not shining.With increasing population in the world and modern economic development,there will be an additional increase in energy demand.Devices that use daylight to separate water into individual chemical elements may well be the answer to this issue,as water splitting produces an ideal fuel.If such devices that generate fuel were to become widely adopted,they must be low in cost,both for supplying and operation.Therefore,it is essential to research for cheap technologies for water ripping.This review summarizes the progress made toward such development,the open challenges existing,and the approaches undertaken to generate carbon-free energy through water splitting.

Scenario Generations for Renewable Energy Sources and Loads Based on Implicit Maximum Likelihood Estimations

Scenario generations for renewable energy sources and loads play an important role in the stable operation and risk assessment of integrated energy systems.This paper proposes a deep generative network based method to model time-series curves,e.g.,power generation curves and load curves,of renewable energy sources and loads based on implicit maximum likelihood estimations(IMLEs),which can generate realistic scenarios with similar patterns as real ones.After training the model,any number of new scenarios can be obtained by simply inputting Gaussian noises into the data generator of IMLEs.The proposed approach does not require any model assumptions or prior knowledge of the form in the likelihood function being made during the training process,which leads to stronger applicability than explicit density model based methods.The extensive experiments show that the IMLEs accurately capture the complex shapes,frequency-domain characteristics,probability distributions,and correlations of renewable energy sources and loads.Moreover,the proposed approach can be easily generalized to scenario generation tasks of various renewable energy sources and loads by fine-tuning parameters and structures.

Efficient Energy Performance within Smart Grid

The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. Energy/power plays a critical role for social, economic and industrial development. Because of industrial generalization, especially in agricultural and economical activities, the energy demand has increased rapidly in developed countries. Generation and usage of energy has direct impact on modern power grid. In this scenario energy management is a hard task because load is dynamic and we don’t have control over it. Renewable or undepleted energy resources have great applications and impact in current electric power system situation. For example it gives pollution free (green) energy which is environment and user friendly. It is cost effective;it uses natural resources for its generation and hence do not waste any coal, gas etc. There are many inducements to empower energy productivity. As current smart grid is complex and non linear in operation and design, it used an optimized method that provides maximum efficiency with minimum input. Our work depicts a case study of hybrid electric aircraft for achieving high performance.

Dynamic Protective Control Strategy for Distributed Generation System with Fixed-speed Wind Turbines

The characteristics of induction generator based fixed-speed wind turbines(FSWT)are investigated.The impacts of different execution time in protective operations are studied under different fault duration and various wind velocity situations,e.g.,FSWT stabilities of load shedding in distribution systems.Based on this research,a dynamic protective control strategy for a distributed generation system(DGS)with FSWT is proposed.Finally,simulation results demonstrate the effectiveness of the strategy.

Electronic Controlled Energy Storage Devices and Applications in Future Smart Grid

This paper discusses the future power system consisting of distributed generations connected to local loads in the form of micro-grid systems.The benefits of having energy storage systems and the role of power electronics in micro-grid systems are presented.This paper also examines how micro-grids have a key role to play in the development of the smart grid.

Study of Coordination between Protective Devices Comprising Distributed Generation in Distribution System

This paper proposes to study the coordination of protective devices when 8 MW synchronous generators are interconnected to distribution System of PEA. The coordination between recloser and drop out fuse is investigated in this paper. The three-phase fault is simulated using digital simulation and electrical network calculation program (DIgSILENT). The results are shown that the short circuit current from substation is reduced comparing to the distribution system without DG connected. It causes to protective device coordination inconsistently, so the maintenance will be delayed more than expected.