Power quality improvement of grid-connected wind energy system using facts devices

ABSTRACT

The increased penetration of wind power into the grid will save the fossil fuels and reduce the impact on the environment; however, it also presents many challenges to power system operation and control, system stability and power quality. In this paper, the use of static compensator (STATCOM) with battery energy storage system (BESS) is to enable smooth and the proper integration of wind energy system to the grid is taken as the main objective. This work presents a novel controller for an integrated STATCOM-BESS for grid-connected wind energy system. The simulation of the proposed system is done in Simulink with hysteresis current controlled pulse width modulation-based controller, which is in the IEC 61400-21 standard. It is observed that the STATCOM with BESS, operated with the specified controller, provides reactive power support, good harmonic mitigation as well as maintaining the source current the voltage without any phase angle difference. The experimental setup composed of Matlab-dSPACE DS1104 interface for generating the gate pulse, isolation and gate driver circuit, and the three-phase inverter is created and the system is tested for various combinations of R load and R-L load, and the measurements are recorded using FLUKE 434 energy analyser.     

Feasibility analysis of distributed solar electricity penetration in cement manufacturing plants

Industrial manufacturing units like cement and steel are benefited little by solar electricity. This paper presents feasibility of application of solar electricity in cement manufacturing plants in a distributed manner. Distributed solar PV systems without battery have been simulated using HOMER Pro micro grid design software to see the effects on net present cost (NPC), levelised cost of energy (COE), pollutant emissions, coal consumption and cost of cement production. The daily solar radiation ranges from 3.79 to 6.71?kWh/m²/day and the total distributed load supplied by solar electricity is 8876.4?kWh/day which is 0.82% of overall plant load. The results show that proposed system reduces pollutant emissions by almost 23% with an increase of NPC by 3.075% and COE by 0.6436% only. It saves 709,139?kg coal per year with 0.6437% increase in cement production cost. Proposed system will be beneficial economically too when PV prices come down in future.     

Impact on power quality due to large-scale adoption of compact fluorescent lamps – a review

The demand of electrical energy has grown tremendously in the last couple of decades across the globe. The energy conservation and management has attracted the attention of stake holders for efficient utilisation of the resources. One of the major steps taken by the authorities towards conservation of electrical energy is replacement of incandescent lamps (ILs) by compact fluorescent lamps (CFLs). CFL uses electronic circuit for its ignition, making them a non-linear load on utility grid. Large-scale replacement of ILs has enormous effects on utility grid in terms of power quality. This paper reviews the work conducted by several researchers investigating the effect of using CFLs on power quality. Basic terminologies related to power quality is defined. The experimental results elaborate the pollution on the grid in the term of total harmonic distortion in current due to adoption of CFLs. The methodologies of harmonic measurement system are reviewed. Different software used for the analysis is presented. The paper will help the researchers to receive a comprehensive overview of power-quality issues.     

Potential for a Danish power system using wind energy generators,solar cells and storage

Some overall properties of a power system in a northern climate based mainly upon renewable energy are studied.

The power system consists of wind energy generators and solar cells in combination with a storage system and a back-up system. The type of power plants constituting the back-up system are not specified. The back-up system could be used to generate power only when the rest of the system is unable to cover the load. The predicted performance of the solar/wind power system is calculated on the basis of hourly meteorological data measured in Denmark during the years 1959 to 1972.

It has been established from this data that to maximise the fraction of annual load covered by solar and wind energy the ratio of solar to wind production capacity is approximately 40% solar to 60% wind. With only small changes in the energy provision, however, the ratio could be varied between 20:80 and 60:40.

The saving in energy resulting from provision of various storage capacities has been studied. This saving will be negligible if less than half of the annual load is covered by the solar/wind power system. For a solar/wind power system with a production capacity of 1.25 times the annual load the marginal energy saving effect of a storage system is reduced by a factor of 10 when the storage capacity is increased from 0 to 24 hours. The marginal costs of producing the electricity rise steeply when more than about 80–90% of the load is to be covered on the basis of renewable energy. Finally it is shown that when 80% of the load is covered by renewable energy the storage capacity should not exceed 40 hours.     

Performance analysis of vortex flow through a swirler by computational fluid dynamics technique

ABSTRACT

In the recent era, it is preferred for energy to be produced from renewable energy resources rather than from non-renewable resources. That’s why the non-renewable sources gradually become obsolete due to its main drawback of creating pollution. On the other hand, the set-up cost for renewable energy resources is very high, so it is difficult to afford financially. Therefore, researchers started their research on pollution control from the non-renewable resources. In this work, the emission level of diesel engine has been successfully planned to control by inducing a variable geometry swirler in the inlet manifold, which will enhance the turbulence inside the cylinder, hence increasing homogeneity between air–fuel composition and low emission. In this paper, it has been shown numerically and justified how the designed geometry of the swirler will increase the efficiency of combustion to control the emission from an I.C. engine.     

Comparison of annual energy performances with different ventilation methods for cooling

Stratum ventilation has been proposed to cope for elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following three factors: the reduction in ventilation and transmission loads and increased COP of chillers. The year-round energy saving is found to be substantial at 25% and 44% at least when compared with displacement ventilation and mixing ventilation, respectively.     

Decrease in CO2 emission per capita as a result of the reduction in power grid losses in Iran

ABSTRACT

In power grids, a significant amount of the generated power in power plants is wasted in the grid between power plants and consumers. The amount depends on different factors. With regard to the vital role of electricity in economic and social development alongside with high investment costs in electricity generation, transmission and distribution, practical solutions for decreasing grid losses and enhancing the efficiency of existing facilities are crucial. Due to the global environmental situation and significant effects of energy consumption on the environment, the general trend is towards the deployment of methods which are more efficient and less fuel consuming. In addition, more implementation of monitoring and controlling equipment and instalment of more efficient equipment in electricity transmission and distribution sectors reveal the effort towards the reduction of pollutants. These facts reveal the importance of this issue amongst authorities in the power industry. In this research through the assessment of power grid losses and studying different types of power plants in Iran, the amount of electricity generation and grid loss are studied. In addition, the impact of different power plants on the amount of environmental pollutants especially CO₂ is presented. Also, some solutions to reduce CO₂ emission are provided.     

CyDER – an FMI-based co-simulation platform for distributed energy resources

The increased integration of distributed energy resources (DERs) is bringing a number of challenges to the power grid. These include reverse power flows in distribution systems and potentially transmission systems and grid stability. So far, specialized tools have been developed to capture some of the impact of DERs at the distribution level. However, distribution system operators lack visibility into the overall system conditions. Furthermore, the impact of increasing DERs is not limited to the distribution level but also influences the transmission grid. To support the planning and operation of the grid, we developed a co-simulation platform called CyDER (A Cyber Physical Co-simulation Platform for Distributed Energy Resources in Smart Grids) that integrates various domain-specific simulation tools. CyDER is based on the functional mock-up interface standard. This paper gives an overview of CyDER and demonstrates its use based on two applications.     

State-of-the-art research on micro grid stability: a review

The usage of renewable energy resources (RES) in energy is receiving great attention as a solution to the problem of a shortfall in electrical energy. Application of RES in a generation system is done with diverse outlines, amongst others in a micro grid system. Employment of micro grid systems offers numerous benefits both for the consumer as well as for the utility provider. Voluminous micro grid expansions are carried out in more than a few countries, because it offers healthier power quality and furthermore it is ecologically friendly. Even though its adoption is growing steadily, there are still several hurdles to proficiently design, regulate, and operate micro grids when linked to the grid, and as well when in the islanded mode, and wide-ranging investigation activities are on-going to confront the issues. It is essential to consider across-the-board opinions of the micro grid amalgamation in a power system network. This paper presents a review of issues in relation to micro grid stability and offers an account of study in areas related to micro grids.     

Fuzzy logic energy management for a microgrid with storage battery

ABSTRACT

This article presents the development of an energy management system using fuzzy logic applied to a microgrid that combines photovoltaic solar energy, wind energy and a storage system with batteries. The model was developed using LabVIEW software and allows to obtain performance results of the photovoltaic generator, the wind turbine and the battery bank. The energy management system can be controlled in real time to take advantage of existing weather conditions. The results indicate that the fuzzy logic system guarantees the continuous operation of the load through the energy resources of the microgrid. The designed microgrid allows to generate 63,288?kWh/year of photovoltaic solar energy and 40,175?kWh/year of wind energy.     

Modular multi-level converter-based DFIG wind power system with MMC-STATCOM

ABSTRACT

Transmission and distribution conversion operation, voltage, current magnitude variation and time-to-time power flow change through grid are the major issues in power system. Variable wind energy system is more popular for power generation through conventional converters and hence harmonic reduction is very less in these converters. In this paper, 9?MW modular multi-level converter-based DFIG wind energy power system parameters are compared with 9?MW DFIG systems using conventional converter. DFIG is operated in four mode condition with proper back-to-back power electronic converters and controllers. In power electronics, the modular multi-level converters are more advanced for reducing transients, peak response oscillations and improving the efficiency of the system. A five-level MMC has been applied in back-to-back converter with phase disposition (PD) PWM technique for DFIG wind system of the same rotor side controller and grid side controller. A conventional converter-based DFIG wind energy system is replaced with five-level MMC-based system with level shift PD-PWM technique. The impact of MMC on DFIG wind energy system is reduced voltage and current harmonics fast settling time compared to conventional converter-based DFIG system. The above MMC DFIG power system voltage is balanced at fault condition with MMC-STATCOM.     

Urbanization,sustainability and the utilization of energy and mineral resources in China

*This paper analyzes a model depicting the trend of Chinese urbanization and explores relationships between urbanization and the supply and demand of major energy and mineral resources and between the gross domestic product (GDP) and the urbanization of China. Then it predicts China’s supply and demand trends from 2005 to 2050. It is predicted that until 2010 China’s GDP and urbanization will grow at high speed, slowing slightly yet still growing strongly on to 2050. It also argues that the supply of cement, steel, aluminum and coal and the demand of timber, cement and steel have significant effects on urbanization. The paper concludes that China will inevitably face a long shortage of resources if future urbanization is faster than predicted, i.e., China cannot meet the targets of the current urbanization strategy while continuing current energy and resource consumption for its industrialization and modernization.     

Reactive power pricing in power markets: a comprehensive review

ABSTRACT

Reactive power is one of the main characteristics that play a major role in power systems. When reactive flow is inadequate, the power system is confronted with voltage collapse and more than enough reactive power production follows the circulation in the network and consequently the occupation of power lines. On the other hand, power market evolves from centralised and vertically integrated structure to a competitive environment. The reactive power market is different from energy market and like others such as spinning reserve, frequency control and power system stabiliser is taken in the category of the ancillary service market. This paper reviews various mechanisms for pricing of reactive power in both levels of transmission and distribution (T&D) system. Additionally, the cost paid for reactive power service in the presence of distributed energy resources is analysed because of their high penetration in the power system, especially in distribution level.     

Validity of decision criteria for selecting power-to-gas projects in Poland

Renewable energy sources ultimately intend to become the only power source in modern economies. In the coming years, new generation systems based on renewable energy sources (RESs), new energy transmission systems, and new management systems will be introduced for the electricity and gas sectors. As RESs work irregularly, proper management is crucial for the reliable operation of the electrical grid. Their utility will depend mainly on energy storage capacity. Power-to-gas (P2G) technology, where electrical energy is converted into, e.g., hydrogen or methane, will become an essential solution. The forthcoming transformation will require substantial financial and technical investments. Decision-makers should consider many factors (e.g., social responsibility, location, distance from gas and electrical grids, and solar and wind resources). The implementation of individual projects should be carried out carefully. Poorly planned projects work inefficiently in terms of costs and technical aspects. This paper aims to identify the conditions necessary for implementing P2G projects. Multi-Criteria approaches based on chosen benchmarks can help to select optimal P2G projects.In the paper, the weights of the proposed decision criteria, such as investment cost, investment return time, substrate resources, environmental attraction and social acceptance, were determined based on the stakeholder surveys using the chosen elements of the Analytical Hierarchical Process (AHP) method. The proposed approach allows considering differing viewpoints and establishing the validity of each of them indirectly. The applied approach based on the AHP method, the validity of technical, economic and environmental criteria was determined based on both the preferences of experts in the field of energy and transportation as well as the energy end-users. As a result of the analysis, two dominant factors were selected: access to substrates and economic efficiency - meaning that a deep analysis of substrates resources should precede the work on P2G projects.     

Householders co-managing energy systems: space for collaboration?

ABSTRACT

The potential role of households as ‘co-managers’ of energy in smart grids is widely discussed in the social science literature. Much remains uncertain about the social relations and practices emerging around novel smart grid technologies and their contribution to sustainability. Drawing on 14 ‘show-and-tell’ home tours with householders in a smart grid trial, an analysis is presented of how home energy management (HEM) is performed in everyday life. The focus is on three technologies: monitoring technologies, smart heat pumps and home batteries. How and why householders do (not) engage with energy management during the pilot project is described. When householders participate in HEM practices, they gain energy management understandings and an awareness of smart grid objectives. Since HEM practices are shared between householders and actors from the energy provision system, they display particular ways of distributing responsibilities, power and agency over technologies, experts and householders. The time and space granted to these three smart grid technologies are shown to depend on the trust relationships between householders and the more or less absent providers of technologies and services. These insights emphasize the need to develop smart grid solutions reflexively with respect to the different spaces and practices in households in which they operate.     

Analysis of feasibility on heating single family houses in rural areas by using sun and wind energy

Households in Lithuania consume about 1/3 of total final consumption of fuel energy. In order to reduce imports of fossil fuel and emissions of dangerous pollutants, solar energy could be used for the above-mentioned needs. That would require large collector areas and volumes for seasonal heat storage. In wintertime the wind speed velocity is much higher than in summertime in Lithuania. Therefore, it is advisable to study meeting the thermal needs of single family houses by combining use of wind and solar energy. To this end analytical research has been made by using deterministic method. The analysis has been carried out for the case when 1 m² of heated room area requires 0.25 m² of solar collector area and 0.5 m² working area of wind turbine rotor. Heat storage is planned for 24 h. By using such a hybrid system during the heating season 42.6–56.2% of heating needs for space and domestic hot water are satisfied. However, for individual days (especially from May to October) a surplus of generated heat is formed and it reaches about 53.6% of space heating needs per year. This relative surplus of energy could be used for transmitting wind power-plant energy to the electric network or in a household and thermal energy can be used for drying agricultural produce, heating greenhouses, open swimming pools and satisfying other needs.     

Multi-objective modelling of simultaneous reconfiguration of NMG-based distribution network and operation of different DERs

ABSTRACT

A Micro-Grid (MG) is envisaged with ever increasing distributed energy resources (DERs) e.g. distributed generation, demand response and electrical vehicles. This paper suggests a method based on multi-objective modelling for day-ahead scheduling of Networked-MGs based distribution network in the presence of different DERs and also this method is able to find the daily reconfiguration instants. The proposed scheme is solved using NSGA-II from distribution network operator viewpoints, who is responsible for providing power demand in higher reliability level and lower costs. Besides, in the suggested scheme voltage deviation and voltage stability as efficient power quality criteria in distribution networks and emission pollutant reduction are incorporated as independent objective functions. Moreover, to quantify the influence of different load models, a 33-node distribution network is adopted with a load class mix of residential, industrial and commercial loads. Eventually, the obtained results are reported which verify the efficiency of the proposed method.     

Multi-step-ahead forecasting of daily solar radiation components in the Saharan climate

ABSTRACT

Accurate estimation of renewable energy sources plays an important role in their integration into the grid. An unexpected atmospheric change can produce a range of problems related to various solar plant components affecting the electricity generation system. Global solar radiation (GSR) assessment has been increased in the past decade due to its important use in photovoltaic application. In this paper, we propose the use of machine learning-based models for daily global and direct solar radiation forecasting in a semi-arid climate, using a combination set of meteorological parameters on a horizontal surface in the Ghardaïa region. The models are presented and implemented on 3-year measured meteorological data at Applied Research Unit for Renewable Energies (URAER) at Ghardaïa city between 2014 and 2016. The results show that both MLP and RBF models perform well for three-step-ahead forecasting with a slight improvement in MLP models in terms of statistical metrics.     

Application of solar energy for milk pasteurisation: a comprehensive review for sustainable development

ABSTRACT

Solar energy is available freely. Hence, nowadays people are working on solar energy when compared with conventional sources of energy. Dairy industries require heat, which can be generated by the use of boiler with the aid of wood. Hence, due to increment in global warming, it is necessary to use renewable energy. The primary aim of this review paper is to study various researchers’ work on solar milk pasteurisation system. Hence, it also covers important aspects required for solar pasteurisation like flat plate collector, heat exchanger and solar water heating system.     

Energy Conversion Goes Local: Implications for Planners

Problem: Emerging energy technologies are bringing planners a new set of issues. The supply-oriented framework from engineering economics within which energy planning has traditionally been conducted may be useful for siting large refineries, power plants, and transmission corridors, but it is not helpful for mitigating conflicts at the site level, encouraging new technology adoptions, managing the demand for energy, or, especially, coordinating the diverse users of smaller, local energy facilities.

Purpose: I provide an alternative conceptual framework for thinking about emerging energy planning tasks. I highlight factors not considered in the traditional model, and introduce terminology for characterizing key characteristics of the changing energy economy.

Methods: I draw on concepts from industrial ecology, urban metabolism, and ecological economics, and apply my new framework to a set of examples illustrating its advantages relative to the traditional approach to energy planning.

Results and conclusions: I propose that planners use network models to think about energy systems and focus especially on nodes where energy is converted from one form to another. Understanding the scale, scope, commodification, and agency of such nodes, and whether and when these attributes are open to change, can improve energy planning decisions for traditional energy investments such as power plants and for energy initiatives such as wind farms, rooftop solar systems, energy-efficient buildings, cogeneration, compact growth, and plug-in hybrid electric vehicles.

Takeaway for practice: Planners should do more than just mitigate energy facility siting conflicts. They should also identify points of governmental leverage on private decision makers, keep track of evolving technologies, bundle energy users with different temporal demand profiles, and help build smarter energy networks. Focusing on energy networks and their nodes should help planners see how they can be most effective.

Research support: This work was supported by the National Science Foundation and the New Jersey Board of Public Utilities.