Reduction Of Nitrogen Oxide Emissions Research Articles

How Photochemically Consumed Volatile Organic Compounds Affect Ozone Formation: A Case Study in Chengdu, China

Surface ozone (O3) pollution has not improved significantly in recent years. It is still the primary air pollution problem in many megacities in China during summertime. In high temperature and intense radiation weather, volatile organic compounds (VOCs) are easily oxidized and degraded to induce O3 pollution. In order to understand the impact of difference between photochemical initial concentration (PIC) of VOCs and the actual measured concentration on O3 formation, a campaign was carried out during O3 pollution in Chengdu (25 July–5 August 2021). During this O3 pollution episode, the maximum value of O3 concentration reached 335.0 μg/m3, and the precursor concentrations increased significantly. The mean values of VOCmeasured and VOCPICs were 19.7 ppbv and 30.7 ppbv, corresponding to O3 formation potential (OFP) of 175.3 μg/m3 and 478.8 μg/m3, respectively, indicating that the consumption of VOCs content could not be ignored. Alkenes accounted for 77.2% of VOCs consumption. Alkenes and aromatics contributed 63.0% and 29.2% to OFP values which derived from PIC of each VOC species. The relative incremental reactivity analysis based on PICs showed that the O3 formation was controlled by the cooperation of nitrogen oxides (NOx) and VOCs, and the effect of NOx emission reduction was better.

Ensuring the Environmental Friendliness of Drillships during Their Operation in Special Ecological Regions of Northern Europe

The features of the operation of the drillship-type vessels in special ecological regions of Northern Europe are considered. The main gap in the study of these systems is to determine the optimal degree of recirculation. The requirements of the International Maritime Organization for the emission of nitrogen oxides from the exhaust gases of marine diesel engines are given. The aim of the study is to determine the optimal degree of recirculation of exhaust gases of a 16V32 STX-MAN marine diesel. During the research, the optimal degree of exhaust gas recirculation varied in the range of 0–21%, the load on the diesel—in the range of 35–95% of the rated power. It was established that in this case, the emission of nitrogen oxides decreases up to 7.7–33.6%, the specific fuel consumption increases up to 0.2–3.5%. It was also found that the use of gas recirculation in the range of 18–21% at loads of 35–55% leads to a critical increase in exhaust gas temperature. It is advisable to use exhaust gas recirculation in the range of 6–15% to ensure the environmental friendliness of the operation of the drillships. In these modes, the maximum reduction in nitrogen oxide emissions is ensured with a minimum increase in specific fuel consumption. Future studies should be directed at the development of the criteria for the environmental stability of sea vessels.

Methods for constrained optimization of expensive mixed-integer multi-objective problems, with application to an internal combustion engine design problem

Engineering design optimization problems increasingly require computationally expensive high-fidelity simulation models to evaluate candidate designs. The evaluation budget may be small, limiting the effectiveness of conventional multi-objective evolutionary algorithms. Bayesian optimization algorithms (BOAs) are an alternative approach for expensive problems but are underdeveloped in terms of support for constraints and non-continuous design variables—both of which are prevalent features of real-world design problems. This study investigates two constraint handling strategies for BOAs and introduces the first BOA for mixed-integer problems, intended for use on a real-world engine design problem. The new BOAs are empirically compared to their closest competitor for this problem—the multi-objective evolutionary algorithm NSGA-II, itself equipped with constraint handling and mixed-integer components. Performance is also analysed on two benchmark problems which have similar features to the engine design problem, but are computationally cheaper to evaluate. The BOAs offer statistically significant convergence improvements of between 5.9% and 31.9% over NSGA-II across the problems on a budget of 500 design evaluations. Of the two constraint handling methods, constrained expected improvement offers better convergence than the penalty function approach. For the engine problem, the BOAs identify improved feasible designs offering 36.4% reductions in nitrogen oxide emissions and 2.0% reductions in fuel consumption when compared to a notional baseline design. The use of constrained mixed-integer BOAs is recommended for expensive engineering design optimization problems.

A numerical study of reducing the concentration of O3 and PM2.5 simultaneously in Taiwan.

Since the 24-hr PM2.5 (particle aerodynamic diameter less than 2.5μm) concentration standard was regulated in Taiwan in 2012, the PM2.5 concentration has been decreasing year by year, but the ozone (O3) concentration remains almost the same. In particular, the daily maximum 8-hr average O3 (MDA8 O3) concentration frequently exceeds the standard. The goal of this study is to find a solution for reducing PM2.5 and O3 simultaneously by numerical modeling. After the Volatile Organic Compounds (VOCS)-limited and nitrogen oxides (NOX)-limited areas were defined in Taiwan, then, in total, 50 scenarios are simulated in this study. In terms of the average in Taiwan, the effect of VOCS emission reduction is better than that of NOX on the decrease in PM2.5 concentration, when the same reduction proportion (20%, 40%) is implemented. While the effect of further NOX emission reduction (60%) will exceed that of VOCS. The decrease in PM2.5 is proportional to the reduction in precursor emissions such as NOX, VOCS, sulfur dioxides (SO2), and ammonia (NH3). The lower reduction of NOX emission for whole Taiwan caused O3 increases on average but higher reduction can ease the increase, which suggests the implement of NOX emission reductions must be cautious. When comparing administrative jurisdictions in terms of grids, districts/towns, and cities/counties, it was found that controlling NOX and VOCS at a finer spatial resolution of control units did not benefit the decrease in PM2.5 but did benefit the decrease in O3. The enhanced O3 control strategies obviously cause a higher decrease of O3 throughout Taiwan due to NOX and VOCS emission changes when they are implemented in the right places. Finally, three sets of short-term and long-term goals of controlling PM2.5 and O3 simultaneously are drawn from the comprehensive rankings for all simulated scenarios, depending on whether PM2.5 or O3 control is more urgent. In principle, the short-term scenarios could be ordinary or enhanced version of O3 decrease with lower NOX/VOCS emissions, while the long-term scenario is enhanced version of O3 decrease plus high emission reductions for all precursors.

The Combined Effect of the Piston Bowl Geometry and Injection Fuel Pressure on the Compression Ignition Engine Characteristics

In this study, the combined effect of the piston bowl geometry and fuel injection pressures on combustion, performance and emission characteristics of compression ignition (CI) engine fueled with baseline Diesel (D100) and microalgae-biodiesel (MA100) was studied. In this paper, the comparison study for the two different piston bowl geometry, namely: hemispherical combustion chamber (HCC) and toroidal re-entrant combustion chamber (TRCC), was carried out with the various fuel injection pressures (200-240 bar) performed. A single-cylinder, direct injection, and four strokes were chosen to simulate the compression ignition (CI) engine by developing a zero-dimensional simulation model using Diesel-RK commercial software. The data was validated by comparing the results against experimental data, which showed that the results obtained from the numerical simulation were in good agreement with the experimental results. MPRR, EGT, HRR, BTE, and NOx exhibited an increase with increased fuel injection pressure, while an inverse trend was observed with ID, CO, and HC. When using MA100 biodiesel with HCC piston bowl geometry at fuel injection pressure (200 bar), the maximum predicted brake specific fuel consumption (BSFC) was 0.545 kg/kWh. A significant reduction of nitrogen (NOx) oxides emissions was also observed with low fuel injection pressures. In contrast, the emission characteristics such as hydrocarbons and CO were enhanced by increasing fuel injection pressure and modifying the piston bowl geometry.

Deep learning based model predictive control for compression ignition engines

Machine learning (ML) and a nonlinear model predictive controller (NMPC) are used in this paper to minimize the emissions and fuel consumption of a compression ignition engine. In this work machine learning is applied in two methods. In the first application, ML is used to identify a model for implementation in model predictive control optimization problems. In the second application, ML is used as a replacement of the NMPC where the ML controller learns the optimal control action by imitating or mimicking the behavior of the model predictive controller. In this study, a deep recurrent neural network including long–short term memory (LSTM) layers are used to model the emissions and performance of an industrial 4.5 liter 4-cylinder Cummins diesel engine. This model is then used for model predictive controller implementation. Then, a deep learning scheme is deployed to clone the behavior of the developed controller. In the LSTM integration, a novel scheme is used by augmenting hidden and cell states of the network in an NMPC optimization problem. The developed LSTM-NMPC and the imitative NMPC are compared with the Cummins calibrated Engine Control Unit (ECU) model in an experimentally validated engine simulation platform. Results show a significant reduction in Nitrogen Oxides (NOx) emissions and a slight decrease in the injected fuel quantity while maintaining the same load. In addition, the imitative NMPC has a similar performance as the NMPC but with a two orders of magnitude reduction of the computation time.

Modeling Ground Ozone Concentration Changes after Variations in Precursor Emissions and Assessing Their Benefits in the Kanto Region of Japan

Ozone (O3) is a pollutant of concern in urban areas because of its effects on health, crops, ecosystems, and materials. Despite efforts to meet the Japanese air quality standard for O3 in the Kanto region, the attainment percentage is close to zero. Considering that O3 formation is sensitive to emissions of volatile organic compounds (VOC) and nitrogen oxides (NOx), this study evaluated a range of reductions in the emissions of both precursors using a regional air quality model (ADMER-PRO) and estimated their benefits measured as the economic change due to O3 concentration differences between scenarios. The simulation period was set during the 2016 O3 season. The results showed that O3 concentrations could be reduced using two approaches: significant reduction in VOC levels combined with minor NOx level changes or significant NOx emission reduction. Significant reduction in NOx levels was the most effective strategy for a generalized decrease in the O3 levels in the Kanto region, and the benefit analysis revealed that the most significant economic impacts could be achieved by adopting the latter approach.

The role of NOx emission reductions in Euro 7/VII vehicle emission standards to reduce adverse health impacts in the EU27 through 2050

Air pollution is the single greatest environmental health hazard in Europe, responsible for over 300,000 premature deaths in the EU27 in 2019. Transport is a significant contributor toward the emission of air pollutants which reduce life expectancy through increased likelihood of morbidity-associated diseases. The introduction of the Euro vehicle emission standards has been successful in driving down the overall level of transport related air pollutants. However, the current regulatory limits have not been updated in nearly a decade. Furthermore, deviations are still evident between the type-approval standards and real-world emissions recorded through remote sensing. Based on the technology potential of current emission control systems, a feasible reduction in new vehicle emissions of nitrogen oxides (NOx) of up to 80% applicable to light- and heavy-duty vehicles that could be realized through the upcoming revision of the Euro standards is modelled. A multi-model approach is employed, combining a stock simulation model and a health impact model which applies the latest methodology of the Global Burden of Disease to quantify the cumulative emissions reduction and corresponding health impacts in the EU27 through 2050. Mandating such a NOx reduction for new vehicles from 2027 would result in a 93-98% reduction in annual NOx emissions from transport by 2050, and reduce cumulative emissions by 4.2-5 million tonnes over the 2027-2050 period. The corresponding reduction in levels of particulate matter and ozone would prevent 34,675 - 41,645 premature deaths, and 568,374 - 682,513 years of life lost. Heavy-duty vehicles experience greater relative emissions reductions compared to their light-duty counterparts due to the current slower deployment of zero-emission vehicles in the sector.

Visualisation and Thermovision of Fuel Combustion Affecting Heat Release to Reduce NOx and PM Diesel Engine Emissions

Research was conducted on fuels with additives that selectively affect the rate of kinetic (dQk/dα) and diffusion (dQd/dα) combustion in the diesel engine cylinder. In addition to the base fuel (DFB), DFKA fuel with an additive reducing dQk/dα, DFDA fuel with an additive increasing dQd/dα, and DFS fuel with both additives were tested. The main purpose of such dQ/dα course control in the engine cylinder was to simultaneously reduce the emissions of nitrogen oxides (NOx) and particulate matter (PM), and to increase the efficiency of the combustion process. Similar to the course of the dQ/dα, the course of the combustion temperature (Tc(α)) affects the NOx produced and the number of afterburned solid particles; the influence of the fuel additives on the functional curves was analysed. In addition to analysis of the temperature Tc(α) calculated from the indicator diagrams, Tc(α) analysis was conducted using the two-colour method, which allows the analysis of the isotherm distributions locally and temporarily. The two-colour method required prior endoscopic visualisation of the fast-changing processes inside the engine cylinder. Parameters defined by pressure, temperature, heat release rate, and visualisation and thermovision in the engine cylinder (as a function of the crank angle) allowed for an in-depth cause and effect analysis. It was determined why combustion of DFS fuel with both additives produced a synergy resulting in the simultaneous reduction in NOx and PM emissions in the exhaust gas and an increase in combustion efficiency. This publication relates to the field of Mechanical Engineering.

Multiple injection strategies with high water port injection rates for enhancing performance and emissions in a boosted SI engine

Water injection has been proven both to reduce emissions of nitrogen oxides and to improve fuel conversion efficiency via knock limit extension in turbocharged spark ignition (SI) engines. However, water injection still has several obstacles to maximize the benefits, such as an increase of particulate matter and unburned hydrocarbon emissions. In order to ameliorate the problems with a sufficient amount of water injection (water to fuel mass ratio > 0.5), this study adopted multiple fuel injection strategies, which inject fuel multiple times in a cycle. A boosted single-cylinder research engine equipped with a water port injector and a piezoelectric gasoline direct injector was utilized for this study over a range of water to fuel mass ratio (up to 1.0) and multiple fuel injection (single vs. triple) conditions. The results show that the drawbacks of water injection including combustion instability, unburned hydrocarbon, and particulate emissions were significantly improved with multiple fuel injections, and the relative thermal efficiency improvement and nitrogen oxide emission reduction were maximized up to 3.9% and 52.7%, respectively, with the combined injection strategy. In addition, the increased carbon monoxide emissions typical with multiple fuel injections were largely mitigated by the water injection strategy.

Long-Term Variations of Meteorological and Precursor Influences on Ground Ozone Concentrations in Jinan, North China Plain, from 2010 to 2020

Ground-level ozone (O3) pollution in the North China Plain has become a serious environmental problem over the last few decades. The influence of anthropogenic emissions and meteorological conditions on ozone trends have become the focus of widespread research. We studied the long-term ozone trends at urban and suburban sites in a typical city in North China and quantified the contributions of anthropogenic and meteorological factors. The results show that urban O3 increased and suburban O3 decreased from 2010 to 2020. The annual 90th percentile of the maximum daily 8-h average of ozone in urban areas increased by 3.01 μgm−3year−1 and, in suburban areas, it decreased by 3.74 μgm−3year−1. In contrast to the meteorological contributions, anthropogenic impacts are the decisive reason for the different ozone trends in urban and suburban areas. The rapid decline in nitrogen oxides (NOX) in urban and suburban areas has had various effects. In urban areas, this leads to a weaker titration of NOX and enhanced O3 formation, while in suburban areas, this weakens the photochemical production of O3. Sensitivity analysis shows that the O3 formation regime is in a transition state in both the urban and suburban areas. However, this tends to be limited to volatile organic compounds (VOCs) in urban areas and to NOX in suburban areas. One reasonable approach to controlling ozone pollution should be to reduce nitrogen oxide emissions while strengthening the control of VOCs.

Investigation into the Impact of Weight on Diesel Trucks’ NOx Emissions: An Overweight Case Study

To build an understanding of the emission contribution, especially nitrogen oxides (NOx) emissions, of many overweight/oversized trucks operating in the Dallas-Fort Worth area, U.S., the North Central Texas Council of Governments commissioned the Texas A&M Transportation Institute to conduct an emission testing study. The study team collected and analyzed data on these vehicles’ activities and emissions characteristics. Vehicle activity data collection was performed using portable activity measurement systems, and exhaust emissions data was measured using two portable emission measurement systems. Using methodologies developed by the Environmental Protection Agency for the MOtor Vehicle Emissions Simulator (MOVES) model, both datasets were processed and expressed as emission rates for three loading scenarios. Researchers observed that, because of the sensitivity of the performance of selective catalytic reduction (SCR) to exhaust temperature, NOx data observed during a test cycle may not result in emission rates that are representative of the real-world operations. The team developed a methodology to adjust the resulting NOx rates for SCR-equipped trucks. The findings of the analysis suggest that the current MOVES opMode equations do not appear to adequately capture the impact of weight on the emission rates of heavy-duty diesel vehicles. The team also found that SCR-equipped trucks can have lower emission rates under heavier loads, especially in higher-speed and higher-power opMode bins, which typically have higher exhaust temperatures. Under normal loads (approximately 55,000 lb), SCR does not seem to provide a NOx emission reduction benefit at speeds under 50 mph compared with exhaust gas recirculation-equipped trucks.

Political differences in air pollution abatement under the Clean Air Act

In this paper, we study how local politics affect state level implementation of a critical federal environmental policy, the Clean Air Act, in the electricity generation sector. The analysis focuses on the installation of capital intensive air pollution abatement technology in highly regulated “nonattainment” areas, which violate federal air quality standards. The primary research design uses a regression discontinuity in the vote share for Republican governors and event study analyses of close elections. In nonattainment areas, Republican gubernatorial control differentially decreases new air pollution abatement capital spending by 90% and the probability of installing the most effective nitrogen oxide abatement technology by nine percentage points, relative to attainment areas and the counterfactual of Democratic gubernatorial control. The health benefits from reduced nitrogen oxide emissions in nonattainment areas likely exceed the additional costs of new air pollution abatement technology at electric utilities. However, the estimated benefit-cost ratios are smaller than those from many other air pollution abatement policies and net benefits may be negative for technology that will operate for fewer than five years.

Catalytic Systems in the Reduction of Nitrogen Oxide Emissions in Diesel-Powered Trucks

In recent years, the number of motor vehicles in circulation has increased in proportion to Brazil’s economic growth, resulting in an increase in emissions of toxic gases from combustion, such as nitrogen oxide, particulate matter, carbon dioxide and volatile organic compounds, among other polluting compounds. This type of pollution has its impacts potentiated in large cities, accumulating due to the configuration of streets and buildings in large urban centers, and can even penetrate indoor environments, having harmful effects on the health of residents. To minimize the emission of these gases, catalytic converters can be used in the vehicle exhausts. Catalytic converters are a promising technology used to reduce exhaust emissions from the engine. In this context, this paper presents an overview of the emission of toxic gases by heavy transport powered by diesel oil and the influence of the use of automotive catalysts in reducing the emission of toxic gases. Additionally, a proposal for monitoring the useful life of automotive catalysts is presented through an electronic sensing system, which makes it possible to determine the catalyst efficiency and the appropriate point for its reactivation or replacement.

Data Optimization Analysis of Integrated Energy System Based on K -Means Algorithm

To learn about the practical application of K -environment algorithms in electronic data analysis. To increase the thermal efficiency of boiler combustion and reduce nitrogen oxide emissions, the paper uses a 300 MW circulating liquid bed boiler for a thermal power plant as a research product. The studied and improved optimization methods have been successfully used to optimize the combustion of circulating liquefied boilers. Based on the advantages and disadvantages of biogeographic optimization algorithm and K -means clustering algorithm, this paper combines the two algorithms into a new improved clustering algorithm k -bbo-cluster. According to the operation mode of circulating fluidized bed boiler, the calculation method of boiler combustion thermal efficiency and the generation mechanism of nitrogen oxides, the boiler thermal efficiency model, nitrogen oxide emission concentration model and its comprehensive model are established by using the least square support vector machine method based on Bayesian structure framework. The learning outcomes of the vector machines that support the minimum squares of the Bayesian structure are less than 0.05 by the difference between MSE, MAE, and MAPE. The study of optimizing the combustion of circulating liquefied bed furnaces in this article can effectively improve the thermal efficiency of circulating liquefied bed furnaces and reduce nitrogen oxide emissions. Protection is important.

Multi-objective performance optimization and control for gas turbine Part-load operation Energy-saving and NOx emission reduction

This work aims to apply the multi-objective optimization method to gas turbine part-load energy-saving and NOx (Nitrogen Oxides) emission reduction problem. For power generation gas turbines, energy-saving is based on raising the thermal efficiency of the system. This is always based on regulating the variable geometries of the plant. However, in this process, the combustion condition would be changed, which would further change the NOx pollutant emission level. Therefore, in this paper, the conflict between gas turbine thermal efficiency enhancement and NOx emission reduction is discovered and analyzed with a nonlinear model. To solve this multi-objective optimization problem, GA (Genetic Algorithm), a global optimization algorithm, is applied. The two objectives are thermal efficiency for energy-saving and NOx Emission Index (EINOx) for pollution reduction. The fuel mass flow rate and compressor Inlet Guide Vane (IGV) position are the decision variables. Optimization is conducted for 50% to 90% nominal power levels and 5 °C to 25 °C ambient temperatures. With the non-inferior solutions on the Pareto Front and a trade-off decision, the selected gas turbine optimum working point can be obtained with a nonlinear converter module. For 15 °C, 70% nominal power working condition, increasing the fuel mass flow rate by 0.216% and IGV degree by 10.344% can bring a 46.273% reduction of EINOx, with the cost of a 0.212% decline in the thermal efficiency. The sensitivity analysis of the Pareto Frontiers to power level and ambient temperature is carried out. Then the level of energy-saving is analyzed by calculating the cost of fuel, and a trade-off suggestion is given. In the end, the values of the decision variables and objective functions under three trade-off scenarios are calculated and listed in a table, with which the final solution can be decided conveniently according to practical demands.

In-Use Passenger Vessel Emission Rates of Black Carbon and Nitrogen Oxides.

This study quantified emission factors of black carbon (BC) and nitrogen oxides (NOx) from 21 engines on in-use excursion vessels and ferries operating in California's San Francisco Bay, including EPA uncertified and Tier 1-4 engines and across engine operating modes. On average, ∼60 fuel-based emission factors per engine were measured using a novel combination of exhaust plume capture combined with GPS location and speed data that can be more readily deployed than common portable emissions measurement systems. BC and NOx emission factors (g kg-1) were lowest and least variable during fast cruising and highest during maneuvering and docked operation. Selective catalytic reduction (SCR) reduced NOx emissions by ∼80% when functional. However, elevated NOx emissions that exceeded corresponding exhaust standards were measured on most Tier 3 and Tier 4 engines sampled, which can be attributed to inactive SCR during frequent low engine load operation. In contrast, BC emissions exceeded the PM emission standard for only one engine, and SCR systems employed as a NOx reduction technology also reduced emitted BC. Using these measured emission factors to compare commuting options, we show that the CO2-equivalent emissions per passenger-kilometer are comparable when commuting by car and ferry, but BC and NOx emissions can be several to more than ten times larger when commuting by ferry.

1.5톤 선박용 보일러의 SCR 시스템 수치해석에 관한 연구

Diesel engines are widely used as transportation engines because for their superior torque and thermal efficiency compared to gasoline engines. In shipping companies, low-grade diesel oil is used to reduce fuel costs, but diesel engines emit up to 100 times more Nitrogen Oxides(NOx) and fine dust than gasoline engines. Currently, global warming and climate change are increasing interest in the air environment, and regulations on air pollution emissions are being strengthened. The International Maritime Organization has applied the Tier III, a nitrogen oxide emission regulation in the ECA area, to vessels built since 2016 and regulations are being strengthened on environmental pollution sources emitted from ships operating in the ocean and docking in ports. There are methods such as EGR and SCR systems to cope with enhanced environmental regulations. EGR reduces the amount of oxygen and increases the concentration of carbon dioxide as a way to reduce NOx emissions during engine combustion, slowing the combustion reaction and lowering the maximum combustion temperature. Previous studies on the comparison of nitrogen oxide reduction rates by boiler load using diesel fuel and LNG fuel have not been conducted in detail. In this study, the nitrogen oxide reduction rate and flow characteristics were investigated through CFD flow analysis according to the boiler load of the SCR system using diesel fuel and LNG fuel using a 1.5 ton marine boiler. In the future, trough the results of numerical analysis, we will develop an efficient LNG propulsion ship SCR system based on comparative analysis with actual experimental values.

Elevated Formation of Particulate Nitrate From N2O5 Hydrolysis in the Yangtze River Delta Region From 2011 to 2019

AbstractAerosol nitrate has become the most abundant compound during aerosol pollution in eastern China. The Chinese government implemented a stringent policy during 2013–2017 to tackle aerosol pollution. However, the response of nitrate to nitrogen oxides (NOx) reduction is unclear owing to the limitation of long‐term measurement. Here, we performed a 9‐year continuous measurement of aerosol compositions in Shanghai and confirmed a decrease in most species except nitrate. The contribution of nitrate to fine particulate matter (PM2.5) increased significantly, reaching up to 35% in pollution episodes after 2017. This is in contrast to the evident reduction in NOx emissions. We found that the elevated dinitrogen pentoxide (N2O5) hydrolysis is responsible for the observed nitrate trend. Increased ozone and decreased nitrogen dioxide (NO) facilitated the formation of N2O5, and increased nitrate proportion promoted the uptake of N2O5 and eventually enhanced the conversion efficiency of NO2 to nitrate. Our results highlight the importance of synergic control of aerosol and ozone pollution.

SST-Based Grid Reinforcement for Electromobility Integration in Distribution Grids

Electric Vehicles (EVs) are gaining acceptance due to the advantages they offer in the reduction of nitrogen oxide and carbon dioxide emissions. The need for emission reduction and the potential of EVs for these reductions is reflected in the current sustainable mobility policies of the EU as well as the German government. Increasing the penetration of EVs in the grid requires an expansion of EV charging infrastructure, which in turn requires either grid reinforcement or solutions for more efficient use of existing infrastructure to avoid or postpone grid reinforcement. Distribution transformers face increased loading due to EV charging and need to be protected from overloading during peak load periods to ensure continuity of service. Therefore, transformers are one of the components that are upgraded or replaced as a part of grid reinforcement. In this paper, we propose the connection of a Solid-State Transformers (SST) between two buses operating at the same-voltage level as an alternative to replacement or upgrading of conventional transformer as well as to prevent their overloading. We analyse how the proposed topology can be useful to reduce the impact of EV integration on the overloading of distribution transformers and node voltage violations in the distribution grid.