Lake Champlain is a major economic driver for Vermont's tourism economy, as well as a primary source of drinking water for many of the state's residents but nutrient pollution represents a potential threat to ecosystem health and economic well-being. From December 2011 to December 2012 a field trial of an EAF steel slag filter was assessed for its feasibility in treating wastewater originating from Swan Valley Cheese (SVC), in Swanton, VT. The study focuses on a period of the filter's operation from May 4 to October 10, 2012. The plant generates approximately 20,000 gallons per day of high P concentration wash water which is treated in an open aerated lagoon. The filter treated effluent from this lagoon. The major goals of this research were to conduct a field trial of an EAF steel slag filter to evaluate its effect on total P (TP), dissolved reactive P (DRP), and total suspended solids (TSS). Research was also conducted on pH reduction for filter effluent. Results indicate that the filter removed 95.83% of TP, 96.65% of DRP, and 52.25% of TSS. Average pH effluent was measured at 10.12 ±1.55. Additionally, a field study was conducted on sampling two unlined bioretention systems treating urban stormwater runoff. Methods used are presented and methodological considerations for future studies are presented to guide researchers in more effective and efficient methods for obtaining influent and effluent samples from bioretention systems that are not necessarily designed for sampling.

<p>Steel heating and melting processes consume the majority of the energy used in advanced short-process steelmaking practices. Economic and environmental pressures from energy consumption drive the research to improve the furnace operation efficiency and energy efficiency. The goal of this research is to utilize computational fluid dynamics (CFD) modeling to provide useful tools and recommendations on the steel heating and melting practices in the steelmaking process. The steel slab reheating process, the steel scrap preheating process and the steel scrap melting process are studied.</p> <p> </p> <p>A transient three-dimensional (3-D) CFD model was developed to simulate the flow characteristics, combustion process and multi-scale, multi-mode heat transfer inside the reheating furnace. The actual geometry of an operating industrial furnace was used and typical operating conditions were simulated. Specific walking speeds of slabs in production were modeled using a dynamic mesh model which is controlled by a user-defined function (UDF) solved using ANSYS Fluent. Fuel variations at different zones with respect to time were also considered. The model was validated with instrumented slab trials conducted at the SSAB Mobile (Alabama) mill. The temperature field in the furnace and the temperature evolution of a slab predicted by the CFD model are in good agreement with those obtained from the instrumented slab trials. Based on the simulation results, the slab reheating process and the temperature uniformity of a slab at discharge were able to be properly evaluated. In addition, a comprehensive two-dimensional (2-D) numerical heat transfer model for slab reheating in a walking beam furnace was developed using the finite difference method. An in-house code was developed. The model is capable of predicting slab temperature evolution during a reheating process based on real time furnace conditions and steel physical properties. The model was validated by using mill instrumented slab trials and production data. The results show that the temperature evolution predicted by the model is in good agreement with that measured by the thermocouples embedded in the instrumented slab. Compared with 3-D CFD simulation of a reheating process, this 2-D heat transfer model used for predicting slab temperature evolution requires less computing power and can provide results in a few seconds. A graphical user interface was also developed to facilitate the input and output process. This is a very convenient and user-friendly tool which can be used easily by mill metallurgists in troubleshooting and process optimization.</p> <p> </p> <p>CFD models for steel scrap preheating and melting processes by the combined effects of the heat source from both oxy-fuel combustion and electric arc were also developed. The oxy-fuel burners firing natural gas (NG) are widely used in EAF operation during the scrap preheating and melting stages. In order to understand the role of oxy-fuel combustion and potentially increase the energy input from NG while decreasing the electricity consumption, numerical simulation of scrap preheating by oxy-fuel combustion in an EAF was firstly conducted. A 3-D CFD model was developed with detailed consideration of gas flow, oxy-fuel combustion, heat transfer between gas and solid scrap and scrap oxidation. The model was validated by a small-scale experimental study and applied onto a real-scale EAF.</p> <p> </p> <p>Scrap melting in bath is comprehensively studied with a CFD model developed to simulate the melting in bath process under given operating conditions. Two sub-models were developed for model integration: steel melting model and coherent jet model. The multiphase volume of fluid (VOF) model and the enthalpy-porosity technique are applied to describe the steel melting process. The coherent jet model calculates the gas jet momentum and is integrated into the flow model to calculate its effect on the fluid flow in the bath. The electric arc was treated as a heat flux to represent the heat transfer from the electric arc during the melting process. Model validations were conducted for each sub-model to ensure their accuracy. Parametric studies were also carried out to obtain useful information for real practice. </p><p>Overall, the CFD models developed in this research work have demonstrated value in improving energy efficiency in the energy-intensive steelmaking processes. The developed CFD models also provide insights for better understanding of the multi-physics processes.<br></p> <p> </p>

Este trabalho tem por objetivo estudar o aproveitamento do pó de aciaria elétrica (PAE) na sinterização de minério de ferro visando a eliminação de zinco. Primeiramente, foi feita uma caracterização física e química do resíduo através de análises químicas, granulométricas, morfológicas e de difração de raios-X. O minério de ferro, principal componente do processo de sinterização, foi caracterizado através de análise química, granulométrica e de umidade. Em seguida, foram fabricadas micropelotas de 3,0 a 5,0mm de diâmetro compostas por 70% de PAE e 30% de moinha de coque, que foram classificadas por peneiramento e secas em esfufa. Depois de aglomerado, o resíduo foi incorporado na sinterização de minério de ferro em diferentes proporções, condições de processo e formas de adição (micropelotas, undersize da micropelotização com granulometria entre 1,0 e 2,0mm, ou mistura de PAE e coque em pó). A cada processo de sinterização foram retiradas amostras de sínter, os materiais foram analisados através de Microscópio Eletrônico de Varredura (MEV), macroscopia e análises químicas por espectrofotometria de absorção atômica para verificar o teor de zinco. Amostras de misturas não sinterizadas também foram submetidas a análises químicas para determinar a quantidade inicial de zinco, ou seja, verificar a quantidade de zinco contido na mistura antes do processo de sinterização. Mediante a comparação do teor de zinco das amostras não sinterizadas com os sínteres, foi possível determinar a eliminação de zinco nos ensaios realizados. Aproximadamente 92% de zinco foi eliminado (junto com os gases de saída) com a incorporação de 10% de micropelotas na mistura a sinterizar. Os resultados mostraram que a eliminação do metal no processo é proporcional à relação redutor/resíduo. / The aim of this work was to study the use of electric arc furnace dust (EAFD) in iron ore sintering process aiming zinc elimination. Firstly, physical and chemical characterizations of the waste were made using X-ray diffraction, microscopy, chemical and size analyses. Iron ore is the main component of the sintering process, this material was characterized by chemical, size and humidity analyses. After, micropellets composed of EAFD 70% and coke breeze 30% with diameters of 3.0-5.0 mm were produced, then they were dried in kiln and classified by sieving. The pellets were incorporated into the iron ore sintering charge using differents proportions, process conditions and addition forms (micropellets, undersize with diameters of 1.0-2.0 mm, or a mixture of EAFD and coke breeze). Sintered samples were collected in each sintering process. These materials were analyzed by scanning electron microscopy (SEM), macroscopy and chemical analysis using atomic absorption spectrophotometry in order to determine the zinc content. Samples of not sintered mixtures were also characterized by chemical analysis aiming the determination the initial amounts of zinc, i.e. in order to check the zinc amounts present in the mixture before the sintering process. The comparation between the zinc contents of sintered samples and not sintered allowed to determine the elimination of zinc during the experiments. About 92% of zinc was eliminated (along with the output gas) with the incorporation of 10% of micropellet in the sintering mixture. Results showed that the zinc elimination in the process is proportional to the ratio reducer/waste.

A redução no volume de resíduos produzidos, industriais e agrícolas, vem se tornando uma exigência constante em todos os processos de produção. A falta de espaço físico para a disposição destes resíduos, a contaminação ambiental causada por eles, além da necessidade de preservação dos recursos naturais não-renováveis e da diminuição do consumo de energia e emissão de poluentes, tornam a reciclagem e a reutilização dos resíduos uma alternativa bastante atraente. A construção civil apresenta-se como um setor bastante apto à utilização de técnicas de reaproveitamento de resíduos, provenientes das mais diversas indústrias. Além de todos os benefícios ambientais, este reaproveitamento, pela construção civil, pode gerar recursos financeiros, bem como, possibilita a melhora das características de alguns materiais de construção, e pode diminuir o custo de construção, fator importante, quando se avalia o déficit de habitacional existente no Brasil. Neste trabalho, desenvolveu-se um estudo baseado no aproveitamento de escória de aciaria elétrica, resíduo gerado a partir da reciclagem do aço, empregada como agregado para concreto de cimento Portland, em substituição total ou parcial dos materiais convencionais. Os resultados obtidos apontaram para a viabilidade de utilização deste resíduo como agregado. / The reduction on the volume of produced wastes, from industries or agriculture, is becoming a current demand in all production processes. The lack of space to dispose these wastes, the environment contamination caused by them, besides the necessity to preserve the non-renewable natural resources, to reduce energy consumption and greenhouse gas emission , are making wastes recycling and reutilization an interesting alternative. The civil construction presents itself as a field quite able to utilize techniques to reuse wastes from different industries. Besides all the environmental benefits, this reuse by the civil construction can create new profits, as well as, the improvement of the characteristics of some construction materials and it can also decrease the costs of the construction, which is a major factor, considering the Brazilian habitation deficit. In the present work a study was developed based on the reutilization of the electric arc furnace slag, a metallurgic waste from the steel recycling process, employed as an aggregate to the concrete of Portland cement, totally or partially replacing the conventional materials. The obtained results indicate this waste reutilization viability.

O setor siderúrgico, assim como os demais setores da indústria, vem buscando alternativas para a redução dos custos de produção e aumento de produtividade. Em aciarias elétricas, os principais custos de produção do aço podem ser divididos, de forma simplificada, entre o custo dos insumos e o custo das matérias primas. Os refratários estão entre os cinco maiores custos na produção do aço em usinas semi-integradas. Entretanto, o conhecimento detalhado da microestrutura e do comportamento desses materiais ainda é bastante restrito aos seus fabricantes. Tendo em vista a importância dos refratários na produção do aço, este trabalho teve como objetivo gerar conhecimento acerca de sua microestrutura e comportamento em operação, com foco na diminuição do consumo e maximização dos lucros da empresa. Para tal, com o intuito de conhecer detalhadamente sua microestrutura e prever seu desempenho, foram realizadas análises de caracterização em laboratório e testes que simularam as condições de operação. Após os testes laboratoriais, os materiais selecionados foram testados em operação em forno elétrico a arco, buscando encontrar o melhor conjunto de materiais sob o ponto de vista de estabilidade do processo e custo de refratários. O cenário que apresentou melhores resultados em relação à performance e ao consumo específico foi a configuração A, onde foram utilizados os tijolos A, massa de soleira X, massa de reparo K e canal EBT P. Além disso, a substituição do tijolo C pelo tijolo A gerou uma redução de custo de 40%, e o conhecimento gerado com a caracterização do canal EBT proporcionou uma redução de 29,9% no preço desse item. / The steel industry, like other sectors of the industry, is seeking alternatives to reduce production costs and increase productivity. In electric steelworks, the main steel production costs can be divided, in a simplified way, between the cost of inputs and the cost of raw materials. Refractories are among the five largest costs in steel production in semi-integrated mills (mini-mills). However, detailed knowledge of the microstructure and behavior of these materials is still quite restricted to their manufacturers. Given the importance of the refractories in the production of steel, this study aimed to generate knowledge about their microstructure and behavior in operation, focusing on the reduction of consumption and maximization of profits. For that, in order to know in detail the microstructure and predict its performance, characterization analyzes and tests simulating the operating conditions were performed in the laboratory. After laboratory tests, the selected materials have been tested in operation in electric arc furnace, seeking to find the best set of materials from the point of view of stability of the process, and cost of refractories. The scenario that best results presented, in terms of performance and the specific consumption, was Configuration A, where bricks A, ramming mix X, repair mix K and EBT P were used. Moreover, the replacement of Brick B by brick A, generated a cost reduction of 40%, and the information gathered with the characterization of EBT, reduced the price of that item by 29.9%.

O Pó de Aciaria Elétrica (PAE) é um resíduo sólido originado na fabricação de aços em Fornos Elétricos a Arco (FEA), classificado como resíduo perigoso pela ABNT NBR 10004- 2004. Isto porque ele contém metais nocivos ao meio ambiente (como chumbo e cádmio), embora seja constituído, em sua maior parte, pelos elementos ferro, zinco e oxigênio. Devido aos custos onerosos para disposição e por tratar-se de resíduo perigoso, a indústria procura pela possibilidade de retorno ao processo produtivo do aço. Uma das alternativas é a reintrodução na aciaria elétrica através de aglomerados autorredutores como parte da carga do FEA. Neste trabalho, são produzidas misturas autorredutoras contendo PAE e coque de petróleo, apresentando as correspondentes caracterizações químicas e físicas. Através de ensaios termogravimétricos é feita uma avaliação do comportamento destas misturas, mostrando a possibilidade do emprego desta técnica na aferição prática do teor ótimo de coque, em aglomerados. Além disto, foram produzidas pelotas autorredutoras através do uso de um disco laboratorial, sendo as pelotas submetidas a testes físicos e mecânicos, com uso de aglomerantes e também testes de autorredução em fornos mufla e em aparato experimental. Como resultados destes experimentos pode-se concluir que o cimento Portland ARI e a combinação de cal hidratada com cinza de casca de arroz possuem melhor resistência a compressão frente aos outros ligantes utilizados. O grau de metalização obtido para a maior parte das amostras não passou de 35%. A remoção de zinco foi de aproximadamente 85%, para temperatura de 1100 ºC, com 45 minutos e com 10% de coque de petróleo. Isto indica a possibilidade de enriquecimento da nova poeira gerada em zinco. Fato este que agrega valor para tratamento do resíduo em outros processos externos. / The Electric Arc Furnace Dust (EAFD) is a solid waste generated by electric steelmaking, in Electric Arc Furnaces (EAF), being considered a hazardous waste by the Environmental Protection Agency. That is because of its harmful metals, although it is composed, in majority, by elements iron, zinc and oxygen. Due to high costs involved for its disposal and because it is a hazardous waste, industry seek for the possibility of returning the EAFD back to the steelmaking process. One of the alternatives is by reintroduction via electric meltshop through self-reducing agglomerates as part of the furnace burden. In this work, self-reducing mixtures of EAFD and petroleum coke were produced, showing as result corresponding chemical and physical characterizations. Using thermogravimetric tests, an evaluation of the mixtures behavior was carried out, demonstrating the possibility of using this technique in a practical measurement of optimal content of coke, in agglomerates. Furthermore, selfreducing pellets were pelletized using a laboratorial disc, with these agglomerates being tested in physical and mechanical strength essays, with different binders employed and also selfreduction tests in vertical electric furnace and experimental apparatus. As part of the results it could be concluded cement and the combination between hydrated lime and rice husk ash achieved the best results, in compressive strength, comparing to other binders. The metallization degree for almost all samples achieved a maximum of 35%. Zinc removal, for temperatures around 1100 ºC, in an experiment of 45 minutes and using 10% of petroleum coke, was approximately 85%. It indicates the dust to be enriched with zinc. This fact adds value to the waste for treatment in other processes.

O pó de aciaria elétrica é um importante subproduto da indústria siderúrgica devido ao seu alto teor de zinco. Assim, tecnologias vêm sendo desenvolvidas visando seu aproveitamento, sendo o forno Waelz a mais difundida delas atualmente. No entanto, sua operação, por contar com um forno rotativo de grandes dimensões que abriga uma infinidade de fenômenos físico-químicos, apresenta difícil previsibilidade ab initio. Por essa razão, este trabalho faz uso de uma ferramenta avançada da termodinâmica computacional, destinada à modelagem de processos, chamada SimuSage, a fim de modelar o seu comportamento. Para a criação do modelo utilizou-se também uma base de dados termodinâmicos advinda do software FactSage e a plataforma de desenvolvimento Lazarus. Com base em dados e resultados operacionais da literatura, foi possível realizar simulações nos modos adiabático e isotérmico, comparando os resultados com os da prática industrial. Constatou-se uma grande capacidade do modelo de reproduzir os resultados da literatura, mesmo quando não há muita informação para aferição dos parâmetros, gerando boa concordância com a composição química relatada dos produtos Óxido Waelz e Escória Waelz. / The electric arc furnace dust is an important by-product of the steel industry due to its high content of zinc. Thus, technologies have been developed aiming for its use, and the Waelz Kiln is the most widespread of them today. However, counting on a very large rotary kiln that houses an infinity of physico-chemical phenomena, its operation is difficult to predict ab initio. For this reason, in order to model its behaviour this work uses an advanced tool of computational thermodynamics designed to process modelling, called SimuSage. To create the model, a thermodynamic database, provided by the FactSage software, as well as a development platform, Lazarus IDE, were also used. Based on operational data and results from de literature, it was possible to perform simulations on both adiabatic and isothermal modes comparing its results with the industrial practice. A great capability of the model to reproduce results from the literature was found, even when there is not much information for the parameters calibration, generating good agreement regarding the reported chemical composition for the products, Waelz Oxide and Waelz Slag.

A presente tese teve como objetivo fornecer subsídios teóricos e experimentais com vistas à reciclagem da carepa gerada em usinas mini-mills através de briquetes autorredutores para uso em FEA. Para atingir os objetivos vislumbrados, o trabalho foi estruturado em quatro principais tópicos: estudo de caracterização e de redutibilidade da carepa, escolha e caracterização do redutor para uso nos briquetes, elaboração e caracterização da mistura e ensaios de laboratório para avaliação do desempenho dos briquetes autorredutores. Os estudos de caracterização da carepa indicaram que este resíduo é constituído principalmente de wustita e se apresenta estratificada em três camadas: camada externa fina e porosa composta de hematita e magnetita, camada intermediária de wustita densa e camada interna de wustita porosa. A cinética de redução da carepa foi investigada em termobalança no intervalo de temperatura entre 830 e 1200°C com CO puro e mistura 90%CO-10%CO2. A energia de ativação aparente encontrada nesses ensaios variou de 71 a 80 kJ/mol e as observações microscópicas demonstraram que a redução da carepa segue um modelo topoquímico. A escolha do agente redutor para compor o briquete se deu através de ensaios de gaseificação ao CO2 e de autorredução em termobalança com três tipos de material carbonoso. A partir desses ensaios observou-se a seguinte ordem decrescente de reatividade e respectivas energias aparentes de ativação: Carvão Vegetal (Ea = 237 kJ/mol), Carvão Mineral (Ea = 214 kJ/mol) e Coque de Petróleo (Ea = 335 kJ/mol). Em virtude da maior reatividade do Carvão Vegetal frente aos demais, este redutor foi escolhido para uso nos briquetes. A mistura utilizada na confecção dos briquetes autorredutores teve como constituintes principais a carepa, os finos de carvão vegetal e aglomerantes (melaço e cal). Ensaios de caracterização em termobalança com atmosfera oxidante e aquecimento rápido indicaram uma perda de massa de cerca de 40%, referente às etapas de secagem, desvolatilização e autorredução da mistura. Nesses ensaios, observou-se elevadas taxas de perda de massa da mistura e uma notável complexidade dos fenômenos envolvidos, com reações simultâneas de combustão, autorredução e de oxidação do ferro, prevalecendo uma ou outra, dependendo da temperatura e da fração reagida de amostra. Através de procedimentos que buscaram reduzir a complexidade dos fenômenos envolvidos nas condições oxidantes, foi possível estimar que a energia de ativação aparente de autorredução está entre 62 e 69 kJ/mol. Os briquetes produzidos em escala industrial foram submetidos a ensaios isotérmicos e não-isotérmicos de alta temperatura. Tais ensaios buscaram determinar os gradientes térmicos no interior do briquete, a energia de ativação aparente e o desempenho cinético do aglomerado em condições de temperatura que se aproximam da prática industrial. A partir das constatações concernentes às taxas das reações químicas individuais (redução e gaseificação), às medidas do perfil de temperatura no interior dos aglomerados, à energia de ativação estimada para o briquete (93 kJ/mol) e ao modelo de redução encontrado nos ensaios de alta temperatura, acredita-se que tanto a cinética de redução da carepa como a transferência de calor sejam obstáculos limitantes da cinética global dos briquetes em estudo. Finalmente, os resultados de metalização obtidos nos testes de alta temperatura dão indícios da possibilidade de uso destes briquetes em FEA. / This dissertation aimed to provide theoretical and experimental basis for recycling of mill scale generated in mini-mill plants through the use of self-reducing briquettes in EAF. To reach these goals, the work was structured around four main topics: characterization and reducibility study of scale, choice and characterization of the reductant to use in briquettes, elaboration and characterization of the mixture and laboratory tests to performance evaluation of self-reducing briquettes. The characterization studies of mill scale have indicated that this waste is composed mainly of wustite and is stratified into three layers with different morphologies: fine porous external layer composed of hematite and magnetite, intermediate layer of dense wustite and inner layer of porous wustite. The kinetics of scale reduction was investigated in thermobalance in a temperature range from 830 to 1200°C with pure CO and a mixture of 90% CO and 10% CO2. The apparent activation energy obtained in these tests ranged from 71 to 80 kJ/mol and the microscopic observations showed that the mill scale reduction corresponds to a topochemical model. The choice of the reductant for composing the briquette was made through tests of gasification with CO2 and of self-reduction in thermobalance with three different carbonaceous materials. From the results, it was observed the following decreasing reactivity order and the related apparent activation energy: Charcoal (Ea = 237 kJ/mol), Mineral Coal (Ea = 214 kJ/mol) and Petroleum Coke (Ea = 335 kJ/mol). Due to the higher reactivity of Charcoal in relation to the others, this reducer was chosen to be used in the briquettes. The main constituents of the mixture used in the manufacture of self-reducing briquettes were scale, charcoal and binders (melasse and lime). The characterization tests in thermobalance with oxidizing athmosfere and rapid heating indicated a mass loss of about 40%, referring to the stages of drying, devolatilization and self-reduction of the mixture. During these tests, it were observed high rates of mixture loss mass and a remarkable complexity of the phenomena, with simultaneous combustion, self-reduction and iron oxidation reactions, where their importance changes according to temperature and fractional reaction of the sample. Through the procedures that aimed to reduce the complexity of the related phenomena in oxidant conditions, it was possible to estimate that the self-reduction apparent activation energy ranges between 62 to 69 kJ/mol. The briquettes produced in the industrial plant were submitted to isothermal and nonisothermal tests of high temperatures. Such tests aimed to determine the thermal gradients into the briquette, the apparent activation energy and kinetic performance of the agglomerate in temperature conditions similar to the ones used in industrial practice. Based on the findings concerning the individual rates of chemical reactions (reduction and gasification), the measures of the temperature profile inside the briquettes, the activation energy estimated (93 kJ/mol) and the reduction model found in high-temperature tests, it is assumed that both the kinetics of mill scale reduction and heat transfer limit the overall kinetic rates of these briquettes. Finally, the results of metallization obtained in the tests conducted at high temperatures indicate the possibility of using these briquettes into the EAF.

This thesis centers around an electric arc furnace (EAF) at a steel mini-mill in Wilton, IA. First, the thesis replicates previous optimization attempts. Next, the modeling is greatly altered to produce a much improved steel-melting model. Then, a new optimal control system is created and used to reduce energy and fuel costs over the melting process. Finally, results are presented. This thesis shows that when the new optimal control is simulated, the system shows significant energy and fuel savings.

Voltage (lighting) flicker is mainly caused by the electric arc furnaces (EAF) facility supplied by the medium and high voltage power network. In addition to that, because of the increase of wind power generation in both quantity and capacity, intermittent power output of wind turbines under wind speed variation could also cause voltage flickers that affect the performance of lighting and electronics devices in the neighboring feeder buses. Successful voltage flicker prediction and propagation estimation would help both utility and customers in dealing with the problem. This dissertation presents a nonlinear model for the short term prediction of voltage flicker due to EAF operations. In this study, synchronized voltage flicker measurement was conducted at several EAF facilities to understand the stochastic behavior of voltage flicker. The electric loading condition during EAF melting process shows a long term qualitative behavior of a dynamic system and illustrates a special structure of a fractal system. With the fractal structure identification, the behavior hidden behind the voltage flicker time series measurement could be grasped. Using a phase space reconstruction technique and Lyapunov exponent (LE) of state trajectory in the phase space, based on actual voltage flicker measurements, it is proved that the voltage flicker time series is chaos. By using LE, three formulations are adopted to build the prediction models and illustrate the feasibility of short term EAF voltage flicker prediction. Currently, some Asian countries are using the Japanese £GV10 flicker voltage standard. Due to the adoption of IEC standard by IEEE and European countries, a rational conversion of flicker planning limits between different standards would help utilities consider revising or changing their voltage flicker standards and planning limits. Statistical analyses of Pst and £GV10 measurement are conducted in this study. Under different EAF types and operation conditions, reasonable conversion factors between Pst and £GV10 standards are derived, and the flicker transfer factor between different voltage levels of the power supply system are presented.