ATP modeling of internal transformer faults for relay performance testing

Transformers are very important elements of any power system. Unfortunately, they are subjected to through-faults and abnormal operating conditions which can affect not only the transformer itself but also other equipment connected to the transformer. Thus, it is essential to provide sufficient protection for transformers as well as the best possible selectivity and sensitivity of the protection. Nowadays microprocessor-based relays are widely used to protect power equipment. Current differential and voltage protection strategies are used in transformer protection applications and provide fast and sensitive multi-level protection and monitoring. The elements responsible for detecting turn-to-turn and turn-to-ground faults are the negative-sequence percentage differential element and restricted earth-fault (REF) element, respectively. During severe internal faults current transformers can saturate and slow down the speed of relay operation which affects the degree of equipment damage. The scope of this work is to develop a modeling methodology to perform simulations and laboratory tests for internal faults such as turn-to-turn and turn-to-ground for two step-down power transformers with capacity ratings of 11.2 MVA and 290 MVA. The simulated current waveforms are injected to a microprocessor relay to check its sensitivity for these internal faults. Saturation of current transformers is also studied in this work. All simulations are performed with the Alternative Transients Program (ATP) utilizing the internal fault model for three-phase two-winding transformers. The tested microprocessor relay is the SEL-487E current differential and voltage protection relay. The results showed that the ATP internal fault model can be used for testing microprocessor relays for any percentage of turns involved in an internal fault. An interesting observation from the experiments was that the SEL-487E relay is more sensitive to turn-to-turn faults than advertized for the transformers studied. The sensitivity of the restricted earth-fault element was confirmed. CT saturation cases showed that low accuracy CTs can be saturated with a high percentage of turn-to-turn faults, where the CT burden will affect the extent of saturation. Recommendations for future work include more accurate simulation of internal faults, transformer energization inrush, and other scenarios involving core saturation, using the newest version of the internal fault model. The SEL-487E relay or other microprocessor relays should again be tested for performance. Also, application of a grounding bank to the delta-connected side of a transformer will increase the zone of protection and relay performance can be tested for internal ground faults on both sides of a transformer

Methodology of formation and realization of competitive strategy of machine building enterprises

The article views approaches of the Russian and foreign scientists to development and realization of competitive strategy of enterprises. Necessity and importance of development of competitive strategy, oriented at formation of competitive advantages, methods, and means of competitive struggle, predetermined by increased competition and growth of consumers’ requirements to product quality. This process plays a very important role in machine building. Machine building is one of the strategically important spheres which ensure development and security of the country. At the same time, Russian machine building lags behind most of developed countries as to the level of development. Main reasons for such lagging behind are: inaccessibility of credit means, low investment and innovational provision, low qualification of management, and old production and technical base. In order to overcome the existing gap, it is necessary to develop long-term competitive strategy of development of machine building enterprises which ensures conquering certain markets of specific products. Based on the analysis of definitions of scientists and specialists in the sphere of strategic management, the notion “competitive strategy of enterprise” is specified. Methodology of formation and realization of enterprise’s strategy are viewed in detail. Specific examples of missions, strategic vision, and strategic goals of leading enterprises of machine building are given. Significance of development of competitive strategy for effective functioning and development of enterprise is shown. Features which distinguish the process of development and realization of competitive strategy from models of strategic planning that exist in scientific literature are determined. It is proved that development of competitive strategy requires paying special attention to analysis of competitive potential of enterprise and level of its competitive activity – for the purpose of creation of effective strategy which would fully express specifics of activities and individuality of enterprise.peer-reviewe

Indirect reporting. The role of the sentence structure in indirect reporting by L2 speakers

Currently research into indirect reporting in bilingual speech production is considered important because: a) indirect reporting involves work of cognitive, pragmatic and linguistic mechanisms in L2 speaker, thus reveals different mechanisms of language acquisition; b) indirect reporting is considered to be one of the most challenging tasks for L2 speakers; c) understanding of these obstacles could enable L2 teachers to foster language proficiency skills in L2 learners more effectively. There is a growing body of literature that looks into the relationship between the original utterance and the report, logical and inferential structure of indirect reports, the role of semantic and pragmatic factors in shaping indirect reports. Most of the studies have been based on examples and data in the English language, where subjects of research were bilinguals with the English language as L2 and various mother tongues L1. The central thesis of this paper is that L2 learners tend to overcomplicate the structure of a sentence in indirect reporting. This study therefore set out to assess the structure of indirect reports by bilingual speakers and determine possible reasons for overcomplicating of sentence structure. In addition, this study provides an opportunity to advance our knowledge of L2 acquisition

Method of control of efficiency of investment projects based on real option theory and method of analysis of hierarchies

The article is devoted to the development of a method for valuation and control of the efficiency of investment projects under conditions of high uncertainty. The limitations of the traditional valuation methods of the efficiency of investment projects are highlighted and a more relevant approach through the application of real option theory is proposed that allows for evaluating a project based on tis multivariance and the possibility of decision making at every stage of its development. The article shows that, despite the high relevance of the real options theory, its practical use is very difficult for a number of reasons. The main problem of estimating the value of real options is the need to use in the calculation a sufficient number of a priori statistics regarding the project, which is unfeasible. The authors propose a method in which the probabilistic characteristics of the model project are replaced with correct expert ratings. The method is referred to as the modified ROV-method (MROV). This method is based on the binomial model of assessing the value of real options by building a decision tree. At each node of the tree the project might develop in line with an “optimistic” or “pessimistic” forecast. Since the development of the project under any scenario depends on a number of criteria of the environment, the task of assessing the value of real options becomes a multicriteria one. One of the most sound and practically relevant methods of solving such problems is the method of analytic hierarchy process, which is the basis of the developed MROV method. The article also details the algorithm of implementing this method to determine quantitative estimates of the relative probabilities of the development of the project on “optimistic” or “pessimistic” scenarios in each node of the binomial tree. The resulting estimates subsequently used as weights in the calculation of the net present value of the optional investment project for a decision on the feasibility of its implementation and inclusion of the real options being evaluated in the project.Статья посвящена разработке метода оценки и управления эффективностью инвестиционных проектов в условиях высокой степени неопределенности. Обозначена ограниченность традиционных методов оценки эффективности инвестиционных проектов и предложен более актуальный подход на основе применения теории реальных опционов, который позволяет оценить проект с учетом его многовариантности и возможности принятия решений на каждом этапе его развития. В статье показано, что, несмотря на высокую актуальность теории реальных опционов, ее практическое использование весьма затруднительно по ряду причин. Основной проблемой в отношении оценки стоимости реальных опционов является необходимость использования в расчетах достаточного количества априорных статистических данных относительно проекта, что на практике является труднореализуемой задачей. Авторами предложен метод, в рамках которого вероятностные характеристики модели проекта заменяются корректными экспертными оценками, названный модифицированным ROV-методом (MROV). За основу данного метода взята биномиальная модель оценки стоимости реального опциона, основанная на построении дерева решений, в каждом узле которого возможно развитие проекта по оптимистическому или пессимистическому прогнозу. Поскольку развитие проекта по какому-либо сценарию зависит от ряда критериев среды, то задача оценки стоимости реального опциона становится многокритериальной задачей. Одним из наиболее обоснованных и практически адекватных методов решения подобных задач является метод анализа иерархий, который и положен в основу разрабатываемого MROV-метода. Также в статье подробно описан алгоритм реализации данного метода для определения количественных оценок относительных вероятностей развития проекта по «оптимистическому» или «пессимистическому» сценарию в каждом узле биномиального дерева решений. Полученные оценки в последующем используются в качестве весов при расчете чистой приведенной стоимости вариативного опционального инвестиционного проекта для принятия решения о целесообразности его реализации и включении в проект, оцениваемых реальных опционов

Interactive forms in the process of teaching bachelors at the university

The article considers the possibilities of using interactive forms of training in the process of preparing bachelorsРассматриваются возможности использования интерактивных форм обучения в процессе подготовки бакалавро

Medindo cidades sustentáveis na Rússia: análise crítica de metodologias-chave

The paper provides insights on the critical analysis of the current methodologies of the sustainability cities measurement for the present-day Russia. Based on meta-analysis of more than 90 peer-reviewed papers published in Russian and English, we examined both authoring and corporate methodologies such as the SGM methodology for Russian sustainable cities, the environmental rating of Russian cities, and the rating of the environmental governance of the Russian cities, the environmental efficacy index and several authoring methodologies. The analysis showed that most of the calculation methods are based on quantitative (statistical) data, what is their advantage, on the one hand, making their results as objective as possible, but on the other hand, it is a disadvantage, because in connection with the delay in publication of statistics or even its absence, it does not allow the annual dynamics to observe. In addition, the difficulty in choosing the most suitable methodology lies in the significant differences in the development of large, medium and small cities in Russia, and many rating methods are developed exclusively for one of the types of cities. Authors concluded that in spite of the high level of the existing methodologies development, there was a shortage of comprehensive studies carried out in the qualitative-quantitative paradigm that would, in addition to index assessment and mathematical models generation, explain complex causal relationships and processes within a city.El documento proporciona información sobre el análisis crítico de las metodologías actuales de la medición de ciudades de sostenibilidad para la Rusia actual. Con base en el metanálisis de más de 90 artículos revisados por pares publicados en ruso e inglés, examinamos tanto las metodologías de autoría y corporativas como la metodología SGM para ciudades sostenibles rusas, la calificación ambiental de las ciudades rusas y la calificación de la gobernanza ambiental de las ciudades rusas, el índice de eficacia ambiental y varias metodologías de autoría. El análisis mostró que la mayoría de los métodos de cálculo se basan en datos cuantitativos (estadísticos), lo que es su ventaja, por un lado, hacer que sus resultados sean lo más objetivos posible, pero por otro lado, es una desventaja, porque en conexión con el retraso en la publicación de las estadísticas o incluso su ausencia, no permite observar la dinámica anual. Además, la dificultad de elegir la metodología más adecuada radica en las diferencias significativas en el desarrollo de ciudades grandes, medianas y pequeñas en Rusia, y muchos métodos de calificación se desarrollan exclusivamente para uno de los tipos de ciudades. Los autores concluyeron que, a pesar del alto nivel de desarrollo de las metodologías existentes, había una escasez de estudios exhaustivos llevados a cabo en el paradigma cualitativo-cuantitativo que, además de la evaluación del índice y la generación de modelos matemáticos, explicaran relaciones y procesos causales complejos dentro de una ciudad.O artigo fornece insights sobre a análise crítica das metodologias atuais da medição das cidades de sustentabilidade para a Rússia atual. Com base na meta-análise de mais de 90 artigos revisados por pares publicados em russo e inglês, examinamos metodologias de autoria e corporativas, como a metodologia SGM para cidades russas sustentáveis, a classificação ambiental de cidades russas e a classificação da governança ambiental. das cidades russas, o índice de eficácia ambiental e várias metodologias de autoria. A análise mostrou que a maioria dos métodos de cálculo são baseados em dados quantitativos (estatísticos), o que é sua vantagem, por um lado, tornando seus resultados tão objetivos quanto possível, mas, por outro lado, é uma desvantagem, porque em com o atraso na publicação das estatísticas ou mesmo sua ausência, não permite que a dinâmica anual observe. Além disso, a dificuldade em escolher a metodologia mais adequada reside nas diferenças significativas no desenvolvimento de grandes, médias e pequenas cidades na Rússia, e muitos métodos de classificação são desenvolvidos exclusivamente para um dos tipos de cidades. Os autores concluíram que, apesar do alto nível de desenvolvimento das metodologias existentes, houve escassez de estudos abrangentes realizados no paradigma qualitativo-quantitativo que, além da avaliação de índices e da geração de modelos matemáticos, explicariam relações e processos causais complexos Uma cidade

In memoriam of Alexander Golovin (1939–2013)

No abstract available

ADULT-ONSET STILL'S DISEASE: DIAGNOSIS AND TREATMENT

The paper describes adult-onset Still's disease (AOSD), a rare multisystemic disease of unknown etiology that is referred to as seronegative rheumatoid arthritis. It presents the major manifestations of AOSD: long-term fever, arthritis or persistent arthralgias, maculopapular eruption, seronegativity for rheumatoid factor, neutrophilic leukocytosis, and disease onset after 16 years of age, as well as additional signs: lymphadenopathy, hepatosplenomegaly, polyserositis, nasopharyngeal infection. It is noted that particular difficulties in the diagnosis of AOSD emerge when it is complicated by the hematophagocytic syndrome (HPS). The distinctive features of AOSD are the development of cutaneous and articular symptoms in practically 80% of patients and their absence in HPS. It is stated that of greater value in the diagnosis of HPS is examination of aspirate of the bone marrow than its biopsy. Most patients develop refractoriness to glucocorticoids and essential anti-inflammatory drugs. The positive results of using anakinra, rituximab, and tocilizumab are promising

Role of the administrative board of establishments of public health services in health protection of working women of pension age

In the Penza region fast rates increases a share of women of a pension age. In RSMU research on studying of their way of life and a state of health is conducted. 38,5% have noted negative influence of work on health. The syndrome of emotional burning out takes place. Direct correlation between age and presence of chronic diseases in a stage of subindemnification and декомпенсации is marked. To heads of establishments of public health services the knowledge of management in public health services for the medical aid organisation is necessary for an investigated contingent