Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Mikhail ANDREEV"

Study of mutual influence of measuring part elements of transformer differential protection and its impact on the primary signal processing DOI:10.15199/48.2018.09.18

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The well-known fact is the rapid growth of energy consumption in the world. Over the past 15 years, the increase was approximately 35-40% [1] and there are no prerequisites for reducing these numbers. Thus, the buildup of generated capacities will also continue. As a result, the modern electric power system (EPS), which already is a complex, dynamic and nonlinear system, will become even more complicated. The situation is aggravated by increasing the share of distributed generation and penetration of renewable energy sources [2]. In accordance with [1], the total generated power of wind and solar energy sources has increased by more than 30% over the past 15 years. Protection of EPS due to these changes becomes extremely difficult and urgent task. According to the statistics [3], one of the main causes of severe accidents in the world is incorrect actions of relay protection (RP) and automation. As for the specific reasons, approximately 20% of the incorrect actions are associated with errors in the schemes and settings, which are connected with discrepancy of protection settings and real operating conditions. This problem and factors determining it are considered by the authors in [4]. An obvious condition for solving the problem is possibility of a detailed analysis of operation of RP devices key elements in its specific regimes [5, 6]. This will allow to reliably estimate the processes in the protected objects, to evaluate the processing error of instrument transformers (IT) - current transformers (CT) and potential transformers (PT), as well as RP elements, and also to determine the parameters of adequate RP settings. The RPs detailed mathematical models reproducing the entire set of elements, including CTs and PTs, ensure this possibility. The main demotivator for creating such models for a long time was the lack of tools for complete and reliable EPS simulation. That is determined by the adequacy of the applied math[...]

Software and hardware tools of the real-time power threephase transformers simulation in electric power systems DOI:10.15199/48.2018.11.23

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According to statistics [1], [2] about 50% of severe accidents in electric power systems (EPS), is caused by incorrect actions of the dispatching personnel and the emergency automatic systems, the main reason of which is the use in the design, research and operation of EPS insufficiently complete and reliable information about all possible processes, especially emergency ones, in EPS. The specific operation of EPS practically excludes the possibility of obtaining this information, and the extreme complexity of modern EPS significantly limits the applicability of their physical modeling. As a result, mathematical modeling is the main approach to obtain the information about all possible normal and emergency processes in EPS. The mentioned constantly high percent of the accident in EPS clearly indicates that the existing digital simulation tools do not provide the required completeness and reliability of mathematical simulation, and the efficiency, required for effective dispatch control of EPS. A detailed analysis of these factors is presented in [3]. The level of mathematical description of processes in various elements of power equipment reached by now allows to solve the problems of the development of mathematical models for all types of equipment of EPS, for example [4], [5], describing the whole spectrum of processes without any decomposition. Power transformers and autotransformers as a part of EPS have significant impact on the processes in EPS as a whole, so mathematical models of power transformers and autotransformers should be sufficiently adequate and take into account the technologically and constructively variety. The listed types of transformers and autotransformers can be combined with a virtual adaptive five-winding transformer and take it as a prototype for the synthesis of a universal mathematical model for all these types. The foregoing determines the urgency of development of software and hardware simu[...]

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