scholarly journals Application of Dynamic Fault Tree Analysis to Prioritize Electric Power Systems in Nuclear Power Plants

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4119
Author(s):  
Sejin Baek ◽  
Gyunyoung Heo
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Dynamic Characteristics ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electric Power System ◽  
Diesel Generator ◽  
Fault Trees

Because the scope of risk assessments at nuclear power plants (NPPs) is being extended both spatially and temporally, conventional, or static fault trees might not be able to express failure mechanisms, or they could be unnecessarily conservative in their expression. Therefore, realistic assessment techniques are needed to adequately capture accident scenarios. In multi-unit probabilistic safety assessment (PSA), fault trees naturally become more complex as the number of units increases. In particular, when considering a shared facility between units of the electric power system (EPS), static fault trees (SFTs) that prioritize a specific unit are limited in implementing interactions between units. However, dynamic fault trees (DFTs) can be available without this limitation by using dynamic gates. Therefore, this study implements SFTs and DFTs for an EPS of two virtual NPPs and compares their results. In addition, to demonstrate the dynamic characteristics of the shared facilities, a station blackout (SBO), which causes the power system to lose its function, is assumed—especially with an inter-unit shared facility, AAC DG (Alternate AC Diesel Generator). To properly model the dynamic characteristics of the shared EPS in DFTs, a modified dynamic gate and algorithm are introduced, and a Monte Carlo simulation is adopted to quantify the DFT models. Through the analysis of the DFT, it is possible to confirm the actual connection priority of AAC DG according to the situation of units in a site. In addition, it is confirmed that some conservative results presented by the SFT can be evaluated from a more realistic perspective by reflecting this.

scholarly journals Separation of Transformers for Class 1E Systems in Nuclear Power Plants

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Sang-Hyun Lee ◽  
Choong-Koo Chang
Keyword(s):  
Power System ◽  
Electric Power ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Voltage Drop ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electric Power System ◽  
Improved Model

In order to supply electric power to the safety related loads, safety and reliability of onsite power have to be ensured for the safety function performance in nuclear power plants. Even though the existing electric power system of APR1400 meets the requirements of codes regarding Class 1E system, there is a room for improvement in the design margin against the voltage drop and short circuit current. This paper discusses the amount that the voltage drop and short circuit current occur in the existing electric power system of APR1400. Additionally, this paper studies with regard to the improved model that has the extra margin against the high voltage drop and short circuit current by separation of unit auxiliary transformer (UAT) and standby auxiliary transformer (SAT) for the Class 1E loads. The improved model of the electric power system by separation of UAT and SAT has been suggested through this paper. Additionally, effects of reliability and cost caused by the electric power system modification are considered.

Predictive and comparative analysis of NPP modernization with an autonomous hydrogen power complex and gas turbine unit

2021 ◽  
Vol 3 ◽  
pp. 22-30
Author(s):  
Valery Yurin ◽  
Dmitry Bashlykov
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Power System ◽  
Electric Power ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Thermal Power ◽  
Electric Power System ◽  
Variable Power

Optimizing existing nuclear power plants adding developing power technology can help find effective ways of improving variable power loads in an electric power system. One of the most promising options is combining a nuclear power plant with a newly developed autonomous hydrogen complex reported in our research. The ability of storing unused energy and releasing it when needed will raise contribution of nuclear power plants in compensating improving variable power loads, shorten emissions as well as contribution of conventional thermal power plants into electric power generation. Also, as we demonstrated in our previous research results, a low-power steam turbine plant used in the said autonomous hydrogen complex can support an auxiliary power system of a nuclear power plant reusing residual reactor heat in case of an outage.

scholarly journals Problems of using pumped storage power plants to improve the reliability and controllability of electric power system of the republic of Uzbekistan

2019 ◽  
Vol 139 ◽  
pp. 01009
Author(s):  
Murodilla Mukhammadiev ◽  
Boborakhim Urishev ◽  
Shirin Esemuratova ◽  
Nigina Djumaniyozova
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Power Plants ◽  
Electric Power Systems ◽  
Electric Power System ◽  
The Republic ◽  
Pumped Storage

This article deals with the analysis and development perspectives of the use pumped storage power plants use to increase the reliability and regime controllability of electric power systems of the Republic of Uzbekistan.

scholarly journals Use of maneuverable properties of hydroelectric power plants and hydro-accumulating power plants for improving reliability and operating efficiency of electric power systems of commonwealth countries (using example of power plants of Russia and the Republic of Uzbekistan)

2020 ◽  
Vol 216 ◽  
pp. 01139
Author(s):  
Yu.S. Vasilyev ◽  
V.V. Elistratov ◽  
I.G. Kudryasheva ◽  
M.M. Mukhammadiyev ◽  
B.U. Urishev
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Electric Power System ◽  
Operating Efficiency ◽  
Hydroelectric Power ◽  
Current Increase ◽  
Pump Station

The possibilities of using shunting properties of HPP units, HAPS (Hydro-accumulating power system) for energy storage and redistribution, as well as Pump Station as a consumer of the regulator in night load dips to increase the reliability of the electric power system (EPS) in the conditions of the current increase in the share of non-nondestructive capacities in Russia and Uzbekistan and the implementation of programs for the development of renewable energy sources, primarily the construction of wind and solar power plants, were considered.

IAEA Guidance on Enhancing the Safety of Electrical Power Systems

2016 ◽  
Author(s):  
Alexander Duchac ◽  
Magnus Knutsson
Keyword(s):  
Power Systems ◽  
Power System ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electrical Power ◽  
Operating Experience ◽  
Electrical Power Systems ◽  
Open Phase ◽  
Phase Condition

An open phase condition is a known phenomenon in the power industry and is now recognized to have adverse impact on the electrical power systems in several nuclear power plants. An open phase condition may result in challenging plant safety. Operating experience in different countries has shown that the currently installed instrumentation and protective schemes have not been adequate to detect this condition and take appropriate action. An open phase condition, if not detected and disconnected in a timely manner, represents design vulnerability for many nuclear power plants. It may lead to a condition where neither the offsite power system nor the onsite power system is able to support the safety functions, and could propagate to station blackout. The design of electrical power systems needs to be evaluated systematically and improved, where necessary, to minimize the probability of losing electric power from any of the remaining supplies as a result of single or double open phase conditions. The improved design should be coordinated with existing measures to ensure that the electrical power system is able to support the safety functions after the open phase condition is detected and disconnected. In this regard, the IAEA has developed a safety publication dealing with design vulnerability of open phase conditions. This paper summarizes the contents of the report, the rationale and criteria to enhance the safety of nuclear power plants by providing technical guidance to address an open phase condition vulnerability in electrical systems used to start up, operate, maintain and shutdown the nuclear power plant.

scholarly journals Competitiveness of power systems with nuclear power plants and with high participation of intermittent renewable energy sources

2021 ◽  
pp. 182-182
Author(s):  
Vojin Grkovic ◽  
Djordjije Doder
Keyword(s):  
Power Systems ◽  
Power System ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Renewable Energy Sources ◽  
Hard Coal ◽  
Wind Generators ◽  
High Participation ◽  
Storage Technologies

In the paper are presented and discussed the results of a more complex research of technology portfolio competitiveness in power systems with high penetration of i-RES. Possible technology portfolios compositions are analyzed. The portfolios comprise very high participation of i-RES, as well as a certain participation of energy storage technologies, but also and other energy technologies like nuclear and fossil fueled power plants. Within the research are developed new competitiveness indicators i.e., dispatchability indicator and the technology portfolio?s assured capacity. The latter is defined on the basis of recently published Ulrich?s and Schiffer?s paper. Obtained results point out that inclusion of pumped-hydro storage plants improves portfolio?s dispatchability. However, within the researched interval up to PHS installed capacities relative to i-RES capacities of 0,3; numerical values of the dispatchability indicators are still below their values for the portfolio without i-RES. Increased participation of nuclear power plants contribute to the improvement of numerical values of the dispatchability indicators. The sensitivity analysis for the case of two times smaller cost of pumped hydro storage capacities is also performed. Hypothetical change of power system?s technology structure in sense of substitution hard coal and lignite fired power plants with wind generators or with nuclear power plants is also analyzed. The analysis points out that the substitution with nuclear power plants enables much better results regarding power system?s ability to change the power on demand than substitution with wind generators, particularly in the countries with high participation of hard coal and/or lignite in electricity generation.

scholarly journals Low-power nuclear power plants in the context of electric power systems transformation

2021 ◽  
Vol 7 (1) ◽  
pp. 55-59
Author(s):  
Ashot A. Sarkisov ◽  
Sergey V. Antipov ◽  
Dmitry O. Smolentsev ◽  
Vyacheslav P. Bilashenko ◽  
Mikhail N. Kobrinsky ◽  
...  
Keyword(s):  
Power Systems ◽  
Low Power ◽  
Electric Power ◽  
Distributed Generation ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The Arctic ◽  
Negative Consequences ◽  
Power Sources

Increasing economic importance of the Arctic, further intensification of northern sea routes, and exceptional sensitivity of the arctic natural environment to anthropogenic impacts are fundamental factors for a comprehensive study of environmental aspects in the application of innovative technologies for the development of infrastructure in the Arctic. Despite the growing interest in low-power nuclear power plants as a distributed generation facility, their possible application in technologically isolated power systems does not lose relevance. The development of both the Arctic and Far Eastern regions of the Russian Federation presents great opportunities and demand for the use of nuclear power sources. Also, development programs for the Russian arctic zone imply a significant increase in the role and number of nuclear power facilities, in other words of potential radiation-hazardous facilities. Large-scale use of nuclear-powered installations in the Arctic necessitates advanced development of a scientifically grounded and modern forecasting system as well as assessments of threats and risks in case of possible radiation emergencies at nuclear- and radiation-hazardous facilities. Also, the development of proposals for necessary measures to minimize negative consequences of such emergencies is required. This is especially true for the case of compact placement of industrial, infrastructure and residential facilities in the Arctic in the immediate vicinity of nuclear facilities. The paper demonstrates that the demand for low-power nuclear power plants and their competitiveness will grow steadily in the conditions of electric-power industry decentralization, further spread of distributed generation and the development of technologically isolated power systems. Approaches to the generation of a low nuclear-power system based on the philosophy of industrialization of production and centralized management are presented. Special features of the environmental impact assessment of low-power nuclear power plants for the development of a methodology to study the radio-ecological hazard related problems are provided.

scholarly journals Research of current distribution by phases in asynchronous electric motor with a combined winding

2022 ◽  
Vol 23 (5) ◽  
pp. 172-183
Author(s):  
A. E. Savenko ◽  
P. S. Savenko
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Electric Propulsion ◽  
Experimental Studies ◽  
Negative Influence ◽  
Electric Power System ◽  
The Arctic ◽  
Diesel Generator ◽  
Power Oscillations

THE PURPOSE. Consider the use of propeller electric installations as part of ship electrical complexes with a single electric power system. Highlight the rudder drives as a special type of electric propulsion of ships in northern latitudes. Investigate unified electric power systems with a propeller electric installation for the existence of power exchange oscillations in them. Propose methods and means for eliminating power oscillations in such systems.METHODS. To carry out the research, a single electric power system with electric rudder propellers of the world's only asymmetric icebreaker Baltika was considered. All the main elements of such system have been analyzed in detail. Experimental studies were carried out aimed at studying the operating modes of a unified electric power system.RESULTS. Experimental oscillograms of currents of parallel operating diesel-generator sets in different modes have been obtained. The existence of exchange and in-phase power oscillations during the operation of the unified electric power system of the icebreaker "Baltika" is noted. The data on the negative influence of power oscillations on the operation of the electrical complex of the icebreaker are presented.CONCLUSION. The use of ice-class sea vessels is an extremely important task for the Russian Federation. The installation of blocks that eliminate exchange and in-phase power oscillations will improve the reliability and efficiency of the use of marine vessels with electric rudder propellers when servicing hydrocarbon production on the Arctic shelf.

scholarly journals Low-Power Nuclear Power Plants in the Context of Electric Power Systems Transformation

2020 ◽  
Vol 2020 (4) ◽  
pp. 5-14
Author(s):  
Ashot Arakelovich Sarkisov ◽  
Sergey Viktorovich Antipov ◽  
Dmitry Olegovich Smolentsev ◽  
Vyacheslav Petrovich Bilashenko ◽  
Mikhail Natanovich Kobrinsky ◽  
...  
Keyword(s):  
Power Systems ◽  
Low Power ◽  
Electric Power ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electric Power Systems ◽  
Systems Transformation

scholarly journals OBJECTIVES OF THE STUDY THE SECURITY OF ELECTRIC POWER SYSTEMS

2020 ◽  
Vol 2018 (1) ◽  
pp. 139-139
Author(s):  
Mihail Dubickiy
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electric Power Systems

The main classes of tasks of the methodical plan within which questions of safety of power systems are considered are allocated. The article considers the main tasks ensure the safety of nuclear power plants.

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