scholarly journals Research on Fire Protection Methods of Cables in Substations

2021 ◽  
Vol 292 ◽  
pp. 01035
Author(s):  
Kai Xue ◽  
Zheng Wang ◽  
Chunguang Ren ◽  
Huixia Wang ◽  
Feng Li
Keyword(s):  
Power System ◽  
Fire Protection ◽  
Important Task ◽  
Normal Operation ◽  
Existing Problems ◽  
Protection Method ◽  
Cable Fire ◽  
Fire Accidents

The normal operation of the substation is inseparable from the important guarantee of the cable. The cables in the substation are not only widely distributed, but also the cables are flammable and spread easily after fire. Once a cable catches fire, the consequences will be disastrous. Therefore, how to fire the cable becomes an important task for the power system. Many engineers and technicians continue to analyze and study the causes of cable fires, but cable fire accidents still occur from time to time. In order to solve the problem of cable fire protection and existing problems, the article combines actual research and analysis, and gives the most effective and safe cable fire protection method．

scholarly journals A Novel Extension Decision-Making Method for Selecting Solar Power Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Meng-Hui Wang
Keyword(s):  
Decision Making ◽  
Solar System ◽  
Power Systems ◽  
Power System ◽  
Solar Power ◽  
Important Task ◽  
Extension Theory ◽  
Solar Systems ◽  
Load Demand ◽  
Generating Capacity

Due to the complex parameters of a solar power system, the designer not only must think about the load demand but also needs to consider the price, weight, and annual power generating capacity (APGC) and maximum power of the solar system. It is an important task to find the optimal solar power system with many parameters. Therefore, this paper presents a novel decision-making method based on the extension theory; we call it extension decision-making method (EDMM). Using the EDMM can make it quick to select the optimal solar power system. The paper proposed this method not only to provide a useful estimated tool for the solar system engineers but also to supply the important reference with the installation of solar systems to the consumer.

Reliable Analysis on Fast Valving of Ultra-Supercritical Unit Under Transient Fault Conditions

2017 ◽  
Author(s):  
Yu Cai ◽  
Wei Li ◽  
Bao Zhang ◽  
Wenjian Wu ◽  
Deren Sheng ◽  
...  
Keyword(s):  
Power System ◽  
Steam Turbine ◽  
Dynamic Model ◽  
Transient Stability ◽  
Power Grid ◽  
Load Shedding ◽  
Control Mode ◽  
Normal Operation ◽  
Transient Fault ◽  
The Stability

Fast valving of ultra-supercritical unit has great effects on over-speed prevention, load-shedding control, transient stability analysis of electrical system and other security problems. The purpose of fast valving is to maintain the stability of power system once fault or load shedding of unit occurs in the electric power system. Therefore, it is of great significance to study the reliability of fast valving for ultra-supercritical unit. In this paper, the KU ( short shedding) logic condition of SIEMENS T3000 system is analyzed as the research object of fast valving. The unit can be avoided over speed by monitoring the unit load and fast valving under faulty grid conditions based on the KU control. A series of measures will be taken after KU is triggered, for instance the governing valving will be closed quickly and the DEH (digital electro-hydraulic) control of the steam turbine will be switched to speeding control mode. On the other hand, the unit will return to normal operation if the transient fault of power grid disappears. The key contributions of this thesis include three parts: Firstly, based on the analysis of control characteristics of ultra-supercritical unit and protective logic and triggered conditions of KU function, a novel dynamic model by coupling the fast valving of steam turbine and the transient stability of generator is established by applying the PSCAD software. Then, the dynamic response process of ultra-supercritical unit is simulated and calculated by adopting the coupling dynamic model when KU function is triggered. Also the influence factors and reliability of fast valving are analyzed under transient fault conditions. Finally, two optimized measures by increasing the time delay and the speed of quantitative judgment are put forward to reduce risks and avoid the misoperation of signal distortion which may be caused by the power transmitter under transient fault conditions. The results of this study can not only help to evaluate the reliability of fast valving function scientifically in power grid transient fault, but also guide the technicians to analyze the stability of the power grid.

Harmonic Analysis of Non-Sinusoidal Harmonic Signals in Electric Power System

2014 ◽  
Vol 1070-1072 ◽  
pp. 779-784
Author(s):  
Dan Luo ◽  
Yi Xiao ◽  
Jie Na Zhou
Keyword(s):  
Power System ◽  
Harmonic Analysis ◽  
Short Range ◽  
Time Windows ◽  
Electric Power System ◽  
Normal Operation ◽  
Calculation Error ◽  
Interpolation Algorithm ◽  
Harmonic Signals ◽  
And Control

Harmonic Analysis and control is very important for the power system because harmonics have serious harm to its normal operation. Harmonic Analysis uses fast Fourier transform (FFT) to solve this problem though it causes the spectrum leakage which Increases the calculation error. To solve this problem, the interpolation algorithm combine with tapered time windows are used. The tapered time windows solve the long-range leakage and the interpolation algorithm solves the problem of short-range leakage.

New Research of Transformer Windings Partial Discharge Based on Non-Even Distribution Parameters Model

2014 ◽  
Vol 521 ◽  
pp. 343-346
Author(s):  
Yu Sheng Quan ◽  
Pu Xin Shi ◽  
Shai Gen Han ◽  
Ning Chen
Keyword(s):  
Power System ◽  
Partial Discharge ◽  
Normal Operation ◽  
Model Parameters ◽  
Distribution Parameters ◽  
New Research ◽  
Discharge Detection

Transformer is the primary equipment of power system. The normal operation of transformers has great significance of the security and stability of a power system. Once partial discharge happened in the winds of a transformer, it will accelerate the aging of the insulation, and may damage the windings. This paper analyzes the effect of partial discharge to transformer windings, and founding a model of non-even distribution parameters. Separate the even distribution parameters model into three parts and partial discharge happens in the second one. The partial discharge leads to changing of the model parameters. And port voltage changes with it. Partial discharge detection achieved according to the changing of port voltage.

scholarly journals Study on Impedance Characteristics of Aircraft Cables

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Weilin Li ◽  
Wenjie Liu ◽  
Xiaobin Zhang ◽  
Zhaohui Gao ◽  
Meng Xie ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Power System ◽  
Electric Power ◽  
Electrical Equipment ◽  
Electric Power System ◽  
Normal Operation ◽  
Variable Frequency ◽  
Forming Mechanism ◽  
Changing Trends ◽  
Impedance Characteristics

Voltage decrease and power loss in distribution lines of aircraft electric power system are harmful to the normal operation of electrical equipment and may even threaten the safety of aircraft. This study investigates how the gap distance (the distance between aircraft cables and aircraft skin) and voltage frequency (variable frequency power supply will be adopted for next generation aircraft) will affect the impedance of aircraft cables. To be more precise, the forming mechanism of cable resistance and inductance is illustrated in detail and their changing trends with frequency and gap distance are analyzed with the help of electromagnetic theoretical analysis. An aircraft cable simulation model is built with Maxwell 2D and the simulation results are consistent with the conclusions drawn from the theoretical analysis. The changing trends of the four core parameters of interest are analyzed: resistance, inductance, reactance, and impedance. The research results can be used as reference for the applications in Variable Speed Variable Frequency (VSVF) aircraft electric power system.

Fire Protection Studies on Steel Staggered-Truss Structure Based on Analytic Hierarchy Process

2010 ◽  
Vol 26-28 ◽  
pp. 608-611 ◽  
Author(s):  
Chang Kun Chen ◽  
Dong Zhang
Keyword(s):  
Analytic Hierarchy Process ◽  
Fire Protection ◽  
Design Method ◽  
Fire Retardant ◽  
Comparative Investigation ◽  
Truss Structure ◽  
Analytic Hierarchy ◽  
Protection Method ◽  
The Stability ◽  
Hierarchy Process

A new design method for fire protection, based on analytic hierarchy process (AHP), was put forward, to explore an economic and secure strategy for fire protection of steel staggered-truss structure (SSTS). The chords and web members of SSTS were classified into different important grades by AHP according to the influence which components make on the stability of structure at elevated temperature. And the components are protected by different levels based on the important grades. Furthermore, a comparative investigation was conducted in order to appraise the economic and practical performance of the provided new fire protection method with traditional fire protection. The results indicate that the proposed fire protection strategy for SSTS based on AHP could achieve higher security with the same volume of fire retardant coatings.

The Balance of Power in World Politics

2016 ◽  
Author(s):  
Randall L. Schweller
Keyword(s):  
Power System ◽  
Balance Of Power ◽  
World Politics ◽  
Shared Responsibility ◽  
Normal Operation ◽  
Democratic Peace ◽  
Material Forces ◽  
Power Politics ◽  
Core Theory ◽  
Minimum Requirements

The balance of power—a notoriously slippery, murky, and protean term, endlessly debated and variously defined—is the core theory of international politics within the realist perspective. A “balance of power” system is one in which the power held and exercised by states within the system is checked and balanced by the power of others. Thus, as a nation’s power grows to the point that it menaces other powerful states, a counter-balancing coalition emerges to restrain the rising power, such that any bid for world hegemony will be self-defeating. The minimum requirements for a balance of power system include the existence of at least two or more actors of roughly equal strength, states seeking to survive and preserve their autonomy, alliance flexibility, and the ability to resort to war if need be. At its essence, balance of power is a type of international order. Theorists disagree, however, about the normal operation of the balance of power. Structural realists describe an “automatic version” of the theory, whereby system balance is a spontaneously generated, self-regulating, and entirely unintended outcome of states pursuing their narrow self-interests. Earlier versions of balance of power were more consistent with a “semi-automatic” version of the theory, which requires a “balancer” state throwing its weight on one side of the scale or the other, depending on which is lighter, to regulate the system. The British School’s discussion of balance of power depicts a “manually operated” system, wherein the process of equilibrium is a function of human contrivance, with emphasis on the skill of diplomats and statesmen, a sense of community of nations, of shared responsibility, and a desire and need to preserve the balance of power system. As one would expect of a theory that made its appearance in the mid-16th century, balance of power is not without its critics. Liberals claim that globalization, democratic peace, and international institutions have fundamentally transformed international relations, moving it out of the realm of power politics. Constructivists claim that balance of power theory’s focus on material forces misses the central role played by ideational factors such as norms and identities in the construction of threats and alliances. Realists, themselves, wonder why no global balance of power has materialized since the end of the Cold War.

scholarly journals The system of landscaping and improvement of Rostov: problems and prospects

2020 ◽  
Vol 175 ◽  
pp. 06006
Author(s):  
Albina Mokina ◽  
Evelina Vereshchagina
Keyword(s):  
Urban Planning ◽  
Urban Environment ◽  
Urban Areas ◽  
Science And Technology ◽  
Important Task ◽  
Final Part ◽  
Modern City ◽  
Existing Problems ◽  
The City

At present, the environment of a large modern city is technologically saturated to the limit, urbanized, and the most important task is a competent system of improvement and greening of urban areas. The article discusses the key projects of the city of Rostov-on-don to improve the quality of the urban environment from 2007 to the present. Existing projects included in the system of Federal projects operate only on small sections of the city territory, and do not solve the entire set of tasks within the entire city budget. This study shows that in urban planning there is no unified system of improvement and landscaping, implemented throughout the city according to a single plan. The article points out that modern systems and technologies are not used in the city, and if they are used, they are not used in a complex way, but only in fragments. The article focuses on the prospects for the integrated application of modern systems. The final part contains conclusions based on research materials. A comprehensive solution based on the collaboration of science and technology, all existing problems in the city territory will improve the main indicators of comfort and investment attractiveness of Rostov-on-don.

Review of Condition Assessment for Power Transformer

2014 ◽  
Vol 681 ◽  
pp. 160-163
Author(s):  
Jin Jiao Kong ◽  
Feng Wang ◽  
Yong Liang Li ◽  
Xu Tao Wu ◽  
Jian Gang Bi
Keyword(s):  
Power System ◽  
Power Transformer ◽  
Condition Assessment ◽  
Condition Based Maintenance ◽  
Future Directions ◽  
Research Status ◽  
Existing Problems ◽  
Assessment Research

Transformer is one of the most important equipment in power system, and accurate condition assessment for transformer is the key for condition based maintenance (CBM). So the study of condition assessment is particularly important. In this paper, the function, role and steps of condition assessment, research status, existing problems and future directions are analyzed and summarized. And this paper can be a reference for transformer’s condition assessment.

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