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.

scholarly journals Investigating Phase Over-Current (OC) Protection in Medium-Voltage networks

2019 ◽  
Vol 4 (6) ◽  
pp. 41-49 ◽  
Author(s):  
Aniagboso John Onah
Keyword(s):  
Power System ◽  
Electric Power ◽  
Electric Power System ◽  
Normal Operation ◽  
Electrical Network ◽  
Power Circuit ◽  
Medium Voltage ◽  
Protection Scheme ◽  
Overcurrent Protection ◽  
Overcurrent Relays

Overcurrent protection is protection against excessive currents or current beyond the acceptable current rating of equipment. It generally operates instantly. Short circuit is a type of overcurrent. Magnetic circuit breakers, fuses and overcurrent relays are commonly used to provide overcurrent protection. There is always a need to protect expensive power equipment. Protective relaying is a very important part of any electric power system that comes into play during trouble, fault or abnormal condition. The purpose is to isolate unhealthy part of electrical power system while the rest continue their normal operation. The entire electric power system from source to load centers is exposed and subject to natural hazards. The effects of these hazards are capable of interrupting normal operations of the system. Since these hazards cannot be prevented, precautions are taken to minimize or eliminate their effect on the system. The relay is a basic component of any protection scheme. The information (or signals) received from the power system actuates the relay, when necessary, to perform one or more switching actions. The signals are proportional to the magnitudes and phase angles of power system voltages and currents. When the relay receives these signals, it decides to close (or open) one or more sets of normally open (or closed) contacts, and consequently, the trip coil of a circuit breaker will be energized to open the power circuit. This paper investigates over-current relay protection scheme applied to medium-voltage electrical network. Methods of current and time grading have been applied in the coordination of the overcurrent relays in a radial network. Different time/current characteristics of relays such as the normal inverse (NI), very inverse (VI), and extreme inverse (EI) have been examined in order to obtain optimum discrimination.

Research and Construction of Information Security Simulation Test Bed for Electric Power System

2013 ◽  
Vol 427-429 ◽  
pp. 2826-2829
Author(s):  
Hao Li Luan ◽  
An Gang Zheng ◽  
Zhen Liu Zhou ◽  
Zheng Yang
Keyword(s):  
Information Security ◽  
Power System ◽  
Electric Power ◽  
Information Technologies ◽  
Electric Power System ◽  
Normal Operation ◽  
Test Bed ◽  
Security Testing ◽  
Layer System ◽  
Common Information

Electric power system relies heavily on common information technologies and platforms, so all common information security issues have been experienced in the electric power information system. Because of attacks destructivity and uncontrollability, it is inappropriate to conduct security analysis in a real Power system directly. Therefore, the paper uses simulation and emulation technology to build a information security test bed for power system at a lower cost and no affect the normal operation and the premise of the aimed system. Simulation contents in the test bed are arranged in four different layers including firmware layer, system layer, network layer and application layer. The test bed also provides a network attack and defense combat system. The test bed can be used for Power system information and network system security testing, engineering validation and evaluation.

scholarly journals Pengembangan Perangkat Lunak Untuk Analisis Aliran Beban Tiga Fasa Pada Jaringan Tegangan Rendah Dengan Metode Newton Berbasis Calculus Wirtinger

2020 ◽  
Vol 10 (2) ◽  
pp. 20-27
Author(s):  
Hayatul Harifin ◽  
Novalio Daratha ◽  
M. Khairul Amri Rosa
Keyword(s):  
Power System ◽  
Electric Power ◽  
Reactive Power ◽  
Initial Conditions ◽  
Flow Analysis ◽  
Electrical Equipment ◽  
Load Flow ◽  
Electric Power System ◽  
Load Flow Analysis ◽  
Load Flow Calculation

AbstractLoad flow analysis is a study to plan and determine the amount of power in an electric power system. During its development, industry requires a large amount of electric power and uses electrical equipment as a means of production. The benefits of an electric load flow analysis are to find out the amount of power in the electric power system whether it still meets predetermined limits, and to find out the amount of voltage at each point, and to obtain initial conditions for the new system planning. Load flow analysis begins calculating the active power and reactive power at each node (bus) installed, loading on the channel or conductor, the load flow calculation will be assisted using the Julia program. From the results of calculations using the Julia program, the voltage at each point with the smallest stress is obtained, namely the 10th point of 209.89 - j10.34V for phase A, -107.39 - j186.87V for phase B, -108.12 + j178,51V for phase CKey Words: Drop Voltage, Julia, Load Flow

scholarly journals Power quality improvement recommendations for shipboard power systems

2020 ◽  
pp. 55-61
Author(s):  
В.Ф. Белей ◽  
М.С. Харитонов ◽  
Р.О. Брижак
Keyword(s):  
Power Systems ◽  
Power System ◽  
Energy Saving ◽  
Electric Power ◽  
Power Quality ◽  
Electromagnetic Interference ◽  
Electrical Equipment ◽  
Electric Power System ◽  
Maritime Industry

В настоящее время на судах и объектах морской индустрии широко внедряется энергосберегающее электрооборудование, что позволяет добиться резкого снижения расхода электроэнергии и массогабаритных показателей оборудования, существенно расширяет функциональные возможности электротехнических комплексов и систем, приводит к улучшению эксплуатационных характеристик. Однако использование новейших энергосберегающих технологий, основанных на нелинейных элементах, и коммутация электрооборудования приводит к ухудшению качества электрической энергии в судовой электроэнергетической системе. В то же время, растет число потребителей, предъявляющих к качеству электроэнергии повышенные требования. В итоге, работа судовых энергокомплексов может отличаться от расчетной, а в ряде случаев становится аварийной. В работе приведены результаты экспериментальных исследований показателей качества электрической энергии в судовой электроэнергетической системе учебного парусного судна «Крузенштерн». Представлены результаты лабораторных исследований на физической модели судовой электростанции с источниками электромагнитных помех, обоснованы организационные и технические решения по снижению уровня электромагнитных помех в судовых электроэнергетических системах. Nowadays, energy-saving electrical equipment is widely introduced on ships and maritime industry facilities. It leads to a decrease in power consumption, weight and dimensions of equipment, significantly expands the functionality of electrical complexes and systems, and provides improvement of operational characteristics. However, the use of the latest energy-saving technologies based on non-linear elements and the switching of electrical equipment leads to a deterioration in the quality of electrical energy in the ship's electric power system. At the same time, the number of consumers with increased requirements for the quality of electricity is growing. As a result, the operation of ship power complexes may differ from the normal one, and in some cases it becomes emergency. The paper presents the results of experimental studies of electric power quality indicators in the ship's electric power system of the sail training ship "Kruzenshtern". The results of laboratory studies on a physical model of a ship power plant with sources of electromagnetic interference are presented, organizational and technical solutions to reduce the level of electromagnetic interference in ship power systems are substantiated.

Study of Electric Power System Neutral Point Grounding Using PSCAD/EMTDC

2011 ◽  
Vol 354-355 ◽  
pp. 866-871
Author(s):  
Ping Ping Han
Keyword(s):  
Theoretical Analysis ◽  
Power System ◽  
Electric Power ◽  
Transmission Lines ◽  
Single Phase ◽  
Electric Power System ◽  
Neutral Point ◽  
Voltage Level ◽  
Direct View ◽  
Simulation Results

Neutral point grounding which is related to voltage level, network structure, insulation, communication and relay protection is very important problem to power system. Nowadays, the choice of neutral point grounding mode mainly relies on operation experiences or theoretical analysis which could not give a direct view of the dynamics of electric power system during disturbances. Therefore, this paper has established the simulation model of electric power system neutral point grounding with PSCAD/EMTDC to show the dynamics of neutral point grounding when disturbed by single-phase grounding in transmission lines, and the application of each neutral point grounding mode has been analyzed according to simulation results. The dynamic model of neutral point grounding in this paper is meaningful to the analysis of high-order, non-linear transients of power system as well.

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