AC Cables Strengthening Railway Low Frequency AC Power Supply Systems

2017 ◽  
Author(s):  
Lars Abrahamsson ◽  
Daniel Serrano Jimenez ◽  
John Laury ◽  
Math Bollen
Keyword(s):  
Power Systems ◽  
Power System ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Supply ◽  
Low Frequency ◽  
Hvdc Transmission ◽  
Reactive Compensation ◽  
Ac Transmission ◽  
Railway Power Systems

In present-day railway power supply systems using an AC frequency lower than the one in the public power system of 50/60 Hz, high voltage overhead transmission lines are used as one measure of strengthening the railway power supply system grids. This option may be economically beneficial, compared to strengthening the grid purely by increasing the density of converter stations or increasing the cross section areas of the overhead catenary wires. High voltage AC transmission lines in the railway power supply system allow larger distances between converter stations than would otherwise be possible for a given amount of train traffic. Moreover, the introduction of AC transmission lines implies reduced line losses and reduced voltage level fluctuations at the catenary for a given amount of train traffic. However, due to the increased public and government resistance for additional overhead high voltage AC transmission lines in general, different alternatives will be needed for the future improvements and strengthening of railway power systems. For a more sustainable transport sector, the share and amount of railway traffic needs to increase, in which case such a strengthening becomes inevitable. Earlier, usage of VSC-HVDC transmission cables has been proposed as one alternative to overhead AC transmission lines. One of the main benefits with VSC-HVDC transmission is that control of power flows in the railway power systems is easier and that less converter capacity may be needed. Technically, VSC-HVDC transmission for railway power systems is a competitive solution as it offers a large variety of control options. However, there might be other more economical alternatives reducing the overall impedance in the railway power system. In public power systems with the frequency of 50/60 Hz, an excess of reactive power production in lowly utilized cables imposes an obstacle in replacing overhead transmission lines with cables. In low frequency AC railway power system, the capacitive properties are less significant allowing longer cables compared to 50/60 Hz power systems. Moreover, in converter-fed railways, some kind of reactive compensation will automatically be applied during low-load. At each converter station, voltage control is already present following the railway operation tradition. Therefore, in this paper, we propose AC cables as a measure of strengthening low-frequency AC railway power systems. The paper compares the electrical performances of two alternative reinforcement cable solutions with the base case of no reinforcement. The options of disconnecting or toggling the cables at low load as well as the automatic reactive compensation by converter voltage control are considered. Losses and voltage levels are compared for the different solutions. Investment costs and other relevant issues are discussed.

Fuel Cost Optimization of Power Systems Inclouding HVDC Line

2012 ◽  
Vol 488-489 ◽  
pp. 1788-1792 ◽  
Author(s):  
Babak Abdi ◽  
Arash Alimardani ◽  
Reza Ghasemi
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Optimal Power Flow ◽  
Cost Optimization ◽  
Problem Definition ◽  
Objective Functions ◽  
Fuel Cost ◽  
Hvdc Transmission ◽  
Hvdc Transmission Lines

Effect of HVDC transmission lines in a power system on different optimal power flow (OPF) objective functions is discussed in this paper. In this study differential evolution optimization algorithm is applied in AC-DC OPF problem, and compared with OPF in the same power system with no HVDC transmission lines to demonstrate the effect of this type of transmission line on the objective functions. In OPF problem definition, generator fuel cost considering valve effect is considered as objective function. The results of the proposed method on IEEE 30-bus power system illustrate that HVDC transmission lines improves the OPF from fuel cost point of view.

scholarly journals Implementation Optimal Location and Sizing of UPFC on Iraqi Power System Grid (132 kV) Using Genetic Algorithm

2018 ◽  
Vol 9 (4) ◽  
pp. 1607
Author(s):  
Ghassan Abdullah Salman ◽  
Mohammed Hasan Ali ◽  
Ali Najim Abdullah
Keyword(s):  
Genetic Algorithm ◽  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Optimal Location ◽  
Unified Power Flow Controller ◽  
Flexible Ac Transmission System ◽  
Intelligent Methods ◽  
Ac Transmission

Electric power systems required efficient processors and intelligent methods for sustainability therefore, in this paper used Flexible AC Transmission System (FACTS) device specifically Unified Power Flow Controller (UPFC) because of its useful properties on series and shunt devices and used Genetic Algorithm (GA) to determine the optimal location and values of UPFC to achieve the following objectives: improve voltages profile, reduce power losses, treatment of power flow in overloaded transmission lines and reduce power generation. Consequently, all of these goals led to a reduction in the total cost of the power system. GA was applied to an Iraqi local power grid system (Diyala 132 kV) to find the optimal values and locations of UPFC for the purpose of achieving the objectives mentioned above using the MATLAB program. The simulation results showed the effectiveness of GA to calculate the optimum values and locations of UPFC and promising results were obtained for the Diyala power network (132 kV) with regard to the desired objectives.

scholarly journals Interline power flow controller (IPFC) characterization in power systems

2018 ◽  
Vol 7 (3) ◽  
pp. 1656 ◽  
Author(s):  
Nabil A. Hussein ◽  
Ayamn A. Eisa ◽  
Hassan M. Mahmoud ◽  
Safy A. Shehata ◽  
El-Saeed A. Othman
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Electrical Power ◽  
System Stability ◽  
Electrical Power System ◽  
Flow Controller ◽  
Ac Transmission ◽  
Power Flow Controller

Flexible AC Transmission Systems (FACTS) have been proposed in the late 1980s to meet and provide the electrical power system requirements. FACTS are used to control the power flow and to improve the power system stability. Interline power flow controller (IPFC) is a versatile device in the FACTS family of controllers and one of its latest generations which has the ability to simultaneously control the power flow in two or multiple transmission lines. This paper is tackling the IPFC performance in power systems; it aims to discuss the availability to define a known scenario for the IPFC performance in different systems. An introduction supported with brief review on IPFC, IPFC principle of operation and IPFC mathematical model are also introduced. IEEE 14-bus and 30-bus systems have chosen as a test power systems to support the behavior study of power system equipped with IPFC device. Three different locations have chosen to give variety of system configurations to give effective performance analysis.  

UPFC Device Application on Power System Oscillations to Improve the Damping Performance

2013 ◽  
Vol 694-697 ◽  
pp. 830-837 ◽  
Author(s):  
Ali Nasser Hussain ◽  
F. Malek ◽  
Mohd. Abdur Rashid ◽  
Latifah Mohamed ◽  
Ismail Daut
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Low Frequency ◽  
Superior Performance ◽  
Low Frequency Oscillations ◽  
System Stabilizer ◽  
Chaotic Particle Swarm Optimization ◽  
The Individual ◽  
Ac Transmission ◽  
Damping Controller

UPFC is considered as an important modern device in the flexible ac transmission systems family that provides the controllability and flexibility for transmission lines. It is also capable of enhancing the stability of the power system by the addition of a supplementary damping controller, which can be installed on any control channel of the UPFC inputs to implement the task of power oscillation damping controller. This paper presents the application of UPFC to enhance damping of low frequency oscillations by the simultaneous coordinated design between power system stabilizer and different UPFC supplementary damping controller in order to identify the design that provided the most robust damping performance in a single machine infinite bus. The parameters of the damping controller were tuned in the individual and coordinated design by using a chaotic particle swarm optimization algorithm that optimized the given eigenvalue-based objective function. The results analysis reveals that the proposed coordinated designs have high ability in damping Low-frequency oscillations and improve the system damping over their individual control responses. In addition, the coordinated design PSS & δE provides superior performance in comparison to the all coordinated designs.

A Novel Fault-location Method for HVDC Transmission Lines Based on Concentric Relaxation Principle and Wavelet Packet

2020 ◽  
Vol 13 (5) ◽  
pp. 705-716
Author(s):  
Congshan Li ◽  
Ping He ◽  
Feng Wang ◽  
Cunxiang Yang ◽  
Yukun Tao ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Traveling Wave ◽  
Fault Location ◽  
Wave Attenuation ◽  
Wavelet Packet ◽  
Low Frequency ◽  
Evaluation Process ◽  
Location Method ◽  
Hvdc Transmission ◽  
Instantaneous Energy

Background: A novel fault location method of HVDC transmission line based on a concentric relaxation principle is proposed in this paper. Methods: Due to the different position of fault, the instantaneous energy measured from rectifier and inverter are different, and the ratio k between them is the relationship to the fault location d. Through the analysis of amplitude-frequency characteristics, we found that the wave attenuation characteristic of low frequency in the traveling wave is stable, and the amplitude of energy is larger, so we get the instantaneous energy ratio by using the low-frequency data. By using the method of wavelet packet decomposition, the voltage traveling wave signal was decomposed. Results: Finally, calculate the value k. By using the data fitting, the relative function of k and d can be got, that is the fault location function. Conclusion: After an exhaustive evaluation process considering different fault locations, fault resistances, and noise on the unipolar DC transmission system, four-machine two-area AC/DC parallel system, and an actual complex grid, the method presented here showed a very accurate and robust behavior.

scholarly journals Global experience of HVDC composite insulators in outdoor and indoor environment

2020 ◽  
Vol 59 (1) ◽  
pp. 606-618
Author(s):  
Mohammad Akbar ◽  
Basharat Mehmood
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Transmission Lines ◽  
Power Transmission ◽  
Green Energy ◽  
Attractive Alternative ◽  
Hvdc Transmission ◽  
Ceramic Insulators ◽  
High Power Transmission ◽  
Aging Performance

AbstractHigh-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

scholarly journals A Novel Methodology for Adaptive Coordination of Multiple Controllers in Electrical Grids

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1474
Author(s):  
Ruben Tapia-Olvera ◽  
Francisco Beltran-Carbajal ◽  
Antonio Valderrabano-Gonzalez ◽  
Omar Aguilar-Mejia
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Large Scale ◽  
Short Circuit ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Electric Power System ◽  
Design Stage ◽  
Positive Interaction

This proposal is aimed to overcome the problem that arises when diverse regulation devices and controlling strategies are involved in electric power systems regulation design. When new devices are included in electric power system after the topology and regulation goals were defined, a new design stage is generally needed to obtain the desired outputs. Moreover, if the initial design is based on a linearized model around an equilibrium point, the new conditions might degrade the whole performance of the system. Our proposal demonstrates that the power system performance can be guaranteed with one design stage when an adequate adaptive scheme is updating some critic controllers’ gains. For large-scale power systems, this feature is illustrated with the use of time domain simulations, showing the dynamic behavior of the significant variables. The transient response is enhanced in terms of maximum overshoot and settling time. This is demonstrated using the deviation between the behavior of some important variables with StatCom, but without or with PSS. A B-Spline neural networks algorithm is used to define the best controllers’ gains to efficiently attenuate low frequency oscillations when a short circuit event is presented. This strategy avoids the parameters and power system model dependency; only a dataset of typical variable measurements is required to achieve the expected behavior. The inclusion of PSS and StatCom with positive interaction, enhances the dynamic performance of the system while illustrating the ability of the strategy in adding different controllers in only one design stage.

scholarly journals Operating Performance of Power Systems Integrated HVDC Solution: KonTum-GiaLai Transmission System Case Considering Penetration of Renewable Energy

2020 ◽  
Vol 18 (4.2) ◽  
pp. 32
Author(s):  
Kim Hung Le ◽  
Ngoc Thien Nam Tran ◽  
Viet Tri Nguyen ◽  
The Khanh Truong ◽  
Minh Quan Duong
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
High Voltage ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Transmission Efficiency ◽  
Transmission System ◽  
Large Power ◽  
Hvdc System ◽  
Hvdc Transmission

The increasing demand for electricity along with the development of distributed generators showed that improving transmission efficiency and reliability is an indispensable requirement in the operation of the power system. Advanced technologies need to be applied to modern power systems for purposes of conveying large power flows, mitigating the risk of faults. High-voltage direct current (HVDC) transmission is now considered an effective solution for investment in large-length power lines, replacing the conventional high-voltage alternative current (HVAC) transmission system, especially in period of increasing generation capacity due to the penetration of renewable energy sources. This study assesses the performance of the HVDC system on an actual power grid based on planning and improvement demands. The calculation results of power flows, power losses and short-circuit faults were investigated using ETAP software X  

scholarly journals Determination of reliability of power supply of ship's responsible power receivers

2020 ◽  
pp. 22-26
Author(s):  
С.Е. Кузнецов ◽  
Н.А. Алексеев ◽  
А.А. Виноградов
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Supply ◽  
Electric Power System ◽  
Time To Failure ◽  
Parallel Operation ◽  
Diesel Generator ◽  
Operating Modes ◽  
Reliability Indicators ◽  
Supply Reliability

Изложена методика расчета показателей безотказности электроснабжения (вероятности безотказного электроснабжения и средней наработки до отказа) ответственных приемников морского судна, подключаемых к аварийному электрораспределительному щиту. Методика реализована применительно к судовой электроэнергетической системе с тремя источниками электроэнергии – двумя основными дизель-генераторными агрегатами, подключенными к главному электрораспределительному щиту, и одним аварийным дизель-генераторным агрегатом, подключенным к аварийному электрораспределительному щиту. Рассмотрены различные режимы работы судовой электроэнергетической системы: при работе до первого отказа одного основного дизель-генератора, при параллельной работе двух основных дизель-генераторов, при работе одного аварийного дизель-генератора; а также после обесточивания с учетом возможности последующего включения резервного или (и) аварийного дизель генератора. Методика, с соответствующими корректировками, может быть использована для расчета показателей безотказного электроснабжения в судовых электроэнергетических системах другой комплектации. Расчет показателей безотказности электроснабжения необходим при проектировании для обеспечения требуемого уровня надежности электроснабжения судовых приемников электроэнергии, а при эксплуатации – для предупреждения отказов и планирования технического обслуживания и ремонта элементов судовых электроэнергетических систем. The methodology for calculating the indicators of the reliability of power supply (the probability of failure-free power supply and the mean time to failure) of critical receivers of a sea vessel connected to the emergency electrical switchboard is presented. The technique is implemented in relation to a ship power system with three sources of electricity - two main diesel generator sets connected to the main electrical switchboard, and one emergency diesel generator set connected to an emergency electrical switchboard. Various operating modes of the ship's electric power system are considered: during operation until the first failure of one main diesel generator, during parallel operation of two main diesel generators, during operation of one emergency diesel generator; as well as after de-energizing, taking into account the possibility of subsequent switching on of the backup and / or emergency diesel generator. The technique, with appropriate adjustments, can be used to calculate indicators of reliable power supply in ship power systems of a different configuration. Calculation of power supply reliability indicators is necessary during design to ensure the required level of power supply reliability for ship power receivers, and during operation - to prevent failures and plan maintenance and repair of elements of ship power systems.

Relay protection and automation of electric power systems

2021 ◽  
Author(s):  
Sergey Goremykin
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Relay Protection ◽  
Electrical Equipment ◽  
Electric Power Systems ◽  
Federal State ◽  
Advantages And Disadvantages

The textbook describes the main issues of the theory of relay protection and automation of electric power systems. The structure and functional purpose of protection devices and automation of power transmission lines of various configurations, synchronous generators, power transformers, electric motors and individual electrical installations are considered. For each of the types of protection of the above objects, the structure, the principle of operation, the order of selection of settings are given, the advantages and disadvantages are evaluated, indicating the scope of application. The manual includes material on complete devices based on semiconductor and microprocessor element bases. The progressive use of such devices (protection of the third and fourth generations) is appropriate and effective due to their significant advantages. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for students in the areas of training 13.03.02 "Electric power and electrical engineering" (profile "Power supply", discipline "Relay protection and automation of electric power systems") and 35.03.06 "Agroengineering" (profile "Power supply and electrical equipment of agricultural enterprises", discipline "Relay protection of electrical equipment of agricultural objects"), as well as for graduate students and specialists engaged in the field of electrification and automation of industrial and agrotechnical objects.

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