Investigation of Signal on Transmission Lines in Power System

2014 ◽  
Vol 577 ◽  
pp. 551-555
Author(s):  
Hui Li ◽  
Liang Yuan
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Transmission ◽  
Additive White Gaussian Noise ◽  
Measurement Unit ◽  
Power Transmission Lines ◽  
Electromagnetic Transient ◽  
Power System Harmonics

Single of phasor measurement unit (PMU) in smart grid is analyzed. On the power transmission links, single of voltage and current are measured by kinds of PMUs, messages of PMUs are concentrated to PDC (Phasor data concentrator) and super PDC in power systems. Signal quality is important to power transmission, power utilization and power control for stability a power system. Harmonics, inter-harmonics, decaying DC (direct current) offset, and additive white Gaussian noise are analyzed. Odd-number harmonics and inter-harmonics affect the quality of power signals. Decaying DC offsert components influence current signal of power transmission line whose model is modeled by EMTP (Electromagnetic transient program) worldwide. Noise is generally a negligible factor on power transmission lines, since signal-to-noise (SNR) is always below 40 dB.

Assessment of technical condition of high-voltage overhead power transmission lines at the stage of their ageing

2021 ◽  
Vol 14 (2) ◽  
pp. 100-107
Author(s):  
E. M. Farhadzadeh ◽  
A. Z. Muradalyiev ◽  
S. A. Muradalyiev ◽  
A. A. Nazarov
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Transmission ◽  
Operational Reliability ◽  
Technical Condition ◽  
Weak Links ◽  
Power Transmission Lines ◽  
Nonlinear Growth ◽  
Overhead Power Transmission Lines

The organization of operation, maintenance and repair of the basic technological facilities of electric power systems (EPS), which are beyond their designed service life (hereinafter referred to as ageing facilities, or AFs) is one of the problems that determine the energy security of many countries, including economically developed nations. The principal cause of insufficient overall performance of AFs is the traditional focus of the EPS management on economic efficiency and the insufficient attention to reliability and safety of AFs. The tendency to nonlinear growth in the frequency of occurrence of unacceptable consequences in the EPS requires ensuring the operational reliability and safety of AFs. The averaged estimates of reliability and safety used at designing power facilities are not suitable for characterization of overall operational performance. Among the basic and the least investigated (in terms of operational reliability and safety) EPS facilities are overhead power transmission lines (OPL) with a voltage of 110 кV and above. This is for a reason. OPL are electric power facilities with elements distributed along a multi-kilometer line (supports, insulators, wires, accessories, etc.). That is what makes the organization of continuous monitoring of the technical condition of each of these elements, and, consequently, the assessment of operational reliability and safety, so problematic. A method is suggested for assessment of “weak links” among the operated OPL on operative intervals of time along with a method for assessment of the technical condition of OPL at examination of a representative sample.

Analysis of mathematical models of transmission lines.

2020 ◽  
Vol 23 (2) ◽  
pp. 16-19
Author(s):  
G. SHEINA ◽  
Keyword(s):  
Mathematical Model ◽  
Power Systems ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Supply System ◽  
Power Transmission ◽  
Supply System ◽  
Power Lines ◽  
Power Transmission Lines ◽  
The Mathematical Model

This paper investigates a mathematical model of one elements of the power supply system - power transmission lines. The type of models depends on the initial simplifications, which in turn are determined by the complexity of the physics of processes. The task of improving the accuracy of modeling of emergency processes in the power system is due to the significant complexity of modern power systems and their equipment, high-speed relay protection, automation of emergency management and the introduction of higher-speed switching equipment. One of the reasons for a significant number of serious emergencies in the system is the lack of complete and reliable information for modeling modes in the design and operation of power systems. The development of a mathematical model of a three-phase power line, which provides adequate reflection of both normal and emergency processes, is relevant. The advanced mathematical model of power transmission lines allows to investigate various operational modes of electric networks. The improved mathematical model of the power transmission line reflects all the features of physical processes at state modes and transient process and provides sufficient accuracy of the results. The type of mathematical model of power transmission lines depends on the accepted simplifications, depending on the task of research. The purpose of this work is to analyze the mathematical model of the power transmission line to study the modes of operation of the power supply system, with the possibility of its application to take into account all the design features of overhead and cable power lines. The mathematical model of the power line for the study of the modes of operation of the power supply system is analyzed. It is used to take into account the design features of overhead and cable power lines, skin effect.

scholarly journals Procedure for calculation of the admissible continuous power transmission currents of overhead wires and contact lines

2021 ◽  
Vol 2131 (4) ◽  
pp. 042065
Author(s):  
Yu I Zharkov ◽  
E P Figurnov ◽  
V I Kharchevnikov
Keyword(s):  
Heat Transfer ◽  
Power Systems ◽  
Transmission Lines ◽  
Power Transmission ◽  
Convective Heat Transfer Coefficient ◽  
Electric Power Systems ◽  
Power Transmission Lines ◽  
Contact Lines ◽  
Heating And Cooling ◽  
Continuous Power

Abstract The proposed methodology summarizes published and original domestic and foreign theoretical and experimental materials on heating and cooling of spiral and shaped wires of overhead power transmission lines and electric power systems and uses those of them that best meet the fundamental laws of heat transfer. Formulas for calculating the surface area for spiral and shaped wires are given. A generalized formula for the convective heat transfer coefficient taking into account the direction and speed of the wind, including for the anti-ice regime, is given. The parameters of this formula do not coincide with the existing ones, since they are based on the experimental data for spiral and shaped wires, and not for round pipes. The formula for calculating the power of heat transfer under solar radiation is given. A generalized formula is given for calculating the continuous allowable current, all components of which are described in detail in the article.

scholarly journals Two-Terminal Algorithm Analysis for Unsymmetrical Fault Location on 110 kV Lines

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1193 ◽  
Author(s):  
Zuzana Bukvisova ◽  
Jaroslava Orsagova ◽  
David Topolanek ◽  
Petr Toman
Keyword(s):  
Power Systems ◽  
Transmission Line ◽  
Transmission Lines ◽  
Computer Aided Design ◽  
Fault Location ◽  
Power Transmission ◽  
Current Data ◽  
Algorithm Analysis ◽  
Power Transmission Lines ◽  
Design Environment

This work analyses a two-terminal algorithm designed to locate unsymmetrical faults on 110 kV power transmission lines. The algorithm processes synchronized voltage and current data obtained from both ends of the protected transmission line and calculates the distance of the fault. It is based on decomposing the equivalent circuit into the positive-, negative- and zero-sequence components and finding the point where the output voltages of the right and the left side of the transmission line are equal. Compared to the conventional distance relay locator, the accuracy of this method is higher and less influenced by the fault resistance, the parallel-operated line effect and line asymmetry, as discussed in this work. It is, however, very sensitive to the synchronization accuracy. The mathematical model of the power system was created in the PSCAD (Power Systems Computer Aided Design) environment and the computational algorithm was implemented in Mathematica software.

A Criticality Assessment Method for Power Transmission Lines in Power System

2013 ◽  
Vol 446-447 ◽  
pp. 817-822
Author(s):  
Wen Ying Liu ◽  
Cai Liang
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Transient Stability ◽  
Power Transmission ◽  
Stability Index ◽  
Assessment Method ◽  
Power Transmission Lines ◽  
Analytic Hierarchy ◽  
Limit Index ◽  
Line Overload

Analytic Hierarchy Process (AHP) is presented in this paper to measure the relative criticality for transmission lines, considering the changes of power system’s status about transmission lines overload, central buses voltage over-limit and transient stability. At first hierarchy structure is modeled, and then indexes of criteria Layer including transmission line overload index, central buses voltage over-limit index and transient stability index were presented. The simulation results show that, the AHP assessment method can give a full consideration to transmission lines’ function, which of huge significance for identifying critical lines and increasing the security of power system.

scholarly journals Comparison between Thyristor Switched Series Capacitors and Thyristor Switched Parallel Capacitors for wind power systems - A Simulation Study

2021 ◽  
Vol 15 ◽  
Author(s):  
D. Kalpaktsoglou ◽  
A. Tsiakalos ◽  
S. Pouros ◽  
Μ. Roumeliotis
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Power Factor ◽  
Transmission Lines ◽  
Power Transmission ◽  
Control Technique ◽  
Power Transmission Lines ◽  
Direct Drive ◽  
Wind Power Systems ◽  
Series Capacitors

This paper compares by simulation the Thyristor Switched Series Capacitors (TSSC) Circuit with the Thyristor Switched Parallel Capacitors (TSPC) Circuit for wind turbines. The well-known TSSC circuit belongs to the Controlled Series Capacitor (CSC) circuits that have been used in power transmission lines in order to correct the power factor and improve the performance of the electrical system. Such a circuit can be used in wind power systems to improve and maximize the efficiency of a wind turbine. A typical direct-drive wind power system employs variable speed electric generators, but the downside is that systems like that suffer from high inductive reactance. A TSSC circuit, therefore, is able to counteract for any reactive losses, and improve the power factor as well as the efficiency. The main issue with the TSSC circuit is the use of a high number of capacitors that must be connected in series, which can increase the cost and the maintenance of the controller. This paper introduces a novel circuit with different control technique than the TSSC that employs capacitors in parallel configuration. The novel TSPC circuit was simulated in PSPICE and the benefits as well as the drawbacks are described

scholarly journals Economic aspects of ensuring the capacity adequacy of electric power systems

2018 ◽  
Vol 58 ◽  
pp. 01010 ◽  
Author(s):  
Nikolay Belyaev ◽  
Andrey Egorov ◽  
Nikolay Korovkin ◽  
Vladimir Chudny
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Computational Models ◽  
Power Transmission ◽  
Present Report ◽  
Electric Power Systems ◽  
Power Transmission Lines ◽  
Engineering Measures ◽  
The Cost

The present report deals with economic issues of selecting means ensuring the capacity adequacy of electric power systems. Cost analysis of various engineering measures ensuring the capacity adequacy has been performed, they are as follows: construction of margin generating capacities, erection of new power transmission lines or increase of transmission capacity of existing power lines. The cost-based analysis has been conducted following investment programs and regulatory acts in place. Recommendations on developing computational models of power systems have been given based on the results obtained in order to assess the capacity adequacy indices with account made for the cost of various engineering measures to be taken for their improvement.

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