scholarly journals The determination of short circuits and grounding faults in electric power systems using time-frequency analysis

2017 ◽  
Vol 26 (2) ◽  
pp. 123
Author(s):  
Vedat Esen ◽  
Bulent Oral Oral ◽  
Tahir Cetin Akinci
Keyword(s):  
Mathematical Method ◽  
Power Systems ◽  
Fourier Analysis ◽  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Electrical Energy ◽  
Power Transmission Lines ◽  
Time Frequency ◽  
Time Band

In order to ensure that electrical energy reaches consumers uninterrupted, researchers constantly try to improve power transmission lines. To realize this improvement, probable faults should be analysed through every known method, and new methods should also be implemented. In this study, firstly, the Keban power transmission line located in the Eastern Anatolia region of Turkey was modelled. After that, probable short circuit scenarios were applied on the model, and the short circuit faults in the scenarios were analysed by using the Fourier analysis. The Fourier analysis is a mathematical method that is used as an effective way to determine the sudden changes in the frequency and time band. The study was successful in determining phase and grounding faults through the analyses of the scenarios using Fourier analysis. The fact that the mathematical method was applied on the probable scenarios on a physical model increases the importance of the study.

scholarly journals Reducing Short Circuit Level in 400 kV Iraqi Grid System by Using FACTS Device

2019 ◽  
pp. 90-99
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Electrical Power ◽  
Short Circuit Current ◽  
Power Grids ◽  
Power Transmission Lines ◽  
Power Stations ◽  
Flexible Alternating Current Transmission

Electrical power systems are different in their sizes because of their amount of generation power stations, substations, transmission lines and loads. Therefore, these factors may impact on short circuit levels values. Capacity of power stations and dummy transmission lines in Extra high voltage grid (400kV) of the Iraqi Electrical power grids cause high short circuit levels values such that exceed both rating of the peak and breaking capacity of switchgear equipment's. Reduction of short-circuit levels by using Fast-acting Flexible Alternating Current Transmission Systems (FACTS) types devices in power grids maintain the operation of power grids with acceptable value of short circuit levels for their electrical equipment's and preventing cascading event outages which may lead to blackouts. This paper mainly studies strategies on how to add Short Circuit Current Limiter (SCCL) device by determining its number, value and location of connection in power grids by programing with (PSS™E version 30.3 Package Program). IEEE 25-bus system is used for testing the adding series SCCL at power transmission lines method procedure. The results of adding series SCCL with power transmission lines give significant reducing short circuit levels for the stations have highest short circuit levels in order to prevent the blackouts of overall power grid.

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.

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.

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.

scholarly journals Power quality in high voltage mains supplying mainline railroads’ traction substations

2019 ◽  
Vol 114 ◽  
pp. 04001
Author(s):  
Yu.N. Bulatov ◽  
A.V. Kryukov ◽  
A.V. Cherepanov
Keyword(s):  
Power Quality ◽  
Transmission Lines ◽  
Large Scale ◽  
Power Transmission ◽  
Short Circuit ◽  
Far East ◽  
Power Transmission Lines ◽  
Quality Factors ◽  
Significant Deterioration ◽  
Traction Substations

The increase in the trains weight and their operation speeds leads to considerable growth of abrupt-variable, non-linear and one-phase traction loads. This, in its own turn, leads to significant deviations, unsymmetry and voltage harmonic distortions in 110-220 kV mains adjacent to traction substations of AC railroads. Significant deterioration in power quality factors is observed in Siberian and Far East regions where 110-220 kV main power transmission lines are immediately adjacent to Transsib traction substations; in this case, in points with lower levels of short circuit power, power quality factors exceed by far the permissible levels. The articles provides the results of studies aimed at solution of power quality enhancement is-sues for mains adjacent to traction substations of Trans-Siberian Railway. To enhance power quality in mains supplying traction substations, smart grid technologies can be used together with multiagent control systems. Technical solutions, based on the results obtained, are proposed that allow to bring the power quality factors to the regulatory values. Due to a big investments amount, an implementation of tar-get program is needed to resolve the large-scale issue of enhancing power quality in mains adjacent to traction substations of AC railroads.

scholarly journals Allocation of 0.4 kV PTL Sectionalizing Units under Criteria of Sensitivity Limits and Power Supply Reliability

2021 ◽  
Vol 11 (24) ◽  
pp. 11608
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Andrey Izmailov ◽  
Alexey Dorokhov ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Short Circuit ◽  
Reducing Power ◽  
Power Transmission Lines ◽  
Electrical Networks ◽  
The Cost ◽  
The Impact ◽  
Supply Reliability

Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.

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