scholarly journals Coupling Between Separate Phases of Coaxial Double Circuit Transmission Lines

1988 ◽  
Vol 13 (2) ◽  
pp. 85-111
Author(s):  
M. Hamed
Keyword(s):  
Phase Shift ◽  
Transmission Lines ◽  
Magnetic Field Intensity ◽  
Mutual Effect ◽  
Mutual Inductance ◽  
Power Lines ◽  
Overhead Transmission Lines ◽  
External Point ◽  
The Magnetic Field ◽  
Circuit Power

The paper studies the so-called coaxial overhead transmission lines. The concentric phases are considered. The mathematical analysis for voltage and current is presented. The telegraphic equations of the double circuit power lines with the mutual effect between circuits are introduced. The condition for single circuit transmission line is checked. The mutual effect between both circuits is studied on the basis of the ratio between the two currents of both circuits. The appeared phase shift between the two vectors of currents is inserted in the investigation. The magnetic field intensity at an external point of a line is mathematically expressed. Its value is approximated for the purpose of zero mutual inductance between phases of the same circuit. The mutual inductance between the two nearest groups of phases due to the linkage flux for the studied line is formulated. Its dependency on the distance from the phases as well as on the ratio of currents of both circuits is analysed. Then, the effect of phase shift on the mutual inductance is investigated. An idea for the control of the ratio between currents of both circuits of a line is presented.

On the vibration analysis of power lines with moving dampers

2017 ◽  
Vol 24 (18) ◽  
pp. 4096-4109 ◽  
Author(s):  
MA Bukhari ◽  
O Barry ◽  
E Tanbour
Keyword(s):  
Transmission Lines ◽  
Equations Of Motion ◽  
Power Lines ◽  
Governing Equations ◽  
Wind Force ◽  
Vibration Displacement ◽  
Mass System ◽  
Overhead Transmission Lines ◽  
Parametric Studies ◽  
Mass Spring

This work investigates the performance of a moving damper for overhead transmission lines. The damper or absorber consists of mass-spring-damper-mass system. The absorber is connected to a single conductor subjected to pretension and wind force. The governing equations of motion are obtained using Hamilton’s principle, and numerical analysis is carried out using MATLAB®. The model is validated by comparing the present results to those in the literature. Parametric studies are conducted to investigate the performance of the proposed absorber. The results indicate that a moving absorber can be more effective than a fixed absorber. It is also demonstrated that the vibration displacement decreases with increasing forcing frequency and decreasing absorber speed.

scholarly journals Procedure for Verifying Population Exposure Limits to the Magnetic Field from Double-Circuit Overhead Power Lines

Electricity ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 342-358
Author(s):  
Marco Landini ◽  
Giovanni Mazzanti ◽  
Riccardo Mandrioli
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Field Measurements ◽  
Power Line ◽  
Power Lines ◽  
Population Exposure ◽  
Exposure Limits ◽  
General Validity ◽  
The Magnetic Field ◽  
Circuit Power

The verification of the limits of the population’s exposure to the magnetic field generated by double-circuit power lines from field measurements carried out on site is not trivial. It requires knowledge of the power line current instant values during the measurement period, the determination of the relationship between current and field at the measurement points (made more complex by the double-circuit overhead line configuration) and the use of that relationship to extrapolate the field values. Nevertheless, the verification of exposure limits for double-circuit power lines from on-site measurements is often conducted with rough, or not particularly stringent, procedures. A practical and straightforward procedure of general validity for non-optimized double-circuit lines is proposed here. No specific measurement position or conductors disposition knowledge is required as well as no complex three-dimensional finite element method code is necessary. The procedure, potentially also applicable to high- and extra-high-voltage lines, is validated on a medium-voltage (15 kV) double-circuit overhead power line study case. Exposure limits assessment suggests that if the line is operated at its rated capacity (230/285 A), the 3 μT quality target is missed. Results are provided with a 95% confidence interval ranging from ±100 nT to ±140 nT in all the cases.

scholarly journals Dynamic Rating Management of Overhead Transmission Lines Operating under Multiple Weather Conditions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1136
Author(s):  
Raquel Martinez ◽  
Mario Manana ◽  
Alberto Arroyo ◽  
Sergio Bustamante ◽  
Alberto Laso ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Weather Conditions ◽  
High Accuracy ◽  
Power Lines ◽  
Calculation Error ◽  
Practical Application ◽  
Estimation Errors ◽  
Temperature Calculation ◽  
Overhead Transmission Lines ◽  
Economic Constraints

Integration of a large number of renewable systems produces line congestions, resulting in a problem for distribution companies, since the lines are not capable of transporting all the energy that is generated. Both environmental and economic constraints do not allow the building new lines to manage the energy from renewable sources, so the efforts have to focus on the existing facilities. Dynamic Rating Management (DRM) of power lines is one of the best options to achieve an increase in the capacity of the lines. The practical application of DRM, based on standards IEEE (Std.738, 2012) and CIGRE TB601 (Technical Brochure 601, 2014) , allows to find several deficiencies related to errors in estimations. These errors encourage the design of a procedure to obtain high accuracy ampacity values. In the case of this paper, two methodologies have been tested to reduce estimation errors. Both methodologies use the variation of the weather inputs. It is demonstrated that a reduction of the conductor temperature calculation error has been achieved and, consequently, a reduction of ampacity error.

Rational Damping Arrangement Design for Transmission Lines Vibrations: Analytical and Experimental Analysis

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
O. Barry ◽  
R. Long ◽  
D. C. D. Oguamanam
Keyword(s):  
Explicit Expression ◽  
Transmission Lines ◽  
Experimental Analysis ◽  
Power Lines ◽  
Rational Approach ◽  
Loop Length ◽  
Overhead Transmission Lines ◽  
Experimental Approaches ◽  
First Time ◽  
Good Agreement

The control of overhead transmission lines vibrations is achieved by Stockbridge dampers. However, the effectiveness of the damper is significantly dependent on its location on the conductor. This paper studies the arrangement of Stockbridge dampers on power lines vibrations using both analytical and experimental approaches. An explicit expression of the loop length is presented for the first time. This expression is used to determine the optimal damper location based on a rational approach. The effectiveness of the proposed approach is validated numerically and experimentally. The results show very good agreement and indicate that Stockbridge dampers are more effective for asymmetrical damping arrangement with the bigger counterweight oriented toward the tower.

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