scholarly journals Comparative Analysis of Optical Signals Emitted by Corona on a Laboratory Model of Transmission Lines Made of Various Materials

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Sławomir Krzewiński ◽  
Paweł Frącz ◽  
Ireneusz Urbaniec ◽  
Tomasz Turba
Keyword(s):  
Transmission Lines ◽  
Optical Radiation ◽  
Power Transmission ◽  
Experimental Tests ◽  
Laboratory Model ◽  
Pure Aluminium ◽  
Power Transmission Lines ◽  
Optical Signals ◽  
Three Phase ◽  
System Operating

The paper presents results of comparative analyses of optical signals generated by corona discharges occurring in the vicinity and on the surface of power transmission lines made of five different materials under laboratory conditions. Three aluminium-based materials were chosen: pure aluminium, aluminium with added magnesium, and aluminium with added silicon, and for comparison purposes also, steel-based lines were considered: copper-coated steel and steel with added chromium and nickel. A three-phase triangular arrangement system operating under maximal voltage equal to 110 kV was applied for experimental tests. The optical radiation was registered using a spectrophotometer. During research works, also the influence of corona generation voltage and distance between power lines was investigated. Based on the achieved results, it was stated that the highest corona intensity was found for aluminium-based lines, for both pure aluminium and aluminium with added magnesium and silicon. The lowest corona intensity was observed for chromium- and nickel-alloyed (stainless) steel.

scholarly journals Application of the MQ RBF-FD method to calculating transient voltages of power transmission lines

2016 ◽  
Vol 19 (2) ◽  
pp. 5-15
Author(s):  
Anh Pham Lan Vu ◽  
Viet Quoc Le ◽  
Tu Phan Vu
Keyword(s):  
Finite Difference ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Lines ◽  
Finite Difference Approximations ◽  
Transient Problems ◽  
Benchmark Circuit ◽  
Three Phase ◽  
Phase Transmission ◽  
Transient Voltages

This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.

scholarly journals Research of Ferr-Resonance Oscillations at the Frequency of Subharmonics in Three-Phase Non-Linear Electric Circuits and Systems

2020 ◽  
Vol 216 ◽  
pp. 01113
Author(s):  
M. Ibadullaev ◽  
A. N. Tovbaev
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Experimental Studies ◽  
Theoretical Research ◽  
Equivalent Model ◽  
Critical Parameters ◽  
Power Transmission Lines ◽  
Power Sources ◽  
Electric Circuits ◽  
Three Phase

It is known that the occurrence and existence of ferroresonant oscillations at the subharmonic frequency (SHC) in power transmission lines (TL) and in power supply systems is extremely undesirable, since they cause ferroresonant overvoltages at different frequencies. At the same time, there is a wide class of nonlinear electrical circuits, in which the excitation of autoparametric oscillations (AIC) at the frequency of the SHC forms the basis of frequency converting devices serving as secondary power sources. It is shown that three-phase nonlinear systems are in one way or another equivalent circuits for power transmission lines, the main elements of which are: longitudinal compensation capacitors, transverse compensation reactors, and transformers with a nonlinear characteristic. To study the regularities of the excitation and maintenance of SHC at a frequency in three-phase electro-ferromagnetic circuits (EFMC), theoretical and experimental studies of an equivalent model of a three-phase circuit with nonlinear inductance were carried out. For the analysis of the steady-state mode of the SHC at the frequency, the method of a small parameter (averaging) was applied. A shortened differential equation of motion for a three-phase nonlinear circuit is obtained. By solving them, the regions of existence of the SHC and the critical parameters of the chain were determined. The obtained results of theoretical research are confirmed by experimental studies.

scholarly journals Effects of Pile Installation on Existing Tunnels Using Model Test and Numerical Analysis with Medium Density Sand

2021 ◽  
Vol 11 (15) ◽  
pp. 6904
Author(s):  
Suk-Min Kong ◽  
Dong-Wook Oh ◽  
Seong-Won Lee ◽  
Chang-Yong Kim ◽  
Yong-Joo Lee
Keyword(s):  
Numerical Analysis ◽  
Model Test ◽  
Transmission Lines ◽  
Power Transmission ◽  
Separation Distance ◽  
Laboratory Model ◽  
Power Transmission Lines ◽  
Underground Structures ◽  
Pile Installation ◽  
Ground Conditions

Vital underground structures such as sewers, power transmission lines, subways, and underpasses are potentially vulnerable to adverse effects from aboveground construction. In this study, the influence of pile installation on nearby existing tunnels was investigated. Both a laboratory model test and finite-element numerical analysis were conducted. Twelve different combinations of horizontal and vertical offsets between the pile and the tunnel were investigated. Different surcharge loads (allowable and ultimate) were also considered. In this way, the appropriate separation distance between the existing tunnel and the piles was established for sandy, medium-compaction soil. Although this study considers simple ground conditions, it facilitates safe construction by confirming the appropriate separation distance and comparing the areas that cannot be penetrated by the structures of each standard.

METHOD OF SYNTHESIS OF CLOSED-LOOP SYSTEMS OF ACTIVE SHIELDING MAGNETIC FIELD OF POWER TRANSMISSION LINES

2016 ◽  
Vol 2016 (4) ◽  
pp. 8-10 ◽  
Author(s):  
B.I. Kuznetsov ◽  
◽  
A.N. Turenko ◽  
T.B. Nikitina ◽  
A.V. Voloshko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Transmission Lines ◽  
Closed Loop ◽  
Power Transmission ◽  
Power Transmission Lines ◽  
Closed Loop Systems ◽  
Active Shielding
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