scholarly journals Investigation of the impact of a standard lightning impulse on the structure of an 11/0.415 kV distribution transformer

2022 ◽  
Vol 202 ◽  
pp. 107588
Author(s):  
Avinash Srikanta Murthy ◽  
Norhafiz Azis ◽  
Jasronita Jasni ◽  
Mohd Lutfi Othman ◽  
Mohd Fairouz Mohd Yousof ◽  
...  
Keyword(s):  
Distribution Transformer ◽  
Lightning Impulse ◽  
The Impact

scholarly journals The Impact of TiO2 Nanoparticle Concentration Levels on Impulse Breakdown Performance of Mineral Oil-Based Nanofluids

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 627 ◽  
Author(s):  
Ziyi Wang ◽  
You Zhou ◽  
Wu Lu ◽  
Neng Peng ◽  
Weijie Chen
Keyword(s):  
Tio2 Nanoparticles ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
Concentration Level ◽  
Breakdown Strength ◽  
Mineral Oil ◽  
Interfacial Region ◽  
Bulk Oil ◽  
Lightning Impulse ◽  
The Impact

The insulation of mineral oil-based nanofluids was found to vary with different concentration level of nanoparticles. However, the mechanisms behind this research finding are not well studied. In this paper, mineral oil-based nanofluids were prepared by suspending TiO2 nanoparticles with weight percentages ranging from 0.0057% to 0.0681%. The breakdown voltage and chop time of nanofluids were observed under standard lightning impulse waveform. The experimental results show that the presence of TiO2 nanoparticles increases the breakdown voltage of mineral oil under positive polarity. The enhancement of breakdown strength tends to saturate when the concentration of nanoparticle exceeds 0.0227 wt%. Electronic traps formed at the interfacial region of nanoparticles, which could capture fast electrons in bulk oil and reduce the net density of space charge in front of prebreakdown streamers, are responsible for the breakdown strength enhancement. When the particle concentration level is higher, the overlap of Gouy–Chapman diffusion layers results in the saturation of trap density in nanofluids. Consequently, the breakdown strength of nanofluids is saturated. Under negative polarity, the electrons are likely to be scattered by the nanoparticles on the way towards the anode, resulting in enhanced electric fields near the streamer tip and the decrement of breakdown voltage.

The impact of photovoltaic systems on distribution transformer: A case study

2006 ◽  
Vol 47 (4) ◽  
pp. 311-321 ◽  
Author(s):  
Humberto Jimenez ◽  
Hugo Calleja ◽  
Raúl González ◽  
Jorge Huacuz ◽  
Javier Lagunas
Keyword(s):  
Photovoltaic Systems ◽  
Distribution Transformer ◽  
The Impact

scholarly journals Impact of Lightning Impulse on Electric Field Stress of Spacer in Single Phase Gas Insulated Busduct

2019 ◽  
Vol 8 (2S3) ◽  
pp. 837-842
Keyword(s):  
Electric Field ◽  
Power Systems ◽  
Triple Point ◽  
High Reliability ◽  
Moderate Pressure ◽  
Field Stress ◽  
Cone Type ◽  
Lightning Impulse ◽  
Reliable Power Supply ◽  
The Impact

During the last two decades, for reliable power supply, GIS have found a broad range of application in power systems because of their high reliability, easy maintenance, small space requirement, etc. Gas insulated sub-stations employs a superior dielectric gas, SF6 at moderate pressure for phase to phase and phase to ground insulation. Several troubles and system outages in GIS have been reported world-wide due to insulation failures which resulted in the intensification of electric field along the spacer surface and especially at the triple point electrode – spacer – gas. Hence, it was required to reduce the rate of insulation failure. In this work, Conventional cone type spacer geometry is taken for which field study has been done. Electric field stresses developed by the cone type spacer on the surface of the spacer and also at the triple junction is determined. It is found that the electric field stress at the surface of the spacer is maintained uniform, the electric field stress at the critical junctions formed by the conductor, solid insulator and SF6 gas is not maintained at minimum value. Metal inserts are considered as a means to reduce the stress at the triple point junction. The impact of Lightning Impulse on the Electric Field Stress along the spacer is carried and the reduction of stress is mitigated with the insertion of Metal Inserts.

Impact of pin Type Insulators on Power Distribution Networks Caused by Lightning Impulse Overvoltage

2015 ◽  
Vol 781 ◽  
pp. 300-303
Author(s):  
Khamhyo Phothilath ◽  
Kittipong Tonmitra ◽  
Pramin Artrit
Keyword(s):  
Power Distribution ◽  
Current Flow ◽  
Distribution Networks ◽  
Lightning Strike ◽  
Power Distribution Networks ◽  
Lightning Impulse ◽  
Flow Through ◽  
The Impact

The impact of pin type insulators may cause from the lightning impulse overvoltage that hits directly to them. To investigate this problem, this work applies the ATP Draw version 5.6 software to simulate the effect of pin type insulators. Therefore, the obtained results are showed that pin type insulators at pole P4 is closely the lightning strike point, has affected more than the poles P3-P1 and P5-P7. In addition, the conductor has been taken by the heat of over current flow through on it. The flashover and breakdown severity is on insulator upon the distance of them.

scholarly journals Lightning Impulse Overvoltage Propagation in HVDC Meshed Grid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3047
Author(s):  
Marek Florkowski ◽  
Jakub Furgał ◽  
Maciej Kuniewski
Keyword(s):  
Security Studies ◽  
Lightning Strike ◽  
Long Distance ◽  
Lightning Stroke ◽  
High Voltage Direct Current ◽  
Surge Arresters ◽  
Lightning Impulse ◽  
Dc Line ◽  
Insulation Coordination ◽  
The Impact

This paper reports on the propagation of lightning overvoltage in a high-voltage direct current (HVDC) meshed grid. Since several topologies of meshed grids have been elaborated in the last decade, we used a common comprehensive reference test platform. The lightning impulse propagation was investigated with regard to the impact of surge arresters and the polarity of the lightning stroke concerning the DC line polarity (±500 kV). Various scenarios were considered, including a direct lightning strike to the DC+ conductor, to the tower, and to the shielding wire in the middle of the span, including backflash on the insulators. The influence of tower footing impedance on overvoltage levels at various nodes was assessed, depicting the critical value. A description of the models used in the simulations was provided. The main focus of the paper was on the wide-area propagation of the overvoltages in the meshed grid, at distant terminals and inside the feeders. An interesting observation was the effects of lightning at the far end of the analyzed grid, propagating through multiterminal and long-distance connections. The presented analysis, based on an exemplary meshed HVDC grid, underlines the importance of the insulation coordination studies and system security studies with respect to the localization of overvoltage protection systems.

scholarly journals Investigation on the Resonant Oscillations in an 11 kV Distribution Transformer under Standard and Chopped Lightning Impulse Overvoltages with Different Shield Placement Configurations

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1466 ◽  
Author(s):  
Murthy ◽  
Azis ◽  
Yousof ◽  
Jasni ◽  
Othman ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
High Voltage ◽  
Low Voltage ◽  
Stress Distributions ◽  
Voltage Distribution ◽  
Distribution Transformer ◽  
Resonant Oscillation ◽  
Initial Voltage ◽  
Transformer Winding ◽  
Lightning Impulse

This paper presents an investigation on the resonant oscillations of an 11 kV layer-type winding transformer under standard and chopped lightning impulse overvoltage conditions based on calculated parameters. The resistances, inductances and capacitances were calculated in order to develop the transformer winding equivalent circuit. The impulse overvoltages were applied to the high voltage (HV) winding and the resonant oscillations were simulated for each of the layers based on different electrostatic shield placement configurations. It is found that the placement of grounded shields between layer 13 and layer 14 results in the highest resonant oscillation and non-linear initial voltage distribution. The oscillation and linear stress distributions are at the lowest for shield placement between the HV and low voltage (LV) windings.

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