Aircraft Electrical Voltage Level Definitions

2021 ◽  
Author(s):  
Keyword(s):  
Voltage Level ◽  
Electrical Voltage

Dependence of Current Harmonics of Greenhouse Irradiators on Supply Voltage

2020 ◽  
pp. 85-88 ◽  
Author(s):  
Nadezhda P. Kondratieva
Keyword(s):  
Mathematical Models ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Feasibility Studies ◽  
Power Losses ◽  
Voltage Level ◽  
Supply Networks ◽  
Current Harmonics ◽  
Cable Lines ◽  
Harmonic Composition

The article describes the results of the study concerning the effect of the voltage level on current harmonic composition in greenhouses irradiators. It is found that its change affects the level of current harmonics of all types of the studied greenhouse irradiators. With decrease of nominal supply voltage by 10 %, the total harmonic distortion THDi decreases by 9 % for emitters equipped with high pressure sodium lamps (HPSL), by 10 % for emitters with electrode-less lamps and by 3 % for LED based emitters. With increase of nominal supply voltage by 10 %, THDi increases by 23 % for lighting devices equipped with HPSL, by 10 % for irradiators with electrode-less lamps and by 3 % for LED based emitters. Therefore, changes of supply voltage cause the least effect on the level of current harmonics of LED based emitters and then the emitters with electrode-less lamps. Change of the level of supply voltage causes the greatest effect on the level of current harmonics of HPSL based irradiators. Mathematical models of dependence of THDi on the level of supply voltage for greenhouse emitters equipped with LED, electrode-less lamps and HPSL lamps were formulated. These mathematical models may be used for calculations of total current when selecting transformers and supply cable lines for greenhouse lighting devices, for design of new or reconstruction of existing irradiation systems of greenhouse facilities, and for calculation of power losses in power supply networks of greenhouse facilities during feasibility studies for energy saving and energy efficiency increasing projects.

scholarly journals Voltage Variations and Their Reduction in a Rural Low-Voltage Network with PV Sources of Energy

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1620
Author(s):  
Agata Szultka ◽  
Seweryn Szultka ◽  
Stanislaw Czapp ◽  
Ryszard Zajczyk
Keyword(s):  
Low Voltage ◽  
Power Production ◽  
Legal Regulations ◽  
Sectional Area ◽  
Overhead Line ◽  
Power Networks ◽  
Cable Line ◽  
Cross Sectional ◽  
Voltage Level ◽  
Wide Scale

Renewable sources of energy (RES), especially photovoltaic (PV) micro-sources, are very popular in many countries. This way of clean power production is applied on a wide scale in Poland as well. The Polish legal regulations and tariffs specify that every prosumer in a low-voltage network may feed this network with a power not higher than the maximum declared consumed power. In power networks with RES, the voltage level changes significantly along the power line and depends on the actually generated as well as consumed power by particular prosumers. There are cases that prosumers connected to this line cannot produce and inject the full permissible power from PV sources due to the level of a voltage higher than the technically acceptable value. In consequence, it leads to the lack of profitability of investments in installations with PV sources. In this paper, voltage variations in a real rural low-voltage network with PV micro-sources are described. The possible two general solutions of voltage levels improvement are discussed—increase in the cross-sectional area of the bare conductors in the existing overhead line as well as the replacement of the overhead line with a cable line. The recommended solution for the analyzed network, giving the best reduction of voltage variations and acceptable cost, is underlined. Such a recommendation can also be utilized in other rural networks.

scholarly journals Electrical voltage by electron spin-vorticity coupling in laminar ducts

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Hamid Tabaei Kazerooni ◽  
Georgy Zinchenko ◽  
Jörg Schumacher ◽  
Christian Cierpka
Keyword(s):  
Electron Spin ◽  
Electrical Voltage

Switching Arc Phenomena in Transmission Voltage Level Vacuum Circuit Breakers

2021 ◽  
Author(s):  
Zhiyuan Liu ◽  
Jianhua Wang ◽  
Yingsan Geng ◽  
Zhenxing Wang
Keyword(s):  
Circuit Breakers ◽  
Voltage Level
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