scholarly journals Impact of rail impedance intrinsic variability on railway system operation, EMC and safety

2021 ◽  
Vol 11 (1) ◽  
pp. 17
Author(s):  
Andrea Mariscotti
Keyword(s):  
Electromagnetic Compatibility ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Transportation Systems ◽  
Rolling Stock ◽  
Interface Element ◽  
Induced Voltage ◽  
Intrinsic Variability ◽  
Electrical Parameters ◽  
Experimental Values

Running rails in electrified transportation systems are the interface element for several phenomena related to system performance, electromagnetic compatibility and safety: useful voltage at rolling stock, short circuit current, induced voltage, stray current, and track circuit operation. This work presents the physical and mathematical groundings of rail electrical parameters (dc and ac resistance, ac internal and external inductance) and experimental results available in the literature, discussing variability and reliability for each interface. The results consist thus of the identification of the relevant rails longitudinal electrical parameters, the presentation of a set of reliable experimental values, and the discussion of the best approach to manage their variability and uncertainty.

scholarly journals Critical Review of EMC Standards for the Measurement of Radiated Electromagnetic Emissions from Transit Line and Rolling Stock

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 759
Author(s):  
Andrea Mariscotti
Keyword(s):  
Time Distribution ◽  
Communication Systems ◽  
Electromagnetic Compatibility ◽  
Transportation Systems ◽  
Operating Conditions ◽  
Rolling Stock ◽  
Intrinsic Variability ◽  
Statistical Characterization ◽  
Electromagnetic Emissions

Accurate and comprehensive methods for the assessment of radiated electromagnetic emissions in modern electric transportation systems are a necessity. The characteristics and susceptibility of modern victim signaling and communication radio services, operating within and outside the right-of-way, require an update of the measurement methods integrating or replacing the swept frequency technique with time domain approaches. Applicable standards are the EN 50121 (equivalent to the IEC 62236) and Urban Mass Transport Association (UMTA) with additional specifications from project contracts. This work discusses the standardized methods and settings, and the representative operating conditions, highlighting areas where improvements are possible and opportune (statistical characterization of measurement results, identification and distinction of emissions and line resonances, and narrowband and broadband phenomena). In particular for the Electromagnetic Compatibility (EMC) assessment with new Digital Communication Systems, the characterization of time distribution of spectral properties is discussed, e.g., by means of Amplitude Probability Distribution and including time distribution information. The problem of determination of site and setup uncertainty and repeatability is also discussed, observing on one hand the lack of clear indications in standards and, on the other hand, the non-ideality and intrinsic variability of measurement conditions (e.g., rolling stock operating conditions, synchronization issues, and electric arc intermittence).

scholarly journals Acid-Base Transport and Control in Locust Hindgut: Artefacts Caused by Short-Circuit Current

1991 ◽  
Vol 155 (1) ◽  
pp. 455-467
Author(s):  
R. BRENT THOMSON ◽  
N. AUDSLEY ◽  
JOHN E. PHILLIPS
Keyword(s):  
Cyclic Amp ◽  
Acid Secretion ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Salt Bridges ◽  
Electrical Parameters ◽  
Acid Base ◽  
Before And After ◽  
And Control ◽  
Stimulation Of

The commonly used method of passing short-circuit current (Isc) across insect epithelia through Ag-AgCl electrodes, without the use of salt bridges, leads to significant OH− production at the cathode (lumen side) when high currents are applied. The alkalization of the lumen previously reported when cyclic AMP was added to short-circuited locust hindgut is a result of this phenomenon rather than cyclic-AMP-mediated stimulation of acid-base transport in the hindgut. When salt bridges are used to pass short-circuit current across locust hindgut, acid secretion (JH) into the lumen equals alkaline movement (JOH) to the haemocoel side, and JH is similar under both open- and short-circuit conditions. JH is similar (1.5 μequiv cm−2 h−1) in recta and ilea. Addition of cyclic AMP inhibits JH across the rectum by 42–66%, but has no effect on the ileum when salt bridges are used. Electrical parameters (Isc, Vt, Rt) reflecting hindgut Cl− transport (JCL) before and after stimulation with cyclic AMP are the same whether or not salt bridges are used. We found no evidence of any coupling between JCl and JH/JOH.

scholarly journals Inductive influence of 25 kV, 50 Hz electrified single rail traction system

2018 ◽  
Vol 180 ◽  
pp. 06004
Author(s):  
Bosko Milesevic ◽  
Ivo Uglesic
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Induced Voltage ◽  
Metallic Structures ◽  
Railway System ◽  
Supply Current ◽  
Traction System ◽  
Current Calculation ◽  
Inductive Interference

The paper presents the methodology for calculation and measurement of induced voltage caused by railway system operation on the sensitive metallic structures. The arrangement and characteristics of railway system 25 kV, 50 Hz are provided. The procedures of short-circuit current calculation and supply current measurement in the railway system are described. The basic theoretic background of inductive interference is explained. The reduction factors of the communication cable, railway system and environment are mentioned and clarified. On a case study, the results of the induced voltage calculation and measurement is compared. It is proved that induced voltage directly depends of supply current or shortcircuit value.

The influence of emitter resistance on the electrical parameters of mono- and multicrystalline silicon solar cells

2019 ◽  
Vol 36 (3) ◽  
pp. 90-94
Author(s):  
Barbara Swatowska ◽  
Piotr Panek ◽  
Dagmara Michoń ◽  
Aleksandra Drygała
Keyword(s):  
Solar Cells ◽  
Contact Resistance ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Multicrystalline Silicon ◽  
Silicon Solar Cells ◽  
Electrical Parameters ◽  
Content Type ◽  
Diffusion Parameters

Purpose The purpose of this study was the comparison and analysis of the electrical parameters of two kinds of silicon solar cells (mono- and multicrystalline) of different emitter resistance. Design/methodology/approach By controlling of diffusion parameters, silicon mono- (Cz-Si) and multicrystalline (mc-Si) solar cells with different emitter resistance values were produced – 22 and 48 Ω/□. On the basis of current-voltage measurements of cells and contact resistance mapping, the properties of final solar cells based on two different materials were compared. Additionally, the influence of temperature on PV cells efficiency and open circuit voltage (Uoc) were investigated. The PC1D simulation was useful to determine spectral dependence of external quantum efficiency of solar cells with different emitter resistance. The silicon solar cells of 25 cm2 area and 240 µm thickness were investigated. Findings Considering the all stages of cell technology, the best structure is silicon solar cell with sheet resistance (Rsheet) of 45-48 Ω/□. Producing of an emitter with this resistance allowed to obtain cells with a fill factor between 0.725 and 0.758, Uoc between 585 and 612 mV, short circuit current (Isc) between 724 and 820 mA. Originality/value Measurements and analysis confirmed that mono- and multicrystalline silicon solar cells with 48 Ω/□ emitter resistance have better parameters than cells with Rsheet of 22 Ω/□. The contact resistance is the highest for mc-Si with Rsheet of 48 Ω/□ and reaches the value 3.8 Ωcm.

Evidence for separate cellular origins of sodium and acid-base transport in the turtle bladder

1986 ◽  
Vol 250 (4) ◽  
pp. C609-C616 ◽  
Author(s):  
J. H. Durham ◽  
W. Nagel
Keyword(s):  
Epithelial Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Transport Processes ◽  
Electrical Parameters ◽  
Acid Base ◽  
Intracellular Potential ◽  
Turtle Bladder ◽  
Stimulation Of

Transmembrane electrical parameters of the epithelial cells in short-circuited turtle bladders were measured to determine whether those cells participating in Na reabsorption also participate in electrogenic transepithelial acidification and alkalinization. Amiloride-induced increases in intracellular potential (Vsca), apical fractional resistance (FRa), and concomitant decreases in short-circuit current (Isc) denote the participation of the impaled cells in Na reabsorption. In bladders from postabsorptive turtles, amiloride increased Vsca by -45 mV, increased FRa by 37%, and decreased Isc from 36 to -10 microA/cm2. In bladders from NaHCO3-loaded turtles, amiloride increased Vsca by -21 mV, FRa by 21%, and decreased Isc from 22 to 0 microA/cm2. Neither the subsequent inhibition of the negative acidification current in postabsorptive bladders, nor stimulation of positive alkalinization current in bladders from NaHCO3-loaded turtles was associated with any transmembrane electrical change that could be attributed to changes in those transport processes. It is concluded that the electrogenic luminal acidification and alkalinization processes of the turtle bladder are not produced by, or electrically coupled to, those cells that are involved in Na reabsorption.

Effect of furosemide on the electrical parameters of frog skin

1982 ◽  
Vol 243 (6) ◽  
pp. F581-F587 ◽  
Author(s):  
A. Corcia ◽  
S. R. Caplan
Keyword(s):  
Active Transport ◽  
Frog Skin ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Relative Increase ◽  
Electrical Potential Difference ◽  
Electrical Parameters ◽  
Active Conductance ◽  
Solution Bathing

When added to the mucosal solution bathing isolated frog skin at concentrations ranging from 5 X 10(-4) to 3 X 10(-3) M, the diuretic furosemide increased both the active transport of sodium and the electrical potential difference across the tissue in a dose-dependent way. The same effect was observed in chloride-free solutions. Mucosal furosemide also decreased the passive unidirectional fluxes of chloride. We believe that as far as electrical parameters are concerned mucosal furosemide has a double effect in frog skin: it increases the active conductance to sodium across the mucosal membrane, thus increasing active transport, and decreases the passive permeability to chloride, thus altering the passive conductance of the skin. The relative increase in short-circuit current was, however, invariably greater than the increase of the active conductance, suggesting the influence of yet a third effect. The effect of mucosal furosemide on active sodium transport was blocked by amiloride (5 X 1-(-5) M) and was independent of vasopressin. Qualitatively the effect was similar to the effect produced by triphenylmethylphosphonium ion.

Induced voltage analysis of superconducting fault current limiter

2013 ◽  
Vol 33 (1/2) ◽  
pp. 38-46 ◽  
Author(s):  
Zhigao Wang ◽  
Shuhong Wang ◽  
Jie Qiu ◽  
Weizhi Gong ◽  
Jingyin Zhang
Keyword(s):  
Short Circuit ◽  
Three Dimensional ◽  
Electric Circuit ◽  
Short Circuit Current ◽  
Fault Current Limiter ◽  
Induced Voltage ◽  
Superconducting Fault Current Limiter ◽  
Content Type ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Purpose – Saturated core type superconducting fault current limiter (SFCL) can effectively limit the short-circuit current in power system. However, the high induced voltage will occur between the terminals of DC superconducting bias winding caused by the variation of magnetic flux linked by DC winding due to the increasing short-circuit current. The DC source may be damaged. Thus, the induced voltage should be considered in DC winding design. The paper aims to discuss these issues. Design/methodology/approach – Three-dimensional finite element method coupled with electric circuit. Findings – The short-circuit current flowing through AC windings and induced voltage of DC winding are analyzed by using three-dimensional finite element method coupled with electric circuit for a 220-kV three-phase SFCL. Several circuit elements, such as a capacitor connected with DC winding in parallel, an additional short-circuit winding wound around DC core column and an energy-released piezoresistor, are, respectively, used for induced voltage reduction. These methods aim to save magnetic coupled energy in DC winding, or oppose the variation of magnetic flux, or limit the voltage of DC winding by using a resistor with low resistance. Originality/value – The different methods for reduction of induced voltage of superconducting DC winding are studied and discussed. The decreased induced voltage may benefit the safety of superconducting DC winding and the source.

Research on the On-Line Measuring Method of Transformer Short-Circuit Reactance

2014 ◽  
Vol 981 ◽  
pp. 636-640
Author(s):  
Yun Bing Wei ◽  
Dong Zhang
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Measuring Method ◽  
Electrical Parameters ◽  
Operation Condition ◽  
Current Compensation ◽  
Measuring Methods ◽  
Exciting Current ◽  
Operation Process ◽  
On Line

The short-circuit reactance is an important parameter to characterize the transformer ability to resist the attack of short-circuit current in the design the operation process. In this paper, the on-line measuring method for short-circuit reactance based on electrical parameters' characteristics was presented, and the feasibility to carry out on-line monitoring for the transformer operation condition was also analyzed. Besides, the principle of two on-line measuring methods based on respectively exciting current compensation and elimination technique was researched, and the calculation equations were deduced. The comparison between the on-line results measured from moving mold experiment and those from off-line short-circuit experiment showed that these two methods were accurate and valid.

scholarly journals Experimental Investigation of the Effects of Partial Shading on Photovoltaic Cells’ Electrical Parameters

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
W. B. Xiao ◽  
F. Y. Hu ◽  
H. M. Zhang ◽  
H. M. Wu
Keyword(s):  
Open Circuit Voltage ◽  
Short Circuit ◽  
Isosceles Triangle ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Electrical Parameters ◽  
Maximum Power Point ◽  
Partial Shading ◽  
Black Card ◽  
Power Point

The short-circuit current (Isc), the open-circuit voltage (Voc), and the maximum power point (VMPP,IMPP) of monocrystalline and multicrystalline silicon solar cells under three kinds of partial shading patterns have been investigated experimentally. The partial shades are, respectively, the nine shelter locations by 1 cm × 1 cm black card, the six shelter locations by 2 cm × 1 cm black card, and the center shelters with isosceles triangle, circle, square, and two rectangles black cards whose areas are 2 cm2. Firstly, the results show that the partial shading causes disproportional high losses on those parameters of both cells but will have a minimal effect onVoc. Secondly, it is found that those parameters of the monocrystalline cell are less dependent on the shading than that of the multicrystalline cell. Thirdly, it is noted thatIscandIMPPof both cells will be decreasing dramatically as a rectangular black shading card with a long side parallel to cell’s finger, compared with that normal to cell’s finger. Finally, it can be seen that the effects of shading on the electrical parameters of both cells will be suppressed when the border lines of shading match the size of the shaded cell.

scholarly journals Influence of Silicon Nanoparticle on the Electrical Properties of Heterostructured CdTe/CdS thin films based Photovoltaic Device

2021 ◽  
pp. 256-261
Author(s):  
A. A. Faremi ◽  
S. S. Oluyamo ◽  
K. D. Adedayo ◽  
Y. A. Odusote ◽  
O. I. Olusola
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Silicon Nanoparticles ◽  
Short Circuit ◽  
Large Body ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Photovoltaic Device ◽  
Electrical Parameters ◽  
Silicon Nanoparticle

This paper presents the influence of silicon nanoparticles at the interface of heterostructured Cadmium telluride and cadmium sulfide thin films based photovoltaic device with improved electrical parameters leading to tremendous improvement in CdS/CdTe thin f ilm based solar cells performance. The films of CdTe, CdS and Si were electrodeposited using electrodeposition technique to form a heterostructured CdTe/Si/CdS/FTO. The films respective structural properties were also examined using X-ray Diffractometer (XRD) before forming a heterostructured material. The heterostructured CdTe/Si/CdS/FTO and the structure without the inclusion of silicon nanoparticle were examined using electrometer for the extraction of electrical parameters such open circuit voltage (VOC), short circuit current density (JSC), and fill factor (FF). Although a large body of experimental results are available to date on the optoelectronics properties of the materials. However, there is relatively low research studies or works on the electrical properties of the materials. Therefore, we formed heterostructured based photovoltaic device and characterized the structure to determine useful electrical properties. The value obtained for VOC, JSC and FF are 418 mV, 25 mA/cm2 and 0.72 which are indicative of pin holes free semiconductor materials and no leakage path emerging from high-grade materials used in the deposition of heterostructured CdTe/Si/CdS. 

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