Railway applications. Current collection systems. Technical criteria for the interaction between pantograph and overhead line (to achieve free access)

2012 ◽  
Keyword(s):  
Free Access ◽  
Overhead Line ◽  
Current Collection

Computer Evaluation of Controlled Pantographs for Current Collection From Simple Catenary Overhead Equipment at High Speed

1983 ◽  
Vol 105 (4) ◽  
pp. 287-294 ◽  
Author(s):  
T. Vinayagalingam
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Overhead Line ◽  
Combined System ◽  
Current Collection ◽  
Constant Height ◽  
Force Profile ◽  
Force Variation ◽  
Computer Simulation Technique

A digital computer simulation technique is used to study the effects of changing pantograph characteristics upon the quality of current collection from simple catenary overhead equipment at high speed. In particular, the likely benefits to be derived by the use of controlled pantographs are assessed. Pantograph performance is judged on the basis of contact force variation and displacement responses of pantograph and contact wire. These studies have shown that the dynamic displacements of the combined system are determined primarily by the overhead line parameters rather than by the pantograph. At higher speeds droppers in the vicinity of the pantograph slacken and this is seen to influence significantly the contact force profile. On a “constant height” overhead line, the proposed “frame compensated” and “panhead inertia compensated” pantographs do not show any marked improvement in the quality of current collection.

Impact of overhead line irregularity on current collection and diagnostics based on the measurement of pantograph dynamics

2007 ◽  
Vol 221 (4) ◽  
pp. 547-559 ◽  
Author(s):  
A Collina ◽  
F Fossati ◽  
M Papi ◽  
F Resta
Keyword(s):  
Direct Measurement ◽  
Contact Force ◽  
Estimation Procedure ◽  
Overhead Line ◽  
Large Database ◽  
Contact Wire ◽  
Current Collection ◽  
Train Speed ◽  
The One

As train speed increases, contact wire irregularity affects the quality of current collection more and more. The possibility of achieving the maximum operating speed depends also on the maintenance level of the overhead line (OHL). In the present paper, the influence of contact wire irregularity (in terms of vertical deviation of its position) is investigated both experimentally and by means of numerical simulation of the dynamic interaction of pantograph and catenary. In a first step, the capability of the simulation to reproduce the effect of a singularity in the contact wire height along the line has been tested by comparison with available experimental results. The same model has been subsequently used to perform numerical experiments concerning the effects of several types of distributed defects on the catenary. Afterwards, considering the data generated with the simulation as experimental data, a procedure to find the signature in terms of the contact force of the considered distributed defects on the OHL has been proposed. In this procedure, the contact force is not measured, but estimated from the motion of the pantograph, by means of an application of the extended Kalman filter. The adoption of an estimation procedure for the contact force, instead of a direct measurement, would allow the installation of a measurement system that is much simpler than the one required for the direct measurement of contact force. For this feature, it could be installed, at least in principle, on ordinary trains, allowing to perform an extensive monitoring and diagnostic activity with a large database.

High Acceleration on Electric Railways: Results on the Liverpool Overhead Line

1903 ◽  
Vol 56 (1442supp) ◽  
pp. 23103-23103
Author(s):  
Herbert C. Fyfe
Keyword(s):  
Overhead Line ◽  
High Acceleration

Pituitary and ovarian response to transient doe-litter separation in nursing rabbits

Reproduction ◽  
2000 ◽  
pp. 361-366 ◽  
Author(s):  
E Ubilla ◽  
PG Rebollar ◽  
D Pazo ◽  
AI Esquifino ◽  
JM Alvarino
Keyword(s):  
Pituitary Gland ◽  
Litter Size ◽  
Artificial Insemination ◽  
Ovarian Response ◽  
Major Effect ◽  
Free Access ◽  
Plasma Prolactin ◽  
Follicular Waves ◽  
Higher Sensitivity

The effects of a transient doe-litter separation on plasma prolactin, FSH and oestradiol concentrations, as well as the effect on LH response to exogenous GnRH administered at the time of artificial insemination, were determined in nursing rabbits. The effects on fertility, and litter size after parturition, as well as litter survival after doe-litter separation, were also studied. Control does (n = 12) had free access to nursing, whereas biostimulated does (n = 12) were separated from their litters for 48 h before artificial insemination. Plasma prolactin concentrations were decreased 24 h after the doe-litter separation (P < 0.05). The response of prolactin to suckling reached 10 times the basal values measured on day 10 after parturition (P < 0.0001). Increased oestradiol concentrations were found during the 48 h after the doe-litter separation: at 0 h, before artificial insemination (P< 0. 0001), 1.0-2.0 h after artificial insemination (P < 0.001), at 2.5 h (P < 0.05), 3.0 h (P < 0.01), and at 3.5 h (P < 0.05) after artificial insemination. Exogenous GnRH administered at the time of artificial insemination caused a greater LH response in does previously separated from their litters during 48 h (P < 0.01). The transient doe-litter separation did not affect plasma FSH concentrations, fertility, litter size or litter survival. These results suggest that a transient separation of nursing does from their litters before artificial insemination results in a decrease in plasma prolactin concentrations that could promote growth of follicular waves, and high steroidogenesis activity, leading to increased oestradiol concentrations and inducing higher sensitivity of the pituitary gland to exogenous GnRH. These findings associated to the absence of suckling episodes would lead to higher LH response and, therefore, exert a major effect on fertility.

For Realization of Power System with Equality and Free Access

2012 ◽  
Vol 132 (3) ◽  
pp. 136-139
Author(s):  
Shunsuke KAWACHI ◽  
Hiroto HAGIWARA ◽  
Akihiro TEGURI ◽  
Jumpei BABA
Keyword(s):  
Power System ◽  
Free Access

Fostering Barrier Free Access for Children with Special Needs in India

2013 ◽  
Vol 1 (2) ◽  
pp. 199-209
Author(s):  
Sukhwinder Kaur
Keyword(s):  
Special Needs ◽  
Free Access ◽  
Children With Special Needs ◽  
Barrier Free

Calculating the Capacitive Current Flowing Off from an Overhead Power Line Energized with the Voltage Induced by the Influencing Overhead Line Located at Different Distances from the Former

Vestnik MEI ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 37-43
Author(s):  
Ilya V. Korolev ◽  
◽  
Olga S. Shcherbacheva ◽  
Victor T. Medvedev ◽  
Dmitriy A. Burdyukov ◽  
...  
Keyword(s):  
Power Line ◽  
Overhead Line ◽  
Capacitive Current ◽  
Overhead Power Line
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