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Magnetic Components Used in the Train Pantograph to Reduce the

Arcing Phenomena

Presented by- Saurabh Mishra PESC-140943019

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contents

Introduction Objective Review of Literatures Research Methodology Detailed description Experimental Model Experimental Results Conclusion References

Introduction

A pantograph always remains in contact with the overhead train line is used to send electricity to the main transformer of the electric train, thus providing power.

Due to many external Disturbances the train line may lose contact with pantograph, causes arcing phenomena to occur.

The arcing produced creates harmonics in the electric over head line and degrades the Power Quality

Physical properties of magnetic components is used improve the contact between the pantograph and the overhead train line

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Objectives

To reduce the arcing caused by contact loss of overhead train line and the pantograph using magnetic components.

To improve the Power Quality in the Over head train line by reducing the current fluctuations.

To optimize the magnetic force based arc prevention methods using Artificial Neural Network.

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Review of Literatures

It is dangerous to the equipment in locomotives for the over-voltage and harmonic caused by the arcing. Over-voltage amplitude and duration caused by the arcing have been studied (T. Li et al, 2011)

Study of electrical characteristics on pantograph arcing. Arcing Voltages ,currents and their harmonics are analysed. (W. Wang et al, 2011),

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Research Methodology

Basic Physical Property of magnetic material is used that is “opposite attracts and like repels” by using a Neodymium Magnet.

Simulating a experimental Model and analysing the Results.

ANN Used for Optimisation of magnetic forces required at different time or motor speed.

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Pantograph

Pantograph is always placed at the top of the train Engine.

Pantograph send electricity to the main transformer of the electric train by making contact with the overhead train line.

A graphite plate is their in pantograph that slides on over head line.

Various Disturbances can cause pantograph rapidly contact and separate with train line results as arcing produced.

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Lower Arm

Upper Arm

Coupling Rod

Damper System

Collector Head

Slide Plate

Base Frame Fig1: General Description of Pantograph

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Power system Structure of the Electrified Railway

Fig.2. Single-phase booster transformer (BT) power supply circuit diagram for the Taiwan rail system.

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Artificial Neural Network

Artificial neural networks are composed of Neurons or processing units.

Artificial Neuron is the basic unit of a Neural network.

Three layered Network input layer, hidden layer and output layer.

Input and output have only layer while the hidden layer may have no layer or multiple layers

A three layered network with feed forward back-propagation algorithm is shown in the figure 5.

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Fig.3. Feed forward back-propagation network.

Fig 4: Model of the artificial neuron.

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The formula that relates the input and output in neural networks can generally be expressed using function based on the weighted sum of the input values.

yj=f(ΣWijXi+bj)f : Transfer function, which simulates the non Linear processing function.bj: The partial weighted value of jth neuron simulates the weighted value

of neuron Wij: The weight value of the connection between the ith and jth neuron.

Xj: The input variable for the jth neuron. Yj: The output value of jth neuron, which simulates output signal of

neuron.

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Experimental Model

An Experimental model is used which resembles the same conductive and motion behaviour as between the train line and the Pantograph.

Ferric disk connected with motor is used, Piece of train line is welded around the ferric disk and touched by electrified graphite rod.

Relative motion between the Ferric Disk and electrified Graphite Rod

gives the same behaviour as between the train line and Pantograph.

Neodymium Magnet is Placed above graphite rod to attract the line that is Welded to the Ferric Disk.

14Fig. 5. Conductive and Motion behaviour between the train line and the pantograph

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Material Hard-drawn copper

Manufacturing standards UIC870

Outer diameter 12.24mm±0.16mm

Cross-sectional area 107mm² ± 3%

Conductivity ≥97% IACS

Resistivity 0.0175Ω-mm²/m(20 ͦ C)

Thermal expansionCoefficient

17μ/ ͦ C (20 ͦ C)

Elongation 3-7%(200mm)

Destruction Rally ≥3906kgf

Weight 0.95kg/m

TABLE ITRAIN LINE MATERIAL SPECIFICATIONS

16Fig. 6.Forces of contact surface between the train line and the pantograph with eight magnetic blocks.

17Fig. 7. Experiment process for setting the motion between the train line and pantograph.

Set the motor speed

The oscilloscope records current waveform

Add neodymium magnet

Eight magnetic

blocks are joined

Motor speed 1780 rpm

Beginning of the Experiment

The End of the Experiment

NO

YES

NO

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Experimental ResultsTABLE II: EXPERIMENTAL MEASUREMENTS

OF RMS CURRENT (IN MILLIAMPERES)

19Fig. 8. Comparison chart of speed and load current with/without magnets.

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TABLE IIINUMBER OF CURRENT FLUCTUATIONS AT DIFFERENT SPEEDS

21Fig. 9. Schematic for iteratively predicting train offline times using neural network algorithms.

Conclusions The contact loss frequency between pantograph and the train

overhead line is reduced.

The measured currents with magnets added is significantly greater than the absence of magnets.

Current fluctuation frequencies are reduced ,decreased collector head current loss thus increases the stability of the power supply system.

The number of pantograph contact losses can be reduced by exploiting the physical properties of magnetic elements.

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References

W. Wang et al., “Experimental study of electrical characteristics on pantograph arcing,” in Proc. 1st ICEPE-ST, 2011, pp. 602–607.

T. Li et al., “Pantograph arcing’s impact on locomotive equipment's,” in Proc. IEEE 57th Holm Conf. Elect. Contacts, 2011, pp. 1–5.

T. Ding, G. X. Chen, and J. Bu, “Effect of temperature and arc discharge on friction and wear behaviors of carbon strip/copper contact wire in pantograph–catenary systems,” Wear, vol. 271, no. 9/10, pp. 1629–1636, Jul. 2011.

G. Bucca, A. Collina, and R. Manigrasso, “Analysis of electrical interferences related to the current collection quality in pantograph–catenary interaction,” Proc. Inst. Mech. Eng., J. Rail Rapid Transit, vol. 225, no. F5, pp. 483–499, 2011. 23

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