Your channel is gem for an electrical engineer as well a rail enthusiast!! Your way of explanation is great, no nervouness, no audio/video issues nothing. Please continue with more such content.
This is really good explanation!!. It makes us happy to understand a topic both theoretically and how exactly it is implemented which is lacking now-a-days. Great work, keep it up!!
Very nice. Now I am seeing the pamban bridge in rameswaram.The centre lift portion also the 25KV traction line is provided. I understand it gets power by induction. Can you explain. Regards. N. Sambasivam
Hi, Could you tell me what confidence is there that no phase-balancing equipment will be required for the HV incoming bulk supplies? How to deal with that ?
Just waaaw ! Sir, if you feel free then please help me with the answer of my confusion. 1. What is the technical reasons behind the use of catenary wire, as the pantograph touches with only contact wire. That reason is so important that Railway expends money on using 2 wires contact wire & catenary wire both. 2. What is the reason behind the use of false catenary wire under ROB, FOB Please sir clear my doubts
wonderful sessions... keep going. I beleive instead of catenary, better to mention as contact wire. My understanding is that Catenary is supporting the contact wire and contact wire carries the current.
Many thanks. Although contact or catenary are replaceable, it is better to mention contact to avoid confusion. However, catenary shares around 30-45% of total traction current along with providing support.
Typically BT RC system is used for analog cables (telephone) along the alignment which are outside the ROW or near viaduct or near at grade section but not within railway premises... For underground this issue does not arise as mainly these services are above ground level...Thus, we install only RC system (No BT) for ROCS... BT & RC is for FOCS... Nowadays, most of the communication is mainly through OFC which are EMI immune so typically BT is not must needed and can be proven with calculation or simulations...
Got a good feel of system sir! How far are two booster Transformers from each other in 25kV system? And can we say that DC system is better when it comes to interference, no time varying current so no induction of emf in any other system?
In India normally a distance of 2.66km (Approx.) is followed... In UK upto 3.2 km (approx) .. in sweden upto 5 km (approx)... Rating of booster will vary in these cases....
And yes DC traction has this advantage that interference is less compared to AC traction... But one much analyze the spacing between cable tray supports, etc. keeping in mind that during fault, tripping of CB can cause sudden change in flux wrt time...
@@railwayengineeringinsights6463 Yes sir. Any impact of sparking between pantograph and contact wire in 25kV system on other systems since sparking produces higher harmonics and can lead to radio interference?
Yes definitely... Due to sparking it is observed that the freq range of EM fields is in kHz to MHz... That's why we need equipment installed in nearby OCS zone to be compliant to EN 50121 railway series... However, I will give more details in later part of my lecture series when I discuss about EMC.
Many thanks. I generally refer to standards (IECs, ENs) and technical papers (IEEE, MDPI). For books I refer not particularly to traction but books on power electronics (Yazdani, BK Bose) and power system (Stevenson, etc.)
In DC traction as the supply frequency is nearly zero, the possibility of induced voltage on nearby cable is negligible (dΦ/dt nearly zero). Due to some harmonics there is some induction, however, that is not of much concern. Thus, no special mitigation needed except for compliance of wayside equipment with relevant standard (EN 50121-4/5/3-2) or industrial based on EM zone.
Can you please include a picture of BT and RCs? I have tried to see RC in the Indian Railways, but never been sure that if its RC or part of the 2x25 KVAC system.
I will add a link. You can refer to my lecture 6 of traction series about 2x25kV. You can recognize the difference between RC and -25 kv feeder by visually checking the insulator being used. It is size of latter will be much greater.
In Indian Railway or Metros, generally the BT spacing is 2.66 km (approx.) or less and the rating of BT generally used are 150 kVA & 280 kVA. However, the nominal power ranges from 100 to 1000 kVA and the winding current is usually limited to something less than 1 kA. In Europe, the two most prominent examples of BT usage are UK for 50 Hz systems (with a BT spacing of 3.2 km for both RR and RC systems) and Sweden for 16.7 Hz systems (with a BT spacing of 5 and 2.8 km for RC and RR configurations respectively). The sizing of BT is similar to sizing of Current Transformer (CT). The secondary voltage of transformer (i.e. the winding connected to RC) is governed by I*Z. Z is the return circuit impedance between two BTs & I is taken from the traction simulation or considering worst case by taking the current flowing on the LV side of traction transformer (27.5 kV side) divided by 4. This is assumed in case TSS is feeding power to both UP & DN line and on both sides.
One Question if person standing on the top of the coach and touches live line .he will get shock... but what about passengers siting inside the coach at that time..will they to get shock?
This scenario is same as live contact wire touching the train body in case of fault. In this condition the circuit breaker feeding 25kV will trip. Due to regular bonding the tracks the train potential even in case of such fault will be within limits as specified by EN 50122-1 for certain interval of time and passengers will not get shock.
Dear Sir, I have very basic question. When birds sit on electrical wires outside , why they dont get electrical shock? I may be asking very silly question but this is my doubt, no body could answer this question properly. Thanks in advance. By the way your lectures are very good, please make an video on Earthing system.
Sir it is because the potential difference leads to flow of current... in case of bird both the legs are nearby touching the conductor ... being such a small distance impedance is very low ... thus voltage difference is very low... making it equipotential surface...that's why bird does not get shock...
Respected Sir please explain each and every aspect of railway ohe design since I want to learn being a layman from distribution Sector having no knowledge of railway ohe
