BHEL Creates World's First DC Locomotive With Regenerative Braking, Promises Rs 25 Lakh Saving Per U

[HariPrasad]

BHEL Creates World's First DC Locomotive With Regenerative Braking, Promises Rs 25 Lakh Saving Per Unit Per Year
Sarthak Dogra | Updated: Feb 11, 2019, 17:49 PM IST

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State run BHEL has come up with a first of its kind technology under the ‘Make in India’ initiative. The PSU has developed India’s first ever electric locomotive with a regenerative braking system through its in-house R&D centre. The locomotive was recently flagged off from the organisation’s plant in Jhansi.

First proposed by the Railway Ministry, the concept involving the energy-efficient regeneration system was put into shape by BHEL in a 5,000 HP WAG-7 electric locomotive. The technology is meant to be an upgrade to the existing dynamic braking system used presently in the locomotives. While the dynamic braking system leads to energy loss in the form of heat while braking, the regenerative braking system avoids this by feeding the energy back to the overhead power lines.

The concept is not new per se, as regenerative braking system is a technology that has since long been appointed in electric vehicles. Only that it is being used in a conventional DC locomotives for the first time ever. A recent PTI report states that the new locos with the regenerative braking tech will add to the railway network’s fleet of conventional electric locomotives.


A tweet by the Ministry of Railways also stresses that the one-of-its-kind braking system in the conventional DC (direct current) locomotive has been produced for the first time in the world. The tweet further mentions that the technology will lead to a cost saving of Rs 25 lakh per locomotive per year.

Earlier, Indian Railways had announced an impending upgrade to its fleet with an electric locomotive capable of reaching speeds of up to 200 kmph. With a 5400 HP, the electric locomotive boasts of being India’s first aerodynamically-designed locomotive, according to the Chittaranjan Locomotive Works (CLW). Then in December, the Railways announced that it had successfully converted a diesel locomotive into an electric one, another world's first, through the Indian Railways’ production unit Diesel Locomotive Works (DLW) in Varanasi. The feat was achieved in a record time of 69 days.

https://www.google.com/amp/s/amp.in...-25-lakh-saving-per-unit-per-year-361976.html

 

[Solomon2]

There's a difference between having a regenerative-braking DC locomotive work and having its railroad system work along with it. The first I can imagine, the second I'm not so sure about.

 

[HariPrasad]

There's a difference between having a regenerative-braking DC locomotive work and having its railroad system work along with it. The first I can imagine, the second I'm not so sure about.

Can you please explain it?

 

[Solomon2]

Can you please explain it?

You're changing the direction of current flow in a DC inductive circuit - that's a mechanical and thermal strain on the system since not all parts of it can change instantaneously. And in this case a system with loose contacts - the locomotive's connection to overhead wires. I can't imagine how there won't be sparking, burnt contact brushes, even visibly jumping transmission lines...I think you'd have to add buffering batteries/capacitors every couple of hundred meters up and down the line? Probably better to keep all the regenerated energy in the train.

 

[Turingsage]

You're changing the direction of current flow in a DC inductive circuit - that's a mechanical and thermal strain on the system since not all parts of it can change instantaneously. And in this case a system with loose contacts - the locomotive's connection to overhead wires. I can't imagine how there won't be sparking, burnt contact brushes, even visibly jumping transmission lines...I think you'd have to add buffering batteries/capacitors every couple of hundred meters up and down the line? Probably better to keep all the regenerated energy in the train.

Because the switching happens internally within the locomotive. The switching takes place electronically in millionths of a second.
You do not even have to develop this as this is relatively old technology with several international suppliers

 

[HariPrasad]

You're changing the direction of current flow in a DC inductive circuit - that's a mechanical and thermal strain on the system since not all parts of it can change instantaneously. And in this case a system with loose contacts - the locomotive's connection to overhead wires. I can't imagine how there won't be sparking, burnt contact brushes, even visibly jumping transmission lines...I think you'd have to add buffering batteries/capacitors every couple of hundred meters up and down the line? Probably better to keep all the regenerated energy in the train.

Thanks though I could not understand it fully.

 

[Nilgiri]

@anant_s Interesting news

 

[anant_s]

WAG-7 class locomotive retrofitted with regenerative braking, trials successful
RailPost Bureau — February 9, 2019

Indian Railways (IR) has successfully trialled a WAG-7 class locomotive fitted with regenerative braking. The experimental upgrade was carried out on locomotive number 24517 homed at Jhansi shed. Trials were held on 17th January 2019, according to sources.

Regeneration has been identified as an important measure for reduction in electricity consumption costs of IR. This project is expected to save the transporter Rs. 25 lakh per unit per year, according to the Ministry.

The Railway Board had in September 2017 approved development of regenerative braking feature for WAG-7 by RDSO in partnership with BHEL. The original timeline for delivery of the prototype was March—April 2018. However, technical issues delayed the project. BHEL’s system was able to recover regenerated energy at speeds above 30 kph. However, IR wanted regeneration abilities at speeds above 10 kph.

Medha Servo Drives, a private vendor supplying key components to IR, was also asked to design and build a prototype regenerative system on another locomotive. Subsequently, WAG-7 27512 was nominated for Medha’s version of the project.

WAG-7

The WAG-7 locomotive class is designed for heavy freight haulage. Based on a design that traces its origins to the 1960s, the class is rated for approx. 5,000 hp. 1,959 units operate on IR’s network as of February 2019.

Legacy Design

Like other locomotives from the same design family, the WAG-7 uses Direct Current (DC) powered traction motors to turn its wheels. These motors are also capable of generating power when used in the ‘dynamic braking’ mode. This mode utilises the electricity generation ability of traction motors to convert kinetic energy of the train into electric energy. Dynamic Braking helps slow the train down without having to use air brakes.

However, in the legacy power equipment design of the loco, electricity regenerated by traction motors cannot be converted to a form suitable for feeding overhead wires. Therefore, it has to be fed into a grid of resistors that convert the electricity to heat. The heat is then dissipated into the atmosphere.

Regenerative braking.

The idea behind regenerative braking is to recover this large amount of otherwise wasted electricity. The electricity can be converted and fed back into the same overhead wire that the loco normally draws power from. Other units elsewhere on the line, and hauling other trains, can theoretically utilise this flow of power rather than from the main electricity grid. Such reuse can result in substantial savings in electricity bills for the railways.

Locomotive classes with modern designs, such as the WAG-9, WAP-5 and the WAP-7, as well as the currently under-trial WAG-12, all have the feature built in. The modern EMUs in use for local trains in Mumbai also feature regenerative braking.

Image source : Ministry of Railways
https://www.railpost.in/index.php/2...-with-regenerative-braking-trials-successful/
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More about WAG 7 Regenerative aspects can be read here
http://www.rdso.indianrailways.gov.in/works/uploads/File/Spec_133_WAG7_RGB_09012018.pdf

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@HariPrasad
request you to post all Indian railway related posts on a dedicated thread created by @Nilgiri .
Indian Railways updates

There's a difference between having a regenerative-braking DC locomotive work and having its railroad system work along with it. The first I can imagine, the second I'm not so sure about.

The system is already successfully working on Indian railways entire 3 phase locomotive fleet (viz WAP 5 & 7 and WAG 9)

WAP 5

WAP 7

WAG 9Hi

 

[HariPrasad]

Pakistan can consider this engines for their railway. This Engine will become free at the end of its life cycle by saving as much electricity as its buying cost. This will give a highly reliable services for many years.

 

[Nilgiri]

Pakistan can consider this engines for their railway. This Engine will become free at the end of its life cycle by saving as much electricity as its buying cost. This will give a highly reliable services for many years.

Actually this is an interesting question.

@anant_s how much electricity would you say a typical locomotive of IR uses in its full lifetime?

@kmc_chacko

 

[anant_s]

how much electricity would you say a typical locomotive of IR uses in its full lifetime?

I don't have data in terms of kW-h saved but in terms of capital cost recovery (discounting interest & maintenance and running costs), a WAP 7 locomotive is able to pay off itself in about 8 years. Means assuming fixed cost of electricity tariff (~ ₹ 6.40 per kW-h), WAP 7 (with transfer cost of ₹ 13.7 Crores with HOG), the total cost is returned back in around 96-100 months by savings made from return of power generated by loco back to traction system.
this power unfortunately is dissipated as resistive (or Ohmic) heating in conventional DC motor locos as well as Diesel locos.

Pakistan can consider this engines for their railway. This Engine will become free at the end of its life cycle by saving as much electricity as its buying cost. This will give a highly reliable services for many years.

For this to happen on ground, you need electric locomotives. To my knowledge all locos on PR are Diesel Electric locomotives.
@Muhammad Omar @ghazi52 you guys can tell better

 

[Nilgiri]

in terms of capital cost recovery (discounting interest & maintenance and running costs), a WAP 7 locomotive is able to pay off itself in about 8 years.

Wow, thanks bhai, that is definitely a no brainer then....I suppose with interest/inflation factored in it would still come to under 10 years roughly. Yes maintenance and running costs we can just ignore that, since that is an intersection to some large degree with diesel/non-regenerative braking locos (i.e we are looking at what is "new" here).

Any idea how to factor in electrification cost of the line as well to annualise per locomotive and get a year figure recovery on that too? i.e roughly how many (regenerative braking) locomotives would you need to run in say 1000 km stretch of (newly) electrified rail to recuperate the total capital costs (locomotive cost +line electrification + any other costs you want to add like interest etc) in X amount of years. I guess maybe we can look at sample frequency rate (i.e set by the population demand for travel) of some typical (electrified) corridor and work the X amount of years? Or something of that nature however best you think it should be set up Take your time my friend (if you are even interested to give this a go).

Math exercises wheeee! @Vergennes @Joe Shearer @GeraltofRivia @jbgt90 @kmc_chacko

 

[Joe Shearer]

Wow, thanks bhai, that is definitely a no brainer then....I suppose with interest/inflation factored in it would still come to under 10 years roughly. Yes maintenance and running costs we can just ignore that, since that is an intersection to some large degree with diesel/non-regenerative braking locos (i.e we are looking at what is "new" here).

Any idea how to factor in electrification cost of the line as well to annualise per locomotive and get a year figure recovery on that too? i.e roughly how many (regenerative braking) locomotives would you need to run in say 1000 km stretch of (newly) electrified rail to recuperate the total capital costs (locomotive cost +line electrification + any other costs you want to add like interest etc) in X amount of years. I guess maybe we can look at sample frequency rate (i.e set by the population demand for travel) of some typical (electrified) corridor and work the X amount of years? Or something of that nature however best you think it should be set up Take your time my friend (if you are even interested to give this a go).

Math exercises wheeee! @Vergennes @Joe Shearer @GeraltofRivia @jbgt90 @kmc_chacko

Cost accounting, not Math.

Roughly, it works like this: from what you guys have written above, a locomotive is a cost, not a source of revenue; its operations have to be converted into revenue (what you have stated as sample frequency rate of a typical corridor). It is possible to set a minimum load factor per locomotive: it won't be run except to haul a minimum number of freight wagons and a minimum number of passenger wagons. Then assign a mix of these, based on historical data. That gives a rough revenue figure. From that point, to deduct the operating cost of each locomotive and yield a contribution per locomotive is a step away, a not very large step. If we know the capital cost of a section of the line, determining the number of locomotives that defray the capital cost through their individual contributions is one more step.

Only BODMAS needed.

If @anant_s is listening in, he can tell us in two hoots of a loco whistle.

 

[Nilgiri]

Cost accounting, not Math.

Roughly, it works like this: from what you guys have written above, a locomotive is a cost, not a source of revenue; its operations have to be converted into revenue (what you have stated as sample frequency rate of a typical corridor). It is possible to set a minimum load factor per locomotive: it won't be run except to haul a minimum number of freight wagons and a minimum number of passenger wagons. Then assign a mix of these, based on historical data. That gives a rough revenue figure. From that point, to deduct the operating cost of each locomotive and yield a contribution per locomotive is a step away, a not very large step. If we know the capital cost of a section of the line, determining the number of locomotives that defray the capital cost through their individual contributions is one more step.

Only BODMAS needed.

If @anant_s is listening in, he can tell us in two hoots of a loco whistle.

Bong alert!

Coming to think of it... the one accounting course (to make sure we weren't completely air-headed engineering sorts) in last year of university here for me was taught by one of you lot...(Bangladeshi prof...I think the only one I have ever had from there...and of course turns up on cue in the accounting stuff haha).

It sure made for a nice solid change from juggling PDE's and stuff.

When Anant said "8 years...it pays itself off"....it gave me quite the nice warm fuzzy feeling that only that kinda stuff can. I will remember this number for sure.

 

[Joe Shearer]

Bong alert!

Coming to think of it... the one accounting course (to make sure we weren't completely air-headed engineering sorts) in last year of university here for me was taught by one of you lot...(Bangladeshi prof...I think the only one I have ever had from there...and of course turns up on cue in the accounting stuff haha).

It sure made for a nice solid change from juggling PDE's and stuff.

When Anant said "8 years...it pays itself off"....it gave me quite the nice warm fuzzy feeling that only that kinda stuff can. I will remember this number for sure.

Finance major, IIM Cal. Trained taught by S. K. Bhattacharyya, who was a double gold medal in cost and chartered accountancy.​