Introduction to Traction Substations 

By on

Following on from my post on railway electrification voltages, I thought an introduction to traction substations would be a good idea.

Traction substations are used to convert electrical power as supplied by the power utility (or rail operators own network) to a form suitable for providing power to a rail system (via third rail or overhead line). Depending on the type of rail system this power would be either direct current (dc) or alternating current (ac).

For dc systems, the traction substation core equipment will be the transformers and rectifiers to used to convert the utility supply to dc. Rectifiers are either 6, 12 or 24 pulse. In addition the dc traction substation will contain circuit breakers to ensure the system is adequately protected and switching devices allowing operation and maintenance of the system.

For ac systems, the traction substation core equipment will be transformers which connect to the three phase power utility supply to convert this to a single phase voltage suitable for the rail electrification system being used. Again circuit breakers and switching devices will be provided to ensure adequate system protection and operation and allow for maintenance.

Alternating current supply on the traction side is single phase and can lead to imbalance on the three phase utility beyond allowable limits. Balancing devices (Scott transformers, static convertors, etc.) are often used to achieve these limits.

Generally traction substations will be controlled by SCADA systems and will likely provide power for auxiliary systems such as signaling and other track side purposes.

Traction substations have harsher operational and stability constraints than normal power distribution substations. These include being subject to frequent short circuits, transient spikes, voltage depressions and voltage rises. The use of thyristor controlled traction drives generate significant harmonics, affecting the supply system.

Given the unique issues associated with rail power, the design, construction and operation of traction substations has many technical challenges. Add into this, loading from many trains running at the same time and modern design is heavily dependent on software support.

Please feel free to add comments below or suggest any items which you thing would be a good topic for a more detailed post.


Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

myElectrical Engineering

comments powered by Disqus

  1. Sanjay's avatar Sanjay says:
    1/2/2013 6:08 AM

    Would like to kbnow about the traction substation equipment ararngements,layout,spacing and building foot print of the traction substation.What standards are followed for the traction substations?Is there any specific requirements laid by IEC in this regard?


Comments are closed for this post:
  • have a question or need help, please use our Questions Section
  • spotted an error or have additional info that you think should be in this post, feel free to Contact Us



Earth Electrode Resistance

Earthing of electrical systems is essential for the correct functioning and the protecting of life and equipment in the event of faults.  The earth electrode...

IEC 61439 Verification Methods

The (relatively new) switchgear and control gear standard, IEC 61439 'Low-voltage switchgear and controlgear assemblies' has three methods which can be...

Magicians of Engineering

The other day I was reading 'Night of the New Magicians' by Mary Pope Osborn with my son.  The story is about a young boy and girl who travel back in time...

Understanding LV Circuit Breaker Fault Ratings

I think this post is going to be helpful to several of our readers. While the IEC low voltage circuit breaker Standard [IEC 60947-2, Low voltage switchgear...

Hazardous Areas – IEC and NEC/CEC Comparison

Depending where in the world you work, you are likely following one of two standards International Electrotechnical Commission (IEC) National...

Post Authorship

In 2011, with the introduction of it’s Panda search ranking algorithms, Google introduced tools for determining the original author of posts.  The intention...

Inductance

When current flows within a wire, a magnetic field is created. The potion of this magnetic field perpendicular to the wire is called the magnetic flux...

Thomas Edison

American inventor Thomas Alva Edison was born in Milan, Ohio on February 11, 1847. He was the youngest of seven children and received little formal schooling...

Useful Motor Technical Information

Sometimes it’s useful to be able to quickly lookup a piece of technical information.  This note is a collection of information related to motors, and in...

Cable Sizing Software

When sizing cables nearly, everyone uses some form of software. This ranges from homespun spreadsheets to complex network analyses software. Each has its...

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note