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



Robotics - Home Innovations

We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations...

RLC Circuit, Resistor Power Loss - some Modelica experiments

Modelica is an open source (free) software language for modelling complex systems. Having never used it before, I thought I would download a development...

Large Hadron Collider

The 27 km, Euro 6 billion  Collider lies on the border between France and Switzerland, took nearly 30 years to complete.  Some of the lofty goals for the...

GE's Shingijutsu Factory

GE's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean production system. They have started applying this at the Louisville...

Differential protection, the good old days

This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection...

Write your best report

Years ago I was told that you should always try to write the best report you can.  Many years later I still think on this as one of the better pieces of...

Battery Sizing

This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.

IEEE Winds of Change

IEEE TV has a part series of videos on wind power and it's implication. For a really good overview to the technologies and issues around wind power, these...

Power Transformers - An Introduction

One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages.  It is more...

Resistors

Resistors are electronic components that oppose the flow of current.  Manufactured in various types and ranges they have a wide application to electronics...

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