Premium Membership ♕

Save 50% on all Video Courses with Enterprise Membership Plan and study specialized LV/MV/HV technical articles and guides.

MV/LV Transformer Substations

An electrical transformer substation consists of a whole set of devices (conductors, measuring and control apparatus and electric machines) dedicated to transforming the voltage supplied by the medium voltage distribution grid (e.g. 15kV or 20kV), into voltage values suitable for supplying low voltage lines with power (400V – 690V).

MV/LV transformer substations – theory and examples of short-circuit calculation – ABB
MV/LV transformer substations – theory and examples of short-circuit calculation – ABB

The electrical substations can be divided into substations and private substations:

Public substations //

These belong to the electricity utility and supply private users in alternating single-phase or three-phase current (typical values of the voltage for the two types of power supply can be 230V and 400V). In turn, these are divided into urban or rural type substations, consisting of a single reduced-size power transformer.

Urban substations are usually built using bricks, whereas rural ones are often installed externally directly on the MV pylon.

Private substations //

These can often be considered as terminal type substations, i.e. substations where the MV line ends at the point of installation of the substation itself.

They belong to the user and can supply both civil users (schools, hospitals, etc.) with power and industrial users with supply from the public MV grid. These substations are mostly located in the same rooms of the factory they supply and basically consist of three distinct rooms:

Delivery room

Figure 1 - Conceptual diagram of the substation
Figure 1 – Conceptual diagram of the substation

Where the switching apparatus of the utility is installed. This room must be of a size to allow any construction of the in-feed/output system which the utility has the right to realise even at a later time to satisfy its new requirements.

The take-up point is found in the delivery room, which represents the border and connection between the public grid and the user plant.

Instrument room

Where the measuring units are located. Both these rooms must have public road access to allow intervention by authorised personnel whether the user is present or not.

User room

Destined to contain the transformer and the MV and LV switching apparatus which are the concern of the user. This room must normally be adjacent to the other two rooms.

Title:MV-LV transformer substations – theory and examples of short-circuit calculation – ABB
Size:0.7 MB
Download:Right here | Video Courses | Membership | Download Updates
MV-LV transformer substations – theory and examples of short-circuit calculation – ABB
MV-LV transformer substations – theory and examples of short-circuit calculation – ABB

Premium Membership

Get access to premium HV/MV/LV technical articles, advanced electrical engineering guides, papers, and much more! It will help you to shape up your technical skills in your everyday life as an electrical engineer.
50% Discount 💥 - Save 50% on all 90+ video courses with Enterprise Membership plan.

More Information


  1. Lumka
    Aug 14, 2018

    what factors differentiate 11kV and 765kV CT’s and VT’s?

  2. Lumka
    Aug 14, 2018

    i want to know the factors that differentiate 400MVA. 132kV/11kV and a 400MVA, 765kV/400kV?

  3. FW Ho
    Sep 27, 2015

    Hi! On your definition of ONAF, it should be oil natural cooling and forced air cooling.

    Thank you.

  4. Ramanath Lakshmanan
    May 24, 2015

    Electrical Engineering is an ever growing field of science, with new and new products are developed and entering the market. Tremendous opportunities exist for a designer to improve upon the systems and methodology of installation and maintenance of installations.
    A real professional will be very much interested to be a part of the forums where ideas and knowledge are exchanged.

    May 24, 2015

    Awesome Website! Thanks for sharing such valuable stuff for free!

  6. Igbal Siddig
    Jul 25, 2014

    asking about civil works steps , construction erection, and method statement for precast substation building

  7. husam
    Jun 16, 2014

    i’am surprised actually with this amount of free valuable information of what ever come in in our minds so thanks a lot


Leave a Comment

Tell us what you're thinking. We care about your opinion! Please keep in mind that comments are moderated and rel="nofollow" is in use. So, please do not use a spammy keyword or a domain as your name, or it will be deleted. Let's have a professional and meaningful conversation instead. Thanks for dropping by!

  ×  3  =  three

Learn How to Design Power Systems

Learn to design LV/MV/HV power systems through professional video courses. Lifetime access. Enjoy learning!

Subscribe to Weekly Newsletter

Subscribe to our Weekly Digest newsletter and receive free updates on new technical articles, video courses and guides (PDF).
EEP Academy Courses - A hand crafted cutting-edge electrical engineering knowledge