Power Substations HV/MV/LV Guides
Power Substations HV/MV/LV Guides

Electricity generation

An electrical substation is a subsidiary station of an electricity generation, transmission and distribution system where voltage is transformed from high to low or the reverse using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.

A substation that has a step-up transformer increases the voltage while decreasing the current, while a step-down transformer decreases the voltage while increasing the current for domestic and commercial distribution. The word substation comes from the days before the distribution system became a grid.

The first substations were connected to only one power station where the generator was housed, and were subsidiaries of that power station.

Equipment in substation

Substations generally have switching, protection and control equipment and one or more transformers. In a large substation, circuit breakers are used to interrupt any short-circuits or overload currents that may occur on the network. Smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. Substations do not usually have generators, although a power plant may have a substation nearby.

Other devices such as power factor correction capacitors and voltage regulators may also be located at a substation.

Substations may be on the surface in fenced enclosures, underground, or located in special-purpose buildings.

High-rise buildings may have several indoor substations. Indoor substations are usually found in urban areas to reduce the noise from the transformers, for reasons of appearance, or to protect switchgear from extreme climate or pollution conditions.

Where a substation has a metallic fence, it must be properly grounded (UK: earthed) to protect people from high voltages that may occur during a fault in the network. Earth faults at a substation can cause a ground potential rise. Currents flowing in the Earth’s surface during a fault can cause metal objects to have a significantly different voltage than the ground under a person’s feet; this touch potential presents a hazard of electrocution.

All documents, EE software and EE books are free to download.

No. Description Download
1 Answering Substation Automation Questions Through Fault Tree Analysis
2 Applying an Ethernet LAN in a Substation
3 Power Plant Accoustic
4 Power Transformer Maintenance And Acceptance Testing
5 Selecting Energy Efficient Distribution Transformers
6 MV-LV transformer substations – theory and examples of short-circuit calculation
7 Electric Power Substations Engineering
8 Implementation of IEC61850 in a Substation Environment New
9 Design Guide for Rural Substations New
10 Guide To Forms Of Separation In LV SwitchGear and ControlGear – UPDATED! New
11 Factory Acceptance Test (FAT) procedure
12 Best Practice Manual For Transformers
13 Schneider Electric – Low Voltage Switchboard Inspection Guide star
14 Difference Between Switchgear and Switchboard star
15 Protection of Electrical Networks star
16 Technical Guideline For Interconnection Of Generators To The Distribution System
17 Power transformer – testing procedures
18 Electric Power Applications, Engine and Generator Sizing
19 Megger – Fault Finding Solutions star
20 Electric Distribution Load Characteristics
21 Power Plant Practices to Ensure Cable Operability star
22 Substation Design Application Guide star
23 XLPE Underground Cable Systems star
24 Guidlines for substation service inspection & condition monitoring star
25 Using of Latched Contactors to Switch Transformers
26 INSTRUCTIONS – Installation, Operation, and Maintenance of Medium Power Substation Transformers
27 Uninterruptible Power Supply (UPS) Types
28 High Voltage Techniques Course star
29 Real-time Monitoring and assessment of CB operations for diagnostics and control applications
30 Capacitor Application Issues New star
31 Medium Voltage Switching Devices Selection for application and purpose
32 Preventive maintenance and reliability of LV overcurrent protective devices New
33 ABB – SF6 or Vacuum MV Circuit Breaker? star
34 Why Is Arc Detection Important? star
35 DC Transmission and Distribution star
36 Underground Power Transmission Lines New star
37 Test Guide for Cast Resin Dry Type Transformer – TRIHAL star
38 Low Voltage Switchgear and Controlgear – Technical Document (Allen-Bradley)
39 Transformer Differential Protection Scheme With Internal Faults Detection Algorithm
40 Grounding Systems
41 Insulator Pollution In Transmission Lines
42 Transformers Basics, Maintenance and Diagnostics
43 Guidelines For Earthing In Maritime Installations – Norwegian Electrical Safety Directorate
44 Fixed or withdrawable MV switchgear? star
45 Power System Earthing Guide star
46 Ground Fault Protection Technical Guide star
47 Introduction to IEC 61439 – A new standard on Switchgear and Controlgear Assemblies
48 Commissioning of HT Electrical System star
49 Electrical design of the on-site generation system star
50 Safety operations on medium voltage switchgear star
51 Mitigate The Magnetic Field Exposure Near Transformer Substation
52 General Technical Specification For 220kV SF6 Gas Insulated Metal Enclosed Switchgear (GIS) New
53 Measuring Earth Resistance star
54 National Electrical Code design considerations as applied to Utility Substations
55 A Practical Guide To Earth Resistance Testing New star
56 Load Shedding For Utility and Industrial Power System Reliability
57 Energy Transmission and Distribution Guide
58 Improving safety on ageing switchgear New
59 Technical Considerations in the Specification and Design of LV Switchboards New star
60 The 21st Century Substation Design New star
61 Switchgear and Motor Control Centres in Oil, Gas and Petrochemical Industry
62 Low voltage switchgear and controlgear application guide for electrical engineers
63 Static Analysis of Power Systems New
64 Practical guide to electrical measurements in LV switchboards – ABB
65 Power System and Substation Automation Guide
66 Reliability of Substation Configurations star
67 Substation Design Guideliness star
68 Power Transformer Maintenance and Field Testing star
69 Selection of CTs and wire sizing in power substations star
70 Copper for Busbars – Guidance for Design and Installation star
71 Thermal design of MV/LV substations star
72 Guidelines for Conducting an Energy Audit in Industrial Facilities star
73 Transformer Protection Application Guide star
74 Instrument Transformers Application Guide
75 How to assemble LV electrical switchboard – Technical guidestar
76 A Guide To Power Factor Correction For The Plant Engineers star
77 Complete Guide To Wind Power Plants New star
78 Design of Electrical Power Supply System in an Oil and Gas Refinery
79 Guidelines to Power Transformer Type, Routine and Special Tests
80 Guidelines to the construction of a low-voltage assembly
81 Guide to High Voltage Direct Current (HVDC) Transmission New
82 Design Manual For High Voltage Transmission Lines New
83 Power Plant Horror Stories – The Loss Of a Generator
84 Electrical Design Of 132/33KV Substation star
85 Operation and Maintenance of a 220/132KV Substation star
86 Design and construction of long-distance HV transmission systems New star
87 Development of 22kV Distribution Systems and Switchgear star
88 Electrical Safety Hazards Handbook star
89 Complete Guide To Diagnostic Insulation Testing Above 1 kV star
90 Transfer Switch Application and Selection Manual star
91 Guide to Low Voltage Circuit Breakers Standards star
92 Battery Maintenance and Testing Guide New star
93 Design Guide For Overhead Distribution Systems New star
94 Guide to MV/LV transformer substations (2000 kVA or two 1000 kVA) New star

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Page edited by E.C. (Google).


  1. Qaisar Jamil Akhtar
    Apr 20, 2016

    Hi, i study your E E portal, That is good attempt to convey your syetem specs to Readers, pls i need substations details on my Email site.

    Thanks & Regards

  2. hossein
    Apr 05, 2016

    Hello my Friend.Could we omit the GCB(Generator Circuit Breaker) of a 160MW Combined Cycle unit (with a 160MW/15.75kV Genarator and a 200MVA/230/15.75kV Unit Transformer)?

  3. Saadat
    Mar 26, 2016

    How can i find the book “Substation Commissioning Training Course” written by Mr. Raymond Lee ??
    It is very Urgent.
    Thank you.
    My email:

  4. zaya
    Dec 11, 2015

    Thank you,7

  5. sathish
    Aug 30, 2015

    I’m a substation supervisor in Bangalore.

  6. Nicks Mutuku
    Jul 13, 2015

    This quite helpful. Keep it up.

  7. Using Voltage Stabilizer and UPS systems can prevent you from any kind of power mishaps.

  8. George
    Oct 23, 2014

    how to make electric motor solo run procedure

  9. Elvis Mulowa
    Jul 24, 2014

    thanks for the good works we are really updated

  10. letlhogonolo mogorosi
    Mar 27, 2014

    I am working as a technician in eskom, i like knowing about different protection we found in our substation,different relays how they operate when flacked what fault to be expected.more especially in distribution substations.i hope ill learn a lot from you thanks.if posible can you send me theorytical guardes.

  11. AIDIL ARIFIN, E Eng.
    Mar 21, 2014

    Thanks & Regards,

  12. B.Venkat Reddy
    Feb 16, 2014

    Excellent Technical Knowledge Site, I Like Very much and Many Thanks for providing such useful technical paper, keep the good works.

  13. cristian
    Jan 19, 2014

    Thanks for your documentations ,my job is electrical technician ,vendor position for italian provider LV & MV electrical equipment.


  14. Aljan24uson
    Oct 25, 2013

    Thanks for this kind of portal site. It is very informative and helps a lot to our fellow electrical practitioners….keep it up guys!!!

  15. DONDON
    Mar 03, 2013

    Can anyone show me the Fault Current Calculation of Transmission Lines?

  16. namnguyen
    Mar 02, 2013

    Thanks for useful technical paper, keep the good works.

  17. alhana89
    Jan 27, 2013

    Thanks for making these references available for us. Keep up the good work, guys!

  18. lollo
    Jan 08, 2013

    Hi the people iv just finished my studies and am currently working,and I have been learning on how to use the new software “Janitza GridVis software” and this software monitors power from High to Low voltage systems and currently i have been tasked yo write a programm that will be used for valves have any of you people got maybe some idea on this new jasic programming??

    • Edvard
      Jan 08, 2013

      To be honest I never heard of it. Can you share with me some information about it, some links.

  19. Rateb Fares
    Oct 25, 2012

    thank you very much

  20. Jones
    Jun 16, 2012

    kindly provide substation earth mat calculation …

  21. engrwaqas_11
    Nov 20, 2011

    thank you very much for such nice work..if possible please upload field testing date e.g. transformers testing, under ground cable testing, relays testing..etc


    Waqas Ahmed

  22. subhransu
    Nov 13, 2011

    want to be a part of this knowledge pool. Help me out.

    Aug 01, 2011


  24. diamond
    Jul 27, 2011

    thanks a lot

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