Power Substation 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.

Guides

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
9	Design Guide for Rural Substations
10	Power plant acoustics
11	Guide To Forms Of Separation In Low-Voltage SwitchGear and ControlGear
12	Guide To Forms Of Separation In LV SwitchGear and ControlGear –UPDATED!
13	Factory Acceptance Test (FAT) procedure
14	Best Practice Manual For Transformers
15	Schneider Electric – Low Voltage Switchboard Inspection Guide
16	Difference Between Switchgear and Switchboard
17	Protection of Electrical Networks
18	Technical Guideline For Interconnection Of Generators To The Distribution System
19	Power transformer – testing procedures
20	Electric Power Applications, Engine and Generator Sizing
21	Megger – Fault Finding Solutions
22	Electric Distribution Load Characteristics
23	Power Plant Practices to Ensure Cable Operability
23	Substation Design Application Guide
24	XLPE Underground Cable Systems
25	Guidlines for substation service inspection & condition monitoring
26	Using of Latched Contactors to Switch Transformers
27	INSTRUCTIONS – Installation, Operation, and Maintenance of Medium Power Substation Transformers
28	Uninterruptible Power Supply (UPS) Types
29	High Voltage Techniques Course
30	Real-time Monitoring and assessment of CB operations for diagnostics and control applications
31	Capacitor Application Issues
32	Medium Voltage Switching Devices Selection for application and purpose
33	Preventive maintenance and reliability of LV overcurrent protective devices
34	ABB – SF6 or Vacuum MV Circuit Breaker?
35	Why Is Arc Detection Important?
36	DC Transmission and Distribution
36	Underground Power Transmission Lines
37	Test Guide for Cast Resin Dry Type Transformer – TRIHAL
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?
45	Power System Earthing Guide
46	Ground Fault Protection Technical Guide
47	Introduction to IEC 61439 – A new standard on Switchgear and Controlgear Assemblies
48	Commissioning of HT Electrical System
49	Electrical design of the on-site generation system
50	Safety operations on medium voltage switchgear
51	Mitigate The Magnetic Field Exposure Near Transformer Substation
52	General Technical Specification For 220kV SF6 Gas Insulated Metal Enclosed Switchgear (GIS)
53	Measuring Earth Resistance
54	National Electrical Code design considerations as applied to Utility Substations
55	A Practical Guide To Earth Resistance Testing
56	Load Shedding For Utility and Industrial Power System Reliability
57	Energy Transmission and Distribution Guide
58	Improving safety on ageing switchgear
59	Technical Considerations in the Specification and Design of LV Switchboards
60	The 21st Century Substation Design
61	Switchgear and Motor Control Centres in Oil, Gas and Petrochemical Industry
62	Low voltage switchgear and controlgear application guide for electrical engineers