Purpose of Substations
Substations are essential for the smooth running of any electrical system.  They are the point where high voltage electricity is reduced (or “stepped down” to use the industry expression) into lower voltage electricity suitable for distribution into commercial and residential areas.

Equipment in a Substation
There are three basic types of equipment in a substation which have the same functions as comparable devices in your home: transformers, breakers, switches.  Some substations also have capacitors.

• Transformers step down the high voltage electricity coming in on the transmission lines, to a much lower voltage suitable to send out on distribution wires.
  
  
• Circuit Switches direct the flow of electricity, like the switches that turn the lights on and off in your home.
  
  
• Breakers interrupt the flow of electricity when unexpected surges or faults occur, in order to protect the system from damage -- like the breakers in the main service panel of your home.
  
  
• Capacitors improve the quality of the electricity supply to customers, in two important ways:  they smooth out voltage depressions caused by increased loads, and they “filter out” voltage distortions.

Substation Buildings
Most substations have a building on site. These buildings house some of the equipment described above, as well as other instruments and devices that ensure the efficient functioning of the system. Substation buildings also contain battery banks -- a series of batteries (similar to car batteries) that provide backup power for the instruments and devices.

Sounds
An operating substation produces sounds. The humming sound you hear when you approach a substation is produced by the stepping down of the high voltage electricity from the transmission line to the distribution level voltage.  Noise is also emitted from transformer cooling systems. The operation of other kinds of substation equipment produces noise that is infrequent and lasts only a few seconds (e.g. opening and closing of breakers).
Substation sound levels are monitored to ensure that they meet the requirements of  the City’s Noise By-law. 

New Electrical Facilities
At ENMAX, we continually strive to be environmentally responsible. This includes the building and development of new electrical facilities in the City of Calgary and surrounding areas. We take great care to research and consider the environmental aspects of constructing new facilities, including substations.
If you'd like to know more regarding the environmental aspects of substations, please phone (403) 514-3296 or e-mail us.