Frequently Asked Questions


Frequently asked questions and things to know about electrical substations.


In the years before electrical distribution was a grid system, there were smaller electrical generation stations. However, when larger power plants came onto the scene, the existing smaller stations were generally converted to distribution stations. In a sense, they became subsidiaries of larger power stations. This is where we get the term substation.

Substations are a key part of an electrical distribution system. Between a generating plant and an electrical user, power may go through several substations at different voltage levels depending on its location in the distribution system. In general, they transform voltage from high levels to low levels so that the electricity can be distributed to the end consumer. Substations are usually owned and operated by an electrical utility, but can also be run by a large industrial or commercial customer. Substations are generally remotely controlled and largely unattended.

For a more technical definition, the ASCE 113 Substation Design Guide defines a substation as “an assemblage of equipment through which electrical energy in bulk is passed for the purpose of switching or modifying its characteristics. Larger substations may contain control houses, transformers, interrupting and switching devices, and surge protection.”


The purpose of an electrical substation is to get electricity from large, high-voltage power lines (transmission lines) safely to the ground so that electricity can then be distributed to homes and businesses that depend on electrical service. Electrical substations generally transform the electricity to lower voltages for transmission and, as such, are a key point in the distribution of electricity to the end user. 

The ASCE 113 Substation Design Guide defines the purpose of an electrical substation as follows: “Substation and switchyard structures are used to support the above-grade components and electrical equipment such as cable bus, rigid bus, and strain bus conductors; switches; surge arresters; insulators; and other equipment. Substation and switchyard structures can be fabricated from latticed angles that form chords and trusses, wide flanges, tubes (round, square, and rectangular), pipes, and polygonal tubes (straight or tapered). Common materials used are concrete, steel, aluminum, and wood.”


There are many different types of electrical substations. They can be divided by their voltage, application, connections, and even construction materials. However, they are generally categorized by the function they perform and/or the problem they solve. These are transmission substations, distribution substations, collector substations, converter substations, switching stations, mobile substations, and railway substations.


An electrical substation has a collection of components within it that each serve a specific function. From the point power lines come into the station to the point lines leave the station, each item plays a key part in the transfer and control of power. There are transformers that measure the voltage as well as current transformers that change the level of voltage. There are disconnect switches and circuit breakers to prevent overloads or surges. There are lightning arresters to protect the substation. In addition, there are security fences to keep people and animals from getting in and causing damage or getting hurt. Plus, there is usually a control building or control area that enables operational adjustments to be made. 

In general, substations have transformers, along with switching and control equipment. Larger substations have circuit breakers to prevent overloads or short circuits that could happen. Smaller stations might have fuses or recloser breakers to protect the distribution circuits. A generator is not a typical feature of a substation as the power is generally created in a plant further up the line. However, an electrical substation may have capacitors and voltage regulators.


Locations are key for substations. They need to be in a place where they can effectively manage the voltage changes and distribution of power as needed. Sometimes these are out-of-the-way places and sometimes they are within urban or suburban areas. It can vary. But an engineering firm will usually work with a construction company to make it happen. In the middle of that relationship is procurement: Getting all of the right pieces to the right place at the right time. That’s where Peak Substation Services comes in. We make it our job to help engineers determine the pieces they need, get them ordered, and make sure they are shipped to arrive at just the right time. Electrical substation packaging is the name of the game. And it’s what we’ve been doing for years. Why not take advantage of our experience?


An electrical switchboard divides power into branch circuits and provides a protective fuse or circuit breaker in the distribution system. Within the context of electrical substations, instead of switchboard, the term that is more widely used is switchyard. 

A switchyard may be used to increase or decrease the voltage of power—and does so through a series of buses, switches, and circuit breakers. Its purpose is to ultimately take power from transmission lines and make it ready to be sent out through distribution lines for end users. 

There are various types of switches within a substation. Some of these are disconnect switches (used to isolate a line, breaker, or transformer), a load interrupter switch, and a circuit breaker.


The difference in utility pole types are based on their need and function. Utility poles or transmission poles are used to support overhead power lines and transformers. The lines are not only placed overhead to keep them out of the way of people and vehicles: They are, more importantly, used to insulate them from the ground. Poles are usually made of wood, concrete, or metal—but can also be made of fiberglass or other composite materials. Larger poles made of metal or concrete are usually used to support high voltage transmission lines, whereas wooden poles are made to aid in the transport of power to consumers via distribution lines. 

Peak Substation Services carries two variations of wooden poles. These are Southern Yellow Pine and Douglas Fir. In addition, we also have dense word cross-arms as well. For more information, please navigate to our “Utility Poles” page. 

Have a question you don’t see listed here? Reach out to us. We’d love to help with your substation project. Use the contact us link or give us a call at (877) 324-0909.

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