DIS-TRAN Steel Blog

SUBSTATIONS: 3 Common Steel Structures Found Inside

Posted by Wendy Gintz on Feb 26, 2015 7:54:00 AM

Before electricity can travel into your home, it must pass through a substation first. A substation is an assemblage of equipment where electrical energy is passed in order to be stepped up or stepped down.

Transformers inside a substation change the voltage levels between high transmission voltages and lower distribution voltages. The high transmission voltages are used to carry electricity longer distances, like across the country, whereas lower distribution voltages travel to industrial, commercial or residential consumers.

In a T&D system, the major components typically consist of transmission lines, distribution lines, substations and switchyards.

For this particular Blog, lets just identify the Main Substation Structures.

1.)    Dead-End Structures

2.)    Static Poles

3.)    Bus Supports/ Equipment Stands

Dead-end Structures are where the line ends or angles off. They are typically constructed with heavier steel in case they are needed to carry heavier tension. The two most common dead-end structures are H-Frame and A-Frame structures.

HFrame Substation Structure   t&d_1-resized-600

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Static Pole, is a single, free-standing pole that creates a shield to protect all of the equipment inside a substation from lightning. Static poles may or may not have overhead shield wires attached to enhance protection. It depends on the size of the substation as to how many static poles are needed.    

NOTE: Tapered tubular design is typically efficient and economical in dead-end andstatic pole situations when compared to AISC standard shape structures.

 

 

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Bus Supports are the most basic structure found inside a substation. Its main purpose is to provide support for rigid bus as it travels though the substation. Rigid bus is stiff and will not move around during     weather events. Unlike rigid, flexible bus is typically used in high   seismic areas in order to be able to move and dampen the seismic forces that occur. 

 

Examples of some equipment stands include:t can be of significant weight and must meet specific guidelines for structural loads, deflection limits or clearance requirements. Equipment Stands are the structures that the actual equipment sit on.

  • Potential Transformers (PT) Stands
  • Current Transformers (CT) Stands
  • Coupling Capacitor Voltage Transformer (CCVT ) Stands
  • Lightning Arresters (LA)
  • Switch Stands

 

When it comes to which type of steel is used, galvanized or weathering, inside a substation, I won’t say that you will never see weathering steel, but it is very rare. Weathering steel is used more in transmission structures than substation. One of the main reasons is because aesthetically, galvanized steel “looks” better inside a substation. Typically a substation is surrounded by a fence, has a metal building inside as well as white rock on the ground surrounding it. So the look of weathering steel, which is usually a dark brown color, aesthetically, goes better with a transmission line running through the woods to blend in versus in a substation.

Let us know if this information was helpful.  Comment below with and questions you may have, we would love to hear from you.

 

 Ultimate Utility Guide

 

Tags: steel structures, DIS-TRAN Steel, standard shape steel structures, switch stands, substation, dead-end structures, H-Frame structures, dead-end h-frame structures

5 Clues About Low Voltage Substation Structures

Posted by Brooke Barone on Jan 17, 2014 2:03:00 PM

I’m not too sure how many Nickelodeon-or should I say past Nickelodeon viewers, are reading this article, but there was a popular show in the late 90s-early 2000s, named Blue’s Clues that featured a dog, Blue, and her owner, Steve. The entire show revolved around Blue leaving Steve a series of clues behind with her paw print, and at the end of every show Steve would sit down in his “Thinking Chair” and put the three clues together to come up with the answer. 

Okay so while Blue’s Clues might not indirectly have anything to do with understanding electricity, it does serve as an example that putting clues together can help you better understand what you're looking for.  

Power has to get from point A to B and can be accomplished by either high kV or low kV. Essentially, they do the same thing, just at different voltages. However, when you're driving down the road and pass a substation, there are distinguishing clues that can help you determine if it's a low or high kV substation. 

Clues to spot a Low kV Substation

Terms you'll see used:

  • Switch Stand- function by disconnecting or isolating the current/voltage throughout a circuit.
  • Metering Support- measures voltage or current that passes through the circuit.
  • Box Bay Structure- distribute current to different circuits leaving the substation. 
high low kV
paw printClue #1: The number one clue is the phase spacing. When you start to see combination structures inside a substation, typically, that signals low voltage because phase to ground or phase to phase numbers get much lower and equipment can be placed closer together. One thing to remember is that electricity arcs in the air, so with high voltage, there’s a high potential to arc, therefore equipment has to be spread out further as well as insulated from anything attached to the ground.

describe the imageClue #2: Low voltage substations basically use the same equipment and structures that are found inside high voltage substations, like switches, metering, or some type of recloser or automated clearing mechanism; however, they are just much more condensed. Instead of dedicating an entire structure to only switches in high voltage, on a low voltage structure, there can be different types of switches or a mixture of switches and metering. Basically you’re taking what took you five or six structures used in high voltage, and condensing it to one or two structures with low voltage.

describe the imageClue #3: Typically, you’ll see Box Bay Structures in low kV substations because they allow you to put multiple types of equipment on it, such as switches or metering, and gives more flexibility in how you run your bus work with fewer foundations, as opposed to having to build 10 to 12 for high voltage.


describe the imageClue #4: Normally Riser Structures are not as common at high kV, but you’ll almost always see riser structures with low kV. Riser structures take electricity from above the ground and place it underground. The reason it’s not commonly used in high voltage is because the amount of insulation that it takes to keep high kV voltage underground is more cost-prohibited.

describe the imageClue #5: Generally, you’ll see Station Service Transformers in low kV substations, which are usually attached to other structures like a bus support.  It’s the same transformer that is put on a lower distribution pole in areas like a neighborhood, and provides usable electricity inside the substation. This is for when they do certain things like maintenance work inside the substation where they might need to use a drill or power saw.

Hopefully these 5 clues will help you next time to determine whether you're looking at a low voltage substation or high voltage substation. 

  

Outdoor Substation Design Guide

Tags: low voltage substation structures, box bay structures, riser structures, switch stands, metering supports, distribution structures, low kV substations, termination structures, station service transformers, distribution pole

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