DIS-TRAN Steel Blog

THE ULTRAVEX ADVANTAGE

Posted by Melissa Hines on Aug 5, 2016 2:48:54 PM

There’s perhaps no better example of “You don’t know what you’ve got ‘til it’s gone” than a power outage. And as a manufacturer supplying products to electric utilities and other large users of electrical power, we know very well how that old saying hits home. When the lights go out and work grinds to a halt, you absolutely know what you’re missing. Times have changed and today’s innovative composite crossarm from DIS-TRAN Overhead Solutions features materials and design far superior to those of the past and are designed to stand up to the worst Mother Nature has to offer.

In early 2016,  DIS-TRAN introduced our patent 9546498 Ultravex™ composite crossarm that is unlike any other crossarm on the market today. The Ultravex ™ crossarm is our most durable arm to date, and features benefits you didn’t know you were missing.

  • For flexibility that exceeds your expectations, our Ultravex™ crossarms come in a single size and use a single bracket for both tangent and deadend installations. This reduces your need for inventory of hardware and arms, yet allows you to build on current installations of standard 3-1/2” x 3-1/2” size. The strength of the Ultravex ™ crossarm can be increased without ever changing the outside diameter size.
  • The Ultravex ™ has some of the highest working loads in the industry. We recommend our working load to be 75% of the ultimate load per NESC Grade C Allowable.
  • Special washers or inserts are not needed when using our Ultravex ™ crossarm. With the highest-in-the-industry wall crush strength, our crossarm can be field drilled without concern for loss of strength.
  • Ultravex™ crossarms offer performance benefits through innovative engineering. Their domed shape reduces contaminant buildup allowing water and debris to shed easily. Their circular inner core provides enhanced strength.Composite.jpg

Our Ultravex ™ composite crossarm is a game changer. We’ve worked with experienced designers that have been engaged in the composite industry for over 40 years. We also conducted extensive testing, and with more than 50 years of experience supporting the overhead power line industries, we know how to respond to those findings. We don’t make these claims lightly; we’ll happily provide you with testing data or load analysis tables to back up our findings for this industry leading product.

We understand that the demands of your business may have kept you from experiencing our leading-edge composite crossarms, but you don’t know what you’re missing. We also think it is best not to wait until disaster strikes to evaluate your equipment and start making improvements. To learn more about the potential cost-savings, inventory reduction, and improved product performance you can expect with Ultravex™ crossarms, visit www.distranoverheadsolutions.com. Feel free to leave a comment below. We would love to hear your thoughts, expectations, and business needs.

 CLICK HERE TO REQUEST  UltravexTM Testing Data

 

Tags: crossarms, fiberglass, tangent, composite, composite crossarm, ultimate loads, deadend, working loads

3 Transmission Structures Broken Down

Posted by Wendy Gintz on Jul 7, 2015 10:45:00 AM

When designing transmission structures...

it’s not as simple as saying “ok, I want self-supporting tangent mono poles with delta configuration for my entire 80 mile stretch.”  While that idea might be more economical than having h-frame or 3-pole structures, it’s just not practical.

Ultimately, the wire configurations determine which type of structure will be used, and typically there will be a mix of these structures in order to follow the right-of-way through small or tight turns. Right-of-ways go alongside or through interstates, highways, fields, woods and even water, so an engineer must keep all these situations in mind when designing.

Three common transmission structures:

  •  Tangent
    • Used when transmission route is straight
    • Generally, no longitudinal loads on the structure
  • Angle
    • Used when transmission route changes direction
    • Used from anywhere less than a 5 degree angle to a 90 degree angle
  • Dead-End
    • As name applies, dead-ends are designed to take the full component of every wire's tension
    • Does not necessarily mean end of transmission line 

                              

tangent_info_graoh_ANGLE_INFORGROAH

 

 

 

 

 

dead-end_infogrpah_pic

 

Whether the structures are tangent, angle or dead-end, wire phases can run in multiple configurations.  Horizontal Configurations provide the lowest profile. Vertical Configurations require the minimum width right-of-way. And Delta Configurations is an attempt to use the value of both horizontal and vertical configurations to maintain phase clearances.

Transmission structures can be classified as either self-supporting or guyed.

Self-Supporting Structures do not use guys: meaning they are not tied to the ground or any other structure in a way that offers additional support. They are better for restrictions to right-of-ways and tend to have loads small enough to not warrant guys.

Guying of structures is used to support the structure and allow for a more economical design in both the steel structure and foundation. Guying reduces bending and deflection. However, the downside is that it requires more right-of-way. 

*Here are some main contributing factors to keep in mind when deciding on whether or not to guy a structure:

  • Structural loading
  • Right-of-way requirements
  • Aesthetic design criteria

**Here are some other contributing factors you may want to consider:

  • Line voltage
  • Electric air gap clearance requirements
  • Ground clearance requirequirements
  • Insulation requirements
  • Number of circuits to be supported
  • Electric and magnetic field limits

There is so much to learn about Transmission Structures.  What questions do you have?  We would love to hear from you so please leave a comment below.

Check out our newest resource for Anchored Transmission Structures.  Click below.
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Tags: transmission structures, guyed structures, tangent, dead-end h-frame structures, configurations

How Do Electrical Transmission and Distribution Systems Work? Find Out.

Posted by Brooke Barone on Aug 9, 2013 9:52:00 AM

A Transmission and Distribution (T&D) System, has a notorious job of delivering electricity to consumers 24/7, 365 days a year.

But before the 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.

Inside a substation is like its own unique “power world” where every pole, bolt, stand, surge arrestor or structure plays its own individual role.

The three main types of structures found inside a substation include:

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.

H-Frame Structure

A-Frame Structure

The second structure, a 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 and static pole situations when compared to AISC standard shape structures.

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. 

Electrical equipment 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.

Examples of some equipment stands include:

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

 So, although the concept seems quick and simple like flipping a light switch, much more is going on behind the scenes.  

Transmission lines act as the utility interstate system where electricity is transmitted at high voltages in order to reduce the energy lost in long-distance transmission.

Although it’s hard to quantify structure types since there are always exceptions to the rules and never-ending configurations, transmission structures can be considered dead-end, strain or suspension.

dead-end structure is where conductors and ground wires are pulled only on one side, unless it is a double dead-end structure, and are used where:

•    Line ends
•    Line turns at a large angle
•    At major crossings like highways or rivers
•    Divide line into segments


For strain structures, the conductors are directly attached through in-line insulators through or around the tower. In suspension transmission structures, the conductor phases pass through the structure, and are suspended from the insulator.

Each structure type can either be classified as tangentwith no line angle, or anglewhen there is a line angle.

Steel transmission structures can be designed with tapered tubular poles, which are hollow, can be multi-sided and have a large base that tapers down, typically in the range of .18 to .45” per foot.

And to dig a little deeper, all of these structures can either be guyed or unguyed. A guyed structure provides extra support by fastening a wire from the structure to the ground or another structure, whereas an unguyed structure is self-supporting.

Transmission Structures

When deciding which type of structure is most economical, as well as best suited for varying conditions, there are many considerations that can influence which to select, such as:


•    Terrain type 
•    Erection techniques
•    Electrical constraints
•    Access & transport situation
•    Procurement & easements
•    Structural loading

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Tags: steel structures, tapered tubular steel poles, transmission structures, substation structures, tangent, switchyards, dead-end structures, electrical transmission and distribution

Back to Basics in Transmission Structures

Posted by Brooke Barone on Dec 13, 2012 11:53:00 AM

Transmission lines act as the utility interstate system where electricity is transmitted at high voltages in order to reduce the energy lost in long-distance transmission.

Although it’s hard to quantify structure types since there are always exceptions to the rules and never-ending configurations, transmission structures can be considered dead-end, strain or suspension.

A dead-end structure is where conductors and ground wires are pulled only on one side, unless it is a double dead-end structure, and are used where:


•    Line ends
•    Line turns at a large angle
•    At major crossings like highways or rivers
•    Divide line into segments


For strain structures, the conductors are directly attached through in-line insulators through or around the tower. In suspension transmission structures, the conductor phases pass through the structure, and are suspended from the insulator.

Each structure type can either be classified as tangent, with no line angle, or angle, when there is a line angle.

Tangent, angle and dead-end structure

Steel transmission structures can be designed with tapered tubular poles, which are hollow, can be multi-sided and have a large base that tapers down, typically in the range of .18 to .45” per foot.

And to dig a little deeper, all of these structures can either be guyed or unguyed. A guyed structure provides extra support by fastening a wire from the structure to the ground or another structure, whereas an unguyed structure is self-supporting.

When deciding which type of structure is most economical, as well as best suited for varying conditions, there are many considerations that can influence which to select, such as:
•    Terrain type
•    Erection techniques
•    Electrical constraints
•    Access & transport situation
•    Procurement & easements
•    Structural loading

Want to learn the three types of transmission structures? Or what to consider before guying a structure? Download your copy of Transmission Structures and Their Configurations today.

 

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Tags: transmission structures, tangent, transmission lines, dead-end structures, angle, electricity, high voltages, steel transmission structures

Design Practice for Flange Plates versus Slip Joint Connections

Posted by Brooke Barone on Oct 11, 2012 11:38:00 AM

Having a good relationship with your vendor will ensure a smooth and confident outcome.

Also, by having seasoned engineers and people who have been in the industry for some time and have experienced things that textbooks cannot prepare one for, more knowledge and expertise will be contributed towards the final product.Dead end tran resized 600

Here are some design practices for using flange plates versus slip joint connections for H-frames, single pole guyed and single pole dead-end structures. There is the concern of the uplift/compression on H-frame poles and the excessive amount of vertical load that can be created for guyed structures, especially guyed dead-end structures, as well as how to apply this for self-supporting dead-end structures.

So, what’s the design practice in this regard?

Most customers leave it up to the fabricator to decide when and where to use slip verses flange joints.  This is typically decided in the quote stage, as this can make or break a job.  If you leave it up to the fabricators, just make sure you know or trust the fabricators that are bidding the project.  There are always new players in the game, so you just need to make sure they’re experienced enough with these type structures to know what they are watching for with these connections. 

In other words, if four out of the five bidders quote structures with flange plates and the low bidder quotes slip joints, then understand why they quoted it that way. 

slip joint resized 600The following are a few suggestions when it comes to these type connections. These are not necessarily found in a design guide book or a required industry standard, just a rule of thumb.

  • Dead-End H-frames/ A-frames: Always use flange plates if the joint is located below the beam connection.  (There have been a few times where the conductor beam was located at 45 ft elevation and the structure was 65 ft tall, so in this case, a slip joint was put above the beam connection.)
  • Transmission H-frames w/ X-Bracing:  Depends on loadings and location of joint.  Most of the time, structures are designed with flange joints because the overlap of the slip joint can vary.  Due to the slip tolerances, it could cause a headache in the field to slip both columns the exact amount for everything to line up.  If slip joints are used, the designer still needs to watch the axial loads.  If they get too high, then they will need to switch over to flange plates. 
  • Guyed Structures:  Always use flange plates if the joint is located below the guy attachment points.  The axial loads tend to get high on these type structures.  Of course, there is always an exception to the rule.  There could be some cases where the axial load remains low for a guyed pole.  In these cases, the loads tend to be small, have some uplift or may have a minimal number of guy wires.  If the customer is requesting slip joints on their guyed poles we watch the axial loads closely. 
  • Switch Poles/Riser Poles/Specialty Poles:  Always use flange plates. (Depending on the arrangement, slip joints on low kV Riser poles can be used.)
  • Single Pole Dead-Ends/Tangents:  Always start out with slip-fit joints.  It’s not often flange plates are used for these type structures, unless the customer requires them.  Normally, the axial load does not get excessive for these type structures.   However, never locate a slip between phases.  If the top shaft gets too long due to phase spacing, switch to flange plates in certain spots.  Sometimes a flange plate is used if there is not enough room to fit a slip on the pole due to lots of brackets/equipment/etc.

In the end, always try to use slip-joints where you can because it’s typically more economical.  As you may have noticed, there is an exception to just about every rule above.  This just means there should always be some flexibility in the project so the design engineer has the ability to make judgment calls as needed.  If the customer works closely with the fabricator on each project then it will run smooth.

 Get expert advice for your project

Tags: flange plates, slip joint connections, dead-end h-frame, transmission h-frame, guyed structures, switch pole, riser pole, specialty pole, tangent

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