Back to Basics in Transmission Structures

Updated August 21, 2026.

Transmission structures are an essential part of the electric utility infrastructure, supporting the conductors that carry electricity over long distances. While transmission structures can take many forms, they can generally be grouped into three main types: dead-end structures, tangent structures, and angle structures.

What Are Transmission Structures?

Transmission lines provide an interstate-like network for the efficient transmission of electricity over long distances. By transporting electricity at high voltages, these lines minimize energy loss and help ensure that power reaches its intended destination reliably and without interruption.

When designing steel transmission structures, tapered tubular poles are one option to consider. These poles have a hollow construction, which allows for ease of installation and maintenance. They can also come in a variety of shapes with multiple sides to accommodate different design needs.

The broad base of these poles gradually narrows as it reaches the top, typically at a rate of .18 to .45 inches per foot. This tapering effect provides added stability to the structure, making it a reliable choice for long-lasting transmission systems.

What Are the Three Main Types of Transmission Structures?

Although it is difficult to quantify structure types because there are always exceptions and numerous possible configurations, transmission structures can generally be broken down into three types:

• Dead-end structures
• Tangent structures
• Angle structures

Each serves a different purpose depending on the transmission line route, loading requirements, and project conditions.

What Is a Dead-End Transmission Structure?

A dead-end structure is a type of power pole where conductors and ground wires are only pulled on one side unless it is a double dead-end structure that terminates on multiple sides of the pole.

These structures are designed to handle higher tension and are typically the larger poles used in power transmission lines.

When Are Dead-End Structures Used?

Dead-end transmission structures are typically used when:

• A transmission line ends
• A transmission line turns at a sharp angle
• The line encounters a major crossing, such as a highway or river
• The line divides into different segments

What Is a Tangent Transmission Structure?

A tangent structure is used where there is little to no line angle.

These are typically the smaller poles of the transmission line and are also the most populated structures along the line. Tangent structures are most commonly used when the transmission route is straight.

What Is an Angle Transmission Structure?

An angle structure is used when wires come into the structure at an angle. These structures support conductors above ground while accommodating changes in the direction of the transmission line.

What Is the Difference Between Guyed and Unguyed Transmission Structures?

Dead-end, tangent, and angle structures can either be guyed or unguyed.

A guyed structure receives extra support by fastening a wire from the structure to the ground.

An unguyed structure is self-supporting and can withstand design loads without extra support.

What Factors Determine Which Transmission Structure Is Used?

When determining which type of transmission structure is most economical and best suited for project conditions, several factors can influence the selection:

• Terrain type
• Erection techniques
• Electrical constraints
• Access and transportation
• Procurement and easements
• Structural loading

Because every transmission project presents different conditions, the appropriate structure type and configuration can vary from project to project.

Choosing the Right Transmission Structure Supplier

It's important to partner with a supplier who can not only provide a range of options but also tailor those options to fit the unique requirements of the project at hand. By collaborating with a supplier that possesses this level of expertise and flexibility, you can increase the likelihood of achieving your desired project outcome.

If you need assistance with an upcoming project, contact DIS-TRAN Steel.

Want to learn more? Download your copy of the Beginner's Guide to Substation and Transmission Structures.