EE 392 Stewardship

Transmission Towers, Power Lines & Birds

David Dukes

Michael Harper

Basic Facts Not only costly to birds but costly to power companies

Actual statistics on bird death are hard to calculate

US Forest Service estimates power lines to kill hundreds of thousands to 175 million birds per year

10.7% of line outages are due to birds

60% of bird deaths are from collisions with the overhead shield wire (OHSW) or optical ground wire (OPGW)

Power lines are estimated to electrocute tens of thousands to hundreds of thousands annually

Most of these electrocutions occur on distribution lines as opposed to transmission lines as the phases are spaced closer together

Birds like to use transmission structures as perches. It is common for osprey to build their nests on these structures.

Prevention Methods

Perch Preventers

Flight Diverters

Nesting Platforms

Spiral Vibration Dampers (SVDs)

GreenJacket Cover Up

Removal of bird trap structures

Zena Bird Perch Preventers

Prevent birds from perching and nesting on power structures

Reduces bird deaths

Reduces power outages

Environmentally friendly

Zenadesign.com

FireFly Bird Flight Diverter

Reflective tag hung on OHSW or OPGW to increase visibility

Can also be installed on side guys and bridle guys

Glows in low light conditions for up to 12 hours

Rotates on the line in the wind

Installed live

Pr-tech.com

Preformed Bird Flight Diverters

Increases visibility to reduce the number of bird collisions with power lines

Installed on OHSW or OPGW for high voltage applications

Can be installed directly on live conductors in low voltage applications

Also acts as a damper to reduced vibrations in the line

Preformed.com

Nesting Platforms Separate structures built away from power lines give birds a

safer place to perch and nest

Similar designs to the one below have been made in which bird or even owl houses can be hung from the structure

Often constructed from salvaged power line material to cut costs

Bird Trap Structures

Power structures like the one to the right are dangerous for birds

This design is mostly seen on distribution lines or lower voltage transmission lines (69kV)

Birds can perch on the lower cross arm and when they fly away are at a greater risk of colliding with 2 of the higher phases

Removal of structures like these will lead to less bird electrocutions

Alternative designs have been created

Cantega GreenJacket Cover Up – “It fits” 20% of substation

outages are caused by wildlife prior to installation

After installation outages and wild life fatality were greatly reduced

Offers a solution to cover up energized areas in substations

Standard cover up available or they will come to your substation and provide a custom solution based on your needs

Live Installation

Cantega.com

References

- AltaLink (http://www.altalink.ca)

- US Forestry Department (http://www.fs.fed.us)

- Cantega Industries (http://www.cantega.com)

- Preformed Line Products (http://www.preformed.com)

- PR Tech (http://www.pr-tech.com)

- Zena Design (http://www.zenadesign.com)

- Analysis of Factors Contributing To Unexplained Transmission Line Faults on a High Voltage Transmission Network (Bekker, Hoch)