Bird protection valve

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Bird protection cover of an overhead line with stand insulators

A bird protection device is referred to as a bird protection device, which consists of an electrically insulating protective cover on overhead line masts . The protective cover is primarily attached in the area of medium-voltage networks and is used to avoid an earth fault that is triggered by birds.

To protect birds, a new version of the Federal Nature Conservation Act came into force in Germany on March 1st, 2010, which in Section 41 requires bird protection on all future medium-voltage lines . The necessary measures to protect against electric shock had to be carried out on existing masts and technical components of medium-voltage lines with a high risk to birds by December 31, 2012.

Technical background

In principle, birds can land and sit safely on (uninsulated) conductors of overhead lines. As long as they do not touch any of the other conductors or any earthed component and are far enough away from them in the case of high voltage , there cannot be a dangerous current flow through the bird's body, as there is no closed circuit.

In the immediate vicinity of an overhead line mast, the risk is significantly higher, as the bird can easily close the circuit by approaching or touching a live conductor cable and the earthed mast and thus trigger an earth fault or even a short circuit between two conductor cables if it is between them on the traverse of the mast. Naturally, larger birds such as storks are particularly at risk.

The widespread installations in the medium-voltage range with stand insulators and mast transformers in open construction are particularly dangerous, since the structural distances between live and earthed parts are here in the order of magnitude of the body of larger birds. In the case of electrical voltages in the range of 10 to 30  kV , an incomplete bridging of the voltage with a few centimeters remaining is sufficient to trigger a fatal arc fault . Due to the usual earth fault compensation , in most cases there is no power failure.

In overhead lines with higher operating voltages, insulators and conductor spacings are already so large that a bird can hardly bridge them.

Bird marker

Bird marker on the earth wire of the overhead line

A bird marker is a wind chime that is mounted on overhead lines and is intended to warn of the obstacle of the conductor.

The protective device is approx. 50 centimeters long and 30 centimeters wide and is attached to the line with clips. The reflective strip strips flutter in the wind, and birds perceive the resulting blinking effect and can avoid it early on. The device minimizes the risk of collision for migratory and breeding birds with the overhead line. Since birds generally move upwards when approaching an obstacle, the bird protection fittings are mounted on the earth wire, which is the topmost one above the live wire.

Individual evidence

  1. ↑ §41 Bird protection on overhead power lines
  2. ↑ F. Kießling, P. Nefzger, U. Kaintzyk: Overhead lines: planning, calculation, execution. According to EN 50341 . 5th edition. Springer Verlag, ISBN 978-3-540-42255-6 .
  3. ↑ Article assembly of bird protection fittings

Web links

Commons : Bird protection on overhead lines  - collection of pictures, videos and audio files