Aerial cables

from Wikipedia, the free encyclopedia
Various aerial cables on a mast (above low-voltage network with 400 V, below telephone line)
At the top, the earth wire of an ENBW high-voltage line comes to the transformer station. Including an aerial cable for data transmission with its own bracing.

An aerial cable , also known as a self-supporting cable (SETRA), is an electrically insulated cable mounted on overhead line masts . This is where aerial cables differ from overhead lines , which consist of individual, bare wires that are stretched with the help of insulators (mostly made of glass or porcelain).

Telecommunication technology

In telecommunications technology , an aerial cable contains several wires . The term is also used for fiber optic cables freely mounted on masts .

Aerial cables are mainly laid for telephone connections in remote buildings and temporary facilities (such as construction sites). In the case of telephone cables on masts, a distinction is made between aerial cables and suspension cables . In the case of aerial cables, the strain relief is integrated symmetrically in the cable jacket. A fiberglass or steel mesh is often used as strain relief. In the case of the aerial cable, a single rope (mostly steel rope) is built into the cable sheath as a strain relief. The cable has a cross-section that is reminiscent of an eight. Here, the bundle of conductors forms the lower circle and - usually connected by a small web - the suspension cable forms the second, usually smaller circle. Both are encased in a common weather and sun-resistant outer cable sheath.

Energy Technology

In the field of electrical power engineering , aerial cables are occasionally still used for energy supply in the low-voltage, rarely in the medium-voltage level up to 30 kV. In the low-voltage range, they are also used for the temporary connection of buildings or construction sites, for example when roads have to be spanned. An alternative is to attach cables to a steel cable with tension wire clamps.

The network operators also use aerial cables to set up their own telephone network . This cable is often integrated in the earth wire . Occasionally, an additional rope is laid on the mast, usually at the height of the top traverse. In the case of lines with an uneven number of conductors, this is also often laid as an anchor phase . There are also aerial cables housed inside overhead line conductors.

At the previous EVS (now part of EnBW AG ), the aerial cables for in-house communication were often installed in a garland shape on the ground wire or an auxiliary wire on the masts until the mid-1980s. A conductor cable was even used for this on a 20 kV line between Ried and Eberdingen. Nowadays, aerial cables for the transmission of messages along power lines are almost always designed as optical fibers because of the disruptive effects of the power line .

Types of aerial cables in power engineering (selection)

  • (N) Y (Zg) 2Y Self-supporting high-voltage aerial cable with glass fibers as strain relief in the outer sheath
  • YMT PVC sheathed cable with support element

literature

  • Telecommunications Engineering Handbook . 7. Part II, line technique. German Postal Union, 1973, p. 84-100 ( online ).
  • FTTH Handbook Issue 5 D&O Committee Issue date: 08/02/2012 . FTTH Council Europe 2012, 2012, p. 52 ( online ).
  • DIN 57250-205 VDE 0250-205: 1983-08 Insulated power lines; PVC sheathed cable with tensile reinforcement
  • DIN 57250-206 VDE 0250-206: 1983-10 Insulated power lines; PVC sheathed cable with suspension cable

Web links

Individual evidence

  1. Self-supporting telecommunication cables (SETRA telephone cables). Retrieved July 17, 2016 .
  2. DIN EN 60794-3-20, family specification for self-supporting fiber optic telecommunication aerial cables. Retrieved August 21, 2013 .