Phase coupler

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A phase coupler is an electrotechnical circuit with at least one capacitor and is mostly used in three-phase systems such as those used in public power supply networks for high-frequency bridging of the outer conductors for the purpose of data transmission. This high-frequency bridging of the outer conductors enables data to be transmitted over several outer conductors using appropriate carrier frequency modems .

In the past, the outer conductors in three-phase networks were also called phase , from which the incorrect name of the phase coupler is derived - the term outer conductor coupler should be correct . The coupling of different phase positions of the external conductors in the area of ​​the low-frequency three-phase supply of 50 Hz (or in some countries also 60 Hz) is undesirable and should be reduced to a minimum by a phase coupler.

commitment

Phase couplers are always used in three-phase systems when power supply lines, which are primarily used for public power supply, are also used to transmit control messages or for data transmission ( powerline ), for example to provide Internet access via power supply lines. For this purpose, the data signal is usually transmitted at high frequencies between the energy supply company and the end customer by means of carrier frequency modems. Since three outer conductors are used in public power grids, these outer conductors are connected to one another by means of phase couplers for message transmission. It does not matter which external conductor the individual carrier frequency modems are connected to.

Since high-frequency signals via power supply lines can only cover comparatively short distances (several 100 m) due to the high attenuation, phase couplers are mostly only used in low-voltage networks.

construction

Internally, a phase coupler usually consists of three identical voltage-proof capacitors , which are connected in the form of a triangle between the three outer conductors. The individual capacitors are usually combined into a compact block that has only three connection terminals for the outer conductors. Capacitors are well tolerated for high-frequency data signals, while they represent a high reactance for the low-frequency AC mains voltage of 50 Hz . The electrical values ​​of the coupling capacitors in the low voltage range are mostly in the range from 150 nF to 470 nF and have a dielectric strength of at least 1 kV.

The phase coupler is often installed in several places in a low-voltage network, for example near the local transformer stations and, depending on the situation, also in the area of ​​the house fuse boxes (basement). By using several phase couplers, the signal transmission between the outer conductors is improved.

Individual evidence

  1. ↑ Network line communication, technical description (PDF; 1.1 MB), page 33 ff., Accessed on December 8, 2011

literature

  • Hendrik C. Ferreira, Lutz Lampe, John Newbury, Theo G. Swart (Eds.): Power Line Communications: Theory and Applications for Narrowband and Broadband Communications over Power Lines . John Wiley & Sons, 2010, ISBN 978-0-470-74030-9 .
  • Bernd Aschendorf: Energy management through building automation. Springer Fachmedien, Wiesbaden 2014, ISBN 978-3-8348-0573-7 .
  • Andreas Friesecke: The Audio Encyclopedia A reference work for sound engineers, 2nd edition, Walter de Gruyter GmbH, Berlin 2014, ISBN 978-3-11-034013-6 .
  • Klaus Eifert: Computer hardware for beginners. 1st edition, 2010, ISBN 978-3-00-032596-0 .
  • Klaus Dembowski: Local Networks. Manual of the complete network technology. Addison-Wesley Verlag, Munich 2007, ISBN 978-3-8273-2573-0 .