ZyXEL Communications PLA-470 V2 - V3.0.5 Guía de instalación descargar pdf (Pagina 20)

CHAPTER 1

Introduction

The PLC (power line communication) designates a technology that uses the medium

and low voltage electrical network to provide telecommunication services.

Although, since its first applications when the frequency range started at a low

level, PLC is today more commonly used for high-frequency applications, also

known as broadband powerline (BPL).

The electrical network has been used for a long time by producers and distribu-

tors of electrical power for the purpose of network monitoring and remote control

at low speed.

Nowadays, an electricity producer or distributor cannot ignore standardiza-

tion. It is interesting to note that the deployment of electrical networks, their inter-

connection, and the ever increasing number of electrical appliances have resulted in

the emergence of the first network standardization bodies such as the IEC (Interna-

tional Electrotechnical Commission).

PLC Technologies

The principle behind the PLC technique is not one that has emerged recently. In

1838, Englishman Edward Davy proposed a solution allowing remote measure-

ments to be taken of battery levels of sites far from the telegraph system between

London and Liverpool. In 1897, he submitted the first patent (British Patent

No. 24833) for a technique for the remote measurement of electrical network

meters communicating over electrical wiring.

In 1950, the first PLC systems, known as Ripple Control, were designed and

then deployed over medium- and low-voltage electrical networks. The carrier fre-

quency was then between 100 Hz and 1 kHz. It was necessary to establish sin-

gle-directional communications via control signals for the remote switching on and

off of public lights or for tariff changes. The first industrial systems named Pulsadis

appeared in France in 1960. The power involved was approximately a hundred

kilovoltamperes (kVA).

Then the first CENELEC band PLC systems appeared, extending from 3 to

148.5 kHz, and allowing bidirectional communications over the LV (low voltage)

electrical network, for instance, for meter readings (remote meter readings) as well

as for a great number of applications relating to the home automation field

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ZyXEL Communications PLA-470 V2 - V3.0.5 Guía de instalación Pagina 20