1.0 Introduction
Power Line Communication (PLC) aims at exploiting the power supply line to send/receive information without using separate dedicated wires. The PLC is nowadays adopted in many application domains, like power utilities to interconnect and control faraway units, automatic remote meter reading, and home and building automation.
The latter is, perhaps, the most promising field for PLC due to the large number of potential customers. Indeed it seems a natural way to connect intelligent home devices like lights, doors and household appliances, to a home control unit. In this field a number of widely adopted communication protocols have been developed, starting from the low speed low cost X10 technology up to recent implementations like HomePlug (Anderson,1998) which is also targeted to high speed communication, in order to support High Definition TV and VoIP.The PLC technology can be classified with respect to the transmission frequency, which determines, in turn, the transmission bitrate.
Low frequency transmission is well regulated in Europe, with a band range from 3 up to 148,5 kHz, and a maximum bitrate of 1 Mbps. Regulation for larger transmission range is ongoing (CENELEC SC205A WG10), allowing for operation up to 30 MHz, and higher bitrate (up to 200 Mbps); a number of devices and technologies are already available on the market.
A common feature of these applications is that the power carrier is AC 50/60 Hz at medium (power utilities) or low voltage (110 and 220 V for home). Conversely, in specific cases, such as the automotive domain, the powerline operates at lower DC voltage complying with batteries and electronic devices (e.g. 3.3, 5, 9, 12 and 42 V), which implies a different coupling technology. Two key aspects drive the research on PLC: (i) physical transmission of the modulated signal and (ii) the data link and upper layers to allow the correct communication among devices.
The former issue is related to the study of the noise and compatibility on the PLC line, which is prone to interference due to non-linear loads that can, for example, show impulsive behaviors (i.e., when a motor is switched on). The latter issue determines the flexibility and re-configurability available during the application design, set up and management. It also addresses the communication determinism in terms of guaranteeing the communication timing constraints, i.e., periodic transmission, end-to-end message deadlines, etc.
When looking at a potential automotive application there are a number of issues that PLC technology should address (Clark,1998). In fact, the automotive communication technologies used today are likely to impose requirements on the PLC technology proposed for automotive usage. There are two scenarios to explore: (1) providing a different communication system with respect to the current technologies used in existing automotive systems. In this case, it is important to provide adequate bandwidth, re sponsiveness, tolerance to EMI etc. (2) providing a physical replacement of existing field buses that is transparent at the application level.
In this case, the PLC should provide a similar, or the same, temporal behaviour as the original bus.The idea of using the power line as a communications path has been explored for decades with varying success. With new standards and technologies, it's an even better choice than it was before. In fact, multiple chip and equipment vendors have adopted PLC
PLC (Power Line Communications) technology uses the existing public and private mains power wiring for the transmission of telecommunication signals, offering Internet access via electrical networks in the home and at work. The areas of developing data transmission solutions via powerlines include outdoor (local loop) and in-house (home networking) solutions.
The obvious advantage of PLC is that it is everywhere in the developed world. PLC can deliver high speed, low cost Internet access with ‘no new wires', as well as the capability for in-building Local Area Networks.Deregulation has been a major factor in the development of Powerline (tele) communications:
- Deregulation in telecommunications allows new market entrants to provide services along electricity networks
- Deregulation in the power supply sector increases the demand for specific energy distribution related information systems.
Another opportunity for Powerline technology has been in the area of home-automation and in-house systems
This material contains electrical diagrams, circuits, illustrations and more (Very detailed)
